Biology · Environmental Studies

Ecosystem Nutrition and Energy Flow

1,235 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 biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Which one of the following is a decomposer?

  1. Fungi

  2. Algae

  3. Protozoa

  4. Insect
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The fungi generally feeds on the dead remains of plants and animals where they break the complex organic substances into the simpler ones through the digestive action. These decomposed material act as a humus for soil and they increase the fertility of the soil. The fungi and the bacteria are the common examples of decomposers. 

Thus, the correct answer is 'Fungi'.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Trophic level in a food chain which cycles the various materials between environment and living organisms is constituted by

  1. Producers

  2. Consumers

  3. Decomposers

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A food chain is series of plants/animals which are interrelated in the form of organism being eaten as food by the other. Trophic levels in a food chain are formed by producers, consumers and decomposers. In the given food chain, plants are producers. The animals eating plants are called as primary consumers and animals eating primary consumers are called as secondary consumers. Decomposers are those which decomposes the waster organic matter and release energy back in the environment. They cycles the various materials between environment and living organisms.
Thus, the correct answer is 'Decomposers.'
Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Decomposers are organisms that 

  1. Elaborate chemical substances, causing death of tissues

  2. Operate in living body and simplifying oragnic substance of cells step by step

  3. Attack and kill plants as well as animals

  4. Operate in relay terms, simplifying step by step the organic constituents of dead body
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Decomposers work in a sequential process to break down the complex organic constituents of dead bodies into simpler, inorganic nutrients.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

In food web, hyenas and vultures are

  1. Primary consumers

  2. Predators

  3. Scavengers

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

Food web is constituted by various interlinked food chains in a community. It is also called as consumer-resource system. In food web, hyenas and vultures are scavengers. Scavengers keep an ecosystem free of the dead animals. They break down the organic matter and recycle the essential nutrients into the ecosystem. They only eat the bodies of dead animals. Hence, they play very important role in maintaining a stable ecosystem.

Thus, the correct answer is 'Scavengers.'

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Decomposers occupy a trophic level

  1. $T _1$
  2. $T _2$
  3. $T _3$
  4. $T _6$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The first trophic level is represented as T$ _1$. It includes producers. The second trophic level is represented as T$ _2$. It includes primary consumers. These are herbivores. The third trophic level is represented as T$ _3$. It includes secondary consumers or carnivores. Decomposers are organisms which decompose the organic matter from dead animals and plants. They occupy the top level in the ecological pyramid. They release essential nutrients back in the environment..

Thus, the correct answer is 'T$ _6$.' 

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Organisms in all trophic levels may be consumed by decomposers

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Food chain, in ecology, the sequence of transfers of matter and energy in the form of food from organism to organism. The trophic level of an organism is the position it occupies in a food chain. Decomposers (detritivores) break down dead plant and animal material and wastes and release it again as energy and nutrients into the ecosystem for recycling. Decomposers, such as bacteria and fungi (mushrooms), feed on waste and dead matter, converting it into inorganic chemicals that can be recycled as mineral nutrients for plants to use again.

So the given statement is true.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

In an ecosystem, bacteria are

  1. Microconsumers

  2. Macroconsumers

  3. Primary consumers

  4. Secondary consumers
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An ecosystem consists of producers and consumers. Plants are the producers of the ecosystem. They obtain their own food by photosynthesis. Consumers are of two types, microconsumers and macroconsumers. Macroconsumers include herbivores, carnivores and detrivores. Microconsumers includes bacteria and fungi. They are also known as decomposers.

Thus, the correct answer is 'Microconsumers.'

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

Pheretima and its close relatives obtain nourishment from

  1. soil insects

  2. small pieces of fresh fallen leaves

  3. decaying fallen leaves and soil organic matter

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

Pheretima or earthworm is a detritivore. Earthworm and its close relatives obtain nourishment from decaying fallen leaves and organic matter.

So, the correct answer is option C, decaying fallen leaves and organic matter.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

In a natural ecosystem, decomposers include

  1. Only microscopic animals

  2. Only bacteria and fungi

  3. The above two types of organisms plus microscopic animals

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

Bacteria are important decomposers; they are widely distributed and can break down any type of organic matter. The primary decomposers of litter in many ecosystems are fungi. Unlike bacteria, which are unicellular organisms, most saprotrophic fungi grow as a branching network of hyphae. While bacteria are restricted to growing and feeding on the exposed surfaces of organic matter, fungi can use their hyphae to penetrate larger pieces of organic matter. Fungi decompose organic matter by releasing enzymes to break down the decaying material, after which they absorb the nutrients in the decaying material.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

In recycling of mineral elements within an ecosystem, the responsible direct acing organism are called

  1. Decomposers

  2. Producers

  3. Primary consumers

  4. Secondary consumers
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Decomposers are the direct agents that break down organic matter, thereby releasing mineral elements back into the ecosystem for reuse by producers.

Multiple choice biology interdependence in living beings - plants and animals animals as consumers scavengers and decomposers interdependence between plants and animals

In the food chain, the saprophytic organisms are

  1. Producers

  2. Consumers

  3. Predators

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

Fungi and bacteria are known as saprophytes. Saprophytes are decay organisms and are responsible for getting dead animals and plants to rot (decompose). They break down the remains into simple chemicals, e.g., nitrates, which contain nitrogen, an important element needed by plants. Without saprophytes the soil would quickly run out of nutrients and the plants would have no food. 

Multiple choice

A frog eats...

  1. meat.

  2. fruit.

  3. bugs.

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

Frogs are insectivores, meaning their diet primarily consists of insects and small invertebrates, commonly referred to as bugs.

Multiple choice general knowledge resources of india and world animal husbandry and fishery green and white revolution agriculture in indian economy

Pick up the correct food chain.

  1. Grass - Chameleon - Insect - Bird

  2. Grass - Fox - Rabbit - Bird

  3. Phytoplankton - Zooplankton - Fish

  4. Fallen leaves - Bacteria - Insect larvae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A food chain represents the flow of energy from producers to consumers. Phytoplankton (producers) are eaten by zooplankton (primary consumers), which are then eaten by fish (secondary consumers).

Multiple choice general knowledge resources of india and world animal husbandry and fishery green and white revolution agriculture in indian economy

Select the correct sequence of food chain in the arctic waters from the following.

  1. zooplankton - diatoms - fish - polar bear - seal

  2. diatoms - zooplankton - fish - seal - polar bear

  3. fish - diatoms - seal - zooplankton - polar bear

  4. diatoms - fish - polar bear - seal - zooplankton
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Arctic marine ecosystems, diatoms are the primary producers. These are consumed by zooplankton, which are then eaten by fish, followed by seals, and finally the apex predator, the polar bear.