Populations and Species

Chapter 16

Study Questions

1.         What shaped curve is formed when the distribution of traits is graphed?

2.         What is the bell curve centered on?

3.         What does it mean when the curve is skewed to one side?

4.         What is meant by the term human gene pool?

5.         Fifty percent of the population of four o’clock flowers are red and fifty percent are white. What is the frequency of the r allele?

6.         How is allele frequency calculated?

7.         How is phenotype frequency calculated?

8.         What is genetic equilibrium?

9.         What are the five assumptions of the Hardy-Weinburg Equilibrium?

10.       What is allele frequency and how is it related to evolution?

11.       Compare the morphological and biological concepts of species?

12.       Why is an understanding of the biological concept of species important for understanding evolution?

13.       What is genetic drift?

14.       Compare stabilizing, directional, and disruptive selection.

15.       What is sexual selection?

16.       Explain how mutation and migration disrupt genetic equilibrium?

17.       What are two shortcomings of the biological concept of species?

18.       What are two examples of postzygotic isolation mechanisms?

19.       What is less metabolically costly to an animal, prezygotic or postzygotic isolation? Why?

20.       What is the hypothesis of punctuated equilibrium?

21.       How can geographic isolation lead to speciation?

22.       How can disruptive selection lead to reproductive isolation?

23.       What is the relationship between adaptation to change and extinction?

24.       What are the limitations of the morphological concept of species?

25.       What type of selection causes the bell curve to narrow?

26.       How might geographic isolation have led to the evolution of two Cerion species?

27.       Why is natural selection considered the most important factor in evolution?

28.       Wood frogs and leopard frogs are reproductively isolated due to breeding at different times. Use disruptive selection to explain how the two similar populations could have become isolated.

29.       What causes variations in the traits of an organism?

30.       What results can be expected from non-random mating?

31.       What type of selection can result in speciation?

32.       Why do prezygotic mechanisms have an advantage of postzygotic isolating mechanisms?\

33.       Describe the five prezygotic isolating mechanisms.

34.       What is a population?

35.       What is a bell curve?

36.       What is gene flow?

37.       What is natural selection?

38.       Explain why stabilizing selection produces a population with variation narrowly centered on the mean.

39.       What is a species?

40.       What two steps occur in the formation of a new species?

41.       What is the result of geographic isolation on a population?

42.       Define reproductive isolation.

43.       What is the difference between prezygotic and postzygotic isolation?

44.       How does temporal isolation prevent interbreeding?

45.       What is the difference between gametic and zygotic mortality?

46.       Compare the gradual model of speciation with the punctuated equilibrium model.