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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
Figure 1. Harbor seal, walrus, dugong, and right whale) The first mammals were certainly terrestrial. There is good evidence that mammals evolved from reptile-like ancestor. Therefore at some point there was a transition from terrestrial environment to an aquatic lifestyle in this group of species. How did that occur?
- 1MB
- 15
Jan 26, 2015 · Marine mammal genomes showed a large number of parallel substitutions (blue) that occurred along the branches of at least two marine mammal lineages since they evolved from a terrestrial...
- Andrew D Foote, Andrew D Foote, Yue Liu, Gregg W C Thomas, Tomáš Vinař, Jessica Alföldi, Jixin Deng,...
- 2015
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
Oct 18, 2012 · University of California Press, Berkeley, CA. 2012. 205 pp., $49.95 (cloth), $25.62 (Kindle). ISBN 9780520270572. Annalisa Berta leads readers through a vast range of topics regarding the evolution of marine mammals in Return to the Sea: The Life and Evolutionary Times of Marine Mammals. In this volume geared towards non-specialists (one might ...
- Mark D. Uhen
- muhen@gmu.edu
- 2013
The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid- Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this ...
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How did marine mammals evolve?
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Nov 15, 2019 · Since Hb and Mb evolved over 550 million years ago (Pesce et al. 2002), increased concentrations of these globins in blood and muscle probably occurred early in ancestral marine mammals as an upregulation of globin expression.
