Biology 1201A Lecture Notes - Lecture 3: Francis Bacon, Calliphoridae, Carl Linnaeus
20 Feb 2017
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17. 0 evolution: the development of the theory// why it matters sheep blowflies occur throughout australia, and have spread world wide to eastern canada fly strikes by australian sheep blowflies cost wool industry over 150 million a year. Organophosphate insecticides are effective because they affect nervous system and kill adult and maggots. Some sheep blowflies have mutation that makes them resistant to the insecticides. The resistance is based on a single mutation that appeared in a few individuals of the specie. The dna of the resistant fly differs slightly from that of the susceptible fly. When sprayed with the insecticide, the resistant flies have enhance fitness and survive to reproduce, while the rest die. The fly has a short life cycle but a high reproductive cycle which ensures a rapid spread of resistant mutated flies. This example shoes how genetic-based change (mutation) and a strong selective pressure (insecticide) can alter the population of sheep blowflies over time.
