Sciences {biology} can include botany, cell biology, development, ecology, evolution, genetics, and zoology.
organism structures {anatomy}|.
nature {natural history, nature}|.
organism functions {physiology}|.
farm animals {animal husbandry}| {husbandry}.
gardening {horticulture}|.
Food can grow in aerated nutrient-rich water {hydroponics}|, with no soil.
wine {viticulture}|.
organism development {embryology}|.
insects {entomology}|.
Animals have natural behaviors {ethology}|, such as aggression, imprinting, instincts, innate releasing mechanisms, and fixed action patterns, which evolve, develop, and have purposes. Environmental stimuli trigger innate complex behaviors. Perhaps, humans have innate behaviors or behavioral tendencies, such as aggression.
fish {ichthyology}|.
birds {ornithology}|.
palm reading {palmistry}|.
skull regions {phrenology}|.
stuffing animal skins and mounting heads {taxidermy}|.
cells {cytology}|.
enzymes {enzymology}|.
structures {morphology, biology}|.
ancient times {paleontology}|.
People study excrement {scatology}|. People study obscenities.
classification {taxonomy}|.
sedation {anesthesiology}|.
bacteria {bacteriology}|.
heart {cardiology}|.
spine manipulation {chiropractic}|.
skin {dermatology}|.
hormones {endocrinology}|.
infectious diseases {epidemiology}|.
disease causes {etiology, disease causes}|.
old age {geriatrics}|.
old age {gerontology}|.
women {gynecology}|.
tissues {histology}|.
immune system {immunology}|.
general disease {internal medicine}|.
nervous system {neurology}|.
pregnancy {obstetrics}|.
cancer {oncology}|.
eye medical problems {ophthalmology}|.
eyesight {optometry}|.
bones and muscles {orthopedics}|.
bones {osteopathy}|.
ear and throat {otolaryngology}|.
Organisms can live on other organisms {parasitology}|.
disease {pathology}|.
children {pediatrics}|.
drug development {pharmaceutics}|.
drug information {pharmacology}|.
rehabilitation {physical therapy}|.
Surgeons can reshape {plastic surgery}| nose, breasts, ears, eye sockets, and penis.
feet {podiatry}|.
colon {proctology}|.
mind diseases {psychiatry}|.
irradiation {radiology}|.
blood {serology}|.
development diseases {tetralogy}|.
therapy {therapeutics}|.
poisons {toxicology}|.
urinary tract {urology}|.
viruses {virology}|.
teeth alignment {orthodontics}|.
gums {periodontics}|.
mouth and teeth devices {prosthodontics}|.
fungi {mycology}|.
algae {phycology}| {algology}.
plants {phytology}|.
Self-contained, integrated structures {life}| have mechanisms for gathering and using energy and matter, to build mechanisms and reproduce similar structures. Living organism species come from one or two genetically similar organisms. Species communities live in local regions. Community ecosystems live in large geographic regions or climate zones. Living things adapt, grow, have irritability, and reproduce. Living things have sizes, shapes, biochemical reactions, molecules, and movements.
Biochemical molecules, organelle molecular structures, cell molecular systems, tissue cell types, and organ-system tissue groups can work as units {organism}| {individual}. Organisms eat each other, live in different environments, and use oxygen differently.
Killing can be for the sake of mercy {euthanasia}|, either by letting people die or by painless killing.
Organisms can react to stimuli {irritability, organism}|.
Perhaps, living things need special energy {life force} for motion and organization. However, molecules and physical laws can make life. Organic molecules, cells, organisms, species, and all life can be purely physical and require no extra information or non-physical energy.
Perhaps, living things can arise directly from molecules or decaying matter {spontaneous generation}|. However, organisms are too complex to arise directly from molecules or decaying matter. Organisms arise only from other living things, which contain information needed to initiate and develop life through complex processes. At life's origin, more-complex molecules, between living and non-living, arose from complex molecules by moderately complex processes.
head {cephalic}.
about head {cranial}.
about body fluids {humoral}.
middle {medial}|.
back {dorsal}.
abdominal, anterior, or lower {ventral}|.
tail {caudal}.
head {rostral}|.
side {lateral, side}|.
opposite side {contralateral}|.
same side {ipsilateral}|.
Experiments simulating primitive Earth conditions can make small organic molecules. Under special conditions, these molecules can make large stable proteins, ribonucleic acids (RNA), and deoxyribonucleic acids (DNA) {origin of life}|. DNA has optimum mutation rate, crossing-over, hybridization, and long length and so can be replication templates.
early-Earth molecules
Experiments replicating early-Earth conditions make formaldehyde, formic acid, lactic acid, acetic acid, urea, sugars, and hydrogen cyanide. From nitrogen, methane, ammonia, water, and hydrogen-gas mixtures, lightning or ultraviolet light can produce amino acids. Metallic carbides and water can react to form acetylene. Formaldehyde can polymerize to make ribose and other sugars.
replication
Living things replicate, so life requires replicating molecules. Proteins cannot be templates, because most amino acids can have no hydrogen bonding. RNAs are easy to create. However, RNA is also easy to hydrolyze, so only short RNA regions can replicate. DNA does not hydrolyze, because deoxyribonucleotides have no oxygen atom and prevent hydrolysis. DNAs are harder to create but can be templates.
cell functions
After DNA formation, DNA regions able to make functional RNAs and proteins arose. To these exons, evolution added and subtracted introns. Archaebacteria have tRNA and rRNA introns. Cyanobacteria eubacteria have leucine-tRNA introns. Eukaryote RNAs typically have introns. Eukaryote DNA has different intron types, such as self-splicing introns. Currently, gene exons have 1000 to 7000 functional DNA regions.
cell functions: photosynthesis
Earth life needs photosynthesis, using metals, enzymes, carbon dioxide, and water.
chirality
Perhaps, chirality is necessary.
sexual reproduction
Earth life needs sexual reproduction, for more variation and more competition. Sexual reproduction began 2.2 x 10^9 years ago. Sexual intercourse began 2 x 10^8 years ago.
mutation
Different DNA types change at different rates. Mitochondrial DNA mutates ten times faster than nuclear DNA. Mitochondrial DNA mostly comes from mother, but some paternal genes can enter and recombine. DNA-change rates can be faster if codon changes do not change amino acids produced. DNA-change rate is slower for histones and other fundamental proteins. DNA-change rate is slower in humans than in other species.
gene duplication
With sexual reproduction, genes can duplicate by unequal crossing over at recombination. If genes duplicate, one copy can change while the other still provides original functions, thus allowing genetic drift.
complexity
DNA amount and gene number can increase for whole genome, tRNA, rRNA, mitochondrial DNA, and globin DNA, increasing organism complexity.
Percentage of planets that can have intelligent life depends on star formation rate, fraction of stars that have planets, percentage of planets that are suitable for life, fraction where life actually exists, intelligent-life probability, and average civilization longevity {Drake equation} (Frank Drake) [1961]. For planets to have life, they must be like Earth and have stars like Sun.
star
Sun is a yellow-orange class-G0 star. Only class F, G, and K stars can have suitable planets, because liquid-water zone is too small for smaller stars, and bigger stars have no rocky planets in that zone. Such stars have masses 0.7 to 1.5 times Sun mass. Lifetimes are long enough, and masses are big enough, for planets. Stars sufficiently like Sun are 1% of all stars.
Stars younger than Sun have time too short for life. Stars older have too few heavy elements. Time range is 3 to 7 billion years, one-third of all stars.
Multiple stars can have no planets. Single stars are one-fifth of all stars.
Stars with slow spins possibly indicate planets. Probably, one sixth of all stars qualify.
Stars must be in galactic arms. Galaxy centers have too much radiation. Edges have low metals and low star-formation rates. Galactic habitable zone is far from center and edge.
orbit
Circular orbits make temperature swings not too great. Probably 100% of planets at correct distance from star have circular orbits.
size
Earth size is big enough to retain oxygen and nitrogen and small enough to lose hydrogen and helium, so as not to have too much gas. Surface gravity is not too strong or too weak for living things. Diameter is 5000 km to 15000 km. Probably, one tenth of all planets have correct size. Therefore, 0.001% of all stars have Earth-like planets. Galaxy has 2.5 x 10^11 stars and so 2.5 x 10^6 habitable planets.
rotation
Planet rotation must not be too fast or slow. Probably 100% of planets at correct distance from star have Earth-like rotation speeds.
atmosphere
On early Earth, volcanoes gave off steam, nitrogen, methane, hydrogen cyanide, ammonia, carbon dioxide, and sulfur dioxide or hydrogen sulfide. If iron was already at core, atmosphere was carbon dioxide, nitrogen, and sulfur dioxide. Soon after Earth formed, atmosphere layered into decreasing-density gases. Ultraviolet light reaching Earth decreased, and temperature lowered. Crust cooled quickly, and lower temperature led to more atmosphere layering. Hydrogen, ammonia, and methane were no longer in oceans, so processes no longer formed organic molecules. Temperature became too low to make organic molecules. All gases can dissolve in oceans.
temperature
If planet surface temperature is hotter than 40 C, proteins denature and water evaporation is too high. If surface temperature is colder than ice, no water is available. Planets must be in circumstellar habitable zones. If planet forms too close to star, it has little water and large greenhouse effect, like Venus. If planet forms too far from star, surface is ice. Distance from star is 10^7 km for optimum temperature. Probably, one tenth of planetary systems have such planets. Composition, size, wind, rain, and sunlight cause tectonic and erosion processes.
minerals
If planet is at correct distance from star, mineral composition is similar to Earth mineral composition.
radiation
Cosmic radiation can react water and carbon dioxide to make organic acids.
energy
3,800,000,000 years ago, ultraviolet light, lightning, meteor impacts, thunder, volcanic heat, and hydrothermal vents provided energy.
meteors and comets
Perhaps, some organic molecules came to Earth in meteors and comets. Meteors have saturated hydrocarbons, porphyrin rings, and organic acids. Spores cannot come from space, because ultraviolet and ionizing radiation kill them.
ocean
First life probably arose in shallow seas or tidal areas. Oceans probably had water, gases, proteins, nucleic acids, carbohydrates, fats, and adenosine phosphate.
tides
Shallow seas with high evaporation rates allow molecule concentration. Tides add water. Large moons can cause tides. On Earth, tides were 30-meters high when Moon formed.
other factors
Probably, Earth life needs continental drift, orbital changes, star evolution, seasons, days and nights, major climactic changes, and magnetic fields.
catastrophe
Earth life needs no life-ending catastrophes, like too many comets or meteors, too much volcanism and earthquakes, too much erosion, or too much greenhouse effect.
life factors
Earth life needs brains, hands, vocal chords, speech centers, forebrains, vision, immune systems, and societies. Earth life must be large enough, be long-lived enough, be few in number, have slow reproduction cycles, and have long childhoods. Earth life must have no mass destruction, optimum competition, optimum population, enough energy and resources, few radioactive wastes, few chemical wastes, optimum ozone, and social cohesion.
number of times
On Earth-like planets, life has probability, possibly 10^-6. Perhaps, galaxies have 10^6 suitable planets. Therefore, galaxies have one planet with life. If other planets have intelligent life, they can send probes to Earth, but there is no evidence for this. Therefore, no other intelligent life forms are in Milky Way Galaxy yet.
first cells
Life began as non-photosynthetic one-celled bacteria-like organisms. First cells reproduced themselves, protected themselves, and found energy.
membrane
All cells have cell membranes. Cell membranes have lipids with embedded proteins. Cells can control membrane-molecule amounts and ratios. All cells have voltage differences across cell membranes, because inner and outer sodium, potassium, and chloride salt concentrations differ.
energy and entropy
Life can overcome dissipative forces and persist. Living systems have high order {negentropy} in small regions, surrounded by large energy sources that they can tap. Living systems must gather energy faster than surroundings can dissipate energy. Sunlight energy, planet interior heat, and lightning can make locally high temperature, for anabolic and catabolic chemical reactions.
Small cells have small fast energy changes. Fast heat and material exchanges among physical compartments allow rapidly removing order from surroundings. High combination and division rates make many new organic molecules and cells. Equilibrium conditions in oceans or tide pools allow reversible chemical reactions.
If life is abundant in universe, why have people not seen other intelligent life {Fermi paradox}?
Planets must have liquid water, not ice or steam {circumstellar habitable zone} (CHZ).
Galaxy centers have too much radiation. Galaxy edges have low metals and low star-formation rates. Stars must be in galactic arms {galactic habitable zone} (GHZ).
Hot water rich in sulfur, iron, hydrogen, and carbon flows from sea floor holes {hydrothermal vent}|. Bacteria-like organisms began there.
If surface had iron 3,800,000,000 years ago, reduction reactions caused methane, ammonia, and hydrogen sulfide {reducing atmosphere}.
Carbon compounds {carbon-based life} can be soluble or insoluble and have intermediate-stability chemical bonds, so they can form and break at moderate energies.
organic molecules
Organic molecules formed in seas. Stable forms persisted. Persisting molecules aggregated.
nucleic acids
When nucleotide concentrations were great enough, nucleotides linked. Nucleic acids used themselves as templates to make copies. Good copiers persisted and used more nucleotides. Mutations resulted in populations with property ranges.
peptides
When amino-acid concentrations were great enough, amino acids linked. Peptides assisted chemical reactions and formed structures.
oxygen
Later, photosynthesis added oxygen to atmosphere, using water, sunlight, and atmosphere carbon dioxide.
Silicon compounds {silicon-based life} cannot substitute for carbon compounds, because silicon compounds are insoluble, silicon makes shorter bonds, and silicates are too stable.
In living organisms, sugars and amino acids are in only one of two possible stereochemical forms {chirality, molecule}|. Sugar and amino-acid chirality probably had survival value, but people do not yet know cause [Gardner, 1960].
Perhaps, living things or organic molecules are in cosmic dust, meteors, comets, asteroids, and planets and then travel to Earth in dust, meteors, or comets {panspermia}.
Glycerin molecules mixed with other molecules can clump together to make stable gels {coascervate}| [1926]. Other molecules can enter, interact inside, and leave.
Nucleic acid and protein can combine. Perhaps, dissolved genes in early oceans evolved to make genes with protein shells {proto-virus}. Proto-viruses can acquire lipid layers, making micelles. Proteins can embed in lipids, to make cell membranes. Food can pass from seawater into simple cells. Chemosynthesis can evolve. Simple cells can replicate. Later, photosynthesis can evolve.
Perhaps, RNAs had genetic codes, were enzymes, and formed structures {RNA world}. RNAs folded and unfolded to perform functions.
Eukaryote-cell organelles can come from eubacteria incorporated into cells {endosymbiosis theory}. Plant chloroplasts came from cyanobacteria. Animal mitochondria came from purple photosynthetic bacteria. For example, Cryptomonas phytoflagellate combines eukaryotic nucleus, photosynthetic prokaryote, and eukaryotic cell.
Evolution has added introns to, and subtracted introns from, DNA, possibly to aid exon recombination {exon shuffling} and combine protein functions.
Bacteria have one circular chromosome {monoploid}|. Polyploid protozoa have several linear-chromosome copies. Perhaps, bacteria are simplified polyploid protozoa.
New species develop from existing species {species evolution} {evolution, species}|.
cells
On early Earth, heat, light, lightning, and meteor collisions formed carbon-containing molecules {organic molecule, life} with attached hydrogen, oxygen, nitrogen, sulfur, and phosphorus atoms. Simple organic molecules combined to make sugars, amino acids, nucleotides, and fatty acids, which combined to make carbohydrates, proteins, nucleic acids, and lipids. Large molecules can have shapes and structures and can have multiple binding and reaction sites. Structural molecules combined to form cells, viruses, and bacteriophages.
species
The first cells were the first species. Cells evolved into single-cell Archaea. Archaea evolved into bacteria and single-cell plants and animals. Single-cell organisms evolved into multicellular plants and animals. Multicellular animals evolved into invertebrates. One invertebrate species evolved into vertebrates. One vertebrate species evolved into fish. One fish species evolved into amphibians. One amphibian species evolved into reptiles. One reptile species evolved into mammals. One mammal species evolved into primates. One primate species evolved into monkeys. One monkey species evolved into apes. One ape species evolved into anthropoid apes (great apes) (hominids). One hominid species evolved into hominins (human ancestors) and Homo sapiens.
features
Prokaryotes have no nucleus. Eukaryotes have nuclei. Multicellular eukaryotes have neurons, sense cells, and muscle cells. Invertebrates can have bilateral symmetry, as in flatworms. Prechordates have notochord beginnings. Chordates have notochord in one development stage. Vertebrates have vertebrae. First fish have cartilage. Bony fish have bones. Lobe-finned fish have fin stumps. Fresh-water lobe-finned fish live in fresh water. Amphibians live on land and in water. Reptiles can live only on land. Mammals make milk. Primates have forward eyes. Old World monkeys have tricolor vision. Hominids, hominins, Homo, Homo habilis, Homo erectus, and Homo sapiens follow.
requirements
Evolution requires objects that carry coded information about how to build and maintain structures and functions and about how to replicate themselves. Evolution requires mechanisms to build objects, maintain objects, replicate objects faithfully, and provide slight variations in coded information. Evolution requires environment that has scarce resources. Evolution requires competition among similar objects. Objects then replicate more or better.
levels
Evolution can affect whole Earth, biomes, ecosystems, clades, or demes. Evolution can act on kingdoms, phyla, classes, orders, families, genuses, species, and varieties. Evolution can act on organs, tissues, cell lines, chromosomes, genes, exons, DNA functional regions, and nucleotides. Different levels can have different selection laws.
environment
If organisms change, other organisms change in response, and relations between other organisms and environment change. Change can cause exponential change. However, change is disruptive and decreases survival for most organisms.
Universal Darwinism
Systems that make copies, have variations, and have a selection mechanism can evolve {Universal Darwinism} [Dawkins, 1976] [Dawkins, 1986] [Dawkins, 1995].
intelligent design
Religionists can believe that God helped form some species. God used special structures and functions that distinguish humans from other species. However, intelligent design does not seem to allow human-appendix creation or maintenance. Complex life forms need to eat less complex forms. Intelligent design allows arbitrary changes and so has no testable hypotheses.
criticisms
Perhaps, both intelligent design and evolution are incorrect. Really, physical laws determine all, with no higher principles. Evolution works only haphazardly, with most species dying out.
Natural selection can make more-complex higher-level organisms {macroevolution}.
Structural constraints allow special forms {orthogenesis}| and guide evolution. Evolution can proceed directly from primitive species to higher species, without side branches. Evolution can jump to new species, without gradual steps.
Food specializations, migrations, and dangerous predators increase ecological-or-environmental pressures and increase evolution. Available genes, gene variability, adaptable behaviors, and food types resist evolution {phylogenetic inertia}.
Interbreeding organisms {species, ecology}| are basic biological units. Similar organisms share gene sets. Related species share similar structures, functions, and genes.
New species can arise from existing species {speciation}|.
hybridization
Hybrids between two different species sum chromosome-pair numbers. If eggs are fertile, self-fertilization starts new species intermediate between parent species. Chromosome doubling created many plant species and some animal species.
chromosome change
New species can arise through chromosome-number or gene-order change. Human chromosomes differ from chimpanzee chromosomes by inversions in nine chromosomes and by fusion of two chromosomes.
New species can appear if species diverge {principle of divergence} {divergence principle}. Typically, species gradually diverge into varieties, then subspecies, and then species. Behavior traits can diverge in ten generations. Major changes, such as brain development, diverge in 100 generations. New species diverge in 2000 generations. Species formation by divergence typically requires subspecies geographic isolation, to prevent gene dilution by other subspecies. Species diverge if organisms have different niches in same geographic area. Species converge if organisms live in separate areas with similar niches.
Species have original varieties {holotype}.
Organisms can perform similar functions using different structures {homoplasy}.
Organisms can have similar internal structures {homogeny} {homology, organism}|. Homology can result from keeping fundamental internal structure during evolution {parallelism, evolution} or having same external pressures during evolution and evolving to similar structures {convergence, evolution}.
Early eukaryotes incorporated primitive bacteria {endosymbiont hypothesis}, which evolved to mitochondria and chloroplasts.
Larval stages can become sexually mature {heterochrony}, to make new species.
Larval stages can become sexually mature, to make new species {paedomorphosis}.
Adult stages can add features, to make new species {peramorphosis}.
Earth has 2,500,000 species in many categories {classification, biology}. Earliest life was one-celled organisms. Archaea included thermophiles. Bacteria included proteobacteria and later cyanobacteria blue-green algae. Eukaryota included metamonad, parabasalid, trypanosoma, ciliates, and flagellates. Multicellular organisms arose from eukaryotes.
Many-celled organisms {metazoa}| {multicellular organism} include fungi, plants, and animals. Metazoa have specialized tissues.
evolution
Only eukaryotes can be multicellular organisms. About 650 million years ago, protozoa clustered, and cells differentiated into different tissues. Later eukaryotes evolved neurons. Later, jellyfish evolved sodium-ion channels for action potentials, which allow neurons to communicate over any distance.
gene transfer
Early eukaryotes incorporated early alpha-proteobacteria to make mitochondria. Early eukaryotes incorporated early cyanobacteria to make chloroplasts. Perhaps, eukaryote cytoskeleton and internal membranes came from early spirochetes, flagellates, or ciliates.
Organism names are genus name followed by species name {binomial system} {binomial nomenclature}|, such as Escherischia coli.
One-celled organisms {prokaryote}| {Monera} {Prokaryota} can have no distinct nucleus or other cell organelles. Prokaryotes include archaebacteria and eubacteria. Eubacteria include blue-green-algae cyanobacteria.
Cells {eukaryote}| (Eukaryota) (Eukarya) can have one cell nucleus surrounded by membrane. Eukaryotes include protozoa, fungi, plants, and animals. Eukaryotes are not Archaea, bacteria, blue-green algae, viruses, or bacteriophages.
The largest organism groups {kingdom, classification}| include non-nucleated single-cell archaebacteria (Archaea), non-nucleated single-cell eubacteria (Bacteria), nucleated single-cell protozoa (Protista) {protist}, nucleated fungi (Fungi), nucleated multi-cell plants (Plantae), and nucleated multi-cell animals (Animalia).
domains
Domains are Archaea, Bacteria, and Eukaryota. Archaea include thermophiles. Bacteria include proteobacteria, cyanobacteria, and other bacteria. Eukaryota include protozoa, yeast and other fungi, algae and other plants, and animals.
algae
Bacteria include cyanobacteria blue-green algae. Other algae are plants.
yeast
Fungi include yeast.
Kingdoms have major organism types {phylum} {phyla} {division, classification}|.
Divisions/phyla have subdivisions {class, classification}|.
Classes have subclasses {order, classification}|.
Orders have suborders {family, classification}|.
Families have subfamilies {genus, classification}|.
Genuses have interbreeding subgenuses {species, classification}|.
Species have subspecies {variety}|.
Humans have varieties {race, people}, such as north European white {Caucasian, people}, south European white {Mediterranean, people}, European and American Indian {mestizo}, Spanish-speaking or Portuguese-speaking country of South and Central America {Hispanic}, Central America {Latino}, Mexico {Chicano}, Africa {Negro} {black, person} {African-American}, and Asia {Asian} {Oriental, people} {Asian-American}.
types
People have three races, totaling 30 varieties.
Races {Caucasoid race} can include the varieties Mediterranean, Nordic, Alpine, Armenoid, and Dinaric. It can have more pale red, white, or light brown skin color, be taller, have longer or broader head, have light to dark hair, and have higher nosebridge. Armenoid has Caucasian and Mongoloid. Dinaric has Caucasian, Negroid, and Mongoloid.
Races {Negroid race} can include the varieties African, South Pacific, Melanesian, Oceania, White Hottentots, Bushmen, extinct Tasmanian, and Negritos or pygmies. It can have browner skin color, longer head, thicker lips, darker and coarser hair, darker eyes, lower nosebridge, and broader nostrils.
Races {Asiao-American Race} {Yellow Race} {Mongoloid race} can include the varieties Tungus in Siberia, Oriental, Eskimo, Indonesian, American Indian, Ainu in Japan, Australoid, and Veddoid, as well as Beijing Man, Lantian Man, and Jinniushan Man. Oriental has Chinese and Japanese. Oceanian has New Guinean, Australian, and Aborigine. Eskimos are more separate from Oriental than Oceanian. Mongoloid race started in Central and East Asia and went to South Asia and Southeast Asia. It can have more yellow or red skin color, be average height, have broader head, have less body hair, have darker eyes, have more epicanthic fold, have lower nosebridge, have higher eye sockets, have flat face bones, have higher superciliary arches, have more spade-shaped incisor insides, and have darker, straighter, and coarser hair.
Aborigines in Australia, Dravidians in south India, Polynesians in South Pacific Ocean, and Ainu in north Japan are hard to classify.
dispersion
Gene differences show that original Homo sapiens split into proto-Africans-and-Europeans, proto-Oceania, proto-American Indians, and proto-Oriental peoples. Then African Negritos and Bushmen separated from European Germanic and Mediterranean, so Europeans were intermediate between proto-African and proto-Oriental peoples.
Alu-repeat and short-tandem-repeat polymorphisms divide people into sub-Saharan Africa, Europe and West Asia, East Asia, Polynesia, and Americas groups. Perhaps, sub-Saharan Africa had two groups, including Mbuti pygmies. Genetic variants are 90% same, so group differences are maximum 10%.
cold adaptations
In cold regions, people tend to have shorter limbs, larger bodies, thicker eyelids, flatter noses, flatter foreheads, and broader cheeks.
factors
Decreased environmental pressures, increased mutation-causing agents, more socially-useful genes, greater specialization, and faster environment changes affect human evolution.
Y-chromosome studies indicate that modern human did not arise from multiple origins {multiregional hypothesis}.
Y-chromosome studies indicate that modern human races arose from African population [-89000 to -35000] {out-of-Africa hypothesis}.
Organism-classification systems {cladistics}| can depend on evolutionary, gene, structural, and functional features.
Species can split into independently evolving lines {clade}|. Different clades have different speciation rates, which can change over time. Clades determine classes and hierarchies, shown in branching diagrams {cladogram}. Cladogram nodes represent shared homologies.
Species members make species members similar to themselves. Among variations, surviving and reproducing member adaptations increase percentages {natural selection, evolution}|. Natural selection affects phenotypes, which relate to genotypes, which vary by mutation or allele recombination.
purpose
Natural selection has no goals. Natural selection is not progress.
creation
Natural selection explains species diversity and adaptations materialistically. Creation mechanisms need have no creator.
examples
Peppered moths become darker or lighter in industrial or rural areas, because birds eat lighter or darker moths in industrial or rural areas. Bacteria develop antibiotic resistance. Insects develop insecticide resistance. Rats develop rat-poison resistance. People still have sickle-cell anemia, because it helps fight malaria. People still have tuberculosis, because it has vitamin-D-receptor gene. People still have cystic-fibrosis CTFR gene, because it helps fight typhoid.
In unpredictable environments, organisms tend to have fast development, many offspring, and offspring with few defenses {r-selection} {r selection} {opportunistic selection}, so population can increase in favorable periods. Unpredictable environments have fewer species. In predictable environments, organisms tend to have slower development, few offspring, and offspring with defenses {k-selection} {K selection}, so population is stable. Predictable environments have more species {selection, evolution}.
Societies evolve through time {social evolution}. Social evolution includes new defenses against predators, higher feeding efficiencies, higher reproductive efficiencies, lower child death rates, more population stability, and new territories and environmental changes. Social evolution is more in stable environments. Social evolution seldom happens in variable environments.
Species members with best adaptations have highest percentage of survival to reproductive age {survival of the fittest, selection}|.
Species die out {extinction, species}|. Extinction typically happens soon after species formation. Extinction can happen if environment capacity is not enough. Increased speciation increases species extinction. Better adaptation prevents extinction. Slow variation and slow environmental change prevent extinction.
Parents can care for relatives' children, or relatives {kinship group} can help each other {kin selection}.
Species members compete for food, mates, and territory {competition, evolution}. Different species compete as predators and prey. Territory competition can cause convergence in dominant species and divergence in dominated species. Species typically relinquish habitat to competitors to keep preferred food, rather than staying and eating new foods.
Animals {predator} can eat other animals {predation, competition}|. Predators kill young, weak, and sick population members.
Aggressive behavior {aggression, ecology} protects territory, establishes dominance, protects sexual property, gets sex partners, disciplines, weans, imposes morals, predates, prevents predation, causes fear, expresses anger, and irritates. Most aggressions happen in competitions between species members. Examples are sexual aggression and food, territory, and status competition. Aggressive behavior patterns and levels evolve to adapt to environments. Species members vary in aggression levels.
In one ecosystem, competition can separate two similar species into separate niches {competition exclusion principle} {Gause's principle} {Gause principle}.
Species members have different gene-allele combinations and so have different trait combinations {variation, species}|.
causes
Mutations or allele recombinations cause genetic variation. Sex increases variation by increasing gene combination.
causes: selection
Evolution typically changes population allele ratios. Climate changes increase variation by increasing environment variety. Isolation increases variation by increasing environment variety.
amount
On average, 6% of vertebrate genes vary from wild type. On average, 15% of plant and invertebrate genes vary from wild type.
effects
Most changes are not adaptive. Species with greater genetic variation evolve faster, because they can use more environmental niches.
effects: duplication
Gene duplication and body part duplication allow duplicates to perform new functions, while originals perform old functions.
effects: whole body
Isolated changes can happen, but, to be adaptive, changes must work together with whole body, which then evolves in response to changes. For example, brain and body evolved together. Finger muscles, bone, nerves, blood supply, and brain motor-and-sensory finger regions evolved together, because dexterity required linked development.
Populations have gene-frequency changes {microevolution}. Microevolution includes gene flow, mutation pressure, and segregation distortion.
natural selection
Natural selection causes most gene-frequency changes. Natural selection can cause adaptations in constant environments or make new genes in fluctuating environments. Natural selection typically stabilizes gene frequencies and decreases homozygote percentage. New species arise from microevolutionary changes by accumulated changes in one direction {progressive evolution}.
drift
Random gene-splicing errors can cause heterozygosity loss by genetic drift, but this factor only affects small populations with inbreeding and consanguinity.
Allele mutations can negatively affect other alleles {canalizing}.
Immigrations into populations {gene flow} have major and fast gene-frequency effects, mainly through hybridization.
Strain combinations {hybrid}| generally show the good results of outbreeding {hybrid vigor}.
Bluish pigmented areas {Mongolian spot} {Mongol spot} {blue spot}, near spine bases, are present at birth in some Asian, south European, American Indian, and black infants and typically disappears during childhood.
Minor gene-frequency-change factors {mutation pressure} include differing allele-mutation rates.
Minor gene-frequency-change factors {segregation distortion} {meiotic drive} include unequal allele production by heterozygous parents.
Males typically have larger size and different shape than females {sexual dimorphism}|.
Trait presence depends on making trait {proximate factor} and keeping trait during reproduction. Trait survival in species members depends on environment, reproduction accuracy, and protection from change {ultimate factor}.
In environments, organisms can adjust behavior {adaptation, organism}| to survive and reproduce.
survival
To reproduce, species members must survive to sexual maturity. They must get food, avoid predators, fight disease, and maintain temperature, in a struggle for survival.
adaptation
To optimize environment use, species can use different foods, decrease development time, increase temperature range, increase air or water pressure range, use protective coloration, use warning coloration, use mimicry, and use other species.
varieties
Genes alleles vary proportions and interactions. Alleles remain available to survive slow, catastrophic, or cyclic environmental changes and to use different environment niches.
Species evolve to new varieties that can occupy surrounding environments {adaptive radiation} {radiation, adaptive}.
As structures shift, functions and adaptations can be different {functional shift} {cooptation}. Small structure shifts are not necessarily adaptive.
Organisms tend to evolve to larger size {Cope's rule} {Cope rule}. Larger organisms typically compete better for sex and food and have better protection from predators. Evolution tends to build larger and more complex organisms.
Animal tops and bottoms can have different colors {countershading}|. For example, bottoms can be light to match sky, and tops dark to match sea.
Organisms can alter their surroundings {environment} [Bateson, 1916] [Cosmides et al., 1992].
Species can pass through trait-development stages {grade, development}.
Negative feedback keeps involuntary muscle actions and chemical levels within normal ranges {homeostasis, animal}.
Longer lives {longevity}| are adaptive in stable environments, harsh and unpredictable environments, low progeny-survival-rate conditions, and low-fertility conditions.
Species can imitate other species {mimicry}|.
Organism features {preadaptation} can find new uses in new environments.
Species can change color for disguise {protective coloration}|.
Species can change skin or coat color and pattern to scare predators {warning coloration}|.
Evolution can make similar structures and functions in different species {convergent evolution}, to adapt to similar environments.
Evolution can make new species varieties, then subspecies, and then new species {divergent evolution}, to adapt to environment niches.
Species try to stay in environment niches {habitat tracking}.
Different habitats cause differences among people {polygenesis}.
New species arise in geographic isolation {allopatry}.
New species do not arise in same location {sympatry}.
Reproductive fitness {fitness} is adaptations that maximize offspring that live to make offspring. Fitness maximizes number of genes passed to offspring, which pass those genes to offspring.
Replicate number and adaptability depend on how well environment and species members interact {differential fitness}.
Gene alleles can affect other-allele fitness {epistasis} {epistasy} {epistatic coupling}. Gene mutation can affect mutation expression at other loci.
Ecosystems can maintain stable alleles in stable species {evolutionary stable strategy}. Evolutionary stable strategies apply game-theory Nash equilibria to ecosystems. If allele change reduces other-species fitness, it reduces species fitness.
One or two organisms can make new organisms {reproduction, organism}|, by sexual or asexual reproduction. Reptiles determine sex by egg temperature, not by Y-chromosome. Birds and mammals determine sex by chromosome. More sexual selection, higher fecundity, and higher rates of survival to reproducing age {differential reproduction} improve survival.
Reproductive processes take time and energy {reproductive effort} away from predation and protection and escape from predation. Reproductive effort is more if reproductive rate is more. Higher non-social animals have low reproductive effort, but higher social animals have high reproductive effort. Societies perform predation and food gathering most, anti-predation next, and reproduction least. Function time varies with food shortage, danger, or mating season.
Net population growth rate {reproductive rate} depends on death rate and birth rate. Young, weak, and sick population members have low reproduction. Older population members have high reproduction, producing more offspring and guarding them better. Stronger and more active population members have high reproduction, especially if they start new colonies and occupy new habitats. Species have optimum fertility rates, based on reproductive rates.
Natural objects {replicator} can copy themselves {replication, nature}, using available resources.
similarity
Replicators and replicates are alike. If replicate survives, it is like replicator survives.
mechanism
Replication requires reproduction mechanisms to assemble parts. Replication requires template patterns to copy.
comparison
Organisms use resources for replication, eating, and escaping, so they must balance these activities. Survival to reproductive age requires eating and escaping.
properties
Replicators are purposive, because they replicate. They are selfish, because they use resources to replicate. They are problem solving, because they gather and use resources to replicate. They are decision making, because they decide when and whether to replicate.
Species members must reproduce more organisms than environment can support {superfecundity, reproduction}. Superfecundity forces species members to compete against each other for mates and food, as well as other resources needed to reproduce. Species members must survive until sexual maturity, with strength to reproduce and win competitions for mates.
Species members must reach reproductive age and development to reproduce {sexual maturity}. Before that stage, species members cannot reproduce {sexual immaturity}.
Parents use energy and time {parental investment} to bring offspring to reproductive age. Children survive better if parents protect, feed, and teach them longer. However, parents can transmit more genes if they have more children, so parental investment is in equilibrium with children number.
factors
Stable predictable environment, longevity, regular reproduction, large size, territoriality, few offspring, difficult environments, many predators, and food specialization favor more and longer parental investment.
kin
Child raising by parents and relatives is altruistic kin selection. In many societies, non-relatives raise offspring, to gain child-raising experience and to limit aggression.
insects
Societies typically have high societal investment in offspring. Insect societies have no parental investment, because adults do not directly affect offspring behavior.
Two opposite-sex animals can produce {mating}| offspring by uniting sperm and egg. Sexual reproduction allows more variation and more sexual selection.
polygamy
Animals can have more than one mate. Polygamy is typical, because parental investment in children is typically unequal. Abundant food at least once a year, heavy predation, precocious young, greater longevity, different gender maturation ages, and different gender niches favor polygamy. High competition for mates leads to polygamy and mate monopolization. Polygamous species tend to have high sexual dimorphism.
monogamy
Animals can have one mate. Monogamy is rare. Monogamy happens in territories with scarce resources that require two animals to maintain or defend. Monogamy happens in difficult environments. Monogamy happens in species with early breeding. Monogamous species tend to have low sexual dimorphism.
Mating {breeding}| related individuals {inbreeding, alleles} tends to pair recessive alleles. Mating unrelated individuals {outbreeding} mixes alleles more.
Species can choose mates for good survival characteristics {selective breeding}|. High competition for mates leads to polygamy and mate monopolization.
Organisms select mates {sexual selection}|. Sexual behaviors tend to resist social evolution.
males
Sexual behaviors can be strategies to ensure that parent has conceived cared-for offspring. For males, sexual selection can involve keeping other males away from females, to prevent reproduction. Males can transmit more genes if they produce more females, rather than males.
males: displays
In many species, male pattern and behavioral displays lure females. Displays are fewer if food is scarcer or predators are more numerous.
females
For females, sexual selection involves selecting mates. Species with more receptive females have less fighting among males. Females can transmit more genes if they produce one male.
One organism can make copies {asexual reproduction}| by budding, cell fission, regeneration, sporulation, or parthenogenesis.
Asexual reproduction can have growth of special cells {budding}|, as in plants, hydra, and yeast.
Asexual reproduction can split cells {fission, cell}|, as in most cells.
Asexual reproduction can have differential growth in broken-off pieces {regeneration, reproduction}, as in flatworms and starfish.
Asexual reproduction can uses special haploid or diploid cells {spore} that detach from organisms {sporulation}|, as in most plants and some animals.
Reproduction can be haploid egg developing into adult {parthenogenesis}|, as in honeybee, wasp, and other arthropods.
Two organisms can make organisms similar to themselves by uniting their DNA {sexual reproduction}|, using conjugation, copulation, or hermaphroditism.
In hermaphroditism and copulation, haploid sperm enter haploid eggs {fertilization, reproduction} to form diploid cells. Fertilization can happen in oceans, rivers, or lakes {external fertilization} or inside bodies {internal fertilization}.
Sex organs {gonad}| produce sperm or eggs.
Sexual reproduction can use DNA-region exchange, after temporary union of two one-celled organisms {conjugation, reproduction}, as in bacteria.
Sexual reproduction can use mutual egg fertilization by sperm from two individuals that have both sex organs {hermaphroditism}|, as in oysters, tapeworms, and earthworms.
New species develop from existing species {evolution theory} {organic evolution} {theory of organic evolution} {theory of evolution}.
reproduction
Species members can make one or more organisms similar to themselves. Species members must reach sexual maturity to reproduce. Species members vary in fecundity.
competition
Species members reproduce more organisms than environment can support {superfecundity, evolution}, so species members compete against each other for mates and food. In environments, species members must get food, avoid predators, fight disease, and maintain temperature {struggle for survival} to reach sexual maturity, have health and strength to reproduce, and win competitions for mates.
adaptation
Species members have traits that affect the struggle for survival.
variation
Species members differ over species-characteristic ranges. Parents and reproduced organisms typically have similar values. Mutation, crossing over, and development can change values, add new values, or add or subtract characteristics. Characteristics and values can affect adaptation, competition, and fecundity by altering strength, size, or skill. See Figure 1. Species members with best-adapted characteristics and values have highest percentage of survival to reproductive age {survival of the fittest, evolution}.
environment
Environments have food sources, predators, diseases, climates, and cycles. Environments constrain species-member reproduction. Environments do not have enough food for all species members to stay alive, or be healthy and strong enough, to reproduce at reproductive age. Predators and diseases eat, kill, or harm species members, so they cannot reproduce at reproductive age. Environments have temperature cycles. Environments affect reproductive methods, such as how mates get together. See Figure 1.
natural selection
Species members compete for resources to reach reproductive age and reproduce. Species members vary in characteristics, so some species members have higher probability to win competitions and reproduce. Species members typically make members similar to themselves, so their characteristics increase percentages {natural selection, evolution theory}. Evolution shifts allele frequencies. See Figure 1. Evolution can also cause new genes.
species
Natural selection makes higher percentage of better-adapted species members, so species are better able to avoid extinction. Natural selection typically makes more surviving species members than before. Competition for food and mates becomes greater, causing higher pressure for survival. Over time, new species varieties arise. Over time, species varieties differ enough to be new species. For sexually reproducing species, new species members cannot reproduce with old species members. New species typically arise in isolated environments different from previous environments. New species can arise by combining two closely related species to make hybrids.
genes
Cells, body, and environment supply energy and needed chemicals to make DNA physical structures that can be stable, vary slightly, replicate accurately, copy more or less, and contain enough information. DNA has four different nucleotides chemically bonded in long or short sequences. DNA positions can have any nucleotide. Genes are templates for making DNA by replication, RNA by transcription, and protein by translation. Copying mechanisms have one error per million DNA units. Besides copying errors, DNA and RNA can suffer physical and chemical mutation damage that changes nucleotides or disrupts sequence {rearrangement}. In sexual reproduction, combining DNA from two sexes mixes sequence segments by crossing-over. These processes cause sequence changes. DNA reproduces, varies, and depends on environment and individual, so it faces competition, has adaptation, and goes through natural selection. Different species have different genes and alleles.
copying instructions
Copying instructions is more accurate than copying products, because products have more and different parts than instructions, and products typically have damage [Blackmore, 1999].
selection levels
Perhaps, natural selection applies to cell lines, organisms, demes, species, and clades, as well as genes. Selection levels can work synergistically, in opposition, or independently.
history
Evolution is not best or perfectly adapted but constrained by history, random effects, and physical laws [Feynman, 1965].
evolution theory: Summary 1
Objects that can reproduce same structures and functions with small changes, and that occupy environments in which they can die before reproduction, tend to evolve characteristics that fit environment. Objects retain only changes that make them survive better.
evolution theory: Summary 2
Organisms produce more offspring than survive to reproduce. Though people can think that God makes organisms that almost all survive to reproduce, except for natural accidents, or that match reproduction rate with death rate, all species actually produce extra offspring, as shown by Darwin. Offspring vary traits. It is easily observable fact that species members vary in observable traits. Observable traits have microscopic traits that vary. Offspring pass microscopic and so observable traits to offspring. It is easily observable fact that all organisms try to reproduce and that offspring typically resemble reproducers. Offspring with traits more favorable for survival to reproductive age produce more offspring with same traits.
evolution theory: Summary 3
Natural selection removes unfit and designs fit. Organisms vary in random ways. Variations typically are harmful but can be adaptive. Variations can accumulate over generations. Natural selection can make more-complex higher-level organisms.
evolution theory: Summary 4
Because organisms over-reproduce, nature has competing organisms and species, so new ones must replace or push aside existing ones {wedge, evolution}, leading to better adapted species. Typically, environment changes slowly compared to species changes.
evolution theory: Summary 5
In geographic areas, organism number increases geometrically through reproduction, but food and mating resources have limits. Species members and all organisms have struggle for existence. Individuals have various trait values. On average, process selects individuals with the most-fit trait values. Over time, natural selection causes organism gene-frequency changes [Darwin, 1859] [Darwin, 1871] [Judson, 1979] [Gould, 2002] [Huxley, 1884] [Ridley, 2003].
Specialized germ plasm reproductive cells transmit protein-coding genes that underlie physiological traits {gene theory}. Body cells do not affect germ-plasm genes, so genes cannot directly inherit learned behaviors {acquired characteristic} [Dubos, 1968] [Keller, 2000].
Evolution has general requirements {generalized theory of evolution}.
variation
Evolution requires objects with properties, such as size or color, with different values. Evolution requires mechanisms to switch among property values and/or mechanisms that can make new values or new properties.
reproduction
Evolution requires objects to have mechanisms that produce new objects with similar property values. Reproductive mechanisms typically use templates that carry coded information about object properties. Reproductive mechanisms do not copy perfectly but allow unit changes, such as mutations.
competition
Objects and reproductive mechanisms require resources. Object reproductions produce more objects than environment resources can support.
species
Systems can have only one object type or can have multiple objects, object groups, and/or hierarchies.
environment
Random events from inside or outside objects can affect objects, to cause new properties and values or affect reproduction.
evolution
Selective systems with variations among reproducing individuals who can pass on traits always evolve.
In small populations, new species can arise quickly under new environmental conditions {punctuated equilibrium} {quantum speciation}. Nature has many small populations. Fossils show many rapid species-evolution examples.
Lamarck said that organism actions cause body changes {Lamarckianism}. For example, giraffes have long necks through continual neck stretching. This theory is false in general, but organism actions can affect evolution in small ways by affecting mutation, crossing-over, and translocation.
learning
Perhaps, neurohormones and neurotransmitters sent from brain can affect germ cells by changing gene expression or causing structural changes. Thus, learned behaviors can trigger chemicals that can alter germ cells. Alterations can correspond to learned behavior.
strength
Perhaps, fittest individuals can sustain useless or harmful innovations that weaker individuals cannot have. Innovations can then evolve into useful traits, and species can evolve.
energy
Perhaps, fittest individuals have more energy, matter, and organization to implement innovations that have no chance in weaker individuals. Innovations can then evolve into useful traits, and species can evolve.
Perhaps, all traits are adaptive {panadaptationism}. This theory is not true, because most traits are side effects and some traits are not good adaptations [Gould and Lewontin, 1979].
Animal diseases can model human diseases {animal model} {model, animal}. Germ-free animals are useful.
variables
Disease progress and outcome depend on species, strain, genotype modifications, gender, and age. Disease agents and treatments have different locations and administration methods.
problems
Animals contract other diseases regularly in laboratory settings, so animals must have no bacteria, such as Helicobacter and Camphlylobacter, or worms, such as Helminthes. Outside organisms can elicit immunologic, inflammatory, and cancerous effects to obviate experiment.
Studies {association study} can compare allele frequency in disease and control populations. Frequency difference indicates that allele relates to disease. Genetic-linkage algorithms compare disease and control allele frequencies to find marker locus. Studies can compare allele frequencies among phenotypes.
Carbon-isotope ratios can date objects up to 100,000 years old {carbon dating}|.
instrument
Mass spectroscopy can measure isotope amounts in very small samples.
location
Lower-atmosphere carbon dioxide has radioactive carbon-14 {radiocarbon} to non-radioactive carbon-12 ratio. Living things have same carbon-isotope ratio as lower atmosphere.
time
Lower-atmosphere carbon-isotope ratio varies over time. Measuring air trapped in glaciers at different depths shows ratios at past times. Carbon-isotope ratio decreases after organisms die, because carbon-14 decays to nitrogen-14. Comparing current reduced ratio to atmosphere ratio at death indicates time of death.
age
Carbon dating is only useful up to 100,000 years ago, because almost all carbon-14 decays in 100,000 years.
changes
Older carbon-dating methods needed more mass and used fire ashes or other organic materials adjacent to formerly living things, not living things themselves. Older carbon-dating methods assumed that atmospheric carbon-isotope ratio is constant. Because ratios actually changed, carbon-dating dates in scientific literature before 1990 are typically too recent. For example, earlier-reported -9000 is actually -11000 or 13,000 years ago.
calibration
Actual lower-atmosphere carbon-isotope ratios, measured at different glacier depths, can find correct dates {calibrated carbon dating}.
Techniques {dissection}| can open plants and animals to observe parts.
Shooting gold or tungsten particles carrying genes into cereal seeds {gene insertion} can cause gene insertion into cereal DNA.
Agrobacterium tumefaciens can attach to plant leaves and then transfer DNA, including foreign genes, into leaves {leaf disk technique}.
Placing lights on joints and limbs allows filming limb movements {limb movement}.
Injecting antigens into mice or rats causes immune responses and makes antibodies {monoclonal antibody}| in spleen lymphocytes.
hybrid cells
In cell culture, lymphocytes can mix with myeloma cell lines to make hybrid cells {hybridoma}. Polyethylene glycol helps hybridization.
screening
Screening can find hybrid cells with large antibody quantities.
antibodies
Rituxan works against lymphoma.
Herceptin {trastuzumab} works against breast cancer. Epidermal-growth-factor receptors (EGFR) make dimerization signals, which tell cells to divide. Herceptin binds to HER2 cell-surface epidermal-growth-factor receptors and prevents dimerization signals. Dimercept binds to HER cell-surface-receptor dimerization sites. Lapatinib kinase inhibitor inhibits HER2 receptors.
Kinase inhibitors inhibit PI3K, AKT, and mTOR in cell-survival pathway.
Letrozole aromatase inhibitor inhibits estrogen synthesis. Tamoxifen aromatase inhibitor inhibits estrogen and progesterone synthesis.
Bevacimuzab inhibits tumor blood-vessel formation at VEGF receptors.
Monoclonal antibodies can inhibit IGF-1 receptors.
nanobodies
Llamas and camels make half their antibodies {nanobody} using only heavy chains, which supply variable segments.
Coherent light sources can split into reflected beams and beams that enter tissue, and then beams can interfere {optical coherence tomography}.
Techniques {surface plasmon resonance} (SPR) can measure protein site-binding strength.
Squeezing nerve fibers causes axoplasm to accumulate on both sides, showing that nerve-fiber axoplasm flows {axon flow} in both directions.
Techniques {Nauta technique} can stain degenerating axons with silver. First, electrodes stimulate neurons with electric current, or fine pipettes stimulate neurons with chemicals. Then fine pipettes inject dye into cells. After axon cutting, dye blackens dying-axon branches.
Techniques {positron emission tomography} (PET) can use radioactive oxygen or carbon isotopes to measure cerebral blood flow or metabolic activity. Oxygen isotopes in glucose or neurotransmitters emit positrons as they decay. Patients receive radioactive tracers by injection or in food. Scanners localize radioactivity to within several millimeters and within one minute. Localized radioactivity shows increased oxygen-metabolism and glucose-metabolism sites. Brain blood flow varies with metabolic activity, so PET indicates locations with increased blood flow.
xenon
Alternatively, patients can receive radioactive xenon by injection into blood. The most active neurons become the most radioactive.
carbon 14
Carbon(14) 2-deoxyglucose is similar to glucose. Neurons can absorb the radioactive compound but cannot metabolize it. Neurons that absorb the most radioactivity are the most metabolically active.
Techniques {immunohistofluorescence} {retrograde marking} [1970] can stain neurons backward from injection site using horseradish peroxidase, colloidal gold wheat-germ agglutin, and fluorescent dyes.
Techniques {single channel recording} {patch clamping} can measure single-neuron electrical activity.
Techniques {single photon emission computed tomography} (SPECT) can measure cerebral blood flow or metabolic activity, using light.
Biology includes anatomy, botany, cell biology, genetics, nutrition, physiology, and zoology.
He lived -535 to -440 and dissected animals. Body has opposing powers, hot/cold and wet/dry, which balance in health. Galen later used this idea.
He lived -460 to -377. The "father of medicine" wrote case histories, disease observations, and Hippocratic oath. He described trephining skull holes. Disease results from humor essence imbalance.
He lived -335 to -280, dissected human body, and compared to other animal bodies. He described brain, brain ventricles, heart, heart valves, nervous system, sense and motor nerves, cornea, sclera, choroid, retina, and lens. He founded medical school at Alexandria.
He lived -304 to -250, dissected animals and humans, and described brain, brain ventricles, heart, heart valves, nervous system, sense and motor nerves, cornea, sclera, choroid, retina, and lens.
He lived 131 to 201 and probably developed the fourth syllogism figure. He diagnosed disease by pulse, dissected animals, and observed living and dead nerves, blood, and organs. Blood flows back and forth through body. Following Erasistratus [-280], body has three spirit types {pneuma, Galen}: natural spirit from liver, vital spirit from left heart ventricle, and animal spirit from brain. The four temperaments {temperaments, Galen} are choleric, melancholic, phlegmatic, and sanguine.
He lived 1514 to 1564 and studied animal and human anatomy.
He lived 1580 to 1638. With his father, he helped invent compound microscopes and used them.
He lived 1628 to 1694, observed plant and animal tissues under microscope, and started embryology and histology.
He lived 1632 to 1723 and observed bacteria [1674], yeast, protozoa, sperm, and capillary blood corpuscles under microscope.
He lived 1709 to 1751, was materialist, and was Boerhaave's student. Cells have intrinsic motion. Human and animal brains are similar.
He lived 1741 to 1801.
He lived 1774 to 1842, studied reciprocal innervation and haptic perception, and related muscles to facial expressions. Spinal-nerve anterior and posterior roots have separate functions {Bell-Magendie law, Bell}: dorsal root is sensory, and ventral root is motor [1822].
He lived 1758 to 1828, founded phrenology, and studied brain white matter, gray matter, and ganglia.
He lived 1787 to 1869 and studied brain neurons. He said fingerprints are unique [1823]. As light intensity decreases, red objects fade faster than blue objects {Purkinje effect} [1825]. He discovered germinal vesicles [1825], skin sweat glands [1833], Purkinje cells [1837], and Purkinje fibers [1839]. He digested protein with pancreatic extract [1836].
He lived 1794 to 1867, studied brain and concluded that cortex acts as one unit, and ablated brain areas to investigate brain function. Cerebellum is for muscle coordination. Medulla is for respiration. Central nervous system has diverse and localized psychological functions.
He lived 1792 to 1876 and discovered ovum in mammals [1826]. Embryos of various vertebrates are similar {Baer laws}.
He lived 1796 to 1874 and developed social and human statistics.
He lived 1795 to 1860 and studied how to induce hypnosis.
He lived 1824 to 1880, developed skull-measuring instruments, and studied prehistoric skull trephining. He first described Cro-Magnon and Aurignacian man. He disproved theory {Celtic myth} that Celts constituted a racial group with inherited characteristics [1866]. Frontal-lobe-third or inferior-gyrus damage {Broca's area, Broca} makes people unable to speak [1861].
He lived 1806 to 1875 and located innervated muscles for behaviors, gestures, and expressions. He studied locomotor ataxia and tried electrical stimulation therapy.
He lived 1844 to 1895 and discovered DNA in trout sperm [1869]. Blood carbon dioxide level regulates breathing.
Fritsch lived 1838 to 1927. Hitzig lived 1838 to 1907. They studied Broca's-area localized motor functions.
He lived 1843 to 1926 and found Golgi cells [1883] and Golgi apparatus [1909]. If silver chromate stains neural tissue, some nerve cells stain black and become visible among unstained, transparent cells [1873].
He lived 1852 to 1934 and studied neurons and brain microscopic structure. Nerve signal goes from neuron axon to next-neuron dendrite.
He lived 1847 to 1929. Cortex association areas myelinate after birth, while sense and motor areas myelinate before birth.
He lived 1857 to 1952, named neuron junctions "synapses", showed that transmission slowed there, and studied antagonistic-muscle reciprocal innervation. He studied peripheral and spinal reflexes, including dog scratch reflex, and relations between reflexes and behavior patterns.
He studied sense exteroceptors, interoceptors, and proprioceptors. Exteroceptive distance receptors detect movements and are at animal leading edges. Distance receptors receive stimuli far from physical source. Brains can build space-time relations to represent environment. Interoceptive receptors receive stimuli where physical sources contact body surface. Proprioceptive receptors receive stimuli from inside body.
Precurrent receptors initiate behavior, and non-precurrent receptor activity stops behavior. Behavior relies on body hierarchical spatio-temporal subsystems that evolution built and linked for survival. Body-limit perception affects behavior.
Organisms evolved to allow more exploration and autonomy, as distance receptors and brain integration evolved. Organisms had more prey and predator knowledge. Anticipatory responses extended control over space and time, so reaction time increased and immediate receptor responses lasted longer.
He lived 1868 to 1918 and mapped 52 cortical areas [1903 to 1908].
He lived 1876 to 1936 and studied ear labyrinth functions.
He lived 1866 to 1959. He studied polio [1910].
He lived 1876 to 1965 and studied sensation locations and spinal and head injuries. He found Adie's syndrome and Holmes' syndrome [1941], with William Adie.
He lived 1888 to 1947. He studied brain injuries [1917]. Blind patients, with V1 area damage, can consciously perceive fast moving highly contrasting stimuli {Riddoch syndrome}.
He lived 1847 to 1930. Occipital lobes have topological maps [1919]. People can lose ability to calculate but retain other abilities.
He lived 1861 to 1940 and studied cerebral cortex and sensation. Cortical memory stores flexible experience representations {schema, Head}.
He lived 1881 to 1973. Hypothalamic stimulation causes emotions and controls internal organs [1928].
He lived 1871 to 1942 and studied human variation.
He lived 1875 to 1955 and started frontal lobotomy for mental illness [1935].
He lived 1899 to 1972 and studied chimpanzee isocortex. He invented Perceptrons, with Walter H. Pitts. Neuron model sends unit output if input is above threshold. Finite device combinations, including loops, can perform any algorithm. Neural networks can recognize figures, so any input feature from figure produces same output. Reliable neural networks can come from unreliable components using redundancy.
He lived 1903 to 1997 and studied cerebellum [1967]. Connections between sense and motor nerves in spinal-cord gray matter are responsible for reflexes [1951]. Matter and mind are separate substances, and interact in synapses {interactionism, Eccles}. Mind has units {psychon, Eccles}.
He lived 1919 to ?. Human chromosome number is 46, rather than 44 or 48 [1955].
He lived 1924 to 1992 and developed neuron motion-detector models, to explain how flies detect motion.
He lived 1895 to 1966 and studied brain.
He lived 1920 to ?. Axons from frog retinal ganglion cells have four groups that respond differently to different stimuli and that end in four distinct optic-tectum layers, all with same topographic map. Frog is normally motionless, so detectors detect environment changes.
Sustained contrast detectors make immediate and prolonged signals when object edge, either lighter or darker than background, moves into receptive field and stops.
Net convexity detectors make immediate and temporary signals when large dark-object small or convex edges pass through visual field. Smooth movement has less effect than jerky movement.
Moving-edge detectors respond to edges moving through receptive field. Net dimming detectors make immediate and prolonged signals with sudden illumination reduction. Frogs can recognize prey and enemy categories.
Heimer lived 1930 to 2007.
He studied frog-retina bug-detector ganglion cells. Thousands of cardinal cells code percepts [Barlow, 1972] [Barlow, 1995]. Qualia are not basic phenomena but brain-developed sensations that depend on memory and processing. Consciousness comes from social communication.
They studied brain and neural networks.
Szentagothai lived 1912 to 1994.
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He studied vertebrate eye.
He lived 1927 to ?.
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Brain works by selection. 0.5-mm-diameter cortical hexagonal columns and their lateral connections represent symbols. Columns vary, compete, and replicate. Symbols integrate and coordinate to make scenes and help each other compete and copy. Consciousness is image or scene that is most populous {scenario spinning}.
He discovered embryonic stem cells [1998].
Perhaps, consciousness is in anterior cingulate. Consciousness unifies body actions. Perhaps, ability to make new reflexes is consciousness purpose. He developed computer simulations (CyberChild) to find neural correlates of consciousness. It uses mammalian nervous system circuits grouped into binary composite units. It has two senses, hearing and touch. It controls vocalization, feeding, and bladder-control muscles. It has pain receptors for low stomach-milk level, low blood-sugar level, full bladder, and dirty diaper. Emergent behavior, such as ability to make new reflexes, indicates consciousness.
Brain scans associate brain regions with psychological functions.
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Consciousness unifies by integrative processes among brain parts.
Experiment cannot induce blushing physically. Experiment can induce blushing only mentally. Trying to restrain blushing only increases it.
He lived 1825 to 1892, studied mimicry [1862] {Batesian mimicry}, and was a naturalist in Amazon [1848 to 1859].
He lived 1818 to 1889 and studied eyes and reaction times.
He lived 1825 to 1893 and studied multiple sclerosis, hysteria, hypnosis, and tabes dorsalis "shooting pains" {lightning pains}.
He lived 1829 to 1910. Organisms have goal-directed feedback mechanisms to stabilize output.
He lived 1848 to 1894. Animals learn by imitation [1886].
He lived 1859 to 1924. Simple animals have forced tropism movements. Animals move towards stimulus source {positive tropism} or away from it {negative tropism}. Simple animals have paired receptors, such as eyes, which send signals to paired muscles, such as legs. When both receptors send equal signals, tension balances between both muscles, and animal moves in straight lines {tonus hypothesis}. However, tonus hypothesis is not true for simple or higher animals.
He lived 1903 to 1989 and studied natural behavior {ethology, Lorenz}, aggression, imprinting, instincts, innate releasing mechanisms, and fixed action patterns.
He lived 1907 to 1988 and studied ethology.
Masters lived 1915 to 2001. Johnson lived 1925 to ?. They studied sexuality.
People can sense unconscious body behavior by signal biofeedback [1968]. After training, people can control one neuron or can change blood pressure or heartbeat.
She lived 1934 to ? and studied chimpanzee behavior. Chimps grunt, pant, bark, roar, scream, squeak, whimper, laugh, click teeth, and smack lips, in 30 different ways with different meanings [1972].
He lived 1917 to 1987.
Monkeys make alarm calls even when they can perceive that other monkeys are not near or that other monkeys are calling already. Monkeys do not have theory of mind. Vervet monkeys make different alarm calls for eagles, leopards, and snakes and use grunts in social interactions.
He lived 1779 to 1848 and discovered proteins [1838] and studied ions and atomic and molecular weights. He invented old chemical symbols [1811] and atomic-weight table [1826].
He lived 1764 to 1833 and discovered enzymes. Wheat gluten enzyme converts starch to sugar and dextrin [1812].
He lived 1800 to 1882 and synthesized urea from ammonium cyanate [1828], the first artificial organic-chemical synthesis.
He lived 1803 to 1873 and described enzyme action chemically {law of the minimum}. He observed that plants use nitrogen and carbon dioxide from air. He invented nitrogen fertilizer. He invented {Liebig condenser}. He silvered mirrors [1835]. He invented beef extract [1865].
He lived 1875 to 1940 and studied enzyme kinetics and analyzed enzyme-substrate complexes as chemical equilibria.
She lived 1879 to 1960 and studied enzyme kinetics and analyzed enzyme-substrate complexes as chemical equilibria.
He lived 1897 to 1985 and studied anaerobic photosynthesis [1931].
He lived 1900 to 1981 and studied tricarboxylic carbohydrate cycle [1937].
He lived 1912 to 1991 and studied enzymes [1938 to 1965].
He lived 1918 to ? and synthesized DNA molecules using DNA polymerase I [1955 to 1958].
Brenner lived 1927 to ?. Meselson lived 1930 to ?. Jacob lived 1920 to ?.
She lived 1910 to 1994 and determined insulin structure.
He lived 1922 to ? and synthesized yeast gene [1960].
He lived 1929 to ?.
TP53 gene kills cell if cell has broken DNA or has low oxygen, by making p53 protein [1979].
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They found ribozyme RNA that can act as enzymes to cut other RNA [1982]. RNA was first molecule able to replicate, because RNA can be catalyst. DNA bases and sugars came from RNA bases and sugars. For example, thymine can come from uracil. RNA works with ribosomal proteins, amino acids, and many enzymes.
He studied RNA viruses [1985].
He lived 1849 to 1926 and developed new plant varieties.
He lived 1864 to 1943 and developed soil improvements and new peanut, soybean, and cotton uses. He rotated peanuts with cotton.
He lived 1578 to 1657 and studied embryology. Blood flows through blood vessels from and to heart.
He lived 1834 to 1919 and studied marine invertebrates. Ontogeny recapitulates phylogeny {theory of recapitulation}. Sperm are mostly nucleic acid [1868].
He lived 1867 to 1941. Cell from 2-cell, 4-cell, 8-cell, or 16-cell frog embryo can develop into complete adult, which can spawn complete children [1895]. Cell non-material transcendental order moves animal development toward adulthood {entelechy, Driesch}.
He lived 1860 to 1948. Dynamical forces and energies make a few main growth and development patterns and determine organism shapes.
He studied brain development from social interactions. People {natural psychologist} talk to themselves to think what to do in different social situations and so understand, predict, and control what other people do. People then evolved systems {inner eye} to image brain processes and states. Such imaging is consciousness. Consciousness emerged abruptly as existing features combined. Sensations are actions and their thoughts.
He lived 1929 to ?.
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He studied brain development from social interactions.
Hox regulatory genes govern fruitfly development [1983].
MYC, BCL-2, APC, and RAS genes check cell division [1985].
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He lived 1873 to 1941 and invented electroencephalogram [1924]. Electrodes can measure scalp electrical potentials {electroencephalography, Berger}. Alpha waves are regular 10-Hz oscillations that happen when people relax and close their eyes. Beta waves are faster and less synchronous oscillations that replace alpha waves when people perform mental activity and keep their eyes open.
He lived 1907 to 1977 and studied ecology.
He lived 1917 to ? and studied ecology and population. He opposed above-ground nuclear testing [1952].
He lived 1707 to 1778, classified plants and animals by structures, and named organisms as genus and species {binomial nomenclature, Linnaeus}.
He lived 1710 to 1784 and related hydra and jellyfish. Hydra and jellyfish parts can move and bud.
He lived 1769 to 1832 and studied fossils, differentiated animals by body structures and nervous systems, and noted adaptations to environment.
He lived 1772 to 1844 and studied fossils and compared fish and land animals, vertebrates and insects, and cephalopods and vertebrates. Fossils have structure homologies {unity of type}. Body type depends on vertebral structure.
He lived 1807 to 1873. Species form hierarchies, with form laws {taxonomy, Agassiz}.
He lived 1804 to 1892 and found horse intermediate fossils. All vertebrates have body plans based on repeating vertebrae, which can evolve.
He lived 1809 to 1882. He developed plant and animals evolution theory. Natural selection of variations leads to the most-successful reproduction {survival of the fittest, Darwin}. Species evolved from earlier species, making branching evolutionary trees. Evolution has caused changes without needing causer. Evolution has support from organism location, because similar environments in different locations have different organisms, and similar, mutually accessible, locations with different environments have similar organisms. Evolution has support from comparative anatomy, because different species have similar hand bones, and species have vestigial structures. Evolution has support from embryology, because segmented-worm and unsegmented-mollusc larvae are similar, and vertebrate embryos have gills. Evolution has support from the fossil record, which shows intermediate forms. Changes have billions of years to happen. Ancient rocks and environment differ from now, and fossil life forms differ from now. Current animals adapted to present environment, not to ancient one. Finches of Galapagos Islands and barnacles were test cases.
He also studied emotions. Human emotional-response and facial-expression origins are pre-human species behaviors.
He lived 1823 to 1913 and independently developed evolution theory with survival of fittest. He studied animal geography and life in Amazon River basin and Malay Archipelago.
He lived 1860 to 1940 and studied integral equations [1883]. Mating, dying, or other-species effects cause predator-number and prey-number change rates {Lotka-Volterra differential equations, Volterra} [1926]. In ecosystems, predator and prey numbers can oscillate until reaching steady state, can continue to oscillate, or can become zero, so species is extinct.
He lived 1893 to 1988 and found Taung child, Australopithecus africanus [1924].
He lived 1880 to 1949. Mating, dying, or other-species effects cause predator-number and prey-number change rates {Lotka-Volterra differential equations, Lotka} [1926]. In ecosystems, predator and prey numbers can oscillate until reaching steady state, can continue to oscillate, or can become zero, so species is extinct.
He lived 1876 to 1956 and studied primates [1929 to 1943].
He lived 1889 to 1988 and discovered genetic drift. Species arise randomly even within clade that has evolutionary direction {Wright's rule}. Selection changes allele frequencies.
He lived 1887 to 1975 and developed cladistics. Organism characteristics are clade units that determine classes and hierarchies. Organisms have homologies, and cladogram nodes represent shared homologies. Cladistics can use property absences.
He lived 1900 to 1975 and studied evolutionary theory.
He lived 1905 to 1975 and studied evolution [1939].
He lived 1904 to 2005 and examined differences between historical and non-historical sciences. New species result from variety geographic isolation {allopatry, Mayr} [1960 to 1970], rather than arising in same location {sympatry, Mayr}.
He lived 1898 to 1976 and opposed evolution by natural selection.
He lived 1903 to 1972 and found fossil hominins [1949 to 1959].
He lived 1927 to ? and developed relaxation methods, to measure 10^-10 second reaction rates [1954]. High mutation rates prevent natural selection [1992].
He lived 1917 to ? and discovered lysosomes [1955] and peroxisomes [1965].
He lived 1936 to 2000. Sexual reproduction results from competition between parasite and host [1963].
He lived 1928 to ?. Small subunit ribosomal RNA can classify organisms [1965].
Genes are natural-selection units, and organisms passively contain them. Evolution changes gene frequency and can make new genes.
He lived 1901 to 1982 and studied evolution.
New speciation is at range fringes in isolated places. Species change little at other times.
He lived 1920 to 2004 and studied population-biology relations {logistic difference equation, Smith}.
Early bacteria incorporated into eukaryotes to make mitochondria and chloroplasts {endosymbiont hypothesis, Margulis} [1970].
He lived 1913 to 1993.
He discovered genus Homo fossils [1974].
He lived 1899 to 1972.
He invented sociobiology.
Ideas or concepts {meme} {mimeme} can exist in brain, replicate, and have selection. Thoughts and ideas in memory or culture replicate themselves in other minds by imitation and transmission. Memes compete for entry into minds. Selective forces act directly on meme physical substrates, because memes restructure brains to make better habitats for themselves and to modify input and output. Perceptions, skills, feelings, and memories have no copies.
Meme sets {memeplex, Wilson} {co-adapted meme complex} can affect survival and reproduction [Dawkins, 1976]. He wrote about Universal Darwinism and replicators [Dawkins, 1995].
Meme copies behavior from another same-species animal {imitation, Dawkins}, but copying varies more than for genes. Memory ties abstractions and agreements together, so imitation is only small part. However, copy does not have same meaning, because brain does not just imitate but processes information. It involves selection and non-selective processes.
Culture also involves sharing knowledge {schema, Dawkins}, not by imitation but by abstraction. Culture also involves sharing beliefs and values {social construction}, not by imitation but by agreement. Culture depends on having a theory of mind and knowing that other people have beliefs, intentions, and desires. Genes {selfish gene} use bodies to reproduce themselves.
Evolution repeats and modifies animal forms {bauplan, Gould}. Evolutionary changes can be in bursts {punctuated equilibrium, Gould}, even after 20,000 years with no change. Most traits are side effects. Timing changes during development cause evolutionary changes.
Organisms produce more offspring than survive to reproduce {superfecundity, Gould}. Darwin defended this idea against people that thought God is more benevolent. Offspring vary in traits. All accept this idea. Offspring pass their traits to offspring. All accept this idea. Therefore, offspring with traits more favorable for survival to reproductive age will produce more offspring with same traits {natural selection, Gould}.
Darwin's evolutionary theory has three main principles to explain natural-selection mechanisms. Natural selection applies to organisms, not classes, genuses, species, tissues, organs, or genes.
Darwin suggested that altruism in humans was trait outside this idea. Perhaps, altruism can explain hybridization and worker-insect sterility. Modern theory suggests genes, cell lines, organisms, demes, species, and clades evolve using selection and drift to change frequencies and parts. They can work synergistically, in opposition, or independently of nearby levels. Other possibilities can be entropy effect or complex system spontaneous ordering.
Natural selection removes unfit and designs fit, because variations from typical or average are small, random, and numerous and not always negative. Small and large variations accumulate over many generations. Variations can have different kinds and sizes {microevolution, Gould}. Modern theory adds structural, historic, and developmental factors. Natural selection gradually makes more-complex organisms and can make new higher-level organism species. However, modern theory adds mass extinctions, species sorting by punctuated equilibrium to alter clades, and other processes taking different times. Other possibilities can be inorganic and organic comparisons or new species-formation ideas.
Because organisms overproduce, nature has competing organisms and species, so new ones must replace or wedge aside existing ones, leading to better-adapted species. This requires that environment changes slowly compared to evolution and observed species changes.
Interactors, rather than replicators, can define selection. Emergent fitness, rather than emergent traits, causes higher-level selection. Species selection is main macroevolution method.
Evolutionary theory involves same framework as other scientific explanations. It involves causation vs. association. Event sequences relate or do not relate. Related events are consequences or not. Structures and functions exist. Logical conclusions come from premises. People can find causation direction. Determinism comes from fundamental-unit laws versus independent-level interactions. Changes are gradual, spurt, maintain stasis, are exponential, or rise and fall. It involves fundamental units, structure hierarchies, change rates, space scales, and time scales.
Darwin felt that nature had progressed, because organism and ecosystem design was good (Paley) and complexity was increasing. Besides, nature ordered itself in the most-efficient way by survival of fittest (Adam Smith).
Increased speciation leads to increased extinction.
Clade selection, species habitat tracking, and grouping in populations can cause stasis.
Organisms tend to evolve to larger size, from individual size advantages and structural factors {Cope's rule, Gould}.
Slow variation and slow environmental change helped ancient organisms alive today survive. Their clades had low speciation.
Clades have various speciation rates, which can change over time and mimic seemingly progressive linear species changes, as in horses and humans.
Humans are stable genetically if punctuated equilibrium is true.
Drift can go into available niches, but bacteria dominate life.
Geometric patterns and physical laws, such as surface-to-volume ratios and coordinate transformations, constrain structures and allow few alternatives. Historical development can impose homologies and regulations. Adaptation consequences {exaptation, Gould} can have later advantages.
Homology is internal structure similarity {homogeny, Gould}. Homology can result from fundamental internal structure {parallelism, Gould} or same external pressures {convergence, Gould}. Organisms can also perform similar functions with different structures {homoplasy, Gould}.
Darwin held that small structure shifts were adaptive, but cumulative-shift adaptations can be different {functional shift, Gould} {cooptation, Gould}. Initial stages have unpredictable uses, constrain future adaptation, and form sequence. Non-adaptive structures {spandrel, Gould} arise in association with adaptive structures, and these structures can later be for adaptation, at all hierarchy levels. Adaptive structures tend to limit further evolution through specialization, but adaptive structures make many more non-adaptive structures with which evolution can work.
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Gene DNA evolves at constant rate in all species over all history. Molecular changes that have less control by natural selection evolve more rapidly, because they have no effects, while harmful ones die out and good ones are rare {Kimura's rule}.
He studied human gene frequencies, race, and population migrations.
Catastrophe has happened at mass-extinction level, and clades, species, demes, organisms, cell lines, and genes can have extinctions {field of bullets model}.
Infections that use intermediate hosts, such as cholera and malaria, evolve to be stronger [1993]. Infections that infect directly evolve to be weak enough to maintain the host. Infections cause most genetic and chronic diseases.
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He studied human origins from hominins [1997].
He studied brain evolution. Brains allow animals to account for environment variations in space and time and make appropriate responses. More advanced brains allow wider spaces and longer times. Brains require much energy and are in animals that can find more and/or better food at higher rate. Complex brains require longer time to develop. Family and group structures were necessary for humans to have advanced brains.
Brains can sense water, food, sexual partners, shelter, and safe locations, as well as predators and dangerous locations. Brains can assign priorities to input. Brains can perform activities to get food or water, reproduce, gain shelter and safe locations, and avoid predators and dangerous locations. Brains can remember input and output.
Brains are more complex if environmental niche is more variable. Animals use larger energy amounts, because warm-blooded. Water, food, sexual partners, shelter, and safe locations are scarcer and predators and dangerous locations are more numerous. Maximize age is higher.
He lived 1822 to 1884 and developed Mendel's inheritance laws by studying dominant and recessive characteristics of pea-plant independent and discrete heredity units.
He lived 1822 to 1911 and studied human mental-property and physical-property genetics. He collected and classified fingerprints {fingerprinting}. He studied human individual differences, using imagery, psychological questionnaires, twin life histories, and family and talented-people educational backgrounds. He developed the correlation coefficient. He participated in scientific exploration to unexplored Africa.
He discovered air pressure systems and invented weather maps [1875]. He invented a polyhedron {Galton's Polyhedron} of possible structural forms to which organisms can jump. More intellectually gifted people have less vivid imagery [1883].
He lived 1843 to 1905 and studied mitosis [1870], meiosis, and chromatin role [1879].
He lived 1833 to 1914. Specialized cells carry genetic information {germ line} {germ plasm theory} [1883]. Selection can operate at levels below and above organisms.
He lived 1848 to 1935, studied evening-primrose mutations [1900], and developed inheritance laws based on cell factors {pangenesis, de Vries} [1889]. Plants can jump from form to form, unconstrained by structures. Phylogenesis results from species selection.
He lived 1861 to 1926 and invented the word genetics for heredity study. Genes carry genetic information and are in chromosomes. New species come from repeated-body-segment structure and number changes. Such modifications can lead to similarity with existing part {homeosis, Bateson}. Parts can have jumps. For example, upper thoracic vertebrae can have no ribs or lower cervical vertebrae can have ribs.
He lived 1863 to 1924 and studied crossing-over.
He lived 1866 to 1945, studied gene linkage, and invented linkage maps, using fruit flies [1909 to 1915]. Genes are in chromosomes.
He lived 1857 to 1936 and studied genetics [1909].
He lived 1890 to 1962. He developed statistical-significance methods {analysis of variance, Fisher} and Fisher experiment-design theory [1920]. Mendelian inheritance in large populations with great variety can result in gradual evolution, but blending inheritance does not work. Variation frequency varies inversely with variation magnitude. Natural selection can increase allele frequency.
He lived 1890 to 1967. X-rays mutate fruitfly cells [1926]. Many mutations cause cancer [1951].
He lived 1878 to 1958 and studied gypsy moths. Genes {rate gene} can control rates and regulate other genes.
He lived 1903 to 1989. One gene makes one protein [1941].
He lived 1909 to 1975. One gene makes one protein.
He lived 1877 to 1955. DNA transfers from cell to cell in chromosomes. DNA contains gene information to transform cells. He studied pneumococcus deadly S strain, with smooth surface, and mild R strain, with rough surface.
He lived 1902 to 1984. DNA transfers from cell to cell in chromosomes. DNA contains information to transform cells.
She lived 1902 to 1992 and studied corn transposable elements {jumping gene, McClintock} [1951].
She lived 1920 to 1958 and performed x-ray crystallography of DNA indicating it was double helix [1953].
He lived 1928 to ? and calculated that DNA was double helix [1953].
He lived 1916 to 2004 and calculated that DNA was double helix [1953]. Perhaps, consciousness depends on thalamus and cortex layers 4 and 6 [1994].
He lived 1910 to 1976 and studied DNA repression and expression in Lac operon [1961].
He lived 1927 to ? and found DNA and RNA triplet code [1962].
He lived 1932 to ?, cloned foreign genes, and expressed repressed genes in mice [1974].
Genes rearrange themselves in early infancy [1978]. Antibody genes can join joining gene by deleting DNA between them. Joining genes join to trunk genes, which determine mobility level. Joined genes determine antigen.
He lived 1927 to ? and helped determine worm and human genetic codes [1982].
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They invented gene knockouts in mice [1990].
He organized scientists to sequence a free-living organism [1995] and the human genome [2001]. Haemophilus influenzae bacterium has 1000 genes with 1,800,000 bp.
They organized scientists to sequence C. elegans animal genome [1998].
They organized scientists to sequence mouse genome.
He lived 1899 to 1985 and suggested clonal-selection theory.
He lived 1915 to 1987 and studied immunology.
He lived 1688 to 1752, developed artificial pupil, and removed kidney stones {kidney stone removal} and cataracts.
He lived 1749 to 1823 {smallpox vaccine}.
He lived 1821 to 1894 and founded perceptual physiology {ophthalmoscope, Helmholtz}. He developed Young-Helmholtz trichromatic color-vision theory and studied lens accommodation. He first timed nerve-signal conduction rate and muscle-action times [1850]. Speed at which electrical impulses travel along nerve fibers limits human reaction time. Pitch discrimination depends on resonance {fixed pitch theory}.
Epistemology
People cannot know external physical events and only have neural signals. Neural signals from senses gain meaning from learned associations, which depend on assumptions that can be incorrect. Perceptions are unconscious inferences. People cannot experience or introspect how they perceive or think. People cannot know data on which brain bases perceptions and beliefs. During perceptions and decisions to perform muscle movements, nerve signals switch. Body sense receptors receive and analyze physical energies from outside world to make independent, simple, and unnoticeable sensations, and brains learn to perceive objects and events that probably produced sensations {classical theory of psychology}.
He lived 1845 to 1913.
He lived 1870 to 1959 {tissue culture}.
He lived 1899 to 1972. Sound vibrations travel from one inner-ear basilar-membrane end toward the other [1928 to 1932]. For sound frequencies, different membrane positions have maximum vibration.
He lived 1918 to ?, determined insulin amino-acid sequence [1950], and developed method to sequence DNA [1977].
He lived 1910 to 1976 and studied body electrical behavior {toposcopy}, muscle contraction, electroencephalograms, electroconvulsive therapy, frequency analysis, and evoked potentials. He implanted brain electrodes to study epilepsy and treat psychiatric illness in conscious humans.
Brain-function electromechanical models, with two control systems and several interacting units, can produce life-like behavior, including learning, as in electromechanical tortoise called M. speculatrix.
Brain electrical potential has negative shift between associated stimuli just before decision becomes public {contingent negative variation} (CNV). Motor cortex sends output before people act [Walter, 1953]. Helical scanner measures and displays frequencies and phases on short time-scales from many brain electrodes.
He lived 1914 to 1995 {polio vaccine}.
He lived 1906 to 1993 {oral polio vaccine}.
He found Shine-Dalgarno sequence [1961].
Cohen lived 1922 to ?. Boyer lived 1936 to ?.
They started gene engineering {genetic engineering}.
They developed method to sequence DNA [1977].
Polymerase chain reaction (PCR) developed to make multiple copies of DNA.
He studied human identification {DNA fingerprinting, Jeffreys}.
Successful therapy {gene therapy, French} treated adenosine deaminase deficiency {adenosine deaminase deficiency} (ADA).
He cloned Dolly the sheep from adult sheep cells {mammal cloning}.
He lived 838 to 923.
He lived 1624 to 1689 and described diseases accurately. Hysteria in women and hypochondrias in men are similar. Hysterical symptoms often accompany depression. He invented opium tincture {laudanum, Syndenham} [1660].
He lived 1818 to 1865 and started hand washing in chlorine solution [1847].
He lived 1822 to 1895 and studied yeast and fermentation [1855], developed pasteurization [1864], and developed rabies vaccine [1883]. Organic molecules can have chirality. Cells come from cells, with no spontaneous generation.
He lived 1821 to 1902 and studied cell theory. Cells arise from each other over continual generations {Omnis cellula e cellula}.
He lived 1827 to 1912, used carbolic acid on wounds to prevent infection [1866], and studied bacteria, antiseptics, heat sterilization, and operative techniques [1877].
He lived 1843 to 1928 and developed operations to treat brain injuries and diseases. Cerebral functions are in fixed brain areas.
He lived 1848 to 1905, studied sensory aphasia and word-usage and word-choice disorders, and invented language brain-flow diagrams. Alcoholics often have thiamine deficiency, which can cause encephalopathy.
He lived 1843 to 1910, stained bacteria [1877], grew bacterial colonies [1890], studied anthrax [1876], tuberculosis, and cholera, and developed tuberculin test [1890]. He developed Koch's postulates about disease.
He lived 1842 to 1925, studied hysteria using hypnosis, and discussed catharsis. Vagus nerve controls breathing. Semicircular canals are for balance.
He lived 1835 to 1911. He noted focal-epilepsy involuntary-movement sequences and deduced motor-cortex excitable-area spatial patterns. Patients can utter words or phrases under stress or during high emotion, though they cannot speak voluntarily.
He lived 1840 to 1902 and studied syphilitic infection, which can cause insanity and paralysis.
Charles lived 1865 to 1939. William lived 1861 to 1939. They performed surgery at Mayo Clinic [1889].
He lived 1854 to 1915. He used methylene blue as antimalarial drug [1891], trypan red and trypaflavin against trypanosomiasis, acriflavine as antibacterial, arsenical compounds (Carbarsone) against amoebas, arsenical compounds (Salvarsan and oxophenarsine) against syphilis bacteria [1907 to 1909]. He discovered drug resistance [1925].
Breinl lived 1880 to 1944 {sleeping sickness, drug}. Atoxyl kills trypanosomes [1905], which cause human trypanosomiasis. Thomas studied yellow fever.
He lived 1879 to 1970 and discovered first oncovirus, Rous sarcoma virus [1909].
He lived 1874 to 1933 and studied focal cerebral-cortex lesions, frontal-lobe functions, motor-center variability, and aphasia.
He lived 1871 to 1945 and studied psychosomatic disease and fear and rage biochemistry. Body maintains chemical and function equilibrium {homeostasis, Cannon}. Body uses feedback signals to indicate needs and to initiate action to obtain needs.
He lived 1881 to 1955. Penicillin is antibacterial drug [1928].
He lived 1898 to 1972 and studied mental deficiency and genetics of Down's syndrome and epiloia or tuberous sclerosis. Maternal age increases children's Down's syndrome, but paternal age does not. Subnormality is not qualitatively different than normal intelligence. Mental deficiency has many factors and causes, and people can perform well on some factors. Mental deficiency is more common in parents and relatives of people with IQ 50 or above than it is in parents of people with IQ lower than 50.
He performed prefrontal lobe leucotomy to cure chronic anxiety, depression with suicide risk, and obsessive-compulsive disorder [1935].
He lived 1891 to 1976, studied local epilepsy, found epileptic brain-lesion locations and extents [1938], and surgically treated local epilepsy. He electrically stimulated brains to find regions needed for language, but he also elicited images and sensations, which are same dream-like sensations that patients experience when epileptic [Penfield, 1975] [Penfield and Perot, 1963]. Removing tissue did not delete sensation.
He lived 1903 to 1998.
Kinsey lived 1894 to 1956. Pomeroy lived 1913 to 2001. Martin lived 1918 to ?. They studied sexual physiology and behavior.
He lived 1924 to 2006. One amino-acid change in hemoglobin causes sickle cell anemia [1956].
Helicobacter pylori bacteria cause ulcers [1982].
Misshapen prion proteins cause scrapie [1982].
DNA sequence of HIV published [1985].
He found first tumor suppressor gene, RB gene [1986].
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He lived 1857 to 1911.
He lived 1877 to 1950. Félix d'Hérelle discovered it in 1917.
He lived 1838 to 1942 and wrote about the beauty and meaning of nature, especially after visiting Yosemite [1868].
He lived 1837 to 1921.
He lived 1893 to 1970.
He lived 1577 to 1644. Plants make organic materials and do not get them from soil, which stays same weight while plant grows.
He lived 1626 to 1697 and proved spontaneous generation does not happen, by showing that maggots did not come from meat [1668].
He lived 1804 to 1881 and invented plant cell theory. Cells are life units.
He lived 1810 to 1882 and invented animal cell theory. Cells are life units.
He lived 1892 to 1964. In atmosphere or ocean, ultraviolet radiation, volcanic heat, lightning, and radioactive-nuclei ionizing radiation can make complex organic molecules from nitrogen, methane, ammonia, water, carbon dioxide, and hydrogen {Oparin-Haldane hypothesis, Haldane}.
He lived 1894 to 1980. Glycerin molecules mixed with other molecules can clump together to make stable gel coascervates [1926]. Other molecules can enter, interact inside, and leave glycerin. In atmosphere or ocean, ultraviolet radiation, volcanic heat, lightning, and radioactive-nuclei ionizing radiation can make complex organic molecules from nitrogen, methane, ammonia, water, carbon dioxide, and hydrogen {Oparin-Haldane hypothesis}.
He lived 1906 to 1997, studied life's origin, and studied found retina vitamin A [1934].
He lived 1930 to ?. Methane, ammonia, and water heated by electric arcs make amino acids [1953 to 1954]. However, amino acids only polymerize if conditions are hot and dry.
Freezing can concentrate and align organic molecules to make nucleic acids, such as adenine [1970]. Mutations degrade good working genetic code to make it more varied {error catastrophe, Orgel}, and this process adds to genetic variability [1963].
Heteropolypeptides can come from hydrogen cyanide [1966]. Dry heating HCN makes heteropolyamidines. Water converts them to polypeptides.
He studied life's origin [1988]. Hydrothermal-vent iron, nickel, and sulfur ions act as catalysts, templates, and energy sources to form biological molecules. Pyrite surfaces hold molecules.
He studied relativity and life's origin.
Minerals have crevices in which molecules can hide from ultraviolet light and become concentrated [1996]. Clay and mineral surfaces can be chemical-reaction substrates, catalysts, and templates. Minerals, such as calcite, can have chirality and select for L or R organic molecules. Biological-molecule metal ions can act as catalysts or energy sources. Magnetite can catalyze ammonia formation from nitrogen and hydrogen. Iron, nickel, and sulfur ions are in hydrothermal vents.
He lived 1923 to ?.
He studied opium effects.
He lived 1737 to 1798 and observed frog muscles twitch when touched by electrified wires {galvanic stimulation} [1780].
He lived 1760 to 1808 and discovered analgesic effects of nitrous oxide [1798].
He lived 1776 to 1832 and studied memory storage and retrieval and physiological bases of normal brain function.
He lived 1783 to 1855, studied emetine and morphine drugs, and studied iodides and bromides in nutrition. He poisoned animals with Javanese arrow poison in various ways, described convulsions and asphyxia, sectioned spinal cord, and isolated strychnine [1818]. Spinal-nerve anterior and posterior roots have separate functions {Bell-Magendie law, Magendie}: dorsal root is sensory, and ventral root is motor [1822].
He lived 1785 to 1853 and observed stomach functions [1822 to 1833].
He lived 1776 to 1847, studied osmosis [1824], studied plant respiration and light sensitivity [1824 to 1830], and worked on cell theory.
He lived 1801 to 1858 and founded modern physiology. Sensation type depends on stimulated neurons, not on what stimulates them {doctrine of specific nerve energies, Muller}.
He lived 1811 to 1868. Muscle cells have electric current [1842].
He lived 1815 to 1848 and first used nitrous-oxide anesthetic [1844] when he extracted his tooth.
He lived 1818 to 1896. Nerve cells have resting potential [1845] that decreases with nerve impulse. Nerves conduct electricity. Nerve impulses transmit chemically [1877].
He lived 1803 to 1861 and studied hormones [1849] and transplantation.
He lived 1813 to 1878, studied pancreas [1849], studied liver and carbohydrates [1851], and noted curare's effects on nerve transmission to muscle [1853]. Anesthetics affect single cell organisms, such as green slime mold, amoebae, and paramecia [1875]. Internal environments {milieu interieur} can have constancies {homeostasis, Bernard}.
He lived 1824 to 1886. After axons are cut, neuron cell bodies often die and disappear {retrograde cell degeneration} [1870], providing method to study nerve pathways.
He lived 1835 to 1922 and studied neuron axons and conduction [1878].
He lived 1853 to 1913 and studied nerve impulse, which has refractory period [1899].
He lived 1848 to 1909. Alternating flashing lights can make afterimages {Bidwell's ghost}.
He lived 1839 to 1917 and measured nerve-impulse conduction speed [1902]. Neural ion concentrations change slightly during nerve impulses and cause nerve potential differences and action potentials {membrane theory} [1902 to 1912]. Local electric current flows between axon resting region and impulse region and causes depolarization {local circuit hypothesis}. This was idea of Ludimar Hermann.
He lived 1849 to 1936 and studied neurosis, peripheral nerves, digestion physiology, classical conditioning, and reflexes.
Contradictory stimuli can disturb balance between nervous-system excitatory and inhibitory processes, and personality affects whether neurosis develops.
Vagus nerve controls blood pressure, and four nerves control and vary heartbeat rhythm and intensity. Depending on saliva and food, tasting food {sham feeding} can release gastric juice, which has enzymes {enterokinase}.
Dogs associate neutral stimulus with reflex. Conditional reflex forms more easily if unconditional stimulus, such as food, follows conditional stimulus, such as bell, than if they are simultaneous or if conditional stimulus follows unconditional stimulus. Conditional reflex forms more easily if conditional stimulus is nearer in time to unconditional stimulus. Conditional stimulus that starts just before unconditional stimulus is as effective as conditional stimulus that started long before unconditional stimulus and lasted until just before. More intense conditional and unconditional stimuli cause greater conditioned responses. Training conditional stimulus allows testing similar conditional stimuli to investigate animal sense discriminations. External inhibition, internal inhibition, new environments, and new stimuli affect conditioning. If conditional and unconditional stimuli no longer pair, conditioned reflex gradually decreases. Maintaining conditioned reflex requires regular reinforcement. Conditioned reflex is similar to other reflexes. Conditional reflex formation is adaptation whereby animal can survive better in changing environment.
He lived 1866 to 1947 and studied light and dark photosynthesis [1905].
He lived 1869 to 1939, stimulated brains and elicited sensation without movement [1908], and described Cushing's syndrome [1912].
He lived 1879 to 1916 and studied nerve impulse, with Francis Gotch. Nerve impulse is all-or-nothing, with refractory period afterward [1909].
He lived 1885 to 1946. He identified four bitter, salty, sour, and sweet primary tastes [1924], which he put at tetrahedron corners. He identified six primary smells [1916], which he put at prism corners.
Evans lived 1882 to 1971. Long lived 1879 to 1953. They isolated human growth hormone [1921].
He lived 1873 to 1961, proved that neurotransmitters cross junction between nerve cells, using vagus nerve to heart, and so proved that synapses were chemical not electrical [1921], and studied acetylcholine chemical synapse.
He lived 1889 to 1977 and recorded afferent-nerve impulses, with Lucas' capillary electrometer [1925]. Neurons use impulse-frequency modulation.
He lived 1890 to 1958 and studied cerebral-cortex lesion effects on intelligence, rat maze learning [1920 to 1930], and mass-action law [Lashley, 1956].
He lived 1902 to 1996. Long-term memory needs protein synthesis.
He lived 1875 to 1968 and studied chemical synapses [1936].
Hodgkin lived 1914 to 1998. Huxley lived 1917 to ?. They used squid giant axons to prove that ions flow across membrane rather than down axon {local circuit hypothesis, Hodgkin}, by locally increasing and decreasing extracellular-fluid conductivity [1937]. Sodium ions have ion channels, and potassium ions have separate ion channels. During action potentials, membranes are first more permeable to sodium ions, flowing in, and then potassium ions, flowing out, so potential becomes negative {Hodgkin-Huxley theory} [1952].
He lived 1896 to 1966 and developed sensation fields {afferent field, Bernstein}. He studied feedback and feedforward mechanisms. He studied human coordination and movement physiology by photographing lights fastened to arms and legs. Human movements have patterns and structures, and people maintain basic patterns no matter which organ or limb they use [Bernstein, 1947].
He lived 1911 to 2003. Action potentials open calcium-ion channels, and calcium inflow leads to release of 5000-transmitter-molecule packets from synaptic vesicles into synapse.
He lived 1912 to 1980 and used lithium carbonate to treat mania [1949].
He lived 1915 to ?. Amygdala stimulation by electrodes {stimoceiver} can trigger aggressive behavior [1955].
He lived 1913 to 1980. Cat-retina ON-center and OFF-center ganglion cells respond to illumination changes [1953].
He lived 1901 to 1978 and discovered vasopressin [1953].
He lived 1909 to 1999. Synaptic vesicles release transmitter packets only at active synapse zones {active zone}, where calcium ion channels are [1961].
He lived 1926 to ?. Long-term memory needs protein synthesis.
He lived 1921 to ?, studied fruit flies, and mutated single genes to affect courtship rituals, vision, circadian rhythms, memory, and learning. He found proteins used in non-declarative memory.
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He studied learning and memory in marine snails.
He developed Cerebellar Model Articulation Controller [1975].
He showed that visual cortical neurons respond to frequency rather than edges or lines {direct spatial information} [1975]. They detect fundamental frequency and higher frequencies, together with orientation. He used gratings, checkerboards, and plaid patterns. Results matched results expected from analysis by Fourier transforms.
He lived 1940 to ?.
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He lived 1946 to 2001 and studied neurophenomenology. Living cells rebuild themselves {autopoiesis, Varela} [1988], with Maturana.
He studied sleep and developed AIM model [Hobson, 2002].
Special neuron stimulation can cause excitation over hours, involving protein-kinase phosphorylation after calcium-ion influx [1991].
Only active synapses can take up protein to permanently alter synapse [1997], with Uwe Frey.
Inhibition or blocking of NMDA receptor complexes, as done by ketamine and nitrous oxide, causes unconsciousness [2000]. Consciousness is a high-level representation that brain has representations, using NMDA-receptor-linked cell assemblies firing synchronously [Flohr, 2000]. However, NMDA receptors are just as involved in non-conscious processes [Hardcastle, 2000]. Many anesthetics, such as etomidate, act on other sites [Franks and Lieb, 2000].
He lived 1795 to 1878, studied psychophysics, invented theory of signs {Lokalzeichentheorie}, measured skin sensitivity to separated stimuli [1826], studied inhibition by vagus nerve [1845], and developed law of sensation [1834], with Fechner. People can distinguish between two similar sensations {just-noticeable difference}. For each sense, ratio of just-noticeable-difference to intensity is approximately constant for all intensities. Subjective sensation increases as logarithm of physical-stimulus magnitude. Just-noticeable difference increases in direct proportion to stimulus intensity. If I is sensation intensity, intensity change divided by intensity equals constant {Weber-Fechner law} {Weber's law}: (I2 - I1) / I1 = Weber's constant. Weber's constant {Weber fraction} represents smallest stimulus intensity difference that people can perceive. If intensity is higher, differences must be larger for people to perceive them. Weber's constant is typically greater than one to three percent, differs for different senses, and tends to increase with age.
He lived 1755 to 1826.
He lived 1837 to 1900 and found rhodopsin retinal pigment {visual purple} in rod photoreceptors for twilight vision [1877].
He lived 1834 to 1918. Lung receptors signal distension, stop inspiration {Hering-Breuer reflex}, and partly control respiration.
He explained brightness perception, color vision, afterimages, and complementary colors by starting from neutral point and moving in anabolic or catabolic direction {opponent color theory, Hering}. Yellow does not subjectively appear to mix green and red and is stable over intensity changes, so yellow is a primary-color complement. Eye-movement, color-detection, and brightness-detection mechanisms are inborn. People see unique blue, unique green, and unique yellow, because they affect all three cones and, at that wavelength, people perceive no other color mixed in. People do not see unique red, because only two cones affect red.
Brain substance can contain memories, and memory is a material process, because memory survives unconsciousness and sleep.
He lived 1823 to 1915 and studied insect behavior and sense capacities.
He lived 1852 to 1932 and studied pain and touch sensations.
He lived 1886 to 1983. Fish can have color vision and can hear. Special honeybees {scout honeybee} convey information about food-source direction and distance by performing symbolic dances after they return to hive floor. Bee determines direction in reference to Sun or to sky light-polarization angle, detectable by bee compound eye. Dances have a symmetry line, which indicates food-source direction. Dance kinds and speeds indicate food-source distance: slow and round for near and fast, and waggly for far.
He lived 1928 to ?. Living cells rebuild themselves {autopoiesis, Maturana}.
He lived 1924 to ? and studied visual-cortex organization, with David Hubel. Not using eye during critical or sensitive period to detect stimulus feature makes visual cortex unable to detect stimulus feature {sensory deprivation, Wiesel}.
He lived 1926 to ? and studied visual-cortex organization, with Torsten Wiesel. Not using eye during critical or sensitive period to detect stimulus features makes visual cortex unable to detect stimulus features.
Brain detects color in round vertical columns, located 0.5 mm apart in regular arrays between primary-visual-cortex orientation columns, using double-opponent neurons, with both ON-center and OFF-center circular fields, to compare colors. He found blobs by staining primary visual cortex with cytochrome oxidase (CO), with Margaret Livingstone. Interblob regions detect orientation.
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He lived 1956 to ?. Neural activity differs in dreaming, awake, or brain-damaged {activity principle, Koch}. Different animal types can have different neural-activity patterns. Perhaps, some neuron set has same ion channels, shape, receptors, axons, or biochemistry {neuronal correlates of consciousness, Koch}.
He lived 1849 to 1919.
He lived 1744 to 1829 and studied invertebrate paleontology and invertebrate classification. Environment forces animals to acquire new characteristics through learning. What individual experience learns, offspring can inherit {Lamarckianism, Lamarck}. However, Lamarckianism is only true for minor specialized cellular transmittance.
He lived 1731 to 1802.
He lived 1822 to 1878.
He lived 1868 to 1947 and studied invertebrates.
He lived 1877 to 1962 and deep-sea dived.
He lived 1908 to 1996 and studied birds.
He lived 1906 to 1974 and studied mosquitoes.
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Date Modified: 2022.0225