BIOB51H3 Lecture Notes - Lecture 21: Alpheidae, Meiosis, Transposable Element
2 Apr 2015
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Selection that favours the average trait value, and there is tighter distribution around the center. Gall-size in gall-making flies (make sure you know this) You shave off the center of the distribution, and favour the extreme. In the next generation, you have the increase in frequency of very large or very small trait values, and a decrease in distribution in the middle. The average is the same, but the distribution is flatter. Depending on what habitat you"re in, you are selected for different types of trait values. Ex. black bellied seedcracker: these are birds that eat different types of seeds. They vary in terms of their beak dimensions, length. However, individuals in the middle are good at eating none: the distribution after selection are separating over time due to disruptive selection. If you continue this long enough, you can have them evolving into two different species with different beak sizes. What is a species: there are many different species concept.
