Question 1

What would happen if phytoplankton of an ocean is completely destroyed for some reason? 1. The ocean as a carbon sink would be adversely affected. 2. The food chains in the ocean would be adversely affected. 3. The density of ocean water would drastically decrease. Select the correct answer using the codes given below:

Accepted Answer

If all phytoplankton in an ocean were to be completely destroyed, it would have negative impacts on the ocean ecosystem. The ocean's ability to absorb carbon dioxide as a carbon sink would be compromised, and the food chains within the ocean would also suffer, as many marine species rely on phytoplankton as a food source. This would result in disruptions to the marine food web. The density of ocean water would not be drastically affected by the destruction of phytoplankton. Therefore, the correct answer is option (a), which states that both the carbon sink function and the food chains in the ocean would be adversely affected.

Question 2

Which one of the following is the best description of the term 'ecosystem'?

Accepted Answer

An ecosystem refers to a community of organisms that coexist and interact with each other in a particular environment. This interaction involves both living organisms such as plants and animals, as well as non-living elements like weather, soil, and climate.

Question 3

Which of the following have species that can establish symbiotic relationship with other organisms? 1. Cnidarians 2. Fungi 3. Protozoa

Accepted Answer

Cnidarians, fungi, and protozoa are organisms that can establish symbiotic relationships with other organisms. Cnidarians like corals have symbiotic relationships with algae, fungi form mycorrhizal associations with plant roots, and certain protozoa can engage in mutualistic relationships with other organisms.

Question 4

Which one of the following is the correct sequence of ecosystems in the order of decreasing productivity?

Accepted Answer

In terms of decreasing productivity, the correct sequence of ecosystems is Mangroves, grasslands, lakes, oceans. Mangroves have the highest productivity, followed by grasslands, then lakes, and finally oceans.

Question 5

In the nature, which of the following is/are most likely to be found surviving on a surface without soil? 1. Fern 2. Lichen 3. Moss 4. Mushroom

Accepted Answer

Lichens and mosses are most likely to be found surviving on a surface without soil. Lichens are a symbiotic association between a fungus and an alga or cyanobacterium, allowing them to grow on bare rock, walls, and tree bark. Mosses, being non-vascular plants, can absorb water and nutrients directly through their leaves, enabling them to thrive in environments without soil.

Ecology & Ecosystems — UPSC Previous Year Questions

Year-wise Distribution

Sample Questions

Ecology & Ecosystems — UPSC Previous Year Questions

Year-wise Distribution

Sample Questions