Text Readings in Lewis	Review questions
Chapter 18 Chapter 20	Pg. 388: To Review; 1, 2, 3, 5, 6, 7, 9, and 10 To Think About; 4 and 7 Pg. 420-1: To Review; 1, 3, 5, 6, and 7 To Think About; 3, 6 and 7

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Objectives
After studying this material you should be able to:

1. Define evolution and describe biological evolution in terms of change in allele frequency in a population.

2. Explain Darwin's main ideas concerning natural selection and evolution.

3. Explain what "fitness" is and why it is necessary for judging the adaptiveness of a trait.

4. Describe evolution as changes in allele frequency resulting from directional, stabilizing, and disruptive selection.

5. Provide examples of evolution resulting from natural selection.

6. Describe what is meant by artificial selection versus natural selection.

7. Describe an example in which natural selection has affected the virulence and/or spread of a human disease.

biological evolution	artificial selection	natural selection
microevolution	macroevolution	allele frequencies
directional selection	stabilizing selection	disruptive selection
genetic variation	selective agent	mutation
differential reproduction	sexual selection	"fitness"
adaptation	balanced polymorphism	sexual dimorphism

Extra Credit Discussion - Book Reviews of The Beak of the Finch
Some of your classmates are reading, reviewing, and discussing this book dealing with natural selection and evolution.

What is Evolution? Biological Evolution? Descent with Modification

BUGHUNT! - A computer model of natural selection.

• Biological Evolution:
  • Microevolution: changes or shifts in allele frequency within a population.

  • Macroevolution: accumulated changes in allele frequency in two populations that precludes their interbreeding leading to the formation of a new species.

• Can an individual change his/her alleles during a lifetime? Can we control that change?

• Can individuals evolve?

• What factors act to increase genetic variation in a population?

• Does natural selection increase or decrease genetic variation in a population?

Natural Selection is the mechanism by which evolution occurs (this is the theory part).

• Observation #1: Organisms vary and some variations are inherited.

• Observation #2: More individuals are born than survive to reproduce.

• Observation #3: Individuals compete with one another for limited resources that enable them to survive.

• Inference #1: Traits or phenotypes of some make them better able to survive and reproduce in certain environmental conditions.

• Inference #2: Selective agent or agent in the environment "weeds out" less adaptive traits before individuals can reproduce or selects for more adaptive traits allowing for survival and reproduction= natural selection.

Fitness:

• What is it (evolutionarily speaking)?

• Survival is necessary, but insufficient as a criterion for judging the adaptiveness of a trait.

• Are the most "fit" organisms always the biggest, strongest and fastest in the population?

• Directional selection: selection for one extreme of a trait
  • cadmium resistance

  • peppered moth

• Stabilizing selection: selection of intermediate forms of a trait
  • human birthweight

• Disruptive selection: selection for two extreme expressions of a trait
  • large and small beak size

• Sexual Selection: The ability of individuals to differentiate and select a mate
  • sexual dimorphism

• Ebola - Why did it not wipe us all out?

• Tuberculosis

• AIDS

• Hantavirus

• Antibiotic Resistance

• Balanced Polymorphism (Advantage for carriers of genetic disease)

  Sickle Cell Disease and Malaria

  • HbS/HbS=sickle cell disease
  • HbA/HbS=sickle cell carrier & malaria resistent
  • HbA/HbA=no sickle cell disease (wild-type) & susceptible to malaria

• Migration
• Genetic Drift
• Mutation
• Non-random mating