Evolutionary Forces
Standard 1.2 Natural selection acts on phenotypic variations in populations.
Performance Indicators
a. Evaluate data-based evidence that describes evolutionary changes in the genetic makeup of a
population over time. [SP 5.3]
b. Connect evolutionary changes in a population over time to a change in the environment. [SP 7.1]
Standard 1.9
Populations of organisms continue to evolve.
Performance Indicators
a. Describe a model that represents evolution within a population. [SP 1.2]
b. Evaluate given data sets that illustrate evolution as an ongoing process. [SP 5.3]
Topic Presentation: Prezi
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Videos By Paul Anderson: “Genetic Drift” “Evolution Continues”
“Crash Course: Biology” Videos: Population Genetics- When Darwin Met Mendel: Biology #18
Text book reading: Ch 23 p. 475-484
Questions to answer:
1. Explain what the “modern synthesis” is. How is it different from Darwin’s original theory of evolution?
2. Why does evolution have to involve the change of the genetic makeup of a population over time?
3. Explain each of the following modes of evolution in a population. For each one, describe the cause of change in
the genetic makeup of a population and how the population evolves as a result of that change, and provide 1 “real
world” examples of the process in action:
1. Natural Selection
2. Genetic Drift
3. Gene Flow
4. Sexual Selection
4. Why is evolution an emergent property of populations of organisms? Why are individuals unable to evolve?
5. Compare the effects of disruptive, directional and stabilizing selection on the genetic makeup of a population.
6. Why do traits have to be heritable for evolution to affect them?
Things you should make sure you understand:
 How to identify a particular mode of evolution in a population if given details of how the environment and genetic
makeup of the population are changing over time.
 How the different modes of evolution affect a population of organisms in similar, and different ways.
Class Activity: Natural Selection and Evolution of the Rock Pocket Mouse
Lab: Artificial Selection in “Fast Plants”