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Mammals
Figure 23.48
Phylogeny of Amniotes
•  Amniotes
–  Finish Reptiles & Birds
–  Synapsid clade gave rise to
mammals
•  Major groups of mammals
•  Primates and Human evolution
April 7, 2017
Birds are the only surviving Dinosaurs
The Origin of Birds
Toothed beak
Wing claw
Early feathers might have
evolved for insulation,
camouflage, or courtship display
Airfoil wing
with contour
feathers
Dinosaur tail with feathers
Long tail with
many vertebrae
Derived Characters of Birds
Finger 1
(b) Bone structure
Palm
Finger 2
(a) Wing
Forearm
Shaft
Vane
Wrist
Finger 3
Shaft
Barb
Barbule
Hook
(c) Feather structure
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Figure 34.UN09
Cephalochordata
Urochordata
Myxini
Petromyzontida
Chondrichthyes
Actinopterygii
Actinistia
Dipnoi
Amphibia
Reptilia
Mammalia Mammals
Figure 23.53 Mammalian Diversity
ANCESTRAL
MAMMAL
3 major clades of
Mammals
Eutherians
(5,010 species)
Therians
Monotremes Marsupials
(324 species)
(5 species)
Prototherians
Which mammalian
orders are closest to
humans?
Prototherians (Monotremes)
Monotremata
Marsupialia
Proboscidea
Sirenia
Tubulidentata
Hyracoidea
Afrosoricida
Macroscelidea
Xenarthra
Rodentia
Lagomorpha
Primates
Dermoptera
Scandentia
Carnivora
Cetartiodactyla
Perissodactyla
Chiroptera
Eulipotyphia
Pholidota
Marsupials
(a) A young brushtail possum
(b) Long-nosed bandicoot
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Eutherians
•  In Australia, convergent
evolution has resulted in a
diversity of marsupials that
resemble the eutherians in
other parts of the world
Eutherian
mammals
Marsupial
mammals
Plantigale
Deer mouse
Mole
Marsupial mole
Sugar glider Flying
squirrel
Wombat
Woodchuck
Wolverine
Tasmanian devil
Kangaroo
Patagonian cavy
Figure 23.54 Phylogeny of the Primates
Diversification
of Primates
Figure 34.46
•  Misconception: Human evolution is like a ladder
leading directly to Homo sapiens
–  Correction: Hominin evolution included many
branches or coexisting species, though only
humans survive today
0.5
Homo
Homo
neanderthalensis sapiens
Homo
ergaster
?
Paranthropus
boisei
1.0
Australopithecus
africanus
1.5
Millions of years ago
–  Correction: Hominins and chimpanzees shared
a common ancestor
Paranthropus
robustus
0
•  Misconception: Early hominins were
chimpanzees
2.0
2.5
Kenyanthropus
platyops
Australopithecus
garhi
Australo3.0 pithecus
anamensis
3.5
Homo
habilis
4.0
4.5
Australopithecus
afarensis
5.0
5.5
6.0
6.5
7.0
Homo erectus
Homo
rudolfensis
Ardipithecus ramidus
Orrorin tugensis
Sahelanthropus
tchadensis
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Figure 34.45
(a) Gibbon
(b) Orangutan
Figure 23.56 Neoteny in the
Evolution of Humans
(c) Gorilla
(d) Chimpanzees
(e) Bonobos
4