PCB 4674 Lecture 11: evolution ch11
14 Apr 2018
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Describe the example of adaptive divergence in trinidadian guppies. There is higher predation downstream and low predation upstream. The barrier waterfalls exclude predators, not allowing them to get upstream. Because of this, guppies upstream have different coloration, tail sizes, and are larger (when this would not be beneficial with predators present) Guppies downstream have dull colors (because it is easier to hide from predators Even though females prefer bright males) and they are smaller. What are the four ways to decide what a species is: phylogenetic species concept, biological species concept, cohesion species concept, operation species concept. Most inclusive group of individuals with a common evolutionary trajectory of character changes. Most inclusive group of individuals that are reproductively compatible (produce viable, fertile offspring w/o reduction in number of offspring) Can"t use for species that reproduce asexually (prokaryotes) Doesn"t deal with two groups that are very divergent, and there is no geographical overlap.
