Nootan solutions for बायोलॉजी [इंग्रजी] इयत्ता १२ आयसीएसई chapter 16 - Ecosystem [Latest edition]

Trophic levels are formed by ______.

An oligotrophic lake is characterised by ______.

A group of interconnected food chains is called a ______.

Energy and nutrients enter a community by way of the ______.

Which is the correct order in the food chain?

An ecosystem is a ______.

A sequence of species through which the organic molecules in a community pass is called ______.

An ecological pyramid of biomass is a representation of the ecosystem’s ______.

Who of the following are the ultimate sources of energy for carnivorous organisms in the food chain of a forest ecosystem?

Differences in climates in various areas of the Earth result largely from ______.

The concept of “trophic structure” of a community emphasizes the ______.

Ecosystems have ______.

Consider the components of a food chain: producers → herbivores → carnivores → top carnivores. Eventually, what happens to all the energy passed from one element to the next?

A natural food web ______.

In what way are decomposers like producers?

Which statement is true concerning this food chain: grass → rabbits → snakes → hawks?

One of the lessons from an energy pyramid is that:

Which of these ecosystems has the lowest primary productivity per square meter?

For any ecosystem, the amount of energy present in the ______ level is greater than that present in any other trophic level.

Which of the following depicts the pattern of flow of energy and materials through an ecosystem?

Which of the following is a factor in vertical structuring of terrestrial ecosystems?

When we study the full assortment of organisms in an area, as well as the abiotic environment that affects them, we are studying the ______.

An ecosystem contains ______.

Which kind of organism would be most likely to perform photosynthesis?

Which is not a consumer?

Which eats only plant foods?

Humans and animals such as bears are biologically adapted to be ______.

Fungi and bacteria are detritus feeders, also known as ______.

Energy flow in an ecosystem begins with ______.

The only heterotrophs required in an ecosystem are ______.

In a grazing food chain ______.

If we weighed all of the organisms at each level of this food web, which would be the heaviest?

Which is not true about a complex food web?

Most natural food chains are only four or five links long. The number of trophic levels is limited because ______.

An ecosystem is characterized by which of the following?

Ecosystems are characterized by:

Which of the following is true of ecological pyramids?

Which term describes the “mailing address” where an organism lives?

Which term describes the “occupation” of an organism within the community?

Green plants form the ______.

When a big fish eats a small fish which eats water fleas supported by phytoplankton, the water fleas are ______.

Producers in an ecosystem are ______.

Most food chains are composed of ______.

Which of the following statements concerning food chains is not true?

Which of the following factors is least likely to affect the type of organism colonizing a pond?

A carefully controlled, closed community was established containing the following organisms. Which organism, if removed, would have the most serious and lasting effect on the others?

The graphic presentation of various aspects of ecosystems are in the form of pyramids. When such a presentation is made with reference to energy at different trophic levels, it will make ______.

Which of the following constitutes the largest ecosystem of the world?

Which of the following can explain the energy stored in an ecosystem?

Which of the following components of an ecosystem has the greatest biomass?

Of the total amount of energy that passes from one trophic level to another, about 10% is ______.

Which of the following is a primary producer in a pond ecosystem?

Which one of the following has the largest population in a food chain?

Secondary producers are:

Name the first victim if carbon dioxide is removed from the Biosphere:

Which of the following is not a producer?

Which of the following is an ecosystem service provided by a natural ecosystem?

How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

Among the following biogeochemical cycles, which one does not have losses due to respiration?

A biotic community is an assemblage of ______.

Which one of the following Clements would consider to be the climax community in a humid environment?

Primary succession takes much longer than secondary succession because it involves ______.

Clements proposed the climax-pattern model of succession. Governing factors for this succession that he proposed were ______.

In ______, a disturbed site in a community recovers and moves again toward the climax state.

All of the following increase as community succession progresses, except for ______.

The seral communities developing on a water body are known as a ______.

The process of mineralisation by microbes helps in the release of ______.

Which of the following ecosystems is most productive in terms of net primary production?

During the process of ecological succession, the changes that take place in communities are ______.

The reservoir for the gaseous type of biogeochemical cycle exists in the ______.

Indian scientist related with ecosystem is ______.

The most important factor controlling the type of biome found on land is the ______.

Energy enters an ecosystem primarily as ______ and leaves an ecosystem primarily as ______.

All the living organisms ultimately depend on ______ as the ultimate source of energy.

The passage of materials from producer through primary, secondary, tertiary, or quaternary consumers is known as ______.

______ are the diagrammatic representations of the trophic structure and function at successive trophic levels of an ecosystem.

Freshwater ecosystems are categorized according to the speed of water flow. There are ______ ecosystems of nonflowing water and ______ ecosystems of flowing water.

In the ecosystem, primary producers are also known as ______.

The interconnection of food chain leads to the food interrelationship of organisms and this complex situation is thus known as ______.

Those animals which live directly on plants for their food are known as ______.

The quantity of abiotic materials at any given time in an ecosystem is termed as ______.

The functional status of an organism in its community is termed as ______.

The place where an organism lives is known as ______.

The word ‘ecosystem’ was coined by ______.

Pyramid of energy is always ______.

In an ecosystem second trophic level is occupied by ______.

In an ecosystem dominated by trees, the pyramid (of numbers) is ______ type.

The major reservoir of carbon on earth is ______.

Plants are called as ______ because they fix carbon dioxide.

In an ecosystem dominated by trees, the pyramid (of numbers) is ______ type.

Common detritivores in our ecosystem are ______.

An orderly sequence of communities over a period of time at the same place is known as ______.

The american ecologist F. E. Clements believed that succession follows a predetermined path until it reaches a final predictable stage, known as the ______ community.

During a succession the number of species ______ and the community biomass ______.

If the succession starts in a predominantly organic environment and is characterised by early dominance of heterotrophs, it is known as ______ succession.

If the succession starts on the area previously colonised but has been cleared off, it is called ______ succession.

Biomass and standing crop ______ with succession.

When one community replaces the other due to the modification of the environment by the community itself, then the succession is called ______.

State whether the following statement is true or false:

Two different regions having the same amount of annual rainfall can exhibit different vegetational constituents.

State whether the following statement is true or false:

An ecosystem is not a self-sufficient unit.

State whether the following statement is true or false:

The pyramid of energy is always upright.

State whether the following statement is true or false:

The only requirement of an ecosystem is a constant input of energy that comes by the process of respiration.

State whether the following statement is true or false:

Bioenergetics can be defined as the process of energy transfer between trophic levels.

State whether the following statement is true or false:

Herbivores are generally more numerous than carnivores.

State whether the following statement is true or false:

All food chains begin with a photosynthetic producer.

State whether the following statement is true or false:

Organisms in all trophic levels may be consumed by decomposers.

State whether the following statement is true or false:

Energy recycling is an important part of every ecosystem.

State whether the following statement is true or false:

A detritus food chain accounts for more energy flow than the grazing food chain, since most organisms die without being eaten.

State whether the following statement is true or false:

A pyramid of biomass is based on the number of organisms at each trophic level.

State whether the following statement is true or false:

Food chains are long and involved, with at least seven or eight trophic levels.

State whether the following statement is true or false:

Generally, a larger human population could be maintained on the same amount of cultivated land if people ate more plants rather than animals.

State whether the following statement is true or false:

Broad-leaved forests occur in the equatorial belt.

State whether the following statement is true or false:

Cropland ecosystem is a natural ecosystem.

State whether the following statement is true or false:

Human intervention in natural community interactions usually makes the community more stable.

State whether the following statement is true or false:

Clements called the first stage of secondary succession the climax community.

State whether the following statement is true or false:

Humans often disrupt natural succession to produce agricultural fields and managed forests.

State whether the following statement is true or false:

All successional trends lead towards relative xerophytism.

State whether the following statement is true or false:

Succession leads to the formation of a more or less stable community.

State whether the following statement is true or false:

Decrease in net community production and a corresponding increase in community respiration is a major functional aspect of succession.

State whether the following statement is true or false:

After fire, a primary succession starts at a very rapid rate.

State whether the following statement is true or false:

Ecological succession is directional, therefore a predictable process.

State whether the following statement is true or false:

Climax indicates a final and stable community in a successional series.

Of the three types of ecological pyramids-biomass, numbers, and energy flow-which one is always shaped like a real pyramid with the largest amount in the producer trophic level?

Arrange the following biotic components in order of their food chain:

predators, herbivores, producers, decomposers.

What is the source of energy used by plants in photosynthesis?

In terms of energy, who is at an advantageous position, a vegetarian or a non-vegetarian?

Which organisms represent the base of an ecological pyramid?

Give the name for a network formed by interlinking of a number of food chains.

Which ecological pyramid can never occur in an inverted form?

What are the starting points of a grazing food chain and a detritus food chain, respectively?

A reindeer moss (lichen) is eaten by the reindeer and which in turn is eaten by man. Which is the primary consumer?

Name two different components of an ecosystem.

Who coined the term ‘niche’ and in which year?

List the biotic components of an ecosystem.

What those organisms are called which break down the complex organic compounds present in dead animals and plants?

Which organism belongs to the first trophic level in the food chain comprising the following: rats, plants, hawks, and snakes?

While comparing two ecosystems ‘A’ and ‘B’, it was observed that ‘A’ has only first and second-order consumers, whereas ‘B’ has plus third, fourth, and fifth-order consumers. Which of the two would be more stable?

Which category of organisms forms the starting point of a food chain?

Which one of the following organisms is likely to have maximum concentration of D.D.T. in its body:

peacock, grasshopper, frog, grass, snake?

Can more than one species occupy the same niche for a very long time?

What type of organisms are primary consumers?

Given below are examples of the terrestrial and aquatic ecosystems. Identify and list them separately:

forests, freshwater, marine, desert, grassland.

Who coined the term ‘ecosystem’ and in which year?

What do you understand by the term ‘food chain’?

How you can define a ‘food web’?

Name the three types of ecological pyramids.

Write the equation that helps in deriving the net primary productivity of an ecosystem.

What does ‘R’ represent in the given equation for productivity in an ecosystem?

GPP − R = NPP

Construct a detritus food chain with minimum three trophic levels.

State the difference between the first trophic levels of detritus food chain and grazing food chain.

All the primary productivity is not available to a herbivore. Give one reason.

What is secondary productivity?

Explain ‘standing crop’ in an ecosystem.

Name an organism which occupies more than one trophic level in an ecosystem.

Arrange the following steps of decomposition in a sequential order:

Catabolism, Leaching, Mineralisation, Humification, and Fragmentation.

Who preferred the term ‘prevailing climax’ in place of climax?

Name the biotic succession starting on a bare rock?

Where would you look for signs of secondary succession?

Among the crustose, foliose, and fruticose lichens, which one is a pioneer species?

Write chief character of pyramid of energy.

Which organisms constitute the last trophic level?

Explain the role of the ‘first trophic level’ in an ecosystem.

How is the detritus food chain connected with the grazing food chain in a natural ecosystem?

Give a reason for the following:

Equilibrium of a forest ecosystem can be disturbed by uncontrolled hunting of big predators.

Suppose the biotic component of an ecosystem consists of plants, grasshoppers, praying mantis, mice, frogs, snakes, bears, owls, and shrews. Develop the food web of this ecosystem, and explain how each of these organisms obtains its food at different trophic levels.

‘All life on earth depends on the Sun.’ Justify this statement.

Plants are said to be producers of food or energy. Do they really produce energy? Explain.

Explain why, in an ecosystem, energy is said to flow while nutrients are said to cycle.

What is the natural ecosystem?

How is a natural ecosystem different from a man-made ecosystem?

What is meant by food web?

Explain with examples the formation of a food web in the ecosystem.

What is a trophic level?

Describe any differences which occur in energy availability at various trophic levels.

In what essential features would you expect a terrestrial ecosystem to differ from a marine one?

Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels? Explain with an example.

What is eutrophication?

Explain eutrophication with reference to an aquatic ecosystem.

Why is there always a loss of chemical energy with each step in a food chain?

Describe the food chain operating in a pond.

State the food habits of each trophic level in the pond food chain.

How do vultures and kites form an important constituent of our biotic environment?

What are the various structural components of an ecosystem? How are they linked together?

Write a short note on the food chain.

Write a short note on the ecological pyramids.

Write a short note on the food web.

Write a short note on the niche.

Write a short note on the agroecosystem.

What is a food chain?

How does the study of food chains in an area or habitat help us?

Give an example of a four-step food chain operating in a large lake.

What are the major ecosystems of the world?

Describe the forest ecosystem in detail.

Describe the flow of energy in an ecosystem with the help of various models.

Describe three types of trophic pyramids, indicating which organisms are on the top and bottom of each.

Distinguish between the following:

Autotrophs and Heterotrophs

Describe four different types of heterotrophs found in natural ecosystems.

With reference to food chains, what is a trophic level?

With reference to food chains, what is an ecological pyramid?

Give a reason for the following:

Equilibrium of a forest ecosystem can be disturbed by uncontrolled hunting of big predators.

Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?

Give a graphic representation of the phosphorus cycle in nature (ecosystem).

Give a graphic representation of the carbon cycle in nature.

Why is the pyramid of energy never inverted?

 Define the Standing crop.

The Net primary productivity of a terrestrial ecosystem is 1500 kg per meter square per year, and the respiratory loss of the ecosystem is 1200 kg per meter square per year. Calculate the gross primary productivity of the given ecosystem.

In an ecosystem, a food chain follows the following pattern:

Grass → Insects → Snake → Peacock.

If 2000 J of energy is available at the level of producers in this food chain, how much energy would be available to the peacock?

In an ecosystem, is the climax stage achieved more quickly during the primary succession or during the secondary succession? Give a reason to justify your answer.

Define a biogeochemical cycle.

Give a graphic representation of the phosphorus cycle in nature (ecosystem).

Can you work out how many trophic levels human beings function at in a food chain?

The pyramid of biomass in the sea is generally inverted. Explain.

Pyramid of energy is always upright, can never be inverted.

What are the shortcomings of ecological pyramids in the study of ecosystems?

Mention any two reasons why the primary productivity varies in different types of ecosystems.

How is the detritus food chain made up of? How do they meet their energy and nutritional requirements?

Biodiversity must be conserved as it plays an important role in many ecosystem services that nature provides. Explain any two services of the ecosystem.

Plants are called as ______ because they fix carbon dioxide.

In an ecosystem dominated by trees, the pyramid (of numbers) is an ______ type.

In aquatic ecosystems, the limiting factor for the productivity is ______.

Common detritivores in our ecosystem are ______.

The major reservoir of carbon on earth is ______.

Which one of the following has the largest population in a food chain?

The second trophic level in a lake is ______.

Secondary producers are:

What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation?

Distinguish between grazing food chain and detritus food chain.

Distinguish between production and decomposition.

Distinguish between upright and inverted pyramids.

Distinguish between a food chain and a food web.

Distinguish between litter and detritus.

Distinguish between primary and secondary productivity.

Describe the components of an ecosystem.

Define ecological pyramids.

Describe with examples of pyramids of number and biomass.

What is primary productivity?

Give a brief description of the factors that affect primary productivity.

Define decomposition.

Describe the processes and products of decomposition.

Give an account of energy flow in an ecosystem.

Write important features of a sedimentary cycle in an ecosystem.

Outline salient features of carbon cycling in an ecosystem.

What will happen to an ecosystem if all producers are removed?

What will happen to an ecosystem if all organisms of herbivore level are eliminated?

What will happen to an ecosystem if all top carnivore population is removed?

A simple food web of five organisms A-E is shown below:

In organisms C were suddenly to be removed from the food web, how would the populations of organisms A, D, and E are affected? Explain your answer.

Differentiate between an agroecosystem and a forest ecosystem.

Differentiate between autogenic and allogenic succession.

Differentiate between autotrophic and heterotrophic succession.

Differentiate between an autotroph and a heterotroph.

Differentiate between biotic and abiotic components.

Differentiate between an ecosystem and a biome.

Differentiate between eutrophic lakes and oligotrophic lakes.

Distinguish between a food chain and a food web.

Differentiate between gross primary productivity and net primary productivity.

Differentiate between habitat and niche.

Differentiate between hydrosere and xerosere.

Differentiate between lentic and lotic habitats.

Differentiate between nektons and benthos.

Differentiate between primary and secondary succession.

Differentiate between the pyramid of energy and the pyramid of numbers.

Differentiate between productivity and decomposition.