Module 8 Lesson 2 - 6

Lesson Summary

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In this lesson, you have learned how to calculate changing frequencies of alleles. These changes can illustrate that a population is evolving. These changes can be in response to a changing environment. For example, the increase in the allele for light brown hair in many species of gopher is increasing because these individuals survive in a habitat that is becoming increasingly arid.

Why do ecologists study population changes? By using past studies, what can they predict? Scientists are learning about the affects of climatic changes on species and their characteristics. They can use these studies to explain changes in populations due to weather conditions, disease, change in prey-predator relationships, and other factors that you have read about in your textbook.

Humans are realizing the effects of our practices on the environment and the effects on other species and their populations. By understanding the causes of changes to allele frequencies, we may understand better the effects that mankind has on the ecosystem. The Hardy Weinberg equation is a tool used to determine if genetic change (evolution) is occurring within a population.

In terms of the allele frequencies, p represents the frequency (number in subgroup/total number) of the dominant allele in the gene pool, and q represents the frequency of the recessive allele in the gene pool. p + q = 1 because the dominant alleles plus the recessive alleles constitute the whole gene pool.