Title: Week 1 overview
Course: BIO-182 RTZ > Section: Week 1 - Mechanisms of Evolution

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TO DO before [assignment due date]:

- Read Chapter 21 (Mechanisms of Evolution).
- Begin (and maybe complete: LaunchPad Learning Curve (Chapter 21)
- Begin (and maybe complete): LaunchPad Learning Activities (Chapter 21)
- Optional: LaunchPad Summary Quiz
- Optional: Exam #1a

CHAPTER OVERVIEW:

Chapter 21 –  Mechanisms of Evolution. This chapter provides the foundation for the theory of evolution by natural selection. People often dismiss this concept by focusing on the word "theory." What many fail to realize is that, in science, a theory does not refer to a single hypothesis but to a series of statements about a natural phenomenon that are supported by evidence from many different fields. Often a theory includes both a pattern and a process statement. For example,  the Cell Theory you studied in Bio181 states that all living organisms are made up of cells (the pattern) and all living cells come from preexisting cells (the process). In the theory of evolution by natural selection, the pattern portion is described by the statement that all organisms share a common ancestor and the process of evolution is natural selection.

- The chapter begins with an overview of the development of the theory of evolution by natural selection. Read this section carefully. Of particular importance is the section which discusses the relationship between genetic variation and phenotypic variation. Try to answer the questions presented in the Recap box 21.1.
- Section 21.2 contains important information. Read this section carefully. Note: mutations are the only source of variation in a population, however, mutations by themselves are not a mechanisms of evolution. Instead, they provide the variation that nature acts upon,selecting those individuals best suited for the current environment.
- Section 21.3 discusses how biologists measure evolutionary change. Read this section carefully; the concepts presented are integral to understanding how evolution occurs and are difficult for some. Remember that one definition of evolution is "a change in allele frequency in a population." When we talk about changes in allele frequency, we delve into the field of population genetics.
  - Population genetics examines both changes in allele frequency and consequences of natural selection on populations. So, in a population allele frequency is a measurable thing and is accomplished by using what is called the Hardy-Weinberg equations (see supplemental material below).
  - The second aspect of population genetics is an examination of the effect of natural selection on the characteristics of a population, a process that can lead to the formation of new species.
- The next section in this chapter looks at the distribution and maintenance of variation within populations. This section wraps up chapter 21 nicely. Skim section 21.4. Be familiar with the terms but focus your attention on the previous two sections.
- Finally, evolution is not omnipotent (all powerful). Constraints are imposed on organisms that limit how far and in what directions they can evolve. Read section 21.5 carefully.
  - If you are interested in learning more about the connection between genes and evolution, read Chapter 20 (Genes, Development, and Evolution). It is a fascinating story that explains genetic evidence for the idea that living organisms share a common ancestor as well as the constraints imposed on evolution of body plans. Truly fascinating, unfortunately, this is not part of BIO182 at this point in time.

SUPPLEMENTAL MATERIAL: Please note that reading/viewing these materials are completely optional,  although you may find some of them interesting and/or helpful.

- Bozeman Biology (Review of Evolution)

https://www.youtube.com/watch?v=sBM9ZKTQ1PQ

- Natural Selection (Bozeman Biology)

https://www.youtube.com/watch?v=R6La6_kIr9g

- Natural Selection (Crash Course Biology)

https://www.youtube.com/watch?v=aTftyFboC_M

- Hardy-Weinberg Equations (Bozeman Biology)

https://www.youtube.com/watch?v=oEBNom3K9cQ

- Population Genetics (Hardy Weinberg Equations; Crash Course Biology)

https://www.youtube.com/watch?v=WhFKPaRnTdQ

- Genetic Drift (Bozeman Biology)

https://www.youtube.com/watch?v=mjQ_yN5znyk

INTERESTING ARTICLES:

1. What Darwin Never Knew: http://www.pbs.org/wgbh/nova/evolution/darwin-never-knew.html
2. Keeping Mates Close and Competition in a Sea Sponge:
3. Evolution Never Stops: http://io9.com/50-000-generations-of-bacteria-prove-that-evolution-nev-1466803805