Class 12 · Organisms and Populations

Competition & Fitness Reduction — NEET Biology

✅ Asked in NEET 2024
✅ NEET 2024 PYQ

Given below are two statements: Statement I: When the fitness of one species is significantly lower in the presence of another species, the process is defined as competition. Statement II: When fungi remain in association with living plants or animals, they are called saprophytes.

QuestionNEET 2024

Given below are two statements: Statement I: When the fitness of one species is significantly lower in the presence of another species, the process is defined as competition. Statement II: When fungi remain in association with living plants or animals, they are called saprophytes.

Answer & NCERT explanation

Correct answer: C Statement I is True but Statement II is False

Statement I is true as competition occurs when fitness of one species decreases in presence of another due to limited resources. Statement II is false because fungi associated with living plants/animals are called parasites or mutualists (like mycorrhizae), not saprophytes. Saprophytes decompose dead organic matter, not living organisms. Therefore, only Statement I is correct while Statement II is incorrect, making option C the right choice.

Read more NCERT concept on the PYQ

📖 NCERT Source

Therefore, competition is best defined as a process in which the fitness of one species (measured in terms of its 'r' the intrinsic rate of increase) is significantly lower in the presence of another species. It is relatively easy to demonstrate in laboratory experiments, as Gause and other experimental ecologists did, when resources are limited the competitively superior species will eventually eliminate the other species, but evidence for such competitive exclusion occurring in nature is not always conclusive. Strong and persuasive circumstantial evidence does exist however in some cases. The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats. Another evidence for the occurrence of competition in nature comes from what is called 'competitive release'. A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range dramatically when the competing species is experimentally removed. Connell's elegant field experiments showed that on the rocky sea coasts of Scotland, the larger and competitively superior barnacle Balanus dominates the intertidal area, and excludes the smaller barnacle Chathamalus from that zone. In general, herbivores and plants appear to be more adversely affected by competition than carnivores.

NCERT Biology · Class 12 · Chapter 11 · Paragraph 47
How NTA Uses This Concept

NTA tests competition as a process where one species reduces another's fitness (r-value), regardless of resource abundance. Students mistakenly think competition only occurs when resources are scarce, but the NCERT clearly states interference competition reduces fitness even with abundant food and space. The key trap: confusing competitive exclusion (elimination in labs) with natural occurrence—nature shows competitive release instead, where species expand range when competitors are removed. Remember: competition fundamentally means fitness reduction in presence of another species, proven through examples like Balanus excluding Chathamalus and goats outcompeting Abingdon tortoises.

❓ Frequently Asked Questions
What does NCERT say about Therefore competition best defined?
Therefore, competition is best defined as a process in which the fitness of one species (measured in terms of its 'r' the intrinsic rate of increase) is significantly lower in the presence of another species. It is relatively easy to demonstrate in laboratory experiments, as Gause and other experimental ecologists did, when resources are limited the competitively superior species will eventually eliminate the other species, but evidence for such competitive exclusion occurring in nature is not always conclusive.
Has this concept appeared in NEET?
Yes — appeared in NEET 2024. Defines competition as fitness reduction in presence of another species
Which chapter is this from?
Organisms and Populations, Class 12 NCERT Biology.

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