1.8.4 Postzygotic Reproductive Isolation

Question 1

postzygotic isolation

Answer 1

• mechanisms stop the flow of genes between organisms after fertilization has occurred. Three categories of postzygotic isolation mechanisms include
  hybrid viability, hybrid fertility, and hybrid breakdown.

Question 2

note

Answer 2

• If fertilization occurs between members of two separate populations, reproductive barriers can still interrupt gene flow.

Question 3

hybrid viability

Answer 3

• The zygote (fertilized egg) may not survive long after fertilization, resulting in spontaneous abortion.

Question 4

hybrid infertility

Answer 4

• the resulting zygote will develop into a viable

organism but will not be able to reproduce.

Question 5

hybrid breakdown

Answer 5

• The resulting zygote will develop into a viable organism and may be able to reproduce, but the offspring of the hybrid might not be viable or successful and might be infertile.

Question 6

If two species breed and produce infertile offspring, then the integrity of each species is maintained by

Answer 6

• hybrid sterility

Question 7

Which of the following is not considered to be a reproductive isolating mechanism?

Answer 7

• feeding behavior

Question 8

A lion and tiger mate, but their offspring is sterile. This is an example of

Answer 8

• postzygotic isolation

Question 9

Which of the following is not an example of a postzygotic barrier?

Answer 9

• Crossing the Northern oriole and the Baltimore oriole results in viable offspring. The offspring are fertile and produce normal, fertile offspring that are capable of reproducing with both the Northern and Baltimore oriole.

Question 10

Although lions and tigers can mate to produce viable hybrid offspring, hybrids have never been observed where their ranges overlap. Hybrids were probably not produced because of

Answer 10

• behavioral isolation