BIOLOGY 1M03 Lecture Notes - Lecture 16: Molecular Phylogenetics, Ecology, Cosmic Calendar
Document Summary
10/20/2014 (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) Physical isolation of some kind appears to be key. Provides greater ecological opportunity for a particular lineage. Access to new (unoccupied) ecospace, in the form of a new habitat or resource how: dispersal (founder effect, morphological/ecological innovation. Rafting rodents over water dispersal from africa south. Mat of vegetation breaks off perhaps in a large storm with rats on it (cid:1) Rodent molecular phylogenies: sister relationships between african and south american clades (~50 mya) Monkey molecular phylogenies: sister relationships between african and south american clades (~37 mya) (cid:1) (cid:1) Dispersal scenario: the physical barrier pre-dates the time of speciation (older than) (cid:1) (cid:1) Vicariance scenario: physical barrier causes speciation so it is roughly the same age as the speciation event (cid:1) More evidence: from n america via asia (but no allied fossils in well-sampled sediments, from australia antarctica s america.
