Many freshwater animals cannot live for long in sea water and vice versa because of:

1. Buoyancy related problems

2. Lack of impermeable skins

3. Thermolabile enzymes

4. Osmotic considerations

Under unfavorable conditions, many zooplankton species in lakes and ponds are known to enter a stage of suspended development called as:

1. Dormancy

2. Hibernation

3. Aestivation

4. Diapause

The given age pyramid represents a:

1. Fast expanding population

2. Slowly expanding population

3. Stable population

4. Declining population

Darwinian fitness is represented by:

1. Low r value

2. High r value

3. High K value

4. Low K value

Under a particular set of selection pressures, organisms evolve towards the most efficient:

1. Thermoregulation

2. Water conservation

3. Respiration

4. Reproduction strategy

A population interaction where one species is harmed whereas the other is unaffected is called as:

(1) Mutualism

(2) Competition

(3) Predation

(4) Amensalism

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

A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species is found to expand its distributional range dramatically when the competing species is experimentally removed. This is called:

1. Competitive Exclusion

2. Competitive Release

3. Competitive Supremacy

4. Competitive Inclusion

Which of the following is not an ectoparasite?

1. Lice on humans

2. Copepods on marine fishes

3. Mistletoe on other plants

4. Female Anopheles on humans