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

The flow of energy among various trophic levels of an ecosystem is

  1. unidirectional

  2. bidirectional

  3. multidirectional

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

Energy flows through ecosystems in one direction only: from the sun to producers (plants), then to herbivores, then to carnivores. Energy is lost as heat at each transfer and cannot cycle back, unlike nutrients which can be recycled through decomposition.

Multiple choice

The plant which belongs to the Reed-Swamp stage in hydrarch succession is

  1. juncus

  2. sagittaria

  3. salix

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

Sagittaria (arrowhead) is an aquatic plant characteristic of the reed-swamp stage in hydrarch (water-based) succession. Hydrarch succession progresses from phytoplankton to submerged plants to floating plants to reed-swamp stage (with plants like Sagittaria, Scirpus) to sedge meadow to woodland to climax forest. Juncus (rush) is also in reed-swamp, but Sagittaria is more representative. Salix (willow) and Trapa (water chestnut) appear in later stages.

Multiple choice

Directions: Choose the correct meaning of the given word.

Herbivorous

  1. Feeding on plants

  2. Feeding on animals

  3. Feeding on humans

  4. Feeding on fish
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Herbivorous comes from Latin "herba" (plant) + "vorare" (to devour/eat), so herbivorous animals feed exclusively on plants. Carnivorous would describe feeding on animals. "Feeding on humans" and "Feeding on fish" are not standard biological categories.

Multiple choice

Directions: For this question, select the best of the answer choices given.

The chanterelle, a type of wild mushroom, grows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree. Which of the following, if true, casts the most doubt on the conclusion drawn above?

  1. The number of wild mushrooms harvested has increased in recent years.

  2. Chanterelles grow not only beneath Douglas firs but also beneath other host trees.

  3. Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.

  4. The harvesting of wild mushrooms stimulates future growth of those mushrooms.

  5. Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The argument assumes that harvesting chanterelles removes them permanently. Option D weakens this by suggesting that harvesting stimulates future growth, meaning the mushrooms could return and continue their beneficial relationship with the trees. This challenges the assumption that harvesting 'seriously endangers' the trees.

Multiple choice

Match the following:

 
a. Autotrophs 1. Organisms not capable of making their own food and depend on others for their food.
b. Heterotrophs 2. Organisms that provide nutrients to another organism without being benefited.
c. Parasites 3. Organisms capable of synthesising its own food from inorganic substances, using light or chemical energy.
d. Hosts 4. Organisms that derive nutrients from another organism.

  1. a - 2, b - 1, c - 4, d - 3

  2. a - 3, b - 1, c - 4, d - 2

  3. a - 3, b - 4, c - 1, d - 2

  4. a - 1, b - 3, c - 4, d - 2

  5. a - 3, b - 1, c - 2, d - 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option. Autotrophs are the organisms capable of synthesising their own food from inorganic substances, using light or chemical energy. Heterotrophs are the organisms not capable of making their own food and depend on others for their food. Parasites are the organisms that derive nutrients from another organism. Hosts are the organisms that provide nutrients to another organism without being benefited.

Multiple choice

Which of the following pairs represents filter feeders only?

  1. Humans and earthworms

  2. Earthworms and tapeworms

  3. Termites and aphids

  4. Oysters and mussels

  5. Aphids and oysters
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Filter feeders collect small organisms and particles from the surrounding water. Example: oysters and mussels.

Multiple choice

A consumer whose carbon atoms have already passed through two species is a:

  1. primary consumer

  2. primary producer

  3. secondary consumer

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

In a food chain, primary consumers eat producers (first species), secondary consumers eat primary consumers (second species), and tertiary consumers eat secondary consumers (third species). A secondary consumer is one whose food has passed through two species - producer then primary consumer.

Multiple choice

_________ make their own food.

  1. Plants

  2. Insects

  3. Humans

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

Plants produce their own food through photosynthesis, a process where they use sunlight, water, and carbon dioxide to create glucose. Animals, insects, and humans cannot produce their own food and must consume other organisms for energy.

Multiple choice

Pyramid of energy is always:

  1. upright

  2. downward

  3. upright in pond and downright in forest

  4. upright in forest and downright in pond

  5. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pyramid of energy is upright because when energy flows from a trophic level to next trophic level, some energy is always lost as heat at each step. Finally, it is lost to atmosphere and never goes back to the Sun.