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May 21, 2007 · Evolution of marine mammals: Back to the sea after 300 million years. Mark D. Uhen. First published: 21 May 2007. https://doi.org/10.1002/ar.20545. Citations: 144. Sections. PDF. Tools. Share. Abstract. The fossil record demonstrates that mammals re-entered the marine realm on at least seven separate occasions.
- Mark D. Uhen
- 2007
Mar 21, 2012 · When did scientists first propose that marine mammals evolved from land-living mammals? What findings led to this conclusion?
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Apr 16, 2009 · Cetaceans (whales, dolphins, and porpoises) are an order of mammals that originated about 50 million years ago in the Eocene epoch. Even though all modern cetaceans are obligate aquatic mammals, early cetaceans were amphibious, and their ancestors were terrestrial artiodactyls, similar to small deer.
- J. G. M. Thewissen, Lisa Noelle Cooper, Lisa Noelle Cooper, John C. George, Sunil Bajpai
- 2009
The return to the sea: The evolution of marine mammals. : : : Both morphological and molecular data tell us that the ancestors of the marine mammals were terrestrial, and that their various marine lifestyles have evolved independently at least seven times! Each lineage shows shared as well as unique evolutionary solutions to the challenges of ...
Due to Erwin’s research, it is now known that the first animal evolved during the Ediacaran and not the Cambrian like previously thought. By studying Permian fossils, Erwin has also contributed to our understanding of why the Permian Extinction—the largest extinction in Earth’s history—came to be.
Although whales are expert swimmers and perfectly adapted to life underwater, these marine mammals once walked on four legs. Their land-dwelling ancestors lived about 50 million years ago. Meet Pakicetus, a goat-sized, four-legged creature that scientists recognise as one of the first cetaceans (the group of marine animals that includes ...
Nov 15, 2019 · However, another hypothesis is that Odobenidae first evolved in the North Pacific and then dispersed into the Arctic Ocean and North Atlantic during an interglacial event in the Pliocene or Pleistocene.
