Primate Evolution 5 November, 2007

Time, time, time…. Earth’s origin Origin of life

Themes Bush analogy (vs. ladder) “Extinction is the rule” Incompleteness of the fossil record “Once we were not alone” The nature of the evidence Fossils Fossils Molecular- protein/DNA Molecular- protein/DNA

Class- Mammalia Derived from a branch of the reptiles- the therapsids ~200 M ybp

Class- Mammalia Characteristics Hair Hair Mammary Glands (w/ or w/o nipples) Mammary Glands (w/ or w/o nipples) “Warm blooded” “Warm blooded” Egg layers- earliest form= “monotremes” Egg layers- earliest form= “monotremes” Lots of unique anatomical features (1 aorta, 3 middle ear bones, one jaw bone (dentary), etc…) Lots of unique anatomical features (1 aorta, 3 middle ear bones, one jaw bone (dentary), etc…)

Mammals, continued… Anatomy Anatomy One jaw bone 3 middle ear bones Specific arterial structures structures Initially small, rat-like, nocturnal insect eaters

Earliest Mammals Modern descendents- platypus (of Australia) & echidna (of New Zealand)

“Advanced” Mammals- the “Placentals” ~ 100 M ybp- “Age of the Dinosaurs” (Cretaceous era) (older fossil?- ~ 130 M ybp, 1 meter in length) “Live bearing mammals” Internal development Internal development Some form of connection between mother and fetus= “placenta” Some form of connection between mother and fetus= “placenta”

Two parallel lineages: Marsupial mammals- kangaroo, wallaby, opossum Young “born” only partially developed Young “born” only partially developed No eggs- internal (initial) development- rudimentary placenta No eggs- internal (initial) development- rudimentary placenta Well-developed nipples- young attach to complete development Well-developed nipples- young attach to complete development

Live bearing Mammals “Eutheria” True placenta True placenta Offspring spend longer developing in mother Offspring spend longer developing in mother

The reality of the situation at ~ 65 M ybp Mammals (monotremes, marsupials & eutherians) were all a very small part of animal diversity Eutherians represented by a very small number of small, nocturnal, shrew-like animals The “K/T Boundary” (cretaceous/tertiary)

The reality of the situation at ~ 65 M ybp The “K/T Boundary” (cretaceous/tertiary)- one of many historical “Mass extinctions” (many living groups, including the dinosaurs)

Mammalian diversification Explosive diversity of mammalian types in “vacuum” of rapid dinosaur extinctions- especially eutherians

~60 M ybp Primates (taxonomic Order) Tree-dwelling Tree-dwelling Omnivorous Omnivorous Branchiate- swing by arms Branchiate- swing by arms Dexterous hands Dexterous hands Claws replaced by nails Claws replaced by nails Opposable thumb Opposable thumb Forward-facing eyes, binocular vision Forward-facing eyes, binocular vision Parental care Parental care

~ 58 M ybp Ancestral Primate “Wet-nosed” primates Mostly nocturnal Tree-dwelling Lemurs “Dry-nosed” primates Mostly diurnal Specialized hands and feet for grasping Tarsiers + Monkeys & Apes (a.k.a. “Simians”) First- cat-sized and arboreal

~ 40 M ybp Ancestral Simian New-World Monkeys N/S America Long prehensile tail Flat nose Tree-dwelling Mostly nocturnal Capuchin, Marmosets, Howler monkey Old-World Monkeys + others Africa & Asia Simple, no tail Narrow nose Tree-dwelling Mostly diurnal Flat fingernails Baboon, Macaque, Great Apes Atlantic Ocean

~ 25 M ybp Ancestral Old World Monkeys, et al Old-World Monkeys Baboon, Macaque, Proboscis Monkey (Apes) “Hominoids” Mostly arboreal Africa, Asia Other anatomical features Gibbon, Great Apes

~ 18 M ybp Ancestral Hominoids “Lesser Apes” Tree-dwelling Strong brachiating Gibbons The “Hominidae” Humans +Great Apes

The “Hominidae”

Orangutans Asia ~ 14 M ybp Sivapithecus (Ramipethecus)- fossil ~ 14 M ybp Initially thought to be an early “homininae” The “Homininae” Evolved in Africa: Gorilla, Chimp, Pygmy Chimp, Human

The “Homininae” ~ 7 M ybp Gorillas 2 (4?) species Knuckle-walk Intelligent Western & Eastern species (w/ subspecies) The “Hominini” Humans, Chimpanzee, Pygmy Chimpanzee (Bonobo)

The “Hominini” 6- 7 M ybp Molecular evidence- “Molecular clocks” Antibody specificity DNA hybridization Chimpanzee Larger, stockier More aggressive Male-dominated social groups Bonobo Gracile More cooperative, more sexual Female-dominated Social groups The “Hominids” Humans + fossils leading to modern humans

The “Hominids” Bipedal Large brain Small canine teeth teethLater: Tool production Tool production Language Language Art Art

BREAK TIME

D F G E B A

Raymond Dart Australopithecus africanus

Donald Johansen Australopithecus afarensis

1994- East Africa & Chad

Importance of A. afarensis “Robust” lineages “Gracile” lineages

“Once we were not alone”

ChimpGorilla CD G B E

Homo sapiens as the “wanderer” The “out of Africa” theory Years before present (byp)