Biology · Environmental Studies

Ecosystem Nutrition and Energy Flow

1,093 Questions

Ecosystem nutrition and energy flow questions cover trophic levels, food chains, and biodegradable materials. These concepts frequently appear in general science sections of major competitive exams. Review these questions to build a solid understanding of ecological interactions.

Trophic levels conceptFood chain orderAutotrophic nutritionEnergy assimilationScavengers and decomposers

Ecosystem Nutrition and Energy Flow Questions

Multiple choice

The trophic levels represent the

  1. steps in a community

  2. steps in a food chain

  3. steps in an ecosystem

  4. steps in a biosphere
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The trophic levels represent the steps in a food chain.

Multiple choice

Select the correct order of organisms in a food chain from the following data?

  1. Human, duck, fish, algae

  2. Algae, fish, duck, human

  3. Algae, duck, fish, human

  4. fish, duck, algae, human
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The correct order follows energy flow: Algae (producer) → Fish (primary consumer) → Duck (secondary consumer) → Human (tertiary consumer). Energy moves up through each trophic level.

Multiple choice

Herbivores are found in which trophic level?

  1. First

  2. Second

  3. Third

  4. Fourth
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Herbivores occupy the second trophic level because they eat plants from the first trophic level (producers). They are primary consumers in the food chain.

Multiple choice

Which of the following statements is true?

  1. Deer is a carnivore.

  2. Lion is an autotrophic animal.

  3. Predators are usually lesser in number than their preys.

  4. Each species is limited in its total biomass by its trophic level.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Each trophic level has limited total biomass because energy is lost at each transfer (10% rule). This means higher trophic levels can support less total biomass. Deer are herbivores, lions are heterotrophs not autotrophs, and predators typically have fewer numbers than prey (not greater).

Multiple choice

Humans are

  1. autotrophic

  2. herbivorous

  3. omnivores

  4. carnivorous
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Humans are omnivores because they can digest and obtain nutrition from both plant sources (vegetables, grains, fruits) and animal sources (meat, dairy, eggs). Our digestive system includes enzymes for both plant cellulose breakdown and meat protein digestion. Autotrophs (option A) make their own food, herbivores (option B) eat only plants, and carnivores (option D) eat only meat.

Multiple choice

The organisms that synthesise their own food are called _______.

  1. Saprophytes

  2. Autotrophs

  3. Herbivores

  4. Heterotrophs
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Autotrophs are organisms capable of synthesizing their own food using simple inorganic substances, typically through photosynthesis (like green plants) or chemosynthesis. Heterotrophs depend on other organisms for food, herbivores specifically eat plants, and saprophytes feed on dead and decaying organic matter.

Multiple choice

What do you call the organisms that eat dead animals?

  1. Herbivores

  2. Carnivores

  3. Omnivores

  4. Scavengers
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Scavengers are organisms that feed on dead animals that they did not kill themselves. Examples include vultures, hyenas, and some insects. Herbivores eat plants, carnivores hunt and kill live prey, and omnivores eat both plants and animals - none of these specifically characterize consumers of dead animals.

Multiple choice

Why do animals consume more energy than plants?

a. Plants are stationary and animals move around. b. Animal body is bulkier than plant body. c. Most of the tissues in plants are dead, unlike animals. d. Structural organisation of organs in animals is more specialised.

  1. Only a and d

  2. Only a and c

  3. Only b and c

  4. Only b and d

  5. Only c and d
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct. Both 'a' and 'c' are correct statements. Plants are stationary and they do not move. Most of the plant tissues are dead and need less maintenance. Hence, animals consume more energy than plants.

Multiple choice

Which of the following correctly represents the order of food chain?

  1. Salmon, Fish, Brown Bear, Bacteria & Fungi

  2. Bacteria & Fungi, Fish, Salmon, Brown Bear

  3. Fish, Salmon, Brown Bear, Bacteria & Fungi

  4. Fish, Salmon, Bacteria & Fungi, Brown Bear
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a food chain, energy flows from producers to consumers to decomposers. The sequence Fish → Salmon → Brown Bear represents increasing trophic levels, where each level preys on the previous one. Bacteria and fungi are decomposers that break down dead organisms at the end of the chain.

Multiple choice

Organisms who depend on dead organic matter for food are called

  1. Saprophytes

  2. Parasites

  3. Autotrophic

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Saprophytes are organisms that obtain nutrition from dead and decaying organic matter, secreting enzymes to break down complex molecules externally. Parasites feed on living hosts. Autotrophic organisms produce their own food.

Multiple choice

What role do animals play in the food chain?

  1. Producers

  2. Consumers

  3. Decomposers

  4. Autotrophs

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Consumers are the second link in a food chain. There are three levels of consumers, primary consumer, secondary consumer and tertiary consumer. All animals that eat plants become the primary consumers. After primary consumers, there are secondary consumers who eat primary consumers, like bear and snake.