A location with luxuriant growth of lichens on the trees indicates that the:-

1. trees are very healthy

2. trees are heavily infested

3. location is highly polluted

4. location is not polluted

In the case of peppered moth (Biston betularia), the black-coloured form became dominant over the light-coloured form in England during the industrial revolution. This is an example of:

Industrial melanism is an example of:
 

Directional selection favours:

(1) Both extremes of a trait

(2) Intermediate form of a trait

(3) Environmental differences

(4) One extreme form over the other extreme form and over intermediate forms of the trait

If more individuals acquire peripheral character value at both the ends of the distribution curve; in such case natural selection has resulted in

 ............... operates to eliminate intermediate phenotypes.

Karn & Penrose showed that birth weight follows a normal distribution, that mortality for newborns is greater for those either under- or over-weight, and that the mean birth weight (7 lbs) coincides with that showing minimum mortality. The type of natural selection operating here is shown by the graph:
 
1. (a)
2. (b)
3. (c)
4. Both (a) and (b)

In a species, the weight of a newborn ranges from 2 to 5 kg. 97% of the newborns with an average weight between 3 to 3.3 kg survive whereas 99% of the infants born with weights from 2 to 2.5 kg or 4.5 kg to 5 kg die. Which type of selection process is taking place?

Natural selection is best defined as occurring when the environment causes :
1. differential success in reproduction

2. differential mortality

3. assortative mating

4. a reduced gene pool

Which one of the following populations would most quickly lead to two groups with few shared traits?
1. a population with disruptive selection
2. a population with directional selection
3. a population with stabilizing selection
4. a population with no selection