Ichy Salmon: variation and adaptation

1. Ichy Salmon: variation and adaptation Learning Goal: Students will understand the relationship between genetic variation and adaptation. Intended Learning Outcomes: The students will be able to: • Name the sources of genetic variation and explain how each contributes to genetic variation. • Be able to identify the selective pressure(s) that could result in an organism’s adaptation to a given environment. • Explain how different populations adapt (evolve) differently in seemingly similar environments. • Explain why mutations and not the environment are the source of genetic variation. • Explain how abiotic and biotic factors can reduce genetic variability • Compare and contrast genetic variation for certain traits in different environments (organism living in tropics vs. temperate vs. a change in temperature). • Predict how generation time and fecundity contribute to the potential for adaptation. • Given the genetic variability of a population predict its ability to adapt to environmental changes. • Describe how an organism’s dispersal patterns can play a role in genetic variability in a population. • Assess the relationships among genetic variation, fitness and population growth in response to environmental change.

2. Clicker exercise 1. Fitness is a term often used by biologists to explain the evolutionary success of certain organisms. Below are descriptions of 4 female salmon. Salmon only reproduce once in their life time. Which salmon might a biologist consider to be the most fit?

3. Clicker exercise 2. Salmon only reproduce once in their lifetime. Which population has the greatest genetic variation and greatest potential to adapt to environmental change?

4. Salmon life cycle

6. Barriers to reproduction • Negligible dispersal • Limited gene flow across populations • One chance to reproduce • Many obstacles along the way

7. Ich life cycle

8. Ichy Salmon • Video & scenario set up http://www.latimes.com/news/nationworld/nation/la-na-ichfish15-2008jun15,0,587682.story

9. Brainstorming • What biotic, abiotic or genetic factors could contribute to the increase in ich infection rates?

10. Making connections • How could this infection affect survivorship, reproduction and population growth?

11. Post-evaluation Assignment • What factors need to be considered to develop a “sound” policy to address the issue of genetic diversity and sustainability?