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Assignment 6
 

Assignment 6

Occasionally populations undergo "crashes," when the population size gets too small. For example, a rapid reduction in population size can occur due to natural disasters such as flood, fire, tornadoes, drought, and other extreme weather conditions. These natural disasters are frequently unselective in nature—they kill individuals throughout the population and are not selective for a particular phenotype. Even if population numbers recover, the effect of a natural disaster can have an impact on the gene pool in a population for many generations because the range of genotypes (both frequency and number) in the population that survived the disaster may not be the same as it was in the original population. Biologists call this effect a bottleneck effect. Working within PopulationGeneticsLab and referring to the detailed instructions on Assignment 6, answer the questions below.
1 .       Conduct an experiment in which there is very little genetic drift. Repeat the experiment with moderate and high frequencies of "disasters" that reduce population numbers to small values. What is the impact of these population bottlenecks?  



2 .       How do these disasters affect the probability of population extinction?  



3 .       Can these effects be mitigated by allowing migration to occur among the population? Yes or no? Design and carry out experiments to examine this idea. Based on your results from these experiments, if you were a conservation biologist, what would these data suggest to you about the design of natural reserves?  








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