Lecture 4-Origin of Species

Question 1

What is reproductive isolation?

Answer 1

When biological factors (Barriers) impede two species from producing viable, fertile offspring

Question 2

What are the Pre-zygotic (before fertilization) barriers?

Answer 2

• Habitat Isolation
• Temporal Isolation
• Behavioral Isolation
• Mechanical isolation
• Gametic Isolation

Question 3

What are the post zygotic (after fertilization) barriers?

Answer 3

• Reduced hybrid viability
• Reduced Hybrid Fertility
• Hybrid Breakdown

Question 4

What is a hybrid zone?

Answer 4

Region where two species come together to produce offspring

Question 5

What is allopatric speciation?

Answer 5

New species form while geologically isolated. Results in reduced gene flow between species, become more diverged

Question 6

What is sympatric speciation?

Answer 6

Subpopulations isolated in midst of parental population. Reduction in gene flow.

Question 7

What is autopolyloidy?

Answer 7

Involves 1 organism. Failure in meiosis results in tetraploid branch. Diploid gametes are produced, resulting in tetraploid offspring karyotypes

Question 8

What is allopolyploidy?

Answer 8

2 organisms, meiotic error=unreduced chromosome number in gametes.