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Explain how hybrid plants and animals are produced.

This module begins your study of evolution and ecology with some of the basic concepts related to species, populations, gene pools, and genetic variety.  Information obtained from population genetics is used as the basis for classifying organisms and studying evolutionary change.  In this module, you will study population genetics and be able to describe how a lack of understanding of population genetics has contributed to the eugenics movement.  In addition, this module will also cover the specifics of evolution and natural selection.  For example, you will look at the factors influencing natural selection—the process that leads to evolution by “selecting” which genes will be passed on to the next generation.

Learning Objectives

Upon completion of this module, you should be able to:

8A		Differentiate between the biological species concept and the morphological species concept.
8B		Explain how hybrid plants and animals are produced.
8C		Distinguish between gene pool and genetic diversity.
8D		Relate cloning and hybridization to asexual and sexual reproduction.
8E		Explain how a lack of understanding about population genetics contributed to the eugenics movements.
8F		State why all organisms of a species are not the same.
8G		Explain how each of the following affects the genetic diversity within populations: mutation, sexual reproduction, population size, and migration.
8H		Describe three processes that could result in different populations of the same species having different gene combinations.
8I		Explain how the concepts of evolution and natural selection are related.
8J		List the five conditions to prevent frequency changes, according to the Hardy-Weinberg concept.
8K		Describe how individuals produced by sexual reproduction can have fitness different from that of their parents.
8L		Explain how natural selection can change the nature of a species.
8M		State why genetic diversity is essential for natural selection to occur.
8N		Describe how mutation and migration affect the genetic diversity of a population.
		Identify and describe three circumstances that can prevent a specific allele from being expressed in the phenotype of an organism.
8P		Explain why excess reproduction is important to the concept of natural selection.
8Q		Describe the contributions of the following individuals to the evolutionary thought: Lamarck, Buffon, Wallace, and Darwin.
8R		List the assumptions by Darwin that were important to his developing the theory of natural selection.
8S		Explain how survival, reproductive success, and mate selection can alter gene frequency from one generation to the next.

Module 5 Reading Assignment

Enger, E. D., Ross, F. C., & Bailey, D. B. (2012).  Concepts in biology (14th ed.). New York: McGraw-Hill. Chapter 12 and 13.

Optional Reading Assignment:

Chapter 14, The Formation of Species and Evolutionary Change.

Evolution and Natural Selection

Evolution is simply change over time, like the trees losing their leaves and mountain ranges rising and eroding; however, this is not biological evolution.  Biological evolution is that all life on earth shares a common ancestor, just like you and a cousin share the same grandmother.  The evolutionary process has given diversity to our environment from species, individual organisms, and molecules.  Charles Darwin discovered the theory of evolution through natural selection.  His process of natural selection included the following theories:

1. More offspring are produced than can possibly survive.
2. Traits vary among individuals, which leads to the differential rates of survival and reproduction.
3. Trait differences are heritable.