Wrapping up

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Wrapping up

• Cenozoic
• Life

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Life in the Cenozoic

• Animals
• Expansion of Mammals
• Hominids
• Plants
• Flowering Plants Rule
• Grasses
• Hominids

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Paleogene Life

• Recovery from Cretaceous extinctions
• Modern life forms
• New animals
• Whales
• Sharks

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Paleogene Life

• Sandy coasts offer new niches
• Sand dollars evolved from sea biscuits
• Flowering plants expanded
• Grasses originated

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Paleogene Life

• Mammals diversified
• Most modern orders present by Early Eocene

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Paleogene Life

• Bats present by early Eocene

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Paleogene Life

• Primates evolved in Paleocene
• Climbing by Early Eocene

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Paleogene Life

• Mammalian carnivores evolved by mid-Paleogene

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Paleogene Life

• Earliest horses by end of Paleocene
• Size of small dogs

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This small dog-sized animal is the oldest found
horse ancestor that lived about 55 mya. It had a
primitive short face and eye sockets in the
middle. Although it has low-crowned teeth, we see
the beginnings of the characteristic horse-like
ridges on the molars.
The earliest evidence of this little horse is
found in the middle Eocene of Wyoming, about 2
million years after the first appearance of
Hyracotherium.
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The Mesohippus, "middle horse, is intermediate
between the eohippus-like horses of the Eocene,
(which don't look much like our familiar "horse")
and more "modern" horses. Fossils of Mesohippus
are Oligocene age.
Species of Miohippus gave rise to the first burst
of diversity in the horse family. Until
Miohippus, there were few side branches, but the
descendants of Miohippus were numerous and
distinct. During the Miocene, over a dozen
genera existed.
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Parahippus appears to be the evolutionary link
between the old forest-dwelling horses and the
modern plains-dwelling grazers. It has 3 toes,
like primitive horses, but the side toes are
smaller. They are "horse-faced," or long-headed
with the eye socket well back from the middle of
the skull.
Merychippus represents a milestone in the
evolution of horses. It retained the primitive
character of 3 toes, but looked like a modern
horse. Merychippus had a long face and long
legs. It had high-crowned cheek teeth, making
it the first known grazing horse and the ancestor
of all later horse lineages. 
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"Grandfather" to the modern horse, Pliohippus
appears to be the source of the latest radiation
in the horse family. It is believed to have
given rise to Hippidion and Onohippidion, genera
that thrived for a time in South American, and to
Dinohippus which in turn led to Equus.
Dinohippus is believed to be the closest relative
to Equus, the genus that includes the living
horses, asses and zebras. 
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Equus is the only surviving genus in the once
diverse family of horses. Domesticated about
3,000 years ago, the horse had a profound impact
on human history in areas such as migration,
farming, warfare, sport, communication, and
travel.  Species of Equus lived from 5 million
years ago until the present. Living species
include horses, asses, and zebras.
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(a) shows Hyracotherium, from 55 mya.
(b) shows Miohippus, from 35 mya. (c)
shows Merychippus, from 17 mya. (d)
shows Equus, the modern horse, with its single
hoof.
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(e) is the foot at 6 weeks. Note, there are three
toes. (f) is the foot at 8 weeks. The
middle toe now dominates. (g) is the
foot at 5 months. The middle toe is now the hoof.

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Paleogene Life

• Mammalian species doubled
• Ungulates
• Odd-toed
• Horses, tapirs, rhinos
• Even-toed
• Cloven-hoofed goats, sheep, pigs, cattle

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Paleogene Life

• Early Eocene elephants
• Moeritherium
• Earliest
• Pig sized

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PALAEOMASTODON. Are known only from Late Eocene
(40 mya) Northern Africa. One of most ancient
Proboscidea,a beginning to families Gomphotheria
and Mastodontidae.
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AMEBELODON. Amebelodon - the genus of mastodon
belonging to family Gomrhotheriidae, was usual in
Northern America in Late Miocene. Top tusks were
small. Probably bottom tusks were large and used
to dig out roots of plants.
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PLATIBELEDON. Fossil remains of platibelodon were
found for the first time in 1920 in Miocene
deposits ( 20 mya) in Asia. In the mandibule,
the tusk like spade, excellently adapted to
extraction of water and marsh vegetation.
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FIST ELEPHANT (PRIMELEPHAS). The most primitive
representative of family is Primelephas, which
probably is a direct ancestor of mammoths and
modern elephants. It fossil remains are found in
Central Africa and are dated as 5 mya. The sizes
of Primelephas are compared to a modern Indian
elephant - height in shoulders about 3 m.
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The extinct genus Mammuthus were large
prehistoric elephants of the Pleistocene epoch.
The shoulder height of the Siberian, or woolly,
mammoth was about 2.7 m, and that of the imperial
mammoth of the No. America was up to 4.1 m.
Mammoths were covered by a long, shaggy, black
outer coat and a dense, woolly undercoat.
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Paleogene Life

• Mesonychids
• Doglike
• Size of small bears
• Diatrymas
• Huge flightless birds
• Clawed feet and slicing beaks

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The extinct Eocene bird Diatryma. Its small wings
were of little use for flight, but the legs were
massively constructed Diatryma was probably a
strong and rapid.
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The extinct Eocene bird Diatryma was up to nine
feet high. It is shown here chasing down an
oreodont artiodactyl.
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Paleogene Life

• Few birds with flight
• Most waded
• No songbirds

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Paleogene Life

• Oligocene mammals
• A few horses in North America
• Rhinoceroses
• Paraceratherium
• Largest land mammal of all time

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Paleogene Life

• Brontotheres
• Rhino-like

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Paleogene Life

• Carnivores evolved in Eocene
• Saber tooth tiger
• Bearlike dogs
• Wolflike animals

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Paleogene Life

• Primates modernized in Oligocene
• Monkeys
• Apelike primates
• Aegyptopithecus

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Neogene Life

• Marine life
• Miocene ancestral whales
• Sperm whale
• Baleen whales
• Dolphin
• Miocene recovery of planktonic foraminifera

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Neogene Life

• Terrestrial Life
• Grasses
• Herbs and weeds
• Requires arid climate
• Cooler climate linked to Antarctic glaciation

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Neogene Life

• Isolation of Antarctica led to glaciation
• Global cooling

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Neogene Life

• Mammals
• Groups of large mammals
• Many adapted to open terrain
• Even-toed ungulates
• Bovidae
• Elephants
• Carnivorous mammals
• New world primates

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Neogene Life

• Spread of C4 grasses
• C4 plants
• Incorporate more carbon 13 than C3 grasses
• Five times more silica
• Wears down teeth of grazers

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Neogene Life

• Why the spread of C4 grasses?
• Global climate change
• Aridity, not CO2, drop
• Alkenones indicate CO2 rise

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Plant Life

• Angiosperms dominate
• Evolution of Grasses

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The Calvin Cycle C3 PlantsWoody Plants, shrubs
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The Calvin Cycle - C4Special leaf anatomy
prominent bundle sheath cells. Adaptation to hot,
dry climates prevention of photorespiration.
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The Calvin Cycle - C4CO2 Pump adaptation to
low CO2
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Grasses

• Evolved during the Cretaceous to Paleogene
• Expanded during Miocene
• Photosynthetic pathway makes them better adapted
  to low CO2 levels

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Link between Grazers and Grasses

• Note that the expansion of Grasses during the
  Miocene was accompanied by an expansion in
  grazers.
• Horses are a good example

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Pop Quiz

• What is thought to be the earliest member of the
  horse family?
• a. Diatryma
• b. Hyracotherium
• c. Equus
• d. Angiosperms

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Hominid Evolution

• Differ from other hominoids
• 1) locomotion is bipedal - vs. quadrupeds and
  brachiates
• 2) brain size - larger than other hominoids
• 3) reduced face - more vertical profile
• 4) reduced canines
• 5) increased manual dexterity

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Human Evolution

• Miocene apes radiated in Africa and Eurasia
• Most were arboreal
• Earliest apes
• 6-7 M year old fossil skull
• Sahelanthropus
• Resembles both apes and humans

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Human Evolution
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Hominid Evolution

• Bipedal Primates - Humans
• Paleoanthropology
• study of ancient humans and their immediate
  ancestors
• two hominid genera
• Australopithecus
• First bipedal primates
• Homo
• First bipedal primates with a significant
  increase in cranial capacity

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Trends in Hominid Evolution

• Four Trends
• 1) Bipedalism
• 2) Cranial Capacity
• 3) Face size
• 4) Material Culture

• Walking upright on two feet
• increased ability throughout time

• Increased area in hominid cranium
• larger brain size

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Trends in Hominid Evolution

• Four Trends
• 1) Bipedalism
• 2) Cranial Capacity
• 3) Face size
• 4) Material Culture

• Reduction in
• face size
• jaw size
• tooth sizes

• Increase in the amount and complexity of human
  made objects

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Australopithecines

• Earliest Hominids
• Five Species
• A. anamensis (4.2 mya)
• A. afarensis (3.8 - 3.0 mya)
• A. africanus (3.2 - 2.5 mya)
• A. robustus (2.6 - 2.0 mya)
• A. boisei (2.6 - 1.2 mya)
• No artifacts - No Culture
• Small cranial capacities
• 400 - 550 cm3

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Appearance of Genus Homo

• Marked by
• increase in cranial capacity
• more adept bipedalism
• smaller teeth
• material culture
• Three species
• Homo habilis
• Homo erectus
• Homo sapiens (2 subspecies)
• Homo sapiens neandartalensis
• Homo sapiens sapiens

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Human Evolution

• Adapted to climbing trees
• Long curved toes and fingers

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Austalopithecus afarensis Common ancestor of all
later hominids - 4.0 to 2.75 m.y. - 1.2 m
tall, bipedal, strong sexual dimorphism, ape-like
features, massive brow ridges, low forehead,
forward jutting jaw Brain capacity -
380-450 cc 10-20 larger than modern chimps -
30-35 of modern hominids Lucy
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Australopithecus afarensis
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Australopithecus africanus 3.0 to 1.6 m.y.
Minor differences from afarensis 1.4 m tall,
slightly flatter face Brain capacity - 400-600
cc
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Human Evolution

• Australopithecines
• Intermediate between humans and apes
• Only slightly larger brain than chimp
• Broad pelvis

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Human Evolution

• Tracks indicate bipedal walking
• Footprints similar to modern humans

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Human Evolution

• Homo
• 2.4 M years ago
• Larger skull
• Similar thigh and pelvis bones

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Early Homo

• Homo habilis
• Larger Cranial Capacity
• 510 - 750 cm3
• 2.4 -1.5 mya

• First use of stone tools
• Oldowan tools
• Chopper/ Pebble tools

• Found only in Africa

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Homo habilis 3.0 to 1.4 m.y. earliest known
Homo genus similar to Australopithecines
brain capacity - 700 cc
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Early Homo

• Homo erectus
• 1.8 - 0.4 mya

• More complex stone tools
• Acheulian tools
• Handaxes

• Larger Cranial Capacity
• 800 - 1050 cm3

• First Hominid Found outside of Africa

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Homo erectus 1.8 m.y. to 300,000 yrs.
prominent brow ridges brain capacity - 1,100
cc constructed and used handaxes, flakes,
scrapers believed to have used fire
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Human Evolution

• Stone tools
• Oldowan culture
• Found at Olduvai Gorge

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Human Evolution

• Homo erectus
• 1.6 million year old boy skeleton
• Africa
• Very similar to modern humans

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Human Evolution

• Neanderthals
• Homo heidelbergensis
• Heidelberg, Germany
• 200,000700,000 years old
• Homo antecessor

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Human Evolution

• Stone tools
• Neanderthals
• Mousterian
• More sophisticated than Homo erectus tools

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Human Evolution

• Stone tools
• Acheulian
• Found in China in association with Java Man

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Human Evolution

• Neanderthal burial sites
• Possible religion

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Human Evolution

• Cro-Magnon culture
• European
• Cave paintings of France and Spain

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Homo sapien 300,000 yrs. to present higher,
rounder cranium, smaller teeth and jaw brain
capacity - 1,300 cc Two subspecies Homo
sapien sapien - modern man Homo sapien
neanderthalensis
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Homo neanderthalensis 150,000 to 32,000 yrs.
Europe and Near East Skull differs from Homo
sapien sapien lower forehead prominent, heavy
brow ridges weak chin. Body tends to be more
massive and more heavily muscled with shorter
limbs. Lived in caves in Europe Made highly
specialized tools of stone and bone Buried their
dead in ritual burials
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Homo sapiens

• Homo sapiens neandertalensis
• 130,000 ya - 35,000 ya

• Larger Cranial Capacity
• 1520 cm3

• cold adapted

• stone tools
• Paleolithic tools
• projectile points
• greater variety of tools

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Homo sapiens

• Homo sapiens sapiens
• 200,000 ya - present
• Larger Cranial Capacity
• 1400 cm3
• distinctive chin
• prominent forehead

• stone tools
• Paleolithic tools
• projectile points
• greater variety of tools

• art
• cave paintings

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Humans

• Brain growth in primates

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The drying of African climates is correlated to
Hominid diversification. 1) Northern Hemisphere
Glaciation - General Drying of
Atmosphere Shifting of High and low pressure
systems.
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Correspondance of evidence for hominid evolution
with climatic proxies. Ranges of commonly
accepted hominid taxa are shown at left, with
evidence for bipedal locomotion and stone-tool
technology.
Splitting of Homo branch related to onset of No.
Hemisphere glaciations.
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ExamMay 8thTuesday8-11 amHere
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5 Major Orogenies of the Western USBreakup of
PangeaSalts in the base of the Gulf of
MexicoWestern Interior SeasOcean Anoxic
EventsIsthmus of PanamaWarm CretaceousOxygen
Isotopes
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Cenozoic CoolingAntarctic GlaciaitonNorthern
Hemisphere GlaciationDinosaursEndothermy vs
EctothermyMammals
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Age of CycadsAngiospermsGrassesRelationship
between Oil production and OAEsK-T
boundaryMilankovitch and Orbital Forcing
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Western Geologic ProvincesColumbia PlateauBasin
and RangeColorado PlateauCascadesYellowstone/Sn
ake RiverHominids
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Panama
Hominids
NHG
Grazing Mammal
Age of Mammals
Grasses
Antarctic Glac
Drake Pass
Himalayas
Eocene Warmth
Mass Extinction
Laramide
Mowry
Ocean Anoxic Events
Angiosperms
Sevier
Age of Reptiles
Sundance
Nevadan
Age of Cycads
No. Atl Rifting
Mammals
Dinosaurs
Pangea
Sonoma
Mass Extinction
Antler