Most often the factor that initiates the speciation of two populations is :

1. geographic separation

2. inability of gametes to fuse

3. different courtship behaviors

4. different copulatory organs

Genetic drift occurs when a few individuals of a species colonize an island. This phenomenon is :

(a) the bottleneck effect

(b) the founder effect

(c) assortative mating

(d) random mating 

Darwin believed that a giraffe has a long neck because:

1. a creator designed it that way

2. catastrophes eliminated short neck forms

3. its ancestors stretched their necks to get food

4. ancestral giraffes with longer necks got more food and left more surviving off-springs.

In a sympatric speciation, there is:

1. geographical isolation between groups of population
2. no geographical isolation between groups of population
3. reproductive isolation of a subpopulation in the midst of the parent population 
4. geographical isolation bout no reporoductive isolation

Which of the following types of natural selection reduces variation but does not change the mean value?

(1) Directional

(2) Stabilizing

(3) Disruptive

(4) All of these

In genetic drift, the term "genetic bottleneck" means:

1. reduction in allele frequencies or richness

2. random change in allele frequency by chance alone

3. sudden increase in the number of individuals

4. reproductive isolation of the population

Which of the following is not a precondition for Hardy-Weinberg Equilibrium?

1. The population should be large

2. The mating should be assortative

3. There is no gene flow into or out of the population

4. All offspring should be equally fertile.