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Unit 4.2 Mechanisms of Evolution Study Guide
1. Define Natural Selection:
2. What are Darwin’s observations that lead to his theory of Natural Selection?
- Organisms have more ____________________ than can survive.
- Individuals in populations have differences called __________________________.
- Some of these differences are ____________________________________.
- Organisms with the favorable genes ___________________ and _________________________.
3. If an organism is well-adapted to its environment, what is likely to happen?
4. If an organism is NOT well adapted to its environment, what is likely to happen?
5. Explain why these statements are incorrect:
a. Adaptations that are favorable in one environment will be favorable in all environments.
b. All of the different species in one environment will all have the same adaptations to survive in that
environment.
c. An adaptation that is favorable in an environment today, will always be favorable in that environment.
6. Using the population and variations in fur color below, come up with an example for each type of natural
selection AND explain how the population would change over time.
Stabilizing
Directional
7. What is the difference between acquired characteristics and genetic characteristics?
8. How do bacteria become resistant to antibiotics (medicine that kills bacteria)?
Use the pictures with each question below to explain an answer:
9. How does founder effect cause changes in allelic frequencies in a gene pool?
Disruptive
10. How does genetic drift in the form of natural disasters change allelic frequencies in a gene pool?
11. How does gene flow cause changes in allelic frequencies in a gene pool?
12. What is the gene frequency of the dark color in each of the populations below?
a.
b.
13. What is speciation? AND, What causes speciation to occur?
14. Explain why each of the following would keep a gene pool from changing:
a. No mutations in DNA:
b. All mating is random:
c. No natural selection/ No beneficial traits:
15. Compare and contrast divergent and convergent evolution:
16. What are the different ways in which reproductive isolation can occur?
- _____zygotic (keeps from reproducing)
- _____zygotic (hybrid offspring affected)
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17.
Allopatric speciation is…..
Sympatric speciation is…..
18. Adaptations are __________ characteristic that helps an organism to __________ long enough to be able to
__________ more successfully – can be ____________________ or _____________________.