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.

For origin of life, which of the following is not a precondition, needed to be fullfilled by the protobionts under consideration ?
1. They should have been able to totally isolate themselve from the general environment
2. They should have been able to replicate
3. They should have acquired a perpetual source of energy 
4. Their replication should have been subject to error via mutation

Adenine was synthesized by Orgel, using the Miller apparatus, when he used the gas:

1. carbon dioxide

2. hydrogen cyanide

3. hydrogen sulfide

4. nitrogen

Which of the following organisms alive today is likely to be most similar to the first life forms that evolved on the earth?

1. Methane producing bacteria

2. Cyanobacteria

3. Unicellular algae

4. Diatoms

What provides new alleles and therefore underlies all other mechanisms that produce variation ?

1. Speciation 
2. Mutation 
3. Recombination 
4. Natural selection 

Which of the following is the most important precondition for speciation to occur?

(a) Reproductive isolation

(b) A crash of the population size

(c) Adaptive radiation

(d) Random mating