AIIMS Botany Ecosystem Class 12 Questions

Select the correct option w.r.t. Age pyramids.

Select the correct match | (I) | (II) | (III) | | :--- | :--- | :--- | | (a) + | (i) - | (P) Amensalism | | (b) - | (ii) - | (Q) Commensalism | | (c) - | (iii) 0 | (R) Predation | | (d) + | (iv) 0 | (S) Competition |

The total amount of organic matter synthesized by producers per unit time and per unit area, in the process of photosynthesis is called as gross primary productivity (GPP). Primary productivity is high and sustained throughout the year in the tropical area while it is limited in temperate area by cold climate and small growing period. Maximum sunlight is available in tropics whereas poles receive minimum sunlight. Due to this, photosynthesis is maximum and net primary productivity (NPP) is highest (>20 t ha⁻¹ year⁻¹) in tropics against average (8 t ha⁻¹ year⁻¹) in temperate forests. So, the correct answer is 'Both Assertion and Reason are incorrect'.

10% law of energy transfer (pyramid of energy) was given by Lindermann. In this, only 10% of total energy received by one trophic level is transferred to next trophic level.

Assertion: A biotic community has higher position than population in ecological hierarchy. Reason: Population of similar individuals remains isolated in the community.

Read the Assertion and Reason carefully to mark the correct option from those given below Assertion Gross primary productivity is always more than net primary productivity. Reason Consumers exhibit secondary productivity in a ecosystem.

In each of the following questions statement of Assertion is given followed by corresponding statement of Reason. Of the statements, mark the correct answer as Assertion (A) The rate of decomposition of detritus is reduced in the regions of high altitude. Reason (R) It happen due to immobilisation of nutrients.

Assertion (A) Presence of green plant is essential for greenhouse effect. Reason (R) Chlorophyll of green plants causes greenhouse effect.

Assertion (A) Genecology is the study of genetic compositions and changes is relation to the origin of ecades, ecotypes, new sps., etc. Reason (R) Autecology deals with the study of a group of organisms.

Assertion : Some marine animals find it difficult to live in fresh water and vice versa. Reason : Some animals can tolerate a narrow salinity range, while others can tolerate a wide salinity range.

Assertion: In a terrestrial ecosystem, detritus food chain is the major conduit for energy flow. Reason: Solar energy is the direct source for energy supply in a detritus food chain.

Assertion: A network of food chains existing together in an ecosystem is known as a food web. Reason: An animal like kite cannot be a part of a food web.

Given below is one of the types of ecological pyramids. This type represents

The Great Barrier Reef along the east coast of Australia can be categorised as

Mr. X is eating curd/yoghurt. For this food intake in a food chain he should be considered as occupying:

Assertion : In a food chain members of successive higher levels are fewer in number. Reason : Number of organisms at any trophic level depends upon the availability of organisms which serve as food at the lower level.

The sphere of living matter together with water, air and soil on the surface of earth is called:-