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How did marine mammals evolve?
Do marine mammals have evolutionary histories?
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May 21, 2007 · The fossil record demonstrates that mammals re-entered the marine realm on at least seven separate occasions. Five of these clades are still extant, whereas two are extinct. This review presents a brief introduction to the phylogeny of each group of marine mammals, based on the latest studies using both morphological and molecular data.
- Mark D. Uhen
- 144
- 2007
- 21 May 2007
Apr 16, 2009 · Around 34 million years ago, the first representatives of the modern groups of whales, odontocetes and mysticetes are found. It is now generally assumed that odontocetes and mysticetes (together called Neoceti) arose from a common Eocene cetacean ancestor and are thus monophyletic.
- J. G. M. Thewissen, Lisa Noelle Cooper, Lisa Noelle Cooper, John C. George, Sunil Bajpai
- 2009
For a time, paleontologists supported a hypothesis put forth by Van Valen (1966) that cetaceans were most closely related to a group of fossil ungulates known as mesony-chians, mainly based on shared characteristics of their teeth (O’Leary and Geisler, 1999; Geisler, 2001), and that the closest living relatives of cetaceans were the artiodac-tyls.
Mar 21, 2012 · March 21, 2012. All cetaceans, including whales, dolphins, and porpoises, are descendants of land-living mammals. How did these terrestrial ancestors morph over millions of years into the...
There was no straight-line march of terrestrial mammals leading up to fully aquatic whales, but an evolutionary riot of amphibious cetaceans that walked and swam along rivers, estuaries and the...
Danielle Hall. Reviewed by Brian Huber, Smithsonian Institution. The ocean may seem like a vast and unchanging landscape, but the reality is that the world beneath the waves has continuously evolved over time. As terrestrial creatures, humans are largely unaware that much of life's history has taken place in the ocean.
Marine mammals were first hunted by aboriginal peoples for food and other resources. Many were also the target for commercial industry, leading to a sharp decline in all populations of exploited species, such as whales and seals.
