BIOL 2200 Lecture Notes - Lecture 7: Sympatric Speciation, Ecomorphology, Assortative Mating
1 Feb 2017
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Document Summary
Natural selection is the most likely to result in speciation. Autopolyploidy = cell division error within a species leads to increase in chromosome number. Can interbreed with other higher ploidy individuals. Reduced hybrid fertility is when the offspring (f1) has little ability to reproduce. Hybrid breakdown is when the f2 generation or later has trouble reproducing. Allopolyploidy = hybridization between species leads to number of chromosomes that cannot be evenly divided. Duplication error can create an even number of chromosomes so that they can interbreed. Sticklebacks are currently in the midst of sympatric speciation. Benthic sticklebacks = bigger and live at the bottom of the lake. Limnetic sticklebacks = smaller and live in the open water. Stream sticklebacks = stay in the stream all their life. Marine sticklebacks = live in the ocean; spawn in freshwater. Despite region, sticklebacks prefer to mate with those from the same ecomorph. Low mating success in different ecomorphs, regardless of region.
