Cassit Birds: Lessons on Genes, Inheritance,and Evolution Lesson Four Written by Jennifer A. Collins Jen's Other Lessons   ~  Education overview  ~   one  ~   two  ~   three  ~   four  ~   |
Concept:
Natural selection acts on phenotypes and cause genetic and phenotypic changes in a population over time.
Overview: Students use their Cassit population to simulate how natural selection can affect a population over time by "killing off" birds with particular features so that they can no longer pass on their genetic material. Students discuss how this can lead to speciation/evolution. Time:40-60 minutes Grouping:partners, class Vocabulary: natural selection, evolution Advance Preparation:
Materials:
Procedure:
1. Explain to students that they are going to simulate a situation where certain features were selected for in a population. For example, explain to students that for some reason, birds with short/fat beaks were unable to get very much food. Ask students to hypothesize reasons why this situation would exist.
2. Have all students with short fat beak birds stand-up. Select over 50% of those birds to be eliminated from the next mating. They should still hold onto their birds for another simulation.
3. Repeat the mating process and record data so that students can see how such an event would affect the overall population. You can repeat this as many times as you see necessary to show how the population changes.
4. You can repeat this process to show how the population could change due to other factors.
Sample Scenarios:
5. Ask students the following questions:
Alternative Ideas:
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