A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is

1. 10         

2. 15           

3. 05           

4. zero

Consider the following four conditions (I-IV) and select the correct pair of them as adaptation to environment in desert lizards.
The conditions:
I.  Burrowing in soil to escape high temperature
II. Losing heat rapidly from the body during high temperature
III. Bask in sun when temperature is low
IV. Insulating body due to thick fatty dermis

1. (I) and (III)
2. (II) and (IV)
3. (I) and (II)
4. (III) and (IV)

What type of human population is represented by the following age pyramid?

1. Stable population

2. Declining population

3. Expanding population

4. Vanishing population

Which one of the following is categorised as a parasite in true sense?

1. Human foetus developing inside the uterus draws nourishment from the mother

2. Head lice living on the human scalp as well as laying eggs on human hair

3. The cuckoo (koel) lays its eggs in crow's nest.

4. The female Anopheles bites and sucks blood from humans.

Study the four statements (1-4) given below and select the two correct ones out of them.

(1) A lion eating a deer and a sparrow feeding on grain are ecologically similar in being

consumers

(2) Predator star fish Pisaster helps in maintaining species diversity of some invertebrates

(3) Predators ultimately lead to the extinction of prey species

(4) Production of chemicals such as nicotine, strychnine by the plants are metabolic

disorders

The two correct statements are

1. (2) and (3)               

2. (3) and (4)

3. (1) and (4)               

4. (1) and (2)

A country with a high rate of population growth took measures to reduce it. The figure below shows age sex pyramids of populations. A and B twenty years apart. Select the correct interpretation about them.

Interpretations

1. 'A' is more recent and shows slight reduction in the growth rate

2. 'B' is earlier pyramid and shows stabilized growth rate

3. 'B' is more recent showing that population is very young

4. 'A' is the earlier pyramid and no change has occured in the growth rate  

Consider the following four statements (i-iv) about certain desert animals such as

kangaroo rat.

(i) they have dark colour and high rate of reproduction and excrete solid urine.

(ii) they do not drink water, breathe at a slow rate to conserve water and have their

body

covered with thick hairs.

(iii) they feed on dry seeds and do not require drinking water

(iv) they excrete very concentrated urine and do not use water to regulate body

temperature.

Which two of the above statements for such animals are true?

1. iii and iv

2. ii and iii

3. iii and i

4. i and ii

The population of an insect species shows an explosive increase in numbers during rainy

season followed by its disappearence at the end of the season. What does this show?

1. S-shaped or sigmoid growth of this insect

2. The food plants mature and die at the end of the rainy season

3. Its population growth curve is of J-type

4. The population of its predators increases enormously

Geometric representation of age structure is a characteristic of:

1. Biotic community

2. Population

3. Landscape

4. Ecosystem

A high density of elephant population in an area can result in:

1. Mutualism

2. Intraspecific competition

3. Interspecific competition

4. Predation on one another