NEETAceToday's NEET Daily

Organisms, environment, population interactions and attributes: NEET MCQs with answers

126 questions on this topic of Ecology and Environment (NEET 2027 syllabus). Here are 12; tap one to see its answer and explanation.

Practise Ecology and Environment freeAll Ecology and Environment questions

Free with a Google sign-in; NEET Daily needs no sign-in at all.

easy

1. Nearly 99 percent of animals and almost all plants cannot maintain a constant internal environment. Such organisms are classified as:

  1. Regulators
  2. Partial regulators
  3. Conformers
  4. Endotherms
Show answer and explanation

Answer: (C) Conformers

Organisms whose internal environment changes with the ambient external conditions are called conformers, comprising about 99% of all animals and nearly all plants.

medium

2. The salt concentration (parts per thousand) in sea water is about:

  1. Zero
  2. 30-35
  3. Less than 5
  4. More than 100
Show answer and explanation

Answer: (B) 30-35

Salinity is less than 5 in inland waters, 30-35 in the sea and more than 100 in some hypersaline lagoons.

NCERT Class 12

hard

3. Given below are two statements. Statement I: In logistic growth, the population becomes stable at the carrying capacity. Statement II: Exponential growth gives a sigmoid curve. Choose the correct answer.

  1. Both Statement I and Statement II are correct
  2. Statement I is correct but Statement II is incorrect
  3. Statement I is incorrect but Statement II is correct
  4. Both Statement I and Statement II are incorrect
Show answer and explanation

Answer: (B) Statement I is correct but Statement II is incorrect

Logistic growth levels off at K. Exponential growth gives a J-shaped curve; the sigmoid curve belongs to logistic growth.

medium

4. A population of 100 individuals produced 7 offspring in a year. The per-capita birth rate (per individual per year) is:

  1. 0.04
  2. 14.3
  3. 0.07
  4. 7
Show answer and explanation

Answer: (C) 0.07

Per-capita birth rate = number of births/population size = 7/100 = 0.07.

easy

5. The monarch butterfly is highly distasteful to its predator (birds) because of a special chemical present in its body. How does the monarch butterfly acquire this chemical?

  1. By feeding on a poisonous weed during its caterpillar stage
  2. By synthesizing it biochemically during the pupal stage
  3. By harboring endosymbiotic cyanobacteria in its gut
  4. By absorbing it from nectar during its adult butterfly stage
Show answer and explanation

Answer: (A) By feeding on a poisonous weed during its caterpillar stage

According to NCERT, the monarch butterfly is highly distasteful to its predator bird because of a special chemical present in its body. Interestingly, the butterfly acquires this chemical during its caterpillar stage by feeding on a poisonous weed.

hard

6. In the shallow South American lakes, visiting flamingoes and resident fishes compete for:

  1. Sunlight
  2. Space for nesting
  3. Oxygen
  4. Their common food, the zooplankton in the lake
Show answer and explanation

Answer: (D) Their common food, the zooplankton in the lake

Flamingoes and fishes compete for zooplankton, showing that totally unrelated species can also compete for the same resource.

medium

7. Logistic growth is considered more realistic than exponential growth because:

  1. Birth rate always remains constant
  2. Resources are always unlimited
  3. Resources for growth are finite and become limiting sooner or later
  4. Populations never stop growing
Show answer and explanation

Answer: (C) Resources for growth are finite and become limiting sooner or later

No population can grow exponentially indefinitely; finite resources lead to competition and a carrying capacity.

medium

8. When MacArthur observed five closely related warbler species living on the same tree, he found they avoided competition by:

  1. Fighting each other
  2. Migrating to different trees
  3. Eating different trees
  4. Behavioural differences in their foraging activities (resource partitioning)
Show answer and explanation

Answer: (D) Behavioural differences in their foraging activities (resource partitioning)

The warblers coexisted through resource partitioning: behavioural differences in foraging activities. Gause's competitive exclusion principle says two closely related species competing for the same resources cannot coexist indefinitely.

NCERT Class 12

medium

9. In a population of 100, there were 16 births and 9 deaths in a year (no migration). The per-capita growth rate r (per individual per year) is:

  1. 0.16
  2. 0.25
  3. 0.07
  4. 7
Show answer and explanation

Answer: (C) 0.07

r = (births − deaths)/N = (16 − 9)/100 = 0.07.

medium

10. Organisms that can tolerate and thrive in a wide range of temperatures are called:

  1. Eurythermal
  2. Stenothermal
  3. Euryhaline
  4. Stenohaline
Show answer and explanation

Answer: (A) Eurythermal

Eurythermal organisms tolerate a wide range of temperatures; most organisms are stenothermal, restricted to a narrow range. Euryhaline and stenohaline refer to tolerance of salinity.

NCERT Class 12

medium

11. A population of 40 individuals produced 6 offspring in a year. The per-capita birth rate (per individual per year) is:

  1. 0.15
  2. 0.125
  3. 6.67
  4. 6
Show answer and explanation

Answer: (A) 0.15

Per-capita birth rate = number of births/population size = 6/40 = 0.15.

easy

12. In a pond ecosystem, if the initial population of lotus plants is 30 and during a year 6 new lotus plants are added through reproduction, what is the birth rate of the population?

  1. 0.2 offspring per lotus per year
  2. 0.5 offspring per lotus per year
  3. 5 offspring per lotus per year
  4. 0.12 offspring per lotus per year
Show answer and explanation

Answer: (A) 0.2 offspring per lotus per year

The birth rate is calculated as the number of new births divided by the initial population size: 6 / 30 = 0.2 offspring per lotus per year.

Keep going with Ecology and Environment. All 340 questions with instant answers, your mistakes saved for revision and your accuracy by topic.
Start practising

Other topics in Ecology and Environment