Читать книгу Oceans For Dummies - Joseph Kraynak - Страница 64

During the Eocene epoch (from 55 to 33.9 million years ago), Earth suddenly went from greenhouse to icehouse. One of the proposed causes of this dramatic change in climate is the Azolla event, during which blooms of azolla freshwater ferns in the Arctic Ocean sucked massive amounts of carbon dioxide out of the atmosphere. During this epoch:

 The ice sheets expanded.

 Deciduous trees, which drop their leaves in the fall, became favored over evergreens.

 Early perissodactyls (odd-toed hoofed animals), artiodactyls (even-toed hoofed animals), and primates appear on land.

 In the oceans, basilosaurids and ambulocetus (both ancestors of modern whales) appear, as well as the ancestor of sirenians (the politically correct name for sea cows such as manatees).

 Most modern mammal orders appear, including bats, rodents, and proboscideans (mammals with long snouts such as wooly mammoths and elephants).

 Giant snakes, such as the titanoboa, and giant flightless birds also make their entrance.

The Eocene ended with the Eocene-Oligocene Extinction event. This was a period of cooling, which may have been caused by another meteorite impact, causing a large turnover of mammalian and aquatic species in particular. During this time the archaeoceti (primitive whales) went extinct.