When certain exotic species are introduced into a geographical area, they become invasive mainly because:

1. The invaded land has unlimited resources for the introduced species

2. The invaded land does not have its natural predator

3. The population of the introduced species in the invaded land is very low

4. Introduced species do not face any competition in the introduced land

In a field experiment, when all Pisaster starfish were removed from an enclosed intertidal area, the result was:

1. Increase in diversity of invertebrates

2. Extinction of many invertebrate species

3. Inability of the Pisaster to enter the area again

4. Replacement of Pisaster by other starfish

In a tide pool, 15 species of invertebrates were reduced to 8 after one species was removed. The removed species may be a:

1. Parasite                   

2. Mutualist

3. Top predator           

4. Herbivore

Which of the following is not a function of predators?

No predator can become proficient at acquiring prey because:

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)

Praying mantis is a good example of:

1. mullerian mimicry

2. warning colouration

3. social insects

4. camouflage

One of the major difficulties in the biological control of insect pest is that

(1) the predator develops a preference for other diets and may itself become a pest

(2) the predator does not always survive when transferred to a new environment

(3) the method is less effective as compared with the use of insecticides

(4) the practical difficulty of introducing the predator to specific areas.

Monarch butterfly escapes from predators by

1. foul smell                     

2. bitter taste

3. colour combination         

4. rough skin

Resemblance of one organism with its surroundings for protection and hiding is

1. mimicry               

2. predation

3. adaptation           

4. camouflage