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The Cenozoic Era. The Shaping of the Modern World. Themes of the Cenozoic. Changes in Life Age of Mammals Make Way birds The Ascent of Humans Mountain Building in Western America continues Formation of the San Andreas Fault A Return to the Ice Several major glacial events
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The Cenozoic Era The Shaping of the Modern World
Themes of the Cenozoic • Changes in Life • Age of Mammals • Make Way birds • The Ascent of Humans • Mountain Building in Western America continues • Formation of the San Andreas Fault • A Return to the Ice • Several major glacial events • Major Volcanic Eruptions
Early Cenozoic • North America grows larger • Formed due to a series of collisions between the North American plate and small terranes in the Pacific • The Interior Western Seaway retreats and most of North America is above sea level (very important event) • The Appalachians are eroded
Early Cenozoic • India begins its collision with Asia, causing the Himalayas to be lifted • “Ring of Fire” forms • Australia separates from Antarctica
Early Cenozoic Era • The demise of the dinosaurs allows not only mammals, but birds to diversify and flourish • Birds got very large (to 10 feet tall) and were predatory • Songbirds also develop in this time period • First flowering plants develop - angiosperms
Early Cenozoic • The climate of the Paleogene was notably drier than previous periods • Also much warmer than it is currently • Lead to more land being above sea level • Allowed for the evolution of first grasses and therefore, grazing mammals (like horses) evolve • Mammals diversify and grow very large • Mammals are an extremely varied group! • All major mammal groups are in place by the middle of the Cenozoic
Marine Animals • The marine mammals evolve at this time • Whales, dolphins, etc • Relative of camels!!! • Lose their visible limbs over time • Sharks take over as the dominant predator in the sea, filling the niche left by extinct mosasaurs and pleisosaurs
The Neogene:Middle of the Cenozoic to Present (23 mya – Present) • During the Neogene, the continents take their modern shapes • North and South America join • Iceland emerges from the sea • Polar Ice Caps form • In North America, the San Andreas Fault forms
The Pliestocene (1.6 mya – 10,000) • The Pleistocene is often referred to as the “Ice Age” • about 4 major ice advances and 3 retreats • Leads to sea level retreats and advances • Great Lakes form • Other major event includes the eruption of the Yellowstone caldera and (even worse!) the eruption of the Toba caldera • Toba nearly wipes out humans
Pleistocene Megafauna • Megafauna refers to the extreme large mammals that dominated this time period • Include the Mammoth, Mastodon, Saber-cat, Giant Sloth and Giant Beaver (among others)
Pleistocene Extinction • At the end of the last Ice Age (about 18,000 - 12,000 ya) most of the large mammals went extinct • This extinction event only affected large mammals • Probable causes include climate changes affecting the web chain and overkill by early humans • Still plenty of room for doubt • One question – is this extinction event a thing of the past, or is it continuing today?????