P10-Lecture 23- Hominids -April 5

P10-Lecture 23- Hominids -April 5 - Hominid Evolution A...

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Unformatted text preview: Hominid Evolution A tangled web Primate Origins and Relationships s Primates include x Prosimians 3 Lemurs, etc. "Apes" (traditional) x Anthropoids 3 "Monkeys" 3 "Apes" 3 Us 34.40 Anthropoid origins and Relationships s Chimps and bonobos are our closest relatives x Morphology 3 E.g. Pendulous scrotum x Molecular data 3 Recent s Divergence 6-8 mya Homininae - Our Twig of the Tree s What does it mean to be human? s What makes us distinctive? s Think about this: x Where would you draw the line between human and non-human? Look to our closest living relatives s Humans most closely related to other great apes - closest to chimps (see end of slides) How do we know? x Physical similarities x Protein similarities x DNA similarities x Behavioral similarities s DNA methods s Sequence same stretch of DNA in different species s Determine differences in nucleotide sequences between species s Example, sequence Xq13.3 on X chromosome x Differences: x 0.9% between humans and chimps x 1.4% between humans and gorillas x 2.9% between humans and orangs. Early Hominin Evolution s Australopithecus afarensis: s Includes "Lucy" s Already fully bipedal! x Shared derived character x 3.9 3.0 mya Here's Lucy: Early Hominin Evolution s Australopithecus afarensis s Already fully bipedal: x Upright posture Early Hominin Evolution s Australopithecus afarensis s Already fully bipedal x femur to humerus ratio (like chimp) x Lengthened femur (legs) x Brains small: 400-500 cc Early Hominin Evolution s Australopithecus afarensis s Already fully bipedal: x Laetoli footprint 3.6 mya x Shape of foot 3 No opposable toe see chimp Laoti footprints Tanzania, Africa Early Hominin Evolution s Other Australopithecines x A. africanus 33 to 2.3 mya 3 Brain size about 450 cc 3 Ancestor to Homo ? 3 Perhaps competitor? Early Hominin Evolution See Fig. 34.42 Early Hominin Evolution s Paranthropus robustus group x 2.7-1.0 mya x E.g. P. boisei x "Nutcracker man" x Brain still small (about 500 cc) x A side branch 3 Evolutionary dead end Early Hominin Evolution Paranthropus Paranthropus See Fig. 34.42 Early Hominin Evolution s Early Homo species x Existed about 2.5 mya x E.g. H. habilis Man" 3 "Handy x Larger brain! up to700 cc Early Hominin Evolution See Fig. 34.42 Early Hominin Evolution s Early Homo x E.g. H. habilis x Earliest known Homo species: 3 Tools! 3 Oldawan technology Early Hominin Evolution s The point x Not linear x BIPEDAL, then H. floresiensis large brains 34.42 Hominin Evolution - The middle period Hominin Evolution - The middle period s Homo erectus s 1.8 mya to < 500,000 ya x Long period of overlap with robust australopithecines x May include several species x From Africa throughout southern Asia s Including H. ergaster Hominin Evolution See Fig. 34.42 Hominin Evolution - The middle period s Homo erectus s 1.8 mya to < 500,000 ya s Taller and smarter x Perhaps taller than 6' x Slim x E.g. Turkana boy H. habilis with H. erectus? 3 Linking Hominin Evolution - The middle period s Homo erectus s 1.8 mya to <500,000 ya x Enlarged brain (900 cc + ) Hominin Evolution - The middle period s Homo erectus s 1.8 mya to < 500,000 ya s Much more sophisticated tools 3 Including use of fire From National Geographic, 2004 "Hobbits" 18,000 ya Descended from Homo erectus coming across the sea? Homo floresciensis 3.3 feet tall 55 lbs ~ 30 year-old Female 18,000 years ago Homo floresiensis Hominin Evolution - The later period Homo heidelbergensis Ancient, modern humans s Appear about 700,000 ya x Africa, Europe, later in east Asia s Body and brain size similar to ours x 1100-1400 cc Homo heidelbergensis Ancient, modern humans s Further development of tools s Apparent ancestor of xH. neanderthalensis - Europe xH. sapiens - Africa Homo neanderthalensis So close, and yet ... s Appear by 150,000 ya x Europe, Middle-East, East to Uzbekistan x Heyday 70-30,000 ya x Die out by about 27,000 ya Homo neanderthalensis So close, and yet ... Homo neanderthalensis So close, and yet ... s Appear by 150,000 ya x Europe, Middle-East, East to Uzbekistan x Heyday 70-30,000 ya x Die out by about 27,000 ya Homo neanderthalensis So close, and yet ... s Skulls quite different x Low forehead x Prominent brow Homo neanderthalensis So close, and yet ... s Skulls quite different x Drawn out face x No chin Homo neanderthalensis Would we call them human? s Beautiful tools of limited variety s Language? Unclear. x Little evidence of symbolism x Possible inability to produce some vowels Homo neanderthalensis Would we call them human? s Beautiful tools of limited variety What is human? Compared to our closest living relatives Modern Human s s s Chimp s s s s s s Bipedal, upright walker, NOT a tree swinger Large brain-- 1400 cc Teeth - indication of diet with more meat, more grinding of food that improves nutrition x Small, flat canines x Larger molars; overall smaller teeth x Thick molar enamel x 1st molars at 5-6 yrs Reduced sexual dimorphism Other miscellaneous physical features x "flat" face; Taller, heavier Lifespan longer : ~90-100 yr s s s Knuckle walker or all fours, tree swinger Small brain- 500cc Teeth- more tearing of food, some chewing x Large pointed canines x Thinner enamel x 1st molars at ~3 yrs Striking sexual dimorph Other miscellaneous x Angled face x Smaller Shorter lifespan x ~50 yrs ...
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This note was uploaded on 05/11/2010 for the course BIOLOGY 105 taught by Professor Richard during the Spring '10 term at George Mason.

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