Lecture 13: Speciation

Question 1

2 models of Speciation:

Answer 1

• allopatric speciation

- sympatric speciation

Question 2

speciation:

Answer 2

the splitting of one species into two

Question 3

speciation results in generation of new

Answer 3

species 
genera
orders
classes
phyla

Question 4

3 types of selection:

Answer 4

• directional
• stabilising
• disruptive

Question 5

Gene flow =

Answer 5

exchange of genes between populations as a result of movement & interbreeding of individuals

Question 6

2 changes that occur during speciation:

Answer 6

1) Divergence - species adapt to different environments

2) Reproductive isolation - species lose the ability to interbreed

Question 7

Allopatric speciation; Reproductive isolation & divergence

Answer 7

Reproductive isolation&raquo_space;> Divergence

Question 8

sympatric speciation; Reproductive isolation & divergence

Answer 8

Divergence&raquo_space;> reproductive isolation

Question 9

Allopatric speciation;

1) reproductive isolation

Answer 9

(temperatures, backgrounds, rainfall)

Question 10

Sympatric speciation: divergence of form

Answer 10

Disruptive selection causes one species to diverge into two forms

Question 11

allopatric speciation

Answer 11

or geographic speciation is speciation that occurs when biological populations of the same species become vicariant, or isolated from each other to an extent that prevents or interferes with genetic interchange

Question 12

sympatric speciation reproductive isolation:

Answer 12

A x A - fit offspring 
A x B - unfit offspring 
B x B - fit offspring. 
-Hybrid offspring are adapted to neither environment. These offspring are removed by natural selection. 
"post-zygotic isolation"

Question 13

characteristic that produce reproductive isolation:

Answer 13

• different habitats
• different morphology (appearance)
• different behaviour
• breed at different times of the year
• sex cells are incompatible
• offspring do not survive or are not sterile

Question 14

sympatric speciation:

Answer 14

the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

Question 15

Allopatric speciation;

2) Divergence

Answer 15

(wide spread, separation occurs in middle = two different species)