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.
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