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 (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (, a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.