primate evolution 5 november, 2007. time, time, time…. earth’s origin origin of life
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Primate EvolutionPrimate Evolution5 November, 20075 November, 2007
Time, time, time….Time, time, time….
Earth’s origin
Origin oflife
ThemesThemes
Bush analogy (vs. ladder)Bush analogy (vs. ladder)
““Extinction is the rule”Extinction is the rule”
Incompleteness of the fossil recordIncompleteness of the fossil record
““Once we were not alone”Once we were not alone”
The nature of the evidenceThe nature of the evidence FossilsFossils Molecular- protein/DNAMolecular- protein/DNA
Class- MammaliaClass- MammaliaDerived from a branch of the reptiles- the Derived from a branch of the reptiles- the therapsidstherapsids
~200 M ybp~200 M ybp
Class- MammaliaClass- MammaliaCharacteristicsCharacteristics HairHair 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 Lots of unique anatomical features (1 aorta, 3
middle ear bones, one jaw bone (dentary), etc…)middle ear bones, one jaw bone (dentary), etc…)
Mammals, continued…Mammals, continued… AnatomyAnatomy
One jaw boneOne jaw bone
3 middle ear bones3 middle ear bones
Specific arterial Specific arterial
structuresstructures
Initially small, rat-like, nocturnal insect Initially small, rat-like, nocturnal insect eaterseaters
Earliest MammalsEarliest Mammals
Modern descendents- platypus (of Modern descendents- platypus (of Australia) & echidna (of New Zealand)Australia) & echidna (of New Zealand)
““Advanced” Mammals- Advanced” Mammals- the “Placentals”the “Placentals”
~ 100 M ybp- “Age of the Dinosaurs” ~ 100 M ybp- “Age of the Dinosaurs” (Cretaceous era)(Cretaceous era)
(older fossil?- ~ 130 M ybp, 1 meter in (older fossil?- ~ 130 M ybp, 1 meter in length)length)
““Live bearing mammals”Live bearing mammals” Internal developmentInternal development Some form of connection between mother and Some form of connection between mother and
fetus= “placenta”fetus= “placenta”
Two parallel lineages:Two parallel lineages:Marsupial mammals- kangaroo, wallaby, Marsupial mammals- kangaroo, wallaby, opossumopossum Young “born” only partially developedYoung “born” only partially developed No eggs- internal (initial) development- No eggs- internal (initial) development-
rudimentary placentarudimentary placenta Well-developed nipples- young attach to Well-developed nipples- young attach to
complete developmentcomplete development
Live bearing MammalsLive bearing Mammals““Eutheria”Eutheria” True placentaTrue placenta Offspring spend longer developing in motherOffspring spend longer developing in mother
The reality of the situation at The reality of the situation at ~ 65 M ybp~ 65 M ybp
Mammals (monotremes, marsupials & Mammals (monotremes, marsupials & eutherians) were all a very small part of eutherians) were all a very small part of animal diversityanimal diversity
Eutherians represented by a very small Eutherians represented by a very small number of small, nocturnal, shrew-like number of small, nocturnal, shrew-like animalsanimals
The “K/T Boundary” (cretaceous/tertiary)The “K/T Boundary” (cretaceous/tertiary)
The reality of the situation at The reality of the situation at ~ 65 M ybp~ 65 M ybp
The “K/T Boundary” (cretaceous/tertiary)- one of many The “K/T Boundary” (cretaceous/tertiary)- one of many historical “Mass extinctions” (many living groups, historical “Mass extinctions” (many living groups, including the dinosaurs)including the dinosaurs)
Mammalian diversificationMammalian diversification
Explosive diversity of mammalian types in Explosive diversity of mammalian types in “vacuum” of rapid dinosaur extinctions- “vacuum” of rapid dinosaur extinctions- especially eutheriansespecially eutherians
~60 M ybp~60 M ybpPrimates (taxonomic Order)Primates (taxonomic Order) Tree-dwellingTree-dwelling OmnivorousOmnivorous Branchiate- swing by armsBranchiate- swing by arms Dexterous handsDexterous hands Claws replaced by nailsClaws replaced by nails Opposable thumbOpposable thumb Forward-facing eyes, binocular visionForward-facing eyes, binocular vision Parental careParental care
~ 58 M ybp~ 58 M ybpAncestral 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~ 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 ybp~ 25 M ybpAncestral Old World Monkeys, et al
Old-World MonkeysBaboon, Macaque, Proboscis Monkey
(Apes) “Hominoids”• Mostly arboreal• Africa, Asia• Other anatomical features
Gibbon, Great Apes
~ 18 M ybp~ 18 M ybpAncestral Hominoids
“Lesser Apes”• Tree-dwelling• Strong brachiating
Gibbons
The “Hominidae”Humans +Great Apes
The “Hominidae”The “Hominidae”
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”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”The “Hominids”
BipedalBipedal
Large brainLarge brain
Small canine Small canine
teethteeth
Later:Later: Tool productionTool production LanguageLanguage ArtArt
BREAK TIMEBREAK TIME
D
F
GE
B
A
Raymond Dart- 1924Raymond Dart- 1924Australopithecus africanusAustralopithecus africanus
Donald JohansenDonald JohansenAustralopithecus afarensisAustralopithecus afarensis
1994-1994-East Africa & ChadEast Africa & Chad
Importance of Importance of A. afarensisA. afarensis
“Robust” lineages
“Gracile” lineages
““Once we were not alone”Once we were not alone”
Chimp Gorilla
CD
G
B
E
Homo sapiensHomo sapiens as the “wanderer” as the “wanderer”The “out of Africa” theoryThe “out of Africa” theory
Years before present (byp)