Lecture 24. 1. Two primate traitsA. Grasping hands (opposable thumbs) and feet: - Dispense with craws. - Developed grasping hands and feet that allow us to grip on to limbs of trees, swing from branches, grasp food, and use tool. - Grasping hands are improved by fully opposable thumb. Fold across the palm. Flatten nails.Ex) Tarsier *Carpolestes simpsoni - Early primate-like species.- Grasping digits, opposable big toes- But not binocular vision. Forward facing eyes.B. Binocular vision; having eyes in front of the head: forward facing eyes, for judging the distance and hunting. Cats and birds also haveit.-> it is important for hunting.*Only primate has both!2. Primate lineagesA. Strepsirrhini (wet-nosed): most ancient primnate lineage(1) Lemurs: - A lot of kinds. - Don’t act like other strepsirrhine groups- But some of them are still diurnal. They are highly social in Madagascar; matriarchal social: female dominant and male hierarchy. - Big eyes: incredible vision, - Nocturnal- Long tail for balancing their body. - Herbivorous, adaptive radiation; 99 different species.(2) Loris and PottoB. Haplorrhini (dry-nosed)- The remaining primates out of strepsirrhini are haplorrhines. - Color vision- Complex social systems; live in large group, long parental care period; much longer time for learning; brain developing. They have very large brain size compare to their body size, complex learn behavior; social transmission of knowledge in most of primate lineages- Ex) Tarsier: Behaviorally like strepsirrhini, but genetically it is haplorrhini. C. Platyrrhini (New world monkeys)- Flatten nose. Nostrils at face side way. - Their ancestor moved away from Africa to South America. - Long prehensile tail. - Ex) Emperor tamari (below), Howler monkeyD. Catarrhini (Old world monkeys, Gibbons, Great apes, human): downward pointing nose: closely space between nostrils. Old world monkeys are the outgroup of hominoidea.(1) Old world monkey: - none of them has prehensile tail, but some of them has Noticeable tail - Tough skin pad on their posterior allow them to sit on the rough space for very long period.- ex) rhesus monkey(below), olive baboon.-(2) Hominoidea; apes (Gibbons, Great apes, human): Only five groups now including human. Apes have much larger brain than monkey. a. Asian apes (Gibbons and Orangutans)o Neither species is closely relative to human. o Orangutans: alone among apes and practically alone among the haplorrhini. Tend to live solitarily. Only meet upfor mating. b. African apes (Gorilla, Bonobos, Chimpanzees and human)o Gorilla’s line diverged away from the ancestor to the chimpanzees and human. Bonobos are type of chimpanzees. -> Human and chimpanzees are slightly closer than to gorillas. *Different between apes and hominins line- Locomotion: Homins became pedalar; walking by two legs. Apes develop knuckle walking. Monkey walks with their palms.3. Hominins (direct ancestor to human)- Vertebral columns are more curved.- Spine comes from the base or the skull rather than the back.- Pelvis is broader; sort of ball shaped that pushes the center of gravity out over our legs instead of back.- Hominins diverged from chimpanzees. - * Bipedalism: only traits that distinguish human from other apesA. Ardipithecus- Tree dwelling; arboreal.- Partial skeleton specimen of female; Ardi- Walk on two feet; be bipedal.- However, her feet are not arched; She couldn’t have run or walk for very long distance. B. Australopithecines- The first hominin group we have many fossils from. - All lived together. - Break into two group: Gracile (slender) and robust.(1) Australopithecus: - Gracile/ slender; 18kg and 1m tall - Similar teeth to modern human- Brain is no larger than great apes’ brain. 35% size of modern human. - Sexual dimorphism; up to 50% larger male than female. - Ex) Lucy, Australopithecus afarensis: Short; 3’8’’ tall, 65 lb. morelike chimpanzee than human, However, pelvis, leg, and foot bones are almost identical to modern human. (2) Paranthropus: - Small and height, robust; much bigger and heavier in skull than their australopithecines relatives. - Massive teeth! Smaller brain case than homo species, but lager than Australopithecus. *Orange is species of human.*All members of the genus Homo are called humans.C. Australopithecus sebida: - May be the lineage homo evolved from. - Combination of apes-like and human-like traits. - Tree climbing fingers, long, strong thumbs. - May have evolved from another Australopithecus; A. africanus. D. Homo habilis (handy man)- The first homo species- Larger brain than australopithecines. - Much flatter face in homo species and australopithecines. - Short height, but long arm, first species used tool.E. Homo. Erectus (cave man)- 1.5m tall.- 75 % size of the modern brain; *H.habilis, and H. erecturs, btw them, big change of brain size. - Much more human looking; Round chin-> probably talk- Lived in small group, - Hunted- Cooked with fire - First species to live Africa. - Also can be found in Europe and Asia. ->they can migrate. - Longest lived human species (almost 2 million years). F. H. neandertalensis- Left Africa and arrived in Europe.- Short, stocky, and powerful with comparatively massive skull way bigger than homo. Sapians. - lived in huts and caves - They cared about the wound, ritual for dead, buried body with weapon, or flowers. G. H. sapiens- Much lower degree of sexual dimorphism for size (only 15%). - Parental care in these species. - Dominate around 34,000 Y.A. - Earliest member of our species came from Africa- Complex social organization - Full language capacity- Art; cave painting- Recognizable lifestyles, Basic progression: Ardipithecus Australopithecus Paranthropus (Australopithecus sebida) Homo habilis Homo. Erectus H. neandertalensis H. sapiens4. What happen 34000Y.A? Where did H.neandertalensis go?A. Assimilation hypothesis: H. Sapiens interbred with other groups, so modern human have traits from several ancestors. Similar species can interbreed, and there is only single lineage. B. Out of Africa hypothesis: H. Sapiens was independent of other homo group, so we did not interbreed and replace other group through competition. - Supporting “Out of Africa” hypothesis:o All descending groups share traits found in these early African line.o Three big circles indicate there were three big migration from Africa.o Genetic diversity is highest in Africa and the rest of world have subset of
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