Give an overview of life through the tertiary, in relation t
Give an overview of life through the tertiary, in relation tThe tertiary consisted of two main epochs. The Paleocene, the Eocene and the Oligocene, which make up the Paleogene; and the Miocene and Pliocene, which make up the Neogene.
The close of the Cretaceous Period marked a major transition in Earth’s history. Ammonoids and marine reptiles disappeared from the sea. Marine taxa that persist as familiar inhabitants of modern ocean, among them bottom dwelling molluscs. On the land, the flowering plants of the Paleogene resembled those of latest Cretaceous time in many ways, but animal life changed dramatically. Taking the place of dinosaurs were the mammals, which were universally small and inconspicuous at the start of the Paleogene interval but in many ways resembled modern mammals by the period’s end.
The most profound geographic change during Paleogene time was a refrigeration of Earth’s polar regions, which resulted in a chilling of the deep sea and, later in the Cenozoic Era, in widespread glaciation. Paleogene mountain-building events in western North America foreshadowed Neogene uplifts of such ranges as the Sierra Nevada and the Rocky Mountains.
During the Neogene, the modern world took shape. The global ecosystems acquired their present configuration and prominent topographic features assumed the forms we are familiar with today.
No mass extinction marked the transition from the Paleogene to the Neogene. During the 24 million years of the Neogene, however, life ad Earth’s physical features have changed significantly. The most far-reaching biotic changes were the spread of grasses and weedy plants and the modernization of vertebrate life. Snakes, songbirds, frogs, rats and mice expanded dramatically too, and humans evolved from apes. The Rocky Mountains and the less rugged Appalachians took shape during the Neogene time, as did the imposing Himalayas. The Mediterranean Sea almost disappeared and then rapidly formed again.
The most widespread physical changes on Earth, however, were climatic. Glaciers expanded across large areas of North America and Eurasia late in Neogene time.
The Paleocene was different climatically from the Mesozoic. For one, it was more temperate around the globe. Secondly it was a lot colder near the poles. Continental drift had slowed down greatly since the Mesozoic, and large seas disappeared off of the continents. The average global temperature was rising and reached a peak in the early Eocene, which was the highest, experienced in the Cenozoic; even the deep seas briefly became warm. Both surface and deep-sea waters near the Antarctic were warmed by about 18 degrees within less than 3000 years. One casualty of these increasing temperatures was the deep-sea species of foraminifera. About 70% became extinct, because the warming terminated the descending cool waters, which provided a vital oxygen supply. New globigerina and star shaped coccolithophores appeared. Mammals diversified and expanded a lot during this Epoch. One of them was Glyptodon, a mammal oddity that evolved in South America. In the seas, sea urchins evolved. Flowering Plants became the major plant of the Cenozoic.
Large...
To view the complete essay, you be registered.