Ecology and Functions of an ecosystem MCQ Quiz - Objective Question with Answer for Ecology and Functions of an ecosystem - Download Free PDF

The correct answer is Uni-directional.

Key Points

Explanation:

Ecosystem: All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

Food chain: A food chain shows the feeding relationship between different organisms in a particular environment and/or habitat.

• A food chain shows how energy is passed from the sun to producers, from producers to consumers, and from consumers to decomposes such as fungi. 
• They also show how animals depend on other organisms for food.

​

Only 10% of energy is transferred to higher levels from the previous one. So, the demand for food is more in higher levels. So, the food chain does not go for more than 3-4 tropic levels. This leads to more complex food forms known as a food web.

Primary (100%) → First level/ Primary (10%) → Second-level/ Secondary (1%) → Third level / Tertiary (0.1%).

Food web is a network of food chains where all the chains are naturally interconnected.

The flow of energy in a food chain is unidirectional, once it reaches the next tropic level it does not come back again.

• The materials like water, carbon (as carbon dioxide) and nitrogen (as minerals) are taken up by the plants from soil, air and water bodies, etc., and made into food. This food is then passed on to the animals like herbivores and carnivores in a food chain.
• After the death and decay of plants and animals, the materials like water, carbon and nitrogen present in their bodies are returned to soil, air and water, from where they were taken originally.
• These materials can then be reused for the growth of new plants. In this way, the same materials are used again and again, the materials are not lost from the environment. So, the flow of materials like water, carbon and nitrogen, etc., in the ecosystem is said to be cyclic. This is not so in the case of energy.

The correct answer is Living Organisms.

Key Points

• Ecosystem- The word Ecosystem was termed by 'Arthur Tansley' which means an interaction that occurs between Biotic and Abiotic components.
• The ecosystem is divided into two components Biotic and Abiotic components.
• Abiotic components consist of Sunlight, oxygen, moisture, minerals, temperature, soil and water.
• Biotic components consist of Living organisms which are Plants (Producers) and Animals (Consumers).

Additional Information

The Correct answer is Statements I and II are correct.

Key Points

• Statement I: The diversity of plants and animals is influenced by the region’s climate and habitat. This is correct because the type of vegetation and animal species found in any region is directly linked to its environmental conditions such as temperature, precipitation, and geographical features.
• For example, tropical rainforests support high biodiversity due to their warm temperatures and abundant rainfall, while deserts have limited biodiversity due to arid conditions.
• Statement II: Adaptations in plants and animals occur to help them survive in their environment. This is correct as organisms evolve specific traits over time to ensure survival in their surroundings. Examples include the thick fur of polar bears for insulation in cold climates and the spines of cacti to conserve water in arid conditions.
• These adaptations are crucial for maintaining biodiversity as they allow species to thrive in varied ecosystems.
• Statement III: Biodiversity remains constant across all ecosystems. This is incorrect because biodiversity varies significantly across ecosystems. Tropical rainforests, for instance, have a higher degree of biodiversity compared to deserts or polar regions due to differences in climate, resources, and habitat complexity.

Additional Information

• Adaptations in plants and animals
  • Adaptations can be classified into three categories: structural (physical features like fur, spines), behavioral (migration, hibernation), and physiological (internal processes like water retention in plants).
  • Examples include the camel’s ability to store fat in its hump for energy and the mimicry of certain insects for protection against predators.
• Biodiversity in ecosystems
  • Tropical rainforests are known as biodiversity hotspots due to favorable conditions for species to thrive.
  • Deserts and polar regions have lower biodiversity due to extreme climatic conditions.
  • Marine ecosystems such as coral reefs also support high biodiversity due to their structural complexity and nutrient availability.

The correct answer is Aquariums.

Key Points

• Artificial ecosystems are environments that have been intentionally created or modified by humans.
• These ecosystems mimic certain aspects of natural ecosystems and are designed to serve specific purposes or meet human needs.
• The main purpose of these ecosystems is to make biotic and abiotic components interact with each other for survival. 
• It is not self-sustaining and needs human help to survive.
• They can exist in various forms, from small-scale urban gardens to large-scale aquaculture systems.
• Most prominent examples of artificial ecosystems include aquariums, agriculture fields, zoos, etc.
• Forest, River, and Ocean comprise the natural ecosystem.

Additional Information

Important Points

• An ecosystem is an interaction of biological community organisms between each other and their physical environment.
• The lithosphere is the outer part of the Earth it is made up of the crust and the top part of the upper mantle. 
• A biome is a large community of vegetation and wildlife which are adapted to a specific climate.
• The five major types of the biome are:
  • aquatic 
  • grassland 
  • forest 
  • desert
  • tundra

• The biosphere is the single largest ecosystem of the earth.
•  The biosphere is known as the sum of all ecosystems also known as the ecosystem also the zone of life on earth. 
• Biosphere is the sum of all and hence is regarded as the largest ecosystem of the earth.

The correct answer is Living organisms and physical factors.

Key Points

• An ecosystem consists of a community of organisms together with their physical environment consists of two components Biotic and Abiotic.
  • Abiotic consists of non-living organisms(air, water, soil, minerals, sunlight.
  • Biotic consists of living organisms (Producers, Consumers, Decomposers).

Additional Information

• The Food Chain is a linear sequence of organisms where nutrients and energy are transferred from one organism to another.
  • Producers make their own food. Example- Green plants.
  • Primary Consumers depend on the producers. Example- Grasshooper
  • Secondary consumers depend on the primary consumer for energy. Example- Frog
  • Tertiary consumer depends on the secondary consumers for the food. Example- Snake
  • Decomposers are microorganisms that decompose the dead and decaying material into humus which enriches the soil. Example- Bacteria, Fungus.

The correct answer is Flows.

Explanation:

Ecosystem: All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

Food chain: A food chain shows the feeding relationship between different organisms in a particular environment and/or habitat.

• A food chain shows how energy is passed from the sun to producers, from producers to consumers, and from consumers to decomposes such as fungi. 
• They also show how animals depend on other organisms for food.

​

Only 10% of energy is transferred to higher levels from the previous one. So, the demand for food is more in higher levels. So, the food chain does not go for more than 3-4 tropic levels. This leads to more complex food forms known as a food web.

Primary (100%) → First level/ Primary (10%) → Second-level/ Secondary (1%) → Third level / Tertiary (0.1%).

Food web is a network of food chains where all the chains are naturally interconnected.

The flow of energy in a food chain is unidirectional, once it reaches the next tropic level it does not come back again.

The correct answer is Nitrogen and phosphorous.

Key Points:

Concept:

• Eutrophication: It is an enrichment of water by nutrient salts that causes structural changes to the ecosystem.
• Compounds that contain nitrogen and phosphorus (fertilizers) drive the eutrophication. These nutrients are generally not toxic.
• Effects on aquatic life: They can have a large impact on the health of rivers and estuaries such as increased overgrowth of algae and aquatic plants, depletion of fish species, general deterioration of water quality.

Explanation:

• To increase crop yield, fertilizers contain nitrates and phosphates.

• When these get washed up into water bodies, the resulting increase of nitrate or phosphate in the water encourages algae growth, which forms a bloom over the water surface.

• The algae leech the nutrient from the water body and kill aquatic life.

• So, eutrophication in the lake is due to the presence of nitrogen and phosphorous.

The correct answer is Ernst Haeckel.

Explanation:

Ecosystem: 

All organisms such as plants, animals, microorganisms and human beings, and their physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

Ecology is the science treating the reciprocal relations of organisms and the external world. 

• The functional unit of the ecological system involves complex actions occurring between its biotic and biotic components.
• The term ecology system was first used by Ernst Haeckel​.
• Dr. Ramdev Mishra is known as the father of ecology in India. He founded the International Society for Tropical Ecology in the year 1956.

Concept:

Ecosystem: 

All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

• Biotic Components: It includes producers, consumers and decomposers. All living things have a direct or indirect influence on other organisms in an environment. Ex- Plants, Animals, Microorganism etc.
• Abiotic components: All the in-organic components of the ecosystem, non-living physical and chemical composition of nature are abiotic components. Ex- stones, water, Humus (organic waste), air etc

Explanation:

There are two type of ecosystem -

• Natural Ecosystem - These are ecosystems that occur naturally and can survive without any intervention from human beings. Examples of natural ecosystems are forests, mountains, rivers, grasslands etc.
• Human-made or Artificial Ecosystem – When human beings modify the already existing ecosystem to meet their purpose or create an ecosystem of their own that mimics the natural condition, those are called artificial ecosystems. Examples of this type of ecosystem include aquariums, crop fields, gardens, dams, lakes, pond ecosystem etc.
  • This is because Pond and Lakes can be artificial as well. But forest can only thrive as a natural habitat.

Ecosystem of a pond - Artificial Ecosystem

Ecosystem of a forest - Natural Ecosystem

Grassland - Natural Ecosystem

The correct answer is Decomposers.

Key Points

• Decomposers has the largest population on a food chain.
• Decomposers are an integral part of food chain.
• The decomposers feed on dead and decaying matter and convert the complex molecules into simpler ones.
• Decomposers involve many types of microorganisms like bacteria, fungi, etc.​

Additional Information

• Producers:​​
  • ​Organisms that can make their own food are called Producers.
  • They are also called autotrophs. Eg: Plants.
• ​Primary consumers:
  • ​Organisms that feed on producers are called Primary consumers. Eg: Deer, Cow etc.
• ​​Secondary consumers:
  • ​This group in the food chain feeds on the primary consumers. Eg: Tiger, Snake etc.

The correct answer is Ecotone.

Key Points

• The area that acts as a boundary or a transition zone between two ecosystems is known as Ecotone.
• It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland ecosystems).
•  An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.
• The word ecotone was coined by Alfred Russel Wallace, who first observed the abrupt boundary between two biomes in 1859.

The correct answer is the Ecological Niche

Key Points

• Ecological Niche
  • A niche refers to the unique functional role and position of a species in its habitat or ecosystem.
  • The functional characteristics of a species in its habitat are referred to as “niche” in that common habitat.
  • In nature, many species occupy the same habitat, but they perform different functions.
    • habitat niche – where it lives, food niche – what is eaten or decomposes & what species it competes with,
    • reproductive niche – how and when it reproduces,
    • physical & chemical niche – temperature, land shape, land slope, humidity & another requirement.
  • Niche plays an important role in the conservation of organisms. If we have to conserve species in their native habitat, we should have knowledge about the niche requirements of the species.

​​Additional Information 

• Ecotone – zone of transition between two ecosystems. E.g. grasslands, mangroves etc.
• Habitat – surroundings in which an organism lives (home).
• Home Range – A home range is an area in which an animal lives and moves on a daily or periodic basis (a little bigger than habitat – home → office → home).

The correct answer is Living Organisms.

Key Points

• Ecosystem- The word Ecosystem was termed by 'Arthur Tansley' which means an interaction that occurs between Biotic and Abiotic components.
• The ecosystem is divided into two components Biotic and Abiotic components.
• Abiotic components consist of Sunlight, oxygen, moisture, minerals, temperature, soil and water.
• Biotic components consist of Living organisms which are Plants (Producers) and Animals (Consumers).

Additional Information