01:119:115 Lecture Notes - Lecture 47: Branch Point, Carl Linnaeus, Niles Eldredge
5 Apr 2016
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Document Summary
Sexual selection for mates of different colors has likely contributed to the speciation in cichlid fish in lake victoria. Sympatric speciation can also result from appearance of new ecological niches. For example, the north american maggot fly lives on native hawthorn trees. 1800s they began to infest apple trees (a non native) Several species now exist, that each prefer a separate type of host tree. Many questions remain concerning how long it takes for new species to form, or how many genes need to differ between species. Broad patterns in speciation can be studied using the fossil record, morphological data, or molecular data. The punctuated pattern in the fossil record and evidence from lab studies suggests that speciation can be rapid. The interval between speciation events can range from 4000 years (some cichlids) to 40,000,000 years (some beetles) with an average of 6500000 years.
