Slide 16

Question 1

2 types of reproductive isolating barriers

Answer 1

1. Pre zygotic
   - habitat isolation
   - temporal isolation (cicadas)
   - mechanical isolation
   - behavioral isolation
2. Post zygotic
   - hybrid inviability
   - hybrid infertility (sterility)

Question 2

Pre zygotic isolation traits can diverge in different populations

Answer 2

1. Divergent natural selection
2. Divergent sexual selection
3. Genetic drift

Question 3

What does this show

Answer 3

Gradual (left) and punctuated (right) speciation

Question 4

Major mechanisms of reproductive isolation (allopatric divergence)

Answer 4

• Genetic drift
• Divergent sexual selection
• Divergent natural/ecological selection

Question 5

Major mechanisms of reproductive isolation (divergence with gene flow in sympatry)

Answer 5

• Reinforcement speciation (secondary contact))
• hybridization (hybrid species)
• sympatric speciation (no allopatric phase)

Question 6

4 geographical modes of speciation

Answer 6

1. Allopatric
   - geographical barrier
2. Peripatric
   - budding of new species, different niche
3. Parapatric
   - budding of new species, same niche
4. Sympatric
   - genetic polymorphism within population