BIOL 2200 Lecture Notes - Lecture 3: Devonian, Pesticide Resistance, Weaning
23 Jan 2017
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Many offspring are produced, but few survive. Traits may vary among individuals within a population and may be heritable. Some heritable traits give individuals an advantage in their environment. Advantageous traits, conferring fitness, become more common. Using finches, darwin was able to deduce that the finches came from a common ancestor. Marine variety has more armor than freshwater variety. Armor trait is controlled by eda gene. Stickleback reproduce in freshwater and then return to the ocean. During the ice age, some sticklebacks were trapped in the lacks. The lake stickleback have less armor because there are fewer predators. Lakes have lower ion concentration (needed to make bones) Some sticklebacks in lake washington were heavily armored, contrary to what one might think. In the 60"s, the lake was cleaned, resulting in increased water clarity. Predation became more common, so armor became more common. Benthic eat invertebrates near the bottom of the lake. Mammals stop being lactose tolerant around weaning.
