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 |
Predators in nature are ‘prudent’ because:
1. | This keeps their own population in check |
2. | Prudence keeps their hunting skills up to date |
3. | Lack of prudence can lead to their own extinction |
4. | This helps in the maintenance of genetic diversity in their gene poll |
Camouflage is:
1. | Cryptic coloration | 2. | Aposematic coloration |
3. | Incidental coloration | 4. | Dispersive coloration |
The monarch butterfly acquires distasteful toxin during:
1. | Caterpillar stage by feeding on a poisonous weed |
2. | Caterpillar stage by feeding on sap of a grass |
3. | Adult stage by feeding on nectar of a flowering plant |
4. | Adult stage by feeding on latex of deadly night shade plant |
About what percent of all insects is phytophagus?
1. | 1 % | 2. | 25 % |
3. | 65 % | 4. | 99 % |
The most common means of morphological defense in plants against herbivory are:
1. | Spines | 2. | Thick cuticle |
3. | Thorns | 4. | Slime |
As a mechanism of defense against herbivory, Calotropis:
1. Has a large number of thorns
2. Secretes cardiac glycosides
3. Produces a neurotoxin, strychnine
4. Releases a hallucinogen
Nicotine, caffeine, quinine and opium produced by plants are actually:
1. | Primary metabolites needed in reproduction |
2. | Secondary metabolites needed for growth |
3. | Alkaloids that are present in seeds |
4. | Defenses against grazers and browsers |
Consider the given statements regarding competition amongst organisms:
I: | Only related species can compete for the same resource |
II: | Competition occurs only when the resources are limiting |
The correct statement/s is/are:
1. | I alone | 2. | II alone |
3. | Both I and II | 4. | Neither I nor II |