How Did You Get Here?

Evolution 2009
A common theme in the talks I am attending is how and why species exist/coexist in certain localities. Two more talks today hit on this theme as well.

Travis Ingram today discussed coexistence. Sets of species can be found together because 1.) the local habitat requires a certain set of adaptations that all the species share, i.e. environmental filtering, 2.) some species have out competed others that are now absent from the community, i.e. assembly rules, 3.) the species coexist in a locality is entirely random, i.e. neutrality, 4.) the trials and tribulations of their evolutionary history selected for their ranges to overlap that locality, i.e. biogeography and species sorting. Ingram focuses on rockfishes from the Northeast Pacific finds that both mediated competition (2) and environmental filtering (1) are important. Interesting, he mentioned that similar patterns are found in plants suggesting generality across taxa.

Elizabeth Jones Sbrocco focuses on number 4 in the marine biodiversity hotspot that is the Indo-Pacific. During the last glacial maximum (LGM) the seas were 120m shallower. This is hypothesized to trap populations in shallow refugia, leading to genetic isolation, and eventually greater biodiversity. Her work demonstrates high levels of genetic structure in two species of clownfish through the region, partly due to contemporary currents but alls due to the localities of refugia during the LGM. The really cool part of the work, which made me wish her presentation could have been longer than 15 minutes, was that old refugia during the LGM were more environmental similar that those in habitats in the clownfish’s contemporary ranges. This implies at some level that adaptation to the refugial environment cannot explain the modern distribution.

Dr. M (1618 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, created to facilitate research to address fundamental questions in evolutionary science. He has conducted deep-sea research for 11 years and published over 40 papers in the area. He has participated in dozens of expeditions taking him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses mainly on marine systems and particularly the biology of body size, biodiversity, and energy flow. He focuses often on deep-sea systems as a natural test of the consequences of energy limitation on biological systems. He is the author and chief editor of Deep-Sea News, a popular deep-sea themed blog, rated the number one ocean blog on the web and winner of numerous awards. Craig’s popular writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.





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