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Evolution in fossil lineages: paleontology and The Origin of Species.
MedLine Citation:
PMID:  21043781     Owner:  NLM     Status:  In-Process    
Of all of the sources of evidence for evolution by natural selection, perhaps the most problematic for Darwin was the geological record of organic change. In response to the absence of species-level transformations in the fossil record, Darwin argued that the fossil record was too incomplete, too biased, and too poorly known to provide strong evidence against his theory. Here, this view of the fossil record is evaluated in light of 150 years of subsequent paleontological research. Although Darwin's assessment of the completeness and resolution of fossiliferous rocks was in several ways astute, today the fossil record is much better explored, documented, and understood than it was in 1859. In particular, a reasonably large set of studies tracing evolutionary trajectories within species can now be brought to bear on Darwin's expectation of gradual change driven by natural selection. An unusually high-resolution sequence of stickleback-bearing strata records the transformation of this lineage via natural selection. This adaptive trajectory is qualitatively consistent with Darwin's prediction, but it occurred much more rapidly than he would have guessed: almost all of the directional change was completed within 1,000 generations. In most geological sequences, this change would be too rapid to resolve. The accumulated fossil record at more typical paleontological scales (10(4)-10(6) years) reveals evolutionary changes that are rarely directional and net rates of change that are perhaps surprisingly slow, two findings that are in agreement with the punctuated-equilibrium model. Finally, Darwin's view of the broader history of life is reviewed briefly, with a focus on competition-mediated extinction and recent paleontological and phylogenetic attempts to assess diversity dependence in evolutionary dynamics.
Gene Hunt
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American naturalist     Volume:  176 Suppl 1     ISSN:  1537-5323     ISO Abbreviation:  Am. Nat.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-03     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984688R     Medline TA:  Am Nat     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S61-76     Citation Subset:  IM    
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA.
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