Cenozoic Era  Began about 65 million years ago Present Era About 1.5% of Earth’s history  Continents haven’t changed much Just a little closer to each other at the start of this Era  Time of increased tectonic activity Mountain ranges formed Alps & Himalayas

 Dramatic changes in climate  At times, continental ice sheets covered 1/3 of earth Various species became extinct and others appeared  Mammals become dominant life-forms Age of Mammals

 Divided into 2 periods Tertiary ○ Time before last Ice Age Quaternary ○ Includes present  Each period divided into Epochs

Cooling  As Australia and Antarctica split, worldwide cooling began Caused by change in ocean currents Previously warm water flowed from Pacific, Atlantic, and Indian Oceans to moderate Antarctica’s temperature  Once split, Antarctica was isolated around South Pole Cold current began to flow Permanent ice cap grew during Oligocene

Miocene Warming  Climate warmed up again Ice cap began to melt Ocean flooded North America  Trend reversed in middle of Miocene Set stage of Ice Ages

Ice Ages  Late Pliocene to Pleistocene  Ice covered much of Northern Hemisphere  Glaciers advanced and retreated at least four times Ohio and Missouri Rivers mark southernmost point of glaciers Glaciers carved our lakes and valleys we see today

Mountain Building  Erosion wore down Rocky Mountains but uplift continued  Volcanism returned at the end of the Eocene

Subduction in the West  Oceanic plate subducted under Pacific Northwest Plate completely disappeared Cascade Mountains uplifted  North American plate began to move against Pacific Plate Transform Boundary that created San Andreas Fault

Basin & Range Province  Created by North American moving against Pacific Plate Southwestern part of United States Hundreds of parallel mountains  Formed as stress in crust pulled it apart

Continental Collisions  Final breakup of Pangaea  Some continents separated while others collided Africa colliding with Eurasia built the Alps ○ Eliminated Tethys Ocean that once separated Eurasia and Gondwana ○ Remnants can be found in 4 bodies of water in Europe India crashed into Asia to form Himalayan Mountains

Tectonic Forces  Scientists think Earth is in a relatively warm phase  Future climate will become cooler  Tectonic forces continue to shape earth  In about 250 million years, tectonic forces will largely eliminate the Atlantic Ocean and once again form a supercontinent

Cenozoic Life  Marine organisms survived mass extinction at the end of the Cretaceous Populated oceans during Cenozoic Era  Forest began to dominate land  Grasses appeared as climate cooled Diversification of many new mammals resulted

Oligocene Epochs  Climate continued to get drier and cooler Favored growth of grasses and cone- bearing and hardwood trees  Earlier types of mammals became extinct  Larger species flourished Deer, pigs, horses, camels, cats, & dogs

Ice Age  Climate began to cool and new animals evolved Mammoth Saber-toothed cat Modern Humans – Homo Sapiens

Baby Mammoth enews/ /Secrets-of year-old-baby-mammoth- revealed.html

Humans  Bipedal locomotion  First bipedal humanlike primates appeared about 6 million years ago during the Late Miocene  Earliest modern humans appeared about 195,000 years ago  Migration was influenced by Ice Age Bering Strait was exposed and Humans likely walked across to North America

Pleistocene Epochs  Several periods of glaciations Animals had special characteristics that allowed them to endure the cold Other animals moved to warmer regions Less-adaptable species became extinct  Fossils of early ancestors of humans appear Hunters which led to extinction of many large mammals

Holocene Epochs  Includes present Began when last ice age ended As ice sheets melted, seas rose and coastlines took shape  Great Lakes formed  Modern humans developed agriculture and began to make tools

In-Class Assignment/Homework  23.3 Cenozoic & Review WKT