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Primate Evolution3 November, 2009
Time, time, time….
Earth’s origin
Origin oflife
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 Molecular- protein/DNA
Class- MammaliaDerived from a branch of the reptiles- the therapsids
~200 M ybp
Mammals Hair, mammary glands Anatomy
One jaw bone
3 middle ear bones
Specific arterial
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 Some form of connection between mother and
fetus= “placenta”
Two parallel lineages:Marsupial mammals- kangaroo, wallaby, opossum
Eutheria- live bearing, placental mammals
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)
~60 M ybpMammalian “explosion” of diversity
Including- Primates (taxonomic Order) Tree-dwelling Omnivorous Branchiate- swing by arms Dexterous hands Claws replaced by nails Opposable thumb Forward-facing eyes, binocular vision Parental care
~ 58 M ybpAncestral Primate
“Wet-nosed” primates• Mostly nocturnal• Tree-dwelling
Lemurs
“Dry-nosed” primates• Mostly diurnal• Specialized hands and
feet for graspingTarsiers + Monkeys & Apes (a.k.a. “Simians”)First- cat-sized and arboreal
~ 40 M ybpAncestral Simian
New-World MonkeysN/S America
• Long prehensile tail• Flat nose• Tree-dwelling• Mostly nocturnal
Capuchin, Marmosets, Howler monkey
Old-World Monkeys + othersAfrica & Asia
• Simple, no tail• Narrow nose• Tree-dwelling• Mostly diurnal• Flat fingernails
Baboon, Macaque, Great Apes
Atlantic Ocean
~ 25 M ybpAncestral Old World Monkeys, et al
Old-World MonkeysBaboon, Macaque, Proboscis Monkey
(Apes) “Hominoids”• Mostly arboreal• Africa, Asia• Other anatomical
featuresGibbon, Great Apes
~ 18 M ybpAncestral Hominoids
“Lesser Apes”• Tree-dwelling• Strong brachiating
Gibbons
The “Hominidae”Humans +Great Apes
The “Hominidae”
The “Hominidae”The “Hominidae”
OrangutansAsia
~ 14 M ybp
Sivapithecus (Ramipethecus)- fossil~ 14 M ybpInitially thought to be an early “homininae”
The “Homininae”Evolved in Africa:Gorilla, Chimp, Pygmy Chimp, Human
The “Homininae”The “Homininae”
~ 7 M ybp
Gorillas2 (4?) species
• Knuckle-walk• Intelligent
Western & Eastern species (w/ subspecies)
The “Hominini”Humans, Chimpanzee, Pygmy Chimpanzee (Bonobo)
The “Hominini”
The “Hominini”
6- 7 M ybp
Molecular evidence- “Molecular clocks” Antibody specificity DNA hybridization
ChimpanzeeLarger, stockierMore aggressiveMale-dominated social groups
BonoboGracileMore cooperative, more sexualFemale-dominated Social groups
The “Hominids”Humans + fossils leading to modern humans
The “Hominids”
Bipedal
Large brain
Small canine
teeth
Later: Tool production Language Art
Importance of A. afarensis &“Once we were not alone”
“Robust” lineages
“Gracile” lineages
BG
G
A
F D
Chimp Gorilla
Two major historical mass migrations; including the recent “out of Africa”
Homo sapiens as the “wanderer”The “out of Africa” theory
Years before present (byp)
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