Science (English Medium) इयत्ता १२ - CBSE Important Questions

What is mutualism?

Apart from being a part of the food chain, predators play other important roles. Mention any two such roles supported by examples.

State Gause’s competitive exclusion principle.

Describe the mutual relationship between fig tree and wasp and comment on the phenomenon that operates in their relationship.

Define the following term:

Commensalism

Mention any two examples where the organisms involved are commercially exploited in agriculture.

What is commensalism?

What is brood parasitism? Explain with the help of an example.

“It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted.” Explain with the help if examples and sketches.

How are productivity, gross productivity, net primary productivity and secondary productivity interrelated ?

The primary productivity in an ecosystem is expressed as ______.

1. gm^-2 yr^-1
2. gm^-2 yr
3. Kcal m^-2 yr^-1
4. Kcal m^-2

Assertion (A): Decomposition process is slower if detritus is rich in lignin and cutin.

Reason (R): Decomposition is largely an oxygen requiring process.

List any four techniques where the principle of ex-situ conservation of biodiversity has been employed.

Identify ‘a’ and ‘b’ in the figure given below representing proportionate number of major vertebrate taxa.

Why should we conserve biodiversity ? How can we do it?

'in-situ' Conservation can help endangered/threatened species. Justify the statement.

Name and describe any three causes of bio-diversity losses.

Explain the concept of "co-extinction" by taking two examples.

List any three major causes of loss of biodiversity.

Enlist two criteria that are used to identify a region for maximum protection as 'Biodiversity hotspots'.