Saturday, December 6, 2014

My Year of Darwin 12/6/2014: Why aint you evolving?

 Charles Darwin

"It is just possible by my theory, that one of two living forms might have descended from the other; for instance, a house from a tapir; and in this case DIRECT intermediate links will have existed between them. But such a case would imply that one form had remained for a very long period unaltered, whilst its descendants had undergone a vase amount of change; and the principle of competition between organism and organism, between child and parent, will render this a very rare event"  Charles Darwin, Origin of Species 1st edition (on Kindle)

I think this is the circumstance that would lead to living fossils. Darwin is describing a case where species A left a number of descendants that changed phenotypically yet a lineage persisted did not undergo phenotypic change. At first I wrote "yet itself persisted" but the modified descendants are also the same species (kinda sorta) just modified. I think I prefer conserved phenotype to living fossil although my term is not very catchy. I should incorporate this into my 225 notes (though I don't teach that section.. maybe I can sneak it into phylogenetics). One interesting question that has probably been asked... if there are habitats where competition is lower (because disturbance or predation keeps the limiting factor from being limited) then can be predict the persistence of relatively more conserved phenotypes? 

I miss Costa Rica.. any tropical forest

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