Download Microevolution is a change in population`s gene pool [1]

GUIDED READING - Ch. 14 - Section 4
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Microevolution is a change in population’s gene pool [1]
1. Natural Selection acts on the INDIVIDUAL. The individual lives or dies and reproduces successfully
or not in its environment. At which level does evolution occur though? Why?
2. What is a population’s gene pool?
3. Which processes lead to genetic variation in a population?
4. a. In the hypothetical mouse population shown, how many allele versions exist?
b. How many total alleles are present in this population’s gene pool?
b. What are the frequencies of the alleles in this population? Show your calculations.
5. What is microevolution?
6. a. If a population is NOT experiencing changes in the allele frequencies of their gene pools, the
population is not evolving. What do we call this condition?
b. Is this a common condition for populations to exist in?
7. a. What if you return to the population of mice 10 years later. Many generations have passed and
the population (and its genetic make-up) is as shown below. What are the new frequencies of
the allele types in this population? Show your work.
b. Has this population evolved? Why do you say yes or no?
8. a. What is genetic drift?
b. Does genetic drift cause evolution? Why?
c. Which size populations are most susceptible to the effects of genetic drift? Why?
9. a. Explain the genetic drift event referred to as the Bottleneck Effect. What is it at the genetic level
and how does it occur?
b. What are examples of environmental disasters that may cause a Bottleneck Effect?
10. Why are conservation biologists concerned about species when their populations get too small?
Explain what could go wrong and why?
11. Let’s see if you understand. In the Bottleneck Effect, only a few individuals survive to reproduce. How
come this is not considered natural selection then?
12. a. Another type of Genetic Drift is the Founder Effect. What is the cause and result of this?
b. What is an example of the Founder Effect we discussed in class and is not discussed in your text?
Explain why it is an example of the Founder Effect and genetic drift.
13. a. What is gene flow?
b. How does gene flow happen?
c. What is the effect on the gene pools of populations experiencing gene flow?
d. What is an example of gene flow that you see happening around you?
14. a. Mutations alter an organisms DNA in a cell. Mutations may happen in any cell in your body either
because the DNA gets damaged because of mutagens, environmental factors that mutate DNA, or
because the DNA is copied wrong during S phase of the cell cycle when the cell is dividing. When
does a mutation however pass into the gene pool of a population? Remember, for this to occur, an
offspring needs to inherit the mutation from a parent
b. How do mutations contribute to the ability of a population to evolve?
15. How do the sayings “struggle for existence” and “survival of the fittest” describe natural selection?
16. Describe what is meant by the biological fitness of an organism. [1}
17. Describe the Grants' hypothesis about how environmental conditions led to microevolution over the
span of 30 years among the finches of Daphne Major.
[1] Campbell, Heyden, Williamson. 2006. Biology: Exploring Life. Prentice Hall: Boston, MA.