The Cenozoic Era

The Cenozoic Era

The Age of MammalsAfter the cretaceous extinction, mammals began to adapt to take advantage of habitats that were once dominated by dinosaurs and reptilesThe Cenozoic Era can be divided into 3 periods: the Paleogene, The Neogene, and the Quaternary.

The Paleogene Period (66 mya – 23 mya)Tectonic plate movement formed the Rocky Mountains, and the Himalayan mountains

Early PaleogeneThe earliest fossils of most major mammal orders are from the early paleogene◦All were very small, under 10 g

The green river formation contains fossils of bats, plants and insects from the paleogene period

Paleogene LandscapeGrasses evolved and open grasslands slowly took the place of forestsThe climate became cooler and drier

Late Paleogene

Late Paleogenelarger mammals, including the first elephants and early horses evolvedSmall mammals and marsupials became more diverse

The Neogene Period (23 Mya – 2.6 Mya)Tectonic activity during the Neogene formed the landscape we see todayThe Andes mountains in South America rose to the altitudes seen todayAntarctica became isolated from South America and Australia

Mammals from this time are found in a fossil bed in Colombia called the La Venta Faunahttp://www.youtube.com/watch?v=ATZkCf2dD2c#t=48

La Venta Fauna, Colombia

The first Human ancestors evolve in Africa about 6 mya

The Quaternary Period (2.6 Mya-today)Two factors have greatly affected life on Earth during the Quaternary Period: The advance and retreat of continental glaciers, which have formed and melted about 30 times in the last 3 million years, and the migration of Homo sapiens – modern humans- to every corner of Earth. Cycles in the Earth’s movement, called Milankovitch Cycles, are thought to have caused the conditions that led to the most recent ice age

Beginning of the last ice age

Early humansFossils of the earliest modern humans date back 200,000 years. http://humanorigins.si.edu/resources/multimedia/videos/one-species-living-worldwide

La Brea Tar PitsLarge mammals that lived during the last ice age are known from fossils found in the La Brea tar pits in Los Angeles, CaliforniaMost large mammals died off at the end of the last ice age ~11,000 years ago.http://www.tarpits.org/la-brea-tar-pits/timeline

The rest is history….The oldest continuously inhabited cities, Damascus and Jericho, were built about 10,000 years ago