Free Ecosystems MCQs with Answers

41. Population of different species (plants and animals) living in the same habitat form a:

• A. Community
• B. Ecosystem
• C. Biosphere
• D. Microhabitat

Explanation: A community is a group of interacting species, which live in the same location.

42. Living part of ecosystem is:

• A. Lithosphere
• B. Hydrosphere
• C. Community
• D. Biosphere

Explanation: The biosphere is the part of an ecosystem which integrates all living organisms and their relationship with one another.

43. A living association between two living organisms of different species that is beneficial to both partners is called:

• A. Commensalism
• B. Parasitism
• C. Mutualism
• D. Predation

Explanation: A symbiotic relationship, or symbiosis, is a close and long-term biological interaction between two different species. The relationship can be categorized into three main types: mutualism, where both species benefit; commensalism, where one benefits and the other is unharmed; and parasitism, where one benefits at the expense of the other.

44. Individual successions are known as

• A. Primary successions
• B. Secondary successions
• C. Seres
• D. Xeroses

Explanation: The term specifically used for each individual succession in animal or plant is called seres. Therefore this is the right option here.

45. Which one of the following is the ultimate distributional unit within which a species is restrained by the limitations of its physical structure and physiology?

• A. Niche
• B. Biome
• C. Ecosystem
• D. Habitat

Explanation: The given statement is the definition of Niche given by Grinnell. Therefore opt A is the right choice here.

46. All herbivores belong to which trophic level in the food chain?

• A. T1
• B. T2
• C. T3
• D. T4

Explanation: Herbivores which are the primary consumers belong to trophic level 2.

47. How many food chains are present in the following food web?

• A. 5
• B. 3
• C. 6
• D. 4

Explanation: A series of organisms each dependent on the next as a source of food is called a food chain. Food web A system of interlocking and interdependent food chains. There are four food chains in the given food web.

48. The relationship in which one organism gets benefit and the other is not affected is called

• A. Mutualism
• B. Commensalism
• C. Predation
• D. Parasitism

Explanation: The relationship in which one organism gets benefit and the other is not affected is called commensalism.

49. During successions, the first organisms that develop on bare rock are:

• A. Lichens
• B. Shrubs
• C. Moss
• D. Herbs

Explanation: Lichens: This option is the correct answer. Lichens are the first organisms that typically colonize and establish on bare rock during primary succession. Lichens are a symbiotic association between fungi and algae or cyanobacteria. They can tolerate extreme environmental conditions and play a vital role in breaking down rock surfaces, contributing to the formation of soil for other plants to establish.

50. The trophic level of a herbivore in a given food web is:

• A. 1
• B. 3
• C. 4
• D. 2

Explanation: D option is the correct answer. The trophic level of a herbivore is generally at the second level. Herbivores are primary consumers that directly feed on plants or algae, which occupy the first trophic level as primary producers. The energy flow in a food chain typically starts with primary producers, followed by herbivores at the second trophic level.