CENOZOIC ERA

AGE OF MAMMALS

Periods & Epochs of the Cenozoic Era

The Age of Mammals

KEY CHANGES

• Pangaea separates into continents

• Polar ice covered many continents

• Warm, humid climate changes into a very cold climate covering ¼ of all land with glaciers

• Colorado & Columbia Plateaus formed

• Himalayas, Alps & Andes mountains formed

Ice Age

CENOZOIC PERIODS

• Tertiary

– Before the ice age

• Quaternary

– From the ice age to the present

TERTIARY EPOCHS

• Paleocene

• Eocene

• Oligocene

• Miocene

• Pliocene

Paleocene

Eocene

Oligocene

Miocene

QUATERNARY EPOCHS

• Pleistocene

• Holocene

Pleistocene

Holocene

MAMMALS

• Increased in number, size, & variety

• Many have gone extinct

– Creodont, oreodon, mastodon, brontotherium,

baluchitherium, giant armadillo, giant ground sloth

• Some still survive today

– Horse, camel, rhinoceros, pig, dog, whale, bat, rabbit

• Humans are distinguished by their brain size &

bipedal (2 leg) motion

Creodont

Oreodon

Mastodon

Brontotherium

Baluchitherium

Giant Armadillo

Giant Ground Sloth

Horse

The Evolution of the Horse

OTHER ANIMALS

• In the oceans

– Foraminifers, mollusks, sponges, corals, fish,

sharks, rays

• On the land

– Insects, spiders, centipedes, scorpions,

amphibians, reptiles, birds

Ray

Shark

Life at a Coral Reef

Centipede

Scorpion

Amphibians

Reptiles

Birds

PLANTS

• Temperatures cooled & became drier

• Tropical plants only survived along the equator

• Sequoia & redwood trees survived in California & Oregon

• Many forests were replaced by grasslands with grazing animals

Tropical Forest

Sequoia Trees

Coastal Redwood Forest

Grasslands

HOMINIDS (HUMANS)

Australopithecus

Homo habilis

Homo erectus

Homo sapien

• 500 cm3 brain, bipedal, human

jaw

• 700 cm3 brain, made & used

simple tools

• 1000 cm3 brain, learned to

control fire

• 1300 cm3 brain, Neanderthals

& Cro-Magnons

The Evolution of the Human Brain

700 000 years – 1.7

million years (homo

erectus) thick flat skull

cap, flaring cheek bones,

30 000 years – 230 000

years stone tools, fire,

cave dwellers, hunters,

thick skulls, chinless jaw,

short strong limbs

10 000 years – 40 000

years artists, hunters,

tool makers, prominent

chin, rising forehead,

similar to modern

humans

Human

Development

Evolution of Humans

Australopithecus Homo habilis

Homo erectus

Neanderthals

Cro-magnon

Modern Human

HOLOCENE EPOCH

• Ice sheets disappeared

• Humans brought about the extinction of other animals & plants

– Hunting & destroying habitat

• Conservation programs were implemented to protect other animals & plants

– Protection programs, sanctuaries, &

regulations