The question of how whales and their relatives could have evolved from terrestrial [[mammal|mammals]] has taxed evolutionary biologists since [[Darwin|Darwin's]] suggestion that they may have evolved from ancient bears. In more recent times molecular and fossil evidence has combined to suggest that modern whales and their relatives arose from ancient [[Artiodactyla|artiodactyls]] (even-toed ungulates) with the closest living relative of all whales being hippos<ref>[http://www.redorbit.com/news/science/41080/molecular_clock_divergence_estimates_and_the_fossil_record_of_cetartiodactyla/index.html] Theodore, JM (2004) Molecular Clock Divergence Estimates And The Fossil Record Of Cetartiodactyla <i> The Journal Of Paleontology</i> <b>78</b>:39-44</ref>. This kinship has been termed the whippo hypothesis. Evolutionary biologists estimate the last ancestor of whales and hippos lived about 25 million years ago <ref> [http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml] UCLA Berkley Understanding Evolution for Teachers website</ref>, which is contrast with the [[Young earth creationism|young earth creationist]] position that that whales were [[creation|created]] about 4000 years ago when [[God]] created the [[earth]]. Other creationists are not convinced that the available fossil evidence supports the [[Theory of evolution|evolutionary view]] but make no reference to the corroborating molecular evidence. <ref>http://www.answersingenesis.org/home/area/re1/chapter5.asp</ref>
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The question of how whales and their relatives could have evolved from terrestrial [[mammal|mammals]] has taxed evolutionary biologists since [[Darwin|Darwin's]] suggestion that they may have evolved from ancient bears. In more recent times molecular and fossil evidence has combined to suggest that modern whales and their relatives arose from ancient [[Artiodactyla|artiodactyls]] (even-toed ungulates) with the closest living relative of all whales being hippos<ref>[http://www.redorbit.com/news/science/41080/molecular_clock_divergence_estimates_and_the_fossil_record_of_cetartiodactyla/index.html] Theodore, JM (2004) Molecular Clock Divergence Estimates And The Fossil Record Of Cetartiodactyla <i> The Journal Of Paleontology</i> <b>78</b>:39-44</ref>. This kinship has been termed the whippo hypothesis. Evolutionary biologists estimate the last ancestor of whales and hippos lived about 25 million years ago <ref> [http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml] UCLA Berkley Understanding Evolution for Teachers website</ref>, which is contrast with the [[Young earth creationism|young earth creationist]] position that that whales were [[creation|created]] about 6000 years ago when [[God]] created the [[earth]]. Other creationists are not convinced that the available fossil evidence supports the [[Theory of evolution|evolutionary view]] but make no reference to the corroborating molecular evidence. <ref>http://www.answersingenesis.org/home/area/re1/chapter5.asp</ref>