Ichy Salmon: variation and adaptation Learning Goal: Students will understand the relationship between genetic variation and adaptation. Intended Learning.

Ichy Salmon: variation and adaptationLearning 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.

Clicker exercise

Salmon A Salmon B Salmon C Salmon D

Body length 30 inches 23 inches 25 inches 32 inches

Fecundity 6000 4000 4500 5800

Age at death

5 yrs 4 yrs 3 yrs 5 yrs

Comments Salmon A is very healthy, strong and clever

Salmon B swims very fast

Salmon C swims further to spawn than any of the other salmon

Salmon D is the first fish to reproduce during a spawning season

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?

Clicker exercise

Salmon Pop A

Salmon Pop B

Salmon Pop C

Salmon Pop D

Range/stream reach

500 km 800 km 200 km 1000 km

Popn Size 1000 500 50 100

Mean Lifespan

4-5 yrs 3-4 yrs 2-3 yrs 4-5 yrs

Mean Fecundity

6000 4000 4500 5800

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

Salmon life cycle

Barriers to reproduction

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

Ich life cycle

Ichy Salmon

• Video & scenario set up

http://www.latimes.com/news/nationworld/nation/la-na-ichfish15-2008jun15,0,587682.story

Brainstorming

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

Making connections

• How could this infection affect survivorship, reproduction and population growth?

Post-evaluation Assignment

• What factors need to be considered to develop a “sound” policy to address the issue of genetic diversity and sustainability?