Hominins {hominin}| (Homininae) vary from anthropoid apes (great apes) (hominids) (Hominidae) in locomotion, hands, tools, sight, sociability, and language.
evolution
Hominins differentiated from Pan ancestors six million years ago.
habitat
Australopithecus lived in savannas, rather than forests, and used more animal food than apes. Perhaps, necessity to eat seeds and nuts aided hand evolution. Hominins developed environments, with more energy available for brain maintenance. Free-ranging energetic environments and multiply skilled bodies allowed energy-intensive cortex to vary, grow, and integrate senses.
anatomy: tailless
Hominins had no tail, allowing more variations in intercourse position, sitting, and spinal shape.
anatomy: face
Hominins have nosebridges and nose tips, jutting chins, short canine teeth, and lips with median furrow that rolls outward.
anatomy: arm
Hominins have shorter arms than great apes and throw accurately.
anatomy: foot
Hominins have feet that arch across and lengthwise. They do not have opposed big toes.
anatomy: hair
Hominins are relatively hairless.
anatomy: posture
Hominins have erect posture.
reproduction
Hominins mature sexually earlier than other great apes, as measured by teeth eruption.
senses
Sense integration allows tracking individuals that are not present, mapping environments, and remembering.
nervous system
Brains were two to three times bigger than great-ape brains.
communication
Hominins blend the dozen meaningful ape sounds to produce new sounds related to objects far away in time or place. They possibly use nouns, verbs, and modifiers with simple syntax. They recall memories.
communication: larynx
Larynx became lower and opened throat space {supralaryngeal space}, which allows more speech sounds.
Varied and separated habitats isolated four hominin species {Australopithecus} {australopithecenes}: first Australopithecus afarensis, then gracile Australopithecus africanus, robust Australopithecus robustus, and robust Australopithecus boisei.
habitat
Australopithecus lived on ground in woodlands and savannas. Perhaps, it slept in trees or cliffs.
digestion
Australopithecus ate vegetables and later meat and had ape-like dentition.
behavior
Australopithecus foraged.
tools
Australopithecus used pumice flakes and stone choppers as rooting tools.
arm
Australopithecus had large hands, long fingers, and short arms.
walking
Australopithecus was bipedal, had short stride, ran slowly, and had no knuckle walking.
development
Maturation time was short.
brain
Brain was one-third modern human size.
Early hominins {Australopithecus afarensis} were gracile, weighed 35 kilograms, and were one meter tall.
evolution
Australopithecus afarensis came from Australopithecus anamensis and was Australopithecus-gahri ancestor.
tools
Australopithecus afarensis used pebble tools.
climbing
Australopithecus afarensis had climbing adaptations in fingers, hands, wrists, elbows, and shoulders, with long arms and short legs.
walking
Australopithecus afarensis was bipedal with full striding gait, putting body weight over one leg while other leg moved. It had arched feet and non-opposable big toes, like modern human feet. It had knee valgus angle. It had great pelvic width. Perhaps, width was for pelvic rotation in walking. It had short, broad, backward, extended, iliac blades.
hand
Australopithecus afarensis had shorter thumbs.
society
Perhaps, Australopithecus afarensis had large kin-related and many-male groups, with some non-kin females.
digestion
Australopithecus afarensis had large and flat cheek teeth, suggesting fruit and leaf diet.
face
Australopithecus afarensis had big faces.
brain
Australopithecus afarensis had 400-cc brains, with 3.1 encephalization quotient. It had forward-placed and downward-directed foramen magnum, indicating head was upright on spine. Bipedalism led to an enlarged occipital-marginal-sinus system, which forced new blood hydrostatic pressures on vertebral venous plexus.
Second Australopithecus {Australopithecus africanus} [first found 1924] was gracile, weighed 35 kilograms, and was four feet tall.
evolution
Australopithecus africanus came from Australopithecus anamensis and was Australopithecus-robustus ancestor.
habitat
Australopithecus africanus lived in grasslands, not forests, and probably lived in one place for long periods. Perhaps, it used windbreaks.
hunting
Australopithecus africanus hunted animals, ate raw meat, cut skins, smashed bones, and took meat home.
tools
Australopithecus africanus selected stones, carried them home, and chipped to make hand-held choppers.
hand
Australopithecus africanus had flattened fingertips.
spine
S-shaped spines, with two curves, allowed more back flexibility and so more upright walking, more erect posture, faster running, and better balance. Upright posture allowed wider and farther vision.
digestion
Australopithecus africanus had no canine teeth and lean jaws, like humans, reflecting different diet.
brain
Australopithecus africanus had low skulls, with 500-cc to 800-cc brains. Many anastomotic channels with emissary veins near foramen magnum take blood to vertebral venous plexus. Perhaps, expanded neocortex frontal lobes allowed improved memory, spatial orientation, temporal orientation, and multisensory abilities.
Paranthropus hominins {Australopithecus robustus} (Paranthropus robustus) were not on human line, were 45 kilograms, were heavyset, and were vegetarian. Paranthropus robustus came from Australopithecus africanus. Perhaps, Australopithecus aethiopicus preceded it. Brain was 500 cc.
Paranthropus hominins {Australopithecus boisei} (Paranthropus boisei) were not on human line, were robust, weighed 50 kilograms, and lived in east Africa. Paranthropus had vegetarian diets, as shown by dentition and face. Brain was 500 cc to 530 cc.
Humans {Homo} {human} are vertebrates, mammals, and primates and share their fundamental behaviors.
evolution
Humans evolved from australopithecines. Strong sexual selection, complex social lives, changing environments, cultural effects, social contacts, increased population density, agriculture, food surpluses, and wars emphasize aggression, fitness, and intelligence. Humans evolved faster than apes. Humans evolved through pedomorphism, accounting for greater brain size, because children have relatively bigger brains.
evolution: environment
Early humans had direct competition with similar species and had predators.
development
Human life span is as expected for great apes with human size and brain.
behavior: hand
Hands have opposing thumbs and many available grips. Humans can gesture.
behavior: walking
Humans walk upright on strong legs. Upright walking requires mechanisms for balance, allows farther vision and greater lateral vision, requires learning gait, allows wider territory and means of sharing territory, and allows hand, foot, arm, and leg differentiation.
behavior: society
Humans live in organized groups. They have faces and know facial expression meaning. They perceive others' needs and desires. They know action effects on others. They react to others' behaviors and communications. They can have rapport. They can influence. They kiss.
behavior: language
Human language probably developed from graded primate vocalizations. Humans can pronounce 40 phonemes. They use voice modulation. They express feelings. Speech depends on upright posture, which allows tongue-position shifts and pharyngeal-tract lengthening. Humans use symbolic thought and language to plan and form strategies. Memories allow using and transmitting past knowledge. Humans have music.
senses
Humans use sight as dominant sense.
brain
In evolving to humans, supragranular layer became upper three cortical layers, middle layer thickened, subgranular layer divided into lower two layers, and secondary and tertiary sulci had increased associational areas.
handedness
Right-handedness first appeared in Lower Old Stone Age, when tool making became common. Starting 300,000 years ago, humans probably had cerebral dominance, because skulls are asymmetric and people inherit brain and skull shape. Human skulls mold to brains. Right-handers typically support and orient objects in left hand, without using visual feedback, and perform fine movements with right fingers, using visual feedback. Most people use right hand for gesticulation.
handedness: abilities
Performance by right-handers and left-handers is equal on all tasks. No special ability or disability distinguishes left-handers.
handedness: factors
Handedness inherits. Social pressures or early experience, especially with objects designed for right-handers, affects handedness. Brain damage before or after birth can shift cerebral dominance or prevent hemispheric specialization. Subnormal and epileptic people have more left-handedness.
handedness: anatomy
In right-handers, left cerebral hemisphere has sense and motor connections to both body sides, and right hemisphere connects to only one side. In left-handers, cerebral lateralization is less. In right-handers, left side has fewer skills, poorer timing and coordination, more variability, and more frequent and slower corrections.
handedness: ratio
Left-handers are 4% to 36% of people in different races and cultures.
handedness: mammals
Mammals besides humans show paw preferences but equally to left or right.
First humans {Homo habilis} split from Australopithecus.
size
Homo habilis was 1.35 to 1.5 meters tall and weighed 50 kilograms.
culture
Homo habilis formed Lower-Paleolithic Oldowan Culture. Perhaps, it had labor division, cooperation, and reciprocity.
culture: tools
Homo habilis chipped sharp flakes from larger stone cores. Perhaps, it carved wood tools.
digestion
Homo habilis ate plants and meat.
hunting
Perhaps, Homo habilis scavenged, hunted, and had food sharing.
body
Homo habilis had curved finger bones, long arms, short legs, and modified pelvic and leg bones.
walking
Upright walking on arched feet allowed better running, jumping, balance, and flexibility.
reproduction
No estrus in females allowed continuous sexual receptivity. Intervals between births are shorter for humans than for great apes.
skin
Few body hairs allowed skin sensitivity.
head
Homo habilis had post-orbital septum and thin brow ridges. Skull back was round.
brain
Large left-brain Broca's motor speech area indicates speech. Advanced vocal cords and brain language areas allowed better communication. Bigger frontal and parietal lobes were in 700-cc brains, with 4.0 encephalization quotient. Brain had sulci and gyrus patterns like Homo sapiens. Two more cell layers in neocortex increased processing complexity and information distribution.
senses
Homo habilis had reduced smell sense and integrated senses.
Early African Homo erectus hunter-gatherers {Homo ergaster} ate meat. Homo ergaster weighed three times more and was two times taller than Australopithecus. Homo ergaster came from Homo habilis.
Early Homo species {Homo erectus} was 1.65 meters tall.
evolution
Homo erectus came from Homo habilis and was ancestor of Homo floresiensis and archaic Homo sapiens.
anatomy: body
Homo erectus had narrow bowl-shaped pelvis and conical thorax. Homo sapiens has barrel shaped thorax.
anatomy: head
Homo erectus had heavy eyebrows, no chins, big jaws, and low skulls. Extra bone was on skull midline {sagittal keel}.
anatomy: senses
Homo erectus had sense organs like modern humans. Skull indents behind eyes, so eye sockets protrude.
anatomy: brain
Brains were 1000 cc, two-thirds of modern brains, with six-layer brain cortex, specialized right and left brain hemispheres, and association areas. Encephalization quotient was 5.5.
anatomy: teeth
Perhaps, Homo erectus gripped and tore using front teeth by prognathism.
anatomy: hand
Homo erectus held fingers to palm and had precision grips.
anatomy: arm
Homo erectus had large femoral heads like Homo sapiens.
anatomy: leg
Arched feet allowed better running and jumping, better balance, and more flexible movements. Arched feet had no grasping.
anatomy: sexual dimorphism
Male and female body sizes were more equal than in Homo habilis.
walking
Homo erectus walked fully erect.
reproduction
Homo erectus had sexual intercourse but no longer had estrus, so females were always sexually ready.
development
Babies were immature at birth, like Homo sapiens.
culture
Homo erectus had Acheulean culture of Lower Paleolithic. Groups with social organization lived in caves or later wood or bone houses and had territories. Homo erectus had birth rituals, long childhood with rites of passage to adulthood, and courtship rituals.
culture: communication
Homo erectus signaled and used simple speech. It planned for events far away in space and time. It realized world of individual things and people existed.
culture: fire
Starting 200,000 years ago, Homo erectus used fire for warming, lighting, scaring animals out of caves, hunting, hardening wood, cooking plants, cooking bones for marrow, and building community. It had specialized fire builders.
culture: tools
Homo erectus used flaked stone tools, chipped hand axes from large stone cores [-1500000], and had stone symmetrical hand axes with two sides [-750000]. Homo erectus carved wooden spears and wooden bowls.
culture: hunting
Homo erectus killed large animals, coordinated hunts, and gathered foods. Savanna had enough food to support two people per square mile. Hunting societies had one leader. Males were hunters and dominated life. Male friendship developed. Females did domestic work. Perhaps, aquatic societies lived on fish and shellfish, shared among all, had no leader, and lived near oceans or fresh water.
Homo erectus possibly used gripping and tearing by front teeth {prognathism}.
Archaic Homo sapiens {Homo heidelbergensis} came from Homo erectus. Homo heidelbergensis had larger brains, flatter faces, and smaller brow ridges. It invented prepared-core technique.
Neanderthals {Homo neanderthalensis} were strong.
evolution
Neanderthals came from archaic Homo sapiens [-700000 to -500000]. They became extinct [-35000]. They are not human ancestors, because Neanderthal mitochondrial DNA is not like Homo-sapiens mitochondrial DNA (Svante Pääbo), though genomes are 99.5 percent the same. Interbreeding among humans and Neanderthals stopped by 370,000 years ago.
posture
Neanderthals had same postures and body movements as Homo sapiens.
body
Neanderthals had barrel chests and short and large limb bones.
head
Neanderthals had reduced skull thickness, low skulls, no chins, broad noses, heavy jaws, low and sloped foreheads, and heavy arched brow ridges.
teeth
Neanderthals had human teeth, which they used as clamps or vises.
handedness
Neanderthals had handedness.
brain
Brain was 900 cc to 1100 cc, with expanded parietal lobes. Special brain language areas were on left side, with right-left brain asymmetry.
language
Neanderthals spoke. Perhaps, Neanderthal throat anatomy inhibited good speech.
walking
Neanderthals walked erect.
habitat
Neanderthals lived in caves in cold climates.
culture
Neanderthals had Upper or Late Acheulian Culture of Lower Paleolithic and Mousterian Culture of Middle Paleolithic. They had customs and laws for societies.
culture: hunting
Neanderthals were big-game hunters, used wood spears with fire-hardened points [-50000], used flint weapons, and wore animal skins.
culture: fire
Neanderthals used fire [-500000] in Zhoukoudian cave in north China and had hearths.
culture: burial
Neanderthals buried the dead [-100000].
culture: painting
Neanderthals gathered red ocher.
Advanced humans {Homo sapiens} probably began in Africa 100,000 to 200,000 years ago. African and non-African Homo sapiens then diverged.
habitat
Early Homo sapiens lived in caves.
brain
Early Homo sapiens had brains the same size as now, with 7.6 encephalization quotient. It had new associational-cortex and frontal-lobe development. It had consciousness.
culture: tools
Early Homo sapiens used chipped stone tools and built tools to make tools.
culture: language
Early Homo sapiens probably spoke and knew symbols and language.
culture: clothing
Early Homo sapiens wore clothing.
culture: fire
Homo sapiens used sustained fire [-40000].
culture: domestication
Homo sapiens domesticated plants and animals [-8000]. Homo sapiens used medicinal herbs in Iraq [-8000].
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Date Modified: 2022.0225