Tracking Human Evolution: Where Do We Fit on the Tree of Life?
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Tracking Human Evolution: Where Do We Fit on the Tree of Life? Geology 230 Fossils and Evolution
Transcript of Tracking Human Evolution: Where Do We Fit on the Tree of Life?
Tracking Human Evolution:Where Do We Fit on the
Tree of Life?
Geology 230
Fossils and Evolution
Crocodiles
hatching from
their amniote
eggs
Pennsylvanian
anapsid or
stem reptile
Amniote Family Tree
Prothero, 2007
Synapsid Skull: one opening behind the orbit (eye)
Diapsid Skull: two openings behind the orbit (eye)
Permian Synapsids, Germany
Triassic synapsid reptiles: Therapsids or
mammal-like reptiles
Therapsida, Mammals and extinct relatives http://tolweb.org/Therapsida/14973
BiarmosuchiaEotitanosuchiaDinocephaliaAnomodontiaTheriodontia
GorgonopsiaTherocephaliaCynodontia
DiviniidaeMammaliaProcynosuchidaeGalesauridaeThrinaxodontidaeCynognathidaegomphodontsChiniquodontidaeProbainognathidaeTritheledontidae (Ictidosauria)
A Gallery of
Therapsids
Carl Buell
From Synapsids to Mammals, a well documented transition series
Prothero, 2007
Prothero, 2007
Multiple bones in the lower jaw of the dino T. rex.
Yanoconodon, Lower Cretaceous Mammal from China
Yanoconodon, Lower Cretaceous of China, retains ear bones attached to inside lower jaw
Morganucodon
Yanoconodon
Human Ear Bones,
or Auditory Ossicles
Cochlea
Class Mammalia - Late Triassic to RecentSuperorder Tricodonta - Late Triassic to Late
CretaceousSuperorder Multituberculata - Late Jurassic to
Early OligoceneSuperorder Monotremata - Early Cretaceous
to RecentSuperorder Metatheria (Marsupials) - Late
Cretaceous to RecentSuperorder Eutheria (Placentals) - Late
Cretaceous to Recent
Evolution of Mammalian Superorders
Eutheria
(Placentals)
Metatheria
(Marsupials)
Live Birth
Mammary Glands?.
.
Monotremes
..
Extinct: U
Mammals in the Age of Dinosaurs
Hadrocodium, a lower Jurassic
mammal with a “large” brain (6 mm
brain case in an 8 mm skull)
Lower Cretaceous mammal from China
Jawbones of a Cretaceous
marsupial from Mongolia
Mammal fossil
from the
Cretaceous of
Mongolia
Repenomamus robustus
fed on psittacosaurs.
Image: Xu Xiaping, 2005
Early
Cretaceous
mammal ate
small
dinosaurs
Repenomamus robustus
Repenomamus robustus
with psittacosaur in the
gut
Modern Elephant Shrew
Weasel hunting
at night
Bats, such as this vampire bat,
hunt at night
Monotremes: Platypus
The Platypus baby
adult
egg
Monotremes: Echidna
The Echidna
Typical
Marsupial, a
Kangaroo
Poorly developed
newborn
kangaroo
attached to a
nipple in the
pouch.
Primate Classification- 1980’s
Order Primates
Suborder Prosimii: tarsiers and lemurs
Suborder Anthropoidea: monkeys, apes, and hominids
Superfamily Hominoidea
Family Pongidae: great apes
Family Hominidae: Homo and hominid ancestors
Primate Classification – 2000’sOrder Primates
Suborder Prosimii: tarsiers and lemurs
Suborder Anthropoidea: monkeys, apes, and
hominids
Superfamily Hominoidea
Family Hominidae: all hominoids
except gibbons
Subfamily Ponginae: orangutans
Subfamily Homininae: gorillas, chimps,
Homo and hominin ancestors
98%
96%
95%
91%
84%
58%
100%% genetic similarity with humans
Prothero, 2007
Tarsiers, a primitive
Primate (Prosimian)
from Southeast Asia.
Tarsier sanctuary, Philippines
A Galago or bush
baby, a primitive
Primate
(Prosimian) from
Africa.
A Slow Loris, a
primitive Primate
(Prosimian) from
Southeast Asia.
Check out the
fingers.
Monkeys, such as baboons, have tails
and are not hominoids.
Proconsul, the oldest hominoid, 18 MY
Hominoids
The Orangutan, a Great Ape from Southeast Asia.
Gorillas, Great Apes from Africa.
Chimpanzees, Great Apes from Africa.
I’m cool
Neoteny in Human Evolution. Humans
resemble baby apes more than adult
apes. Humans are said to be
paedomorphic.
Chimp skull on the left, human skull on the right
Chimp
Homo sapiens
Consequences of Neoteny
• Large brain and cranium
• Small jaws and teeth with small face
• Retention of juvenile growth patterns
• Long juvenile period = extended learning
• Retardation of onset of puberty
• Longer life span
• Naked skin
Next: The Hominid Fossil Record
