Chapter 16 Focus Q's

Chpt 16.1

1.  Explain the two serious handicaps Darwin worked under while developing his theory of evolution.

2.  What did scientists realize in the 1930's about genes and variation?

3.  How are evolutionary changes described today?

4.  How many alleles do genes have?

5.  What is a population?

6.  What is a gene pool?

7.  What is the relative frequency of an allele?

8.  Are dominant alleles more frequent than recessive alleles?

9.  In a population of 44 tulips, there are 88 alleles for flower color (2 in each plant).  Of the 88 total number of alleles, 68 are for red (R) and the rest are for white (r).  What is the allele frequency for each type of allele (R and r)?

10.  Explain the two main sources of genetic variation.

11.  How does crossing over add to genetic variation?

12.  How many phenotypes of the single gene trait are present in a population?  Give an example.

13.  What type of graph represents a single gene trait?  Why?

14.  What are polygenic traits?  How many phenotypes of a polygenic trait are present in a population?

15.  What type of graph represents polygenic traits?

Chpt 16.2

1. What is fitness?

2.  What is evolutionary adaptation?

3. Natural selection never acts on genes...why?

4.  What happens to the allele contribution of an individual when that individual dies?

5.  What is a single gene trait?

6.  How does Natural selection affect single gene traits?  Explain.

7.  How can an allele have NO pressure from natural selection?  What is a human trait that has NO pressure from natural selection?

8.  What are polygenic traits?

9.  Describe a situation where directional selection is takes place.

10.  Describe a situation where stabilizing selection is takes place.

11.  Describe a situation where disruptive selection is takes place.

12.  Genetic drift is a change in the allele frequency in a gene pool due to ___________.

13.  What is the founder effect?

14.  What condition does the Hardy Weinberg principle describe?

15.  What are the 5 conditions that must all be met in order for genetic equilibrium to occur?

16.  What is the Hardy-Weinberg equation?

Chpt 16.3

1.  What do natural selection and genetic drift do to allele frequencies?

2.  What is speciation?

3.  Define species.

4.  Why can a genetic change in one organism of a population spread through a species?

5.  What is meant by reproductive isolation and how does it affect the gene pool?

6.  Complete the data table:

Type of Isolation Definition Example







7. Read the section: "Testing Natural Selection" and answer the following Q's:

        a.  What was Darwin's hypothesis?

        b.  How did the Grant's plan to test Darwin's hypothesis?

        c.  What were the two assumptions Darwin's hypothesis relied on?

        d.  How did the Grant's show variation?

        e.  What did the distribution curve look like for the variations they measured?

        f.  How did the Grant's "most interesting" discovery differ from what other scientists already knew?

        g.  How did the Grant's show directional selection in the finches?

8.  Read the section: "Speciation in Darwin's Finches" and complete the following table:

Step in Speciation Explanation of step Example