Basic
1. ‘Ecology’ is the study of the relationship between–
(a) Organism and environment
(b) Man and forest
(c) Soil and water
(d) Husband and wife
[U.P.R.O./A.R.O. (Pre) 2014]
Ans. (a) Organism and environment
- The word ‘ecology’ comes from Greek ‘Oikos’, meaning house or environment.
- It is the study of how organisms interact with each other and their surroundings, which includes non-living things.
- Ernst Haeckel, a German scientist, was the first to use the term ‘ecology’ (‘Oekologie’).
- He saw it as the study of the relationship between an organism and its environment.
- Nowadays, ecology is used to describe the relationships between humans and their physical surroundings, as well as plants, animals and climate.
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2. The term Ecosystem was proposed by –
(a) G. Tailor
(b) E. Hartigan
(c) D.R. Stoddart
(d) Tansley
[Uttarakhand P.C.S. (Pre) 2005]
Ans. (d) Tansley
- In 1935, the term ‘ecosystem’ was created by A. G. Tansley.
- It is the relationship between living things (such as animals, plants, and microbes) and their environment (like air, water, minerals, and soil).
- Everything is connected to one another and form a system.
- Ecosystems can range in size from a tiny drop of water to the whole Earth.
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3. Which of the following is not true about the ecosystem?
(a) It represents all living organisms and the physical environment in any given space-time unit.
(b) It is a functional unit.
(c) It has own productivity.
(d) It is a closed-system.
[U.P.P.C.S. (Mains) 2014]
Ans. (d) It is a closed-system.
- An ecosystem is a community of living organisms, such as plants and animals, that interact with their environment, which includes air, water, and soil.
- It is an open system, meaning that energy and materials can enter and leave it.
- It can be found in many different places, and consists of both living and non-living things that interact with each other.
- It is capable of transforming, circulating, and storing energy.
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4. Which four components constitute an ecosystem?
(a) Water, Carbon, Oxygen, Sulphur
(b) Soil, Temperature, Humidity, Rainfall
(c) Abiotic materials, Producers, Consumers, Decomposers
(d) Herbivores, Carnivores, Bacteria, Parasites
[Jharkhand P.C.S. (Mains) 2016]
Ans. (c) Abiotic materials, Producers, Consumers, Decomposers
- An ecosystem is made up of four main parts: abiotic materials, biotic factors (which include producers, consumers and decomposers or reducers).
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5. Which one of the following is the best description of the term ‘ecosystem’?
(a) A community of organisms interacting with one another.
(b) That part of the Earth which is inhabited by living organisms.
(c) A community of organisms together with the environment in which they live
(d) Flora and fauna of a geographical area.
[I.A.S. (Pre) 2015]
Ans. (c) A community of organisms together with the environment in which they live
- Organisms and non-living things in an area make up the ecosystem.
- Ecology is the study of organisms and how they interact with their environment.
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6. Which of the following is an artificial ecosystem?
(a) Ponds
(b) Field
(c) Forest
(d) None of these
[Jharkhand P.C.S. (Pre) 2013]
Ans. (b) Field
- Fields and gardens are man-made environments, while forests, ponds and lakes are all natural.
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7. Which of the following is an artificial ecosystem?
(a) Rice field
(b) Forest
(c) Grassland
(d) Lake
[U.P.P.C.S. (Pre) 2016]
Ans. (a) Rice field
- Humans make and control artificial ecosystems, such as orchards, farms, gardens, and reservoirs.
- Aquatic ecosystems include things like lakes, rivers, and oceans, while terrestrial ecosystems include grasslands, forests, and deserts.
- Agriculture within human ecosystems is very important for the growth of society and development.
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8. The number of organisms that can be supported by the environment in a given area is known as:
(a) Population
(b) Carrying Capacity
(c) Pyramid of number or biomass
(d) None of the above
[Uttarakhand P.C.S. (Pre) 2012]
Ans. (b) Carrying Capacity
- The most amount of organisms an ecosystem can support without damaging it is known as its carrying capacity.
- This is the maximum population size the ecosystem can handle.
- Therefore, option (b) is correct
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9. Which one of the following terms describes not only the physical space occupied by an organism but also its functional role in the community of organisms?
(a) Ecotone
(b) Ecological niche
(c) Habitat
(d) Home range
[I.A.S. (Pre) 2013]
Ans. (b) Ecological niche
- A species’ ecological niche is its place in an ecosystem, which includes where it lives and what it does.
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10. The actual location or place where an organism lives is called:
(a) Habitat
(b) Ecosystem
(c) Niche
(d) Biome
(e) None of the above/More than one of the above
[U.P.P.C.S. (Pre) 2019]
Ans. (a) Habitat
- Where an organism lives is known as its habitat.
- The organism needs things like food, water, air, and shelter from its habitat.
- A biome is a large area where certain plants and animals live together.
- Examples of biomes are forests, grasslands, deserts, and tundras.
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11. Which one of the following ecosystems covers the largest area of the earth’s surface:
(a) Desert Ecosystem
(b) Grassland Ecosystem
(c) Mountain Ecosystem
(d) Marine Ecosystem
[U.P. Lower Sub. (Spl) (Pre) 2003]
Ans. (d) Marine Ecosystem
- There are two main types of ecosystems: aquatic and terrestrial.
- Marine ecosystems are the largest, covering 71% of the Earth’s surface and holding 97% of the Earth’s water.
- Therefore, option (d) is the correct answer.
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12. Which one of the following is the largest ecosystem of the world?
(a) Ocean
(b) Grassland
(c) Forest
(d) Mountains
[U.P.P.C.S. (Pre) 2014]
Ans. (a) Ocean
- Aquatic ecosystem is the environment made up of living and non-living things in a body of water and their interactions.
- It is divided into two sections: marine and freshwater.
- Marine ecosystem covers 71% of the Earth’s surface and has 97% of the world’s water
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13. Which of the following does not help to maintain ecological balance?
(a) Cutting forest
(b) Afforestation
(c) Rainwater Management
(d) Biosphere Reserves
[U.P.U.D.A./L.D.A. (Pre) 2013]
Ans. (a) Cutting forest
- Protecting wildlife and stopping pollution helps keep nature in balance.
- Cutting down trees contributes to this imbalance.
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14. Which one of the following is one of the main causes of ecological imbalance in India?
(a) Deforestation
(b) Desertification
(c) Floods and Famines
(d) Rainfall variations
[R.A.S./R.T.S.(Pre) 2012]
Ans. (a) Deforestation
- Cutting down trees in India is one of the main reasons why the environment is out of balance.
- Other things that contribute to this are deserts spreading, floods and droughts, and changes in rainfall.
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15. Which of the following is an act that disturbs the ecological balance?
(a) Lumbering
(b) Social forestry
(c) Vanamahotsav
(d) Afforestation
[U.P.R.O./A.R.O. (Pre) 2014]
Ans. (a) Lumbering
- Cutting down trees disrupts the natural environment.
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16. The highest trophic level in an ecosystem is obtained by:
(a) Herbivores
(b) Carnivores
(c) Omnivores
(d) Decomposers
[U.P.U.D.A./L.D.A. (Pre) 2002]
Ans. (c) Omnivores
- In an ecosystem, there are four levels of organisms that make up a food chain.
- The first level is made up of producers, the second is primary consumers (which eat plants), the third level is secondary consumers (who eat meat), and the fourth level is tertiary consumers (which eat both plants and meat).
- Lastly, decomposers feed off of all the other levels.
- Thus, option (c) is the correct answer.
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17. Which of the following is not a biotic component of an ecosystem?
(a) Air
(b) Plant
(c) Bacteria
(d) Animals
[R.A.S./R.T.S. (Pre) 2013]
Ans. (a) Air
- Biotic components are the living things that make up an ecosystem.
- Examples of biotic components include plants (producers), animals and humans (consumers), and fungi and bacteria (decomposers).
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18. The primary source of energy in Eco-body is –
(a) Energy emitted by fermentation
(b) Preserved vegetable sugar
(c) Solar energy
(d) None of the above.
[U.P.P.C.S. (Mains) 2015]
Ans. (c) Solar energy
- Solar energy is the main source of energy in nature.
- It is what powers an ecosystem.
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19. Driving force of an ecosystem is:
(a) Carbohydrate
(b) Biomass
(c) Carbon
(d) Solar energy
[U.P.R.O./A.R.O. (Re-Exam) (Pre) 2016]
Ans. (d) Solar energy
- Nature’s main source of energy is the sun.
- This is what keeps an ecosystem running.
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20. Concerning the food chains in ecosystems, which of the following kinds of an organism is/are known as decomposer organisms/organisms?
1. Virus
2. Fungi
3. Bacteria
Select the correct answer using the code given below:
(a) Only 1
(b) 2 and 3
(c) 1 and 3
(d) All of these
[I.A.S. (Pre) 2013]
Ans. (b) 2 and 3
- Decomposers are like nature’s cleaners, breaking down the material from plants and animals that have died.
- This material, called “organic matter,” is from living organisms. Decomposers are mostly tiny microorganisms like bacteria and fungi, like yeast and mold.
- They break down the bodies of dead organisms and turn them into compounds that can be used by plants and other living things.
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21. Which of the following are the primary consumers in an ecosystem? Select the correct answer from the codes given below:
1. Ants
2. Deer
3. Fox
4. Tiger
Code :
(a) 1 and 2
(b) 2 and 3
(c) 1, 2 and 3
(d) 2, 3 and 4
[U.P.P.C.S. (Mains) 2006]
Ans. (a) 1 and 2
- Herbivores are usually the primary consumers in a food chain, like deer.
- Ants can be both primary consumers and decomposers because they eat plants and get energy from cellulose.
- Tigers are carnivores and foxes are omnivores.
- Primary consumers mostly eat plants, so option (a) is the right choice.
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22. In a food chain, man is:
(a) producer
(b) only primary consumer
(c) only secondary consumer
(d) primary as well as secondary consumer
[U.P.P.C.S. (Pre) 2016]
Ans. (d) primary as well as a secondary consumer
- In a food chain, there are different levels known as autotrophs, primary consumers, secondary consumers, and tertiary consumers.
- Primary consumers are herbivores that eat plants, secondary consumers are small carnivores that eat primary consumers, and tertiary consumers are larger carnivores.
- Humans are both primary and secondary consumers, eating both plants and meat.
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23. 10 Percent of law is related to:
(a) Transfer of energy as food from one trophic level to other
(b) Transfer of heat from one matter to another
(c) Transfer of birds from one zone to another
(d) Transfer of water from one zone to another
(e) None of these
[Chhattisgarh P.C.S. (Pre) 2016]
Ans. (a) Transfer of energy as food from one trophic level to other
- This law states that when energy is transferred from organic food to the next level of the food chain, only about 10% of the energy is kept as body mass.
- When animals are eaten, 10% of the energy from their food is stored in their body.
- When a carnivore or omnivore eats that animal, only 10% of that energy is stored in their body.
- This means that only 10% of energy is converted into body weight at each level of the food chain.
- Some of the energy is lost in the process of transferring energy from one organism to another, in respiration, and in incomplete digestion.
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24. In the marine environment, the main primary producers are:
(a) Phytoplanktons
(b) Seaweeds
(c) Marine angiosperms
(d) Aquatic bryophytes
[U.P.P.C.S. (Mains) 2005]
Ans. (a) Phytoplanktons
- Phytoplankton, or microalgae, are like normal plants in that they need sunlight to survive and have chlorophyll.
- They are light in weight so they float in the top part of the ocean where the sun’s rays can reach them.
- They also need certain minerals like nitrates, phosphates and sulfur to turn into proteins, fats and carbs to stay alive.
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25. Among the biotic components of the ecosystem, the producer system is –
(a) Cow
(b) Peacock
(c) Tiger
(d) Green Plants
[U.P.P.C.S. (Pre) 2013]
Ans. (d) Green Plants
- Plants are organisms that can make their own food.
- They turn energy from light into carbohydrates, fats, and proteins. This is called photosynthesis.
- These plants are called autotrophs and are the first step in the food chain of any ecosystem.
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26. Trophic level-I includes –
(a) Herbivorous animals
(b) Carnivorous animals
(c) Omnivorous animals
(d) Green plants
[M.P.P.C.S. (Pre) 2016]
Ans. (d) Green plants
- The food chain is made up of different levels, called trophic levels.
- The first level is made up of plants, which make energy from the sun available to other living things.
- After that, there are herbivores (animals that eat plants), small carnivores (animals that eat other animals) and then large carnivores.
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27. What is true about ecosystems?
(a) Primary consumers are least dependent upon the producer
(b) Primary consumers are out-number producers
(c) Producers are more than primary consumers
(d) Secondary consumers are the largest and most powerful
[U.P.P.C.S. (Pre) 2019]
Ans. (c) Producers are more than primary consumers
- In most ecosystems, the number of producers is bigger than the number of primary consumers, and the number of primary consumers is bigger than the number of secondary consumers and so on.
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28. Which one of the following pairs is correctly matched?
(a) Mountain – Most stable ecosystem
(b) Abiotic Component – Bacteria
(c) Green plants – Ecosystem
(d) Rainfall – Global Warming
[U.P.P.C.S. (Pre) 2015]
Ans. (c) Green plants – Ecosystem
- The pairs mentioned in the question all have to do with ecosystems, but only (c) is the correct match.
- An ecosystem is made up of living things like plants, animals, and microorganisms, along with the non-living things in their environment.
- Since plants are living, they are part of an ecosystem.
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29. The correct order in the food chain of the various components of a terrestrial grass ecosystem is –
(a) Grass, Grasshopper, Frog, Snake
(b) Grass, Grasshopper, Snake, Frog
(c) Grasshopper, Frog, Grass, Snake
(d) Grasshopper, Snake, Frog, Grass
[U.P.P.S.C. (GIC) 2010]
Ans. (a) Grass, Grasshopper, Frog, Snake
- Food is something that helps an organism to survive.
- Plants can make their own food, but animals need to eat plants for food.
- The food chain shows how energy moves through organisms in an environment.
- The order goes like this: Plants (Producer) > Grasshopper (Primary Consumer) > Frog (Secondary Consumer) > Snake (Tertiary Consumer).
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30. Which of the following constitutes a food chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat
(e) None of the above
[Chhattisgarh P.C.S. (Pre) 2016, Chhattisgarh P.C.S. (Pre) 2015]
Ans. (b) Grass, goat and human
- Grass is an autotroph, goats are herbivorous consumers, and humans are omnivorous consumers which create a food chain.
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31. The pyramid of energy in any ecosystem is
(a) Always upright
(b) May be upright and inverted
(c) Always inverted
(d) None of the above
[M.P.P.C.S. (Pre) 2020]
Ans. (a) Always upright
- The Pyramid of Energy is always upright and can never be flipped because energy is lost as heat each time it moves up a trophic level.
- Each bar in the energy pyramid shows how much energy is available in each level at a given time or over the course of a year in a certain area. That’s why option (a) is the right answer.
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32. Biomass Pyramid is reversed in which type of ecosystem?
(a) Forest
(b) Pond
(c) Grassland
(d) Drylands
[U.P.P.S.C. (GIC) 2010]
Ans. (b) Pond
- The Pyramid of Biomass is a visual representation that shows the amount of biomass in different groups in an ecosystem.
- In grasslands and forests, the amount of biomass becomes smaller as you move away from the producers at the bottom.
- This makes the pyramid look like it is upright.
- In contrast, a pond has small producers, so their biomass is the smallest and increases as you move up the pyramid, making it look upside down.
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33. An inverted pyramid of biomass can be found in which ecosystem?
(a) Marine
(b) Grassland
(c) Forest
(d) Tundra
[R.A.S./R.T.S. (Pre) 2021]
Ans. (a) Marine
- In a marine ecosystem, there is an upside-down pyramid of biomass.
- This pyramid is normally upside-down because the biomass of fish is much higher than the biomass of phytoplankton.
- Therefore, option 1 is correct.
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34. Which one of the following organisms is likely to show the highest concentration of DDT, once it has been introduced into the ecosystem?
(a) Grasshopper
(b) Toad
(c) Snake
(d) Cattle
[I.A.S. (Pre) 1997]
Ans. (c) Snake
- DDT is a kind of pollution that does not break down and gets more concentrated as it goes up the food chain.
- In this situation, the snake would have the most DDT since it is the top predator.
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35. The amount of energy during the transfer from one trophic level to another in an eco-system–
(a) Increases
(b) Decreases
(c) Remains constant
(d) May increase or decrease
[U.P. R.O./A.R.O. (Pre), 2017]
Ans. (b) Decreases
- Energy is what makes all living things work.
- It moves from the producers to the top consumers in one direction, and it passes through different levels of organisms (producers, herbivores, carnivores, etc.).
- Some energy is lost in the form of heat as it moves through each level, so the amount of energy becomes less and less in the ecosystem.
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36. The amount of energy during the transfer from one trophic level to another in an ecosystem–
(a) Increases
(b) Decreases
(c) Remains constant
(d) May increase or decrease
[U.P.P.C.S. (Pre) 2019]
Ans. (b) Decreases
- Energy keeps living things functioning.
- It flows in one direction from the producers to the top consumers and goes through different organisms (producers, herbivores, carnivores, etc.).
- Energy is lost in the form of heat as it passes through each level, so the amount of energy decreases in the ecosystem.
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37. Which one of the following trees is not eco-friendly?
(a) Babul
(b) Eucalyptus
(c) Neem
(d) Pipal
[U.P. U.D.A./L.D.A. (Mains) 2010, U.P.P.C.S. (Mains) 2011]
Ans. (b) Eucalyptus
- Eucalyptus trees use up more water than other trees, which is why they’re sometimes called “the enemy of the environment.
- ” The water level decreases where Eucalyptus grows, which is mainly in Australia.
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38. The example of “Lentic Habitat” in the freshwater community is:
(a) Ponds and swamps
(b) Waterfalls and rivers
(c) Ponds and rivers
(d) All the above.
[MP.P.C.S. (Pre) 2014]
Ans. (a) Ponds and swamps
- Lentic Ecosystems are bodies of still water, such as ponds, lakes, swamps and marshes.
- Lotic Ecosystems are dynamic water habitats, like rivers.
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39. The transitional zone between two distinct communities is known as:
(a) Ecotype
(b) Arcade
(c) Ecosphere
(d) Ecotone
[U.P.P.C.S.(Pre) 2012]
Ans. (d) Ecotone
- An ecotone is an area where two different habitats meet and mix.
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40. Which of the following is the most stable ecosystem?
(a) Desert
(b) Mountain
(c) Ocean
(d) Forest
[U.P.P.C.S. (Pre) 2013]
Ans. (c) Ocean
- Oceans are the birthplace of life on Earth and have the most number of different species.
- There is no other ecosystem on land that can compare to a coral reef when it comes to the variety and diversity of species and the different ways they survive.
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41. Which of the following is an example of an anthropogenic biome?
(a) Fresh water
(b) Grassland
(c) Rain forest
(d) Cropland
[U.P. P.C.S. (Pre) 2018]
Ans. (d) Cropland
- Freshwater, grasslands, and rainforests are examples of natural habitats, while cropland is an example of a man-made habitat.
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42. Consider the following statements:
1. Most of the world’s coral reefs are in tropical waters.
2. More than one-third of the world’s coral reefs are located in the territories of Australia, Indonesia, and the Philippines.
3. Coral reefs host far more animal phyla than those hosted by tropical rainforests.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
[I.A.S. (Pre) 2018]
Ans. (d) 1, 2 and 3
- Corals are animals without a backbone.
- Hard corals create coral reefs by producing a hard skeleton that can form big structures, like Australia’s Great Barrier Reef.
- Most of the world’s coral reefs are located in tropical oceans very close to the equator.
- Around a third of the coral reefs on the planet are located in the territories of Australia, Indonesia and the Philippines.
- Coral reefs are some of the most varied habitats on the earth, taking up only a tiny fraction of the ocean floor, but they are home to more than 25% of all the fish species known to us.
- 32 out of the 34 different animal groups are found on coral reefs, which is more than the number found in tropical rainforests (9).
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43. Which one of the following is the largest ecosystem of the earth?
(a) Hydrosphere
(b) Biome
(c) Lithosphere
(d) Biosphere
[U.P. R.O./A.R.O. (Pre) 2017]
Ans. (a) Hydrosphere
- The Biosphere is the biggest ecosystem on Earth.
- It is a place where life can live, and it is made up of air, water, and land.
- The Biosphere is a thin layer around the Earth’s surface, but it doesn’t exist in the most extreme parts of the world such as the poles, mountains, and oceans.
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44. The cycling of elements in an ecosystem is called:
(a) Chemical cycles
(b) Biogeochemical cycles
(c) Geological cycles
(d) Geochemical cycles
[U.P.P.C.S.(Pre) 2012]
Ans. (b) Biogeochemical cycles
- In Earth science, a biogeochemical cycle is a way that certain chemicals move through living and non-living parts of Earth.
- Examples of these cycles include nitrogen, phosphorus and carbon.
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45. In the case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrients to enter the cycle?
(a) Carbon cycle
(b) Nitrogen cycle
(c) Phosphorus cycle
(d) Sulphur cycle
[I.A.S (Pre) 2021]
Ans. (c) Phosphorus cycle
- Phosphorus is found in many forms on Earth, like the phosphate ion (PO4 3-).
- It’s usually found in rocks, soil, and water, and is released by things like weathering, leaching and mining. Some of it is taken up by plants, animals, and other organisms, and comes back to the environment when they die.
- A lot of it ends up in the ocean, and it can be brought back to land by fishing and collecting seabird droppings.
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46. The movement of nutrient elements through various components of an ecosystem is called:
(a) Bio-geo-chemical cycle
(b) Bio-geological cycle
(c) Ecological succession
(d) Biological cycle
[U.P.P.C.S. (Pre) 2020]
Ans. (a) Bio-geo-chemical cycle
- Phosphorus is found in many places on Earth, usually as a phosphate ion (PO4 3-).
- It is found in rocks, soil, and water, and is released from things like weathering, leaching, and mining.
- Plants, animals, and other organisms take up some of it, and then when they die it returns to the environment.
- A lot of it goes into the ocean, and people can bring it back to land by fishing and collecting bird droppings.
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47. Which one of the following is not related to ecological balance?
(a) Water management
(b) Afforestation
(c) Industrial Management
(d) Wildlife protection
[U.P.P.C.S. (Pre) 2005]
Ans. (c) Industrial Management
- Taking care of water, planting trees, and protecting animals helps maintain a healthy environment, while industrial activities do not.
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48. “Ecology is permanent economy” is the slogan of which movement?
(a) Appiko Movement
(b) Narmada Bachao Andolan
(c) Chipko Movement
(d) None of the above
[U.P.P.C.S. (Mains) 2007]
Ans. (c) Chipko Movement
- Chipko Movement’s motto is “Ecology is permanent economy”.
- Narmada Bachao Andolan opposed the building of a big dam on the Narmada River.
- Appiko Movement was formed in Karnataka to protect the environment.
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49. Chipko movement is related to:
(a) Plant conservation
(b) Tiger project
(c) Crocodile conservation
(d) Plant reproduction
[U.P.P.C.S. (Pre) 2015]
Ans. (a) Plant conservation
- In 1973, Gaura Devi, along with other women from her village in the Garhwal Himalayas, stopped loggers from cutting down trees by hugging them.
- This brave and nonviolent act of illiterate tribal and village women, who were fighting for their traditional forest rights, was called the ‘Chipko Andolan’.
- It began the modern Indian environmental movement.
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50. Consider the following statements relating to the ecosystem:
1. The term ecosystem was first used by A.G. Tansley.
2. Those organisms which produce their food themselves are termed autotrophs.
3. Consumers consume their food through the process of photosynthesis.
4. Decomposers convert inorganic matter into organic matter.
Which of the above statements is correct:
Code:
(a) 1 and 2
(b) 1 and 3
(c) 2 and 4
(d) 3 and 4
[U.P.U.D.A./L.D.A. (Pre) 2002]
Ans. (a) 1 and 2
- A.G. Tansley was the first one to use the term “ecosystem”.
- That means statement (1) is true.
- Biotic components are living things that make up an ecosystem.
- Autotrophic components are organisms that make their own food.
- So, statement (2) is also true. Statement (3) is incorrect because consumers are organisms that get energy by eating other organisms, which are called heterotrophs.
- Statement (4) is wrong too because organic matter in an ecosystem is recycled by decomposers, which are bacteria and fungi that break down the organic matter of dead plants and animals into inorganic material.
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51. Which one of the following is the correct sequence of ecosystems in the order of decreasing productivity?
(a) Oceans, lakes, grasslands, mangroves
(b) Mangroves, oceans, grasslands, lakes
(c) Mangroves, grasslands, lakes, oceans
(d) Oceans, mangroves, lakes, grasslands
[I.A.S. (Pre) 2013]
Ans. (c) Mangroves, grasslands, lakes, oceans
- Mangroves are the most productive ecosystems, followed by grasslands, lakes, and oceans, in order of decreasing productivity.
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52. Concerning food chains in ecosystems, consider the following statements
1. A food chain illustrates the order in which a chain of organisms feeds upon each other.
2. Food chains are found within the population of a species.
3. A food chain illustrates the number of organism, which is eaten by others.
Which of the statements given above is /are correct?
(a) Only 1
(b) 1 and 2
(c) 1, 2 and 3
(d) None of these
[I.A.S. (Pre) 2013]
Ans. (a) Only 1
- It is clear that energy must move from one living thing to another.
- When animals that eat plants eat, the energy goes from the plants to the animals.
- In an ecosystem, some animals eat other living things, and some eat dead organic matter.
- This creates a “detritus food chain” which usually has four or five steps.
- Food chains are not found within one species, as this would mean a human eating another human (because humans are all the same species).
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53. Which of the following statements is correct?
(a) The energy flow in the biospheric ecosystem is unidirectional.
(b) The energy flows in the biospheric is cyclical.
(c) Relative loss of energy in the natural ecosystem decreases with increasing trophic levels.
(d) Species at progressively higher trophic levels appear to be less efficient in using available energy
[U.P.P.C.S. (Pre) (Re. Exam) 2015]
Ans. (a) The energy flow in the biospheric ecosystem is unidirectional.
- The energy that enters an ecosystem from the sun is used by plants for photosynthesis to make food.
- This energy is then passed on from one organism to another in a food chain.
- As the organisms use the energy, some of it is lost as heat to the environment and can’t be used by the plants again.
- This is why the flow of energy in an ecosystem is one-way.
- According to the laws of thermodynamics, energy can’t be created or destroyed in a closed system and it gets weaker when it changes form.
- This also happens in nature, as the amount of energy decreases as it goes up the food chain.
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High-Level
1. Who of the following used the term ‘deep ecology’ for the first time?
(a) E.P. Odum
(b) C. Raunkiaer
(c) F.E. Clements
(d) Arne Naess
[U.P.P.C.S. (Mains) 2014]
Ans. (d) Arne Naess
- Arne Naess was a Norwegian philosopher who invented the phrase “deep ecology” in 1972.
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2. The concept of the ecological niche was enunciated by –
(a) Grinnell
(b) Darwin
(c) E.P. Odum
(d) C.C. Park
[U.P.P.C.S. (Pre) 2005]
Ans. (a) Grinnell
- Joseph Grinnell said that the “ecological niche” is the most important way to tell apart different species and subspecies.
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3. The measurement unit of the ecological footprint is:
(a) Global hectares
(b) Nanometer
(c) Hoppus cubic foot
(d) Cubicton
[U.P.R.O./A.R.O. (Pre) 2016]
Ans. (a) Global hectares
- The ecological footprint is a way to measure how much people use of the Earth’s resources.
- It is a way to compare how much people use to the Earth’s ability to regenerate. It is the amount of land needed to provide food, fuel, and other resources to sustain life.
- It includes things like food, wood, and fossil fuels and the amount of carbon dioxide released.
- It is measured in Global Hectares.
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4. The minimum area of the land required to completely sustain the life of the person is called his –
(a) Biota
(b) Ecological footprint
(c) Biome
(d) Niche
[U.P.P.C.S. (Pre) 2012]
Ans. (b) Ecological footprint
- The ecological footprint is a measure of how much of the Earth’s resources people use.
- It looks at how much is used compared to the planet’s ability to regenerate what is taken.
- It looks at the land needed to provide food, fuel, and other resources.
- It also includes things like the amount of wood and fossil fuels used and how much carbon dioxide is released.
- This is all measured in Global Hectares.
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5. Which one of the following statements best describes the term ‘Social Cost of Carbon’? It is a measure, in monetary value, of the:
(a) long-term damage done by a tonne of CO2 emissions in a given year.
(b) requirement of fossil fuels for a country to provide goods and services to its citizens, based on the burning of those fuels.
(c) efforts put in by a climate refugee to adapt to living in a new place.
(d) contribution of an individual person to the carbon footprint on the planet Earth.
[I.A.S. (Pre.) 2020]
Ans. (a) long-term damage done by a tonne of CO2 emissions in a given year.
- The Social Cost of Carbon (SC-CO2) calculates the financial cost of one tonne of carbon dioxide emission in a given year.
- The EPA and other federal agencies use this number to assess the climate effects of their regulations.
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6. Read the list of Ecological concerns and the year in which the Acts were executed in India:
| Ecological Concerns |
Year, Act was passed |
| A. Wildlife Protection |
(i) 1986 |
| B. Environment Protection |
(ii) 2013 |
| C. The Scheduled Tribes and other Traditional forest dwellers (Recognition of Forest Rights) |
(iii) 1972 |
| D. The Forest Conservation Act |
(iv) 1988 |
Which of the following is not correctly matched?
Code:
A B C D
(a) iii i ii iv
(b) iv ii iii i
(c) i ii iii iv
(d) ii iii iv i
[R.A.S./R.T.S.(Pre) 2013]
Ans. (c) i ii iii iv
- The list is not correct.
- Wildlife Protection was in 1972, Environment Protection was in 1986, Scheduled Tribes and Other Traditional Forest Dwellers Recognition of Forest Rights was in 2006, and Forest Conservation was in 1980.
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7. The Millennium Ecosystem Assessment describes the following major categories of ecosystem services, supporting, regulating, preserving, and cultural.
Which one of the following is a supporting service?
(a) Production of food and water
(b) Control of climate and disease
(c) Nutrient cycling and crop pollination
(d) Maintenance of diversity
[I.A.S. (Pre) 2012]
Ans. (c) Nutrient cycling and crop pollination
- The World Development Report of 2010 states that there are five main types of eco-system services.
- Provisioning Services are things like providing food and water, Regulating Services are things like controlling climate and disease, Supporting Services are necessary for other services, Cultural Services involve people, and Preserving Services maintain diversity.
- Supporting Services are indirect and take a long time, like soil formation, nutrient cycling, crop pollination, and water cycling.
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8. Which one of the following is the correct sequence of a food chain?
(a) Diatoms-Crustaceans-Herrings
(b) Crustaceans-Diatoms-Herrings
(c) Diatoms-Herrings-Crustaceans
(d) Crustaceans-Herrings-Diatoms
[I.A.S. (Pre) 2014]
Ans. (a) Diatoms-Crustaceans-Herrings
- The usual sequence of a typical ocean food chain is Diatoms, Crustaceans, and then Herrings.
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9. Which of the following statements is true about Bionomics?
1. It means “management of life’.
2. It is synonymous with ecology.
3. It stresses the value of natural systems which influence human systems.
Code :
(a) Only 1
(b) 1 and 2
(c) 2 and 3
(d) 1, 2 and 3
[U.P. U.D.A./L.D.A. (Pre) 2001]
Ans. (c) 2 and 3
- Bionomics (from the Greek words bio, meaning life, and nomos, meaning law) is the study of how organisms interact with their environment.
- It is also known as ecology and focuses on how natural systems affect human systems, not on managing life.
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10. Which of the following shows a density gradient of the water system?
(a) Ecocline
(b) Halocline
(c) Pycnocline
(d) Thermocline
[U.P.P.C.S. (Mains) 2016]
Ans. (c) Pycnocline
- Pycnocline is a change in density in a water system.
- Halocline is when the salinity of the water changes.
- Thermocline is when the temperature of the water changes depending on how deep it is.
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11. In the context of ecosystem productivity, marine upwelling zones are important as they increase marine productivity by bringing the:
1. Decomposer micro-organisms to the surface.
2. Nutrients to the surface.
3 Bottom-dwelling organisms to the surface.
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 2 only
(c) 2 and 3
(d) 3 only
[I.A.S. (Pre) 2011]
Ans. (b) 2 only
- Winds blowing over the ocean push water away, so the water from below the surface comes up to fill the space.
- This is called “upwelling” and the water that rises is usually cold and full of nutrients.
- These nutrients provide food for the creatures in the surface waters, making areas where upwelling is common good places for fishing.
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12. Concerning ‘Eco-Sensitive Zones’, which of the following statements is/are correct?
1. Eco-sensitive zones are the areas that are declared under the Wildlife (Protection) Act, of 1972.
2. The purpose of the declaration of Eco-Sensitive Zones is to prohibit all kinds of human activities in those zones except agriculture.
Select the correct answer using the code given below:
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
[I.A.S. (Pre) 2014]
Ans. (d) Neither 1 nor 2
- The Environment (Protection) Act, of 1986 mentions eco-sensitive zones.
- Statement 1 is wrong because certain activities like flying over protected areas in an aircraft or hot air balloon, and discharging effluents and solid waste in natural water bodies or terrestrial areas are not allowed.
- Some activities such as cutting down trees, building hotels and resorts, using natural water for commercial purposes, laying down electrical cables, changing the agriculture system, and widening roads are regulated.
- Local communities can do agriculture and horticulture, rainwater harvesting, organic farming, use green technology, and renewable energy sources.
- So, statement 2 is also wrong and option (d) is the correct answer.
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13. Given below are two statements, one is labeled as Assertion (A) and the other as Reason (R).
Assertion (A): Various components of an ecosystem are not interdependent.
Reason (R): Human activities have an impact on the environment.
Choose the correct answer from the code given below.
Code:
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, and (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
[U.P.R.O./A.R.O. (Mains) 2016, U.P.P.C.S. (Pre) 2021]
Ans. (d) (A) is false, but (R) is true.
- Organisms in an ecosystem rely on each other.
- When the amount of one organism goes up or down, it can have an effect on the rest of the ecosystem.
- For instance, if foxes in a particular food chain were killed, then the population of rabbits would go up since they would no longer be hunted by the foxes.
- Humans have a big effect on the environment too, like overpopulation, pollution, burning fossil fuels, and cutting down trees.
- These things cause climate change, soil erosion, bad air quality, and water that isn’t safe to drink.
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14. In the grassland, trees do not replace the grasses as a part of an ecological succession because of:
(a) Insects and fungi
(b) Limited sunlight and paucity of nutrients
(c) Water limits and fire
(d) None of the above
[I.A.S. (Pre) 2013]
Ans. (c) Water limits and fire
- Ecological succession is the process by which an ecosystem changes over time.
- For example, in a grassland, the trees have been removed by past fires, which changes the ground.
- Without the trees, water washes away the soil, allowing grass to take its place.
- The grass absorbs most of the water, preventing shrubs from growing and stopping the ecological succession.
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15. The concept of ‘Ecological Transition’ was first used by:
(a) Elton
(b) Bennett
(c) Berkeley
(d) Ratzel
[U.P.P.C.S. (Pre) 2020]
Ans. (b) Bennett
- John W. Bennett first used the term “Ecological Transition” in his book of the same name.
- It refers to how, from the Western Renaissance onwards, people began to view the natural world from a human-centered perspective.
- This transition is also shown in the way Nature has been combined with Culture and how local self-sufficiency (the ability of a local group to meet their needs with what is available in a certain area) has decreased.
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16. The entire sequence of communities that successively change in a particular area are called:
(a) Ecological succession
(b) Sere
(c) Community dynamics
(d) Pyramid of biomass
[U.P.P.C.S. (Pre) 2020]
Ans. (b) Sere
- A ‘Sere’ is a series of different types of communities that develop in a certain area.
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17. Which one of the following is the correct sequence of the phases of biotic succession?
(a) Nudation, Migration, Ecesis, Reaction, Stabilization
(b) Migration, Nudation, Ecesis, Reaction, Stabilization
(c) Ecesis, Migration, Nudation, Reaction, Stabilization
(d) Stabilization, Reaction, Nudation, Migration, Ecesis
[U.P.P.C.S. (Mains) 2016]
Ans. (a) Nudation, Migration, Ecesis, Reaction, Stabilization
- Nudation is when an area is cleared out completely and nothing lives there.
- This usually happens because of things like soil erosion, bad weather, or human activity.
- Invasion or migration is when non-native organisms come to an area and reproduce quickly.
- Ecesis is when the first plants start to appear in an area and this depends on the soil.
- Reaction is when species change the environment and this can cause some species to be replaced by others.
- Finally, stabilization is when a mature and stable community forms and the environment is stable enough to support it.
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18. Which one of the following is the correct order of biological organization ranging from organism to biosphere?
(a) Population- Ecosystem- Community – Landscape
(b) Landscape- Community-Ecosystem-Population
(c) Population – Community- Ecosystem- Landscape
(d) Population- Landscape- Community- Ecosystem
[U.P.P.C.S. (Pre) 2017]
Ans. (c) Population – Community- Ecosystem- Landscape
- Organisms are grouped into populations, which are groups of the same species living in the same area that can breed with each other.
- Populations make up communities, which are two or more different species in the same place.
- Together, living things and non-living things, like water and air, form an ecosystem.
- A biome is a large area with similar climates, and it can contain multiple ecosystems.
- The biosphere is all living things and the places they interact with, like the lithosphere and hydrosphere.
- Several communities form an ecosystem and one or more ecosystems can be found in an area.
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19. Consider the following statements about the eco-system:
1. The production at the autotroph level is said to be primary productivity.
2. The secondary productivity refers to the production at the heterotroph level.
Of the above, the correct statement is/are:
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 and 2
[U.P. R.O./A.R.O. (Pre) 2017]
Ans. (c) Both 1 and 2
- Green plants are the primary producers and herbivores are the secondary producers.
- These plants and animals are known as autotrophs and heterotrophs
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20. Which of the following is the correct sequence of ecosystem in order of decreasing productivity?
(a) Ocean, Lakes, Grasslands and Mangroves
(b) Mangroves, Oceans, Grasslands and Lakes
(c) Mangroves, Grasslands, Lakes and Oceans
(d) Oceans, Mangroves, Lakes and Grasslands
[U.P.R.O./A.R.O. (Pre) 2021]
Ans. (c) Mangroves, Grasslands, Lakes and Oceans
- The mangroves are the most productive of all ecosystems, followed by grasslands, lakes, and then oceans.
- Even though oceans take up 70 percent of the Earth’s surface, the productivity of oceans is only 55 billion tons, so option (c) is correct.
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