Chapter 1, Problem 6SA

Evolution Biologists define evolution as the change in the frequency of alleles (variations of a gene) in a population. Consider the following situation: Two colors of grasshoppers-brown and red-result from the two variations (alleles) of the color gene in this species. These grasshoppers live in two areas: an area with brown soil, and on an adjacent mountain with reddish soil. All the grasshoppers in both areas were accidentally killed by a fire. Ecologists re-introduced 1000 red and 1000 brown grasshoppers into each of the two soil areas. And, grasshoppers are a great food source for any bird that can catch them. 1. What do you think the ecologists discovered when they returned to the experimental sites five years later? 2. What factor controls the actual color of a grasshopper? 3. What determines the color frequency of grasshoppers in the two soil areas? 4. Is there only one direction of change during evolution? Explain your answer.

What is Microevolution? A) The change of a population over several generations B) The history of a species from its origin C) The history of all populations and their descendants

Say there is a population of plants that live in a wetland, and are adapted to tolerate both flooding and drought. One year, the wetland floods completely, and only the most water-tolerant plants are able to survive. The wetland never drains, and over many years the plants adapt to stay submerged all year. Many generations later, the wetland returns to being wet and dry, and the entire population dies out. Is this an example of a historical constraint or genetic correlation?