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Scavengers and decomposers - class-VI

Description: scavengers and decomposers
Number of Questions: 49
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Tags: interdependence in living beings - plants and animals biology habitat interdependence of organism and the environment
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Earthworm is a 

  1. Herbivore

  2. Secondary consumer

  3. Tertiary consumer

  4. Detrivore


Correct Option: D
Explanation:

Decomposer is an organism which decomposes dead organic matter. They breakdown organic matter of dead animals and plants and release nutrients in the environment. Detritivores are also called as detritus eaters. They are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal matter). Earthworm is an example of detrivore.

Thus, the correct answer is 'Detrivore.'

The last chain of food is

  1. producers

  2. decomposers

  3. parasites

  4. none of the above


Correct Option: B
Explanation:
A. Producers are photosynthetic green plants. They are autotrophs as they convert solar radiations into chemical energy and prepare their own food.
B. Decomposers are micro consumers that reduce organic remains. They form the last step of the food chain because they breakdown detritus (the dead remains of plants and animals) into smaller particles.
C. Parasites are the organisms that live in or on the host organism from which they derive their nutrition.
So, the correct answer is 'Decomposers'.

The decomposers in an ecosystem

  1. convert inorganic material, to simpler forms

  2. convert organic material to inorganic forms

  3. convert inorganic materials into organic compounds

  4. do not break-down organic compounds


Correct Option: B
Explanation:
Decomposers are micro consumers and include certain bacteria and fungi. They are known as saprophytes and release the minerals trapped in organic remains of plants and animals. The process of decomposition occurs outside the body of decomposers. They release enzymes on the organic dead remains which decompose them into simple inorganic substances which are absorbed by decomposers.
So, the correct answer is 'convert organic material to inorganic forms'.

Which of the following microorganisms convert nitrogenous waste into nitrogen compound?

  1. Bacteria and Fungi

  2. Fungi and Protozoan

  3. Protozoan and Algae

  4. Protozoan and Bacteria


Correct Option: A
Explanation:

Bacteria and fungi belongs to the class of decomposers. They act on the waste materials and converts the nitrogen present in the waste to useful nitrogenous compounds. It also increases the nitrogen content of the soil and increases the fertility of the soil.

So, the correct answer is option A.

Which of the following is nature's cleaner?

  1. Consumers

  2. Producers

  3. Decomposers and scavengers

  4. Symbionts


Correct Option: C
Explanation:
A food chain is series of plants/animals which are interrelated in the form of organism being eaten as food by the other. It consists of producers, consumers and decomposers. Plants are producers. The herbivores are primary consumers and carnivores are secondary consumers. Decomposers and scavengers are those which decomposes the waster organic matter and release energy back in the environment. Hence, they are also called as nature's cleaner. They are present in the apex of the pyramid.
Thus, the correct answer is 'Decomposers and scavengers.'

Bacteria and fungi are

  1. Scavengers

  2. Primary consumers

  3. Secondary consumers

  4. Decomposers


Correct Option: D
Explanation:

Decomposers are microorganisms which decomposes organic matter. These include bacteria and fungi. They breakdown organic compounds obtained from the dead animals and leaves and releases carbon and energy back in the environment. They usually occupy the apex of the pyramid.

Thus, the correct answer is 'Decomposers.'

A detritivore is a/an

  1. Animal feeding on plant matter

  2. Animal feeding on decaying organic matter

  3. Plant feeding on an animal

  4. Animal feeding on another animal


Correct Option: B
Explanation:

A detritivore is an animal feeding on decaying organic matter. It is a heterotroph that obtains nutrients by consuming detritus. Examples include millipedes, earthworms, fiddler crabs, sea cucumbers. 

Thus, the correct answer is 'Animal feeding on decaying organic matter.'

The organisms, which attack dead animals are

  1. First link of the food chain are known as primary producers

  2. Second link of the food chain are known as herbivores

  3. Third link of the food chain are known as tertiary consumers

  4. Present at the end of food chain are detritivores


Correct Option: D
Explanation:

The organisms which attack dead animals and obtain nutrition from their detritus (decomposing parts of plant and animals, even feces) are called as detritivores (kind of heterotrophs). They are present at the end of the food chain because they consume the highest trophic level organisms by their biomacromolecular digesting enzymes. Therefore, concluding the food chains often.

So, the correct answer to the question is 'Present at the end of the food chain are detrivores'.

Which of the following is an example of transformer:-

  1. Grass

  2. Cow

  3. Fungi

  4. Lion


Correct Option: C
Explanation:

In biology, transformers are the organisms that transform or convert one form of food into another. These organisms are comonly refrred to as decomposers. They convert dead organic matter into simpler inorganic molecules. Such animals include fungi, some bacteria, etc.

So, the correct answer is 'Fungi'.

Efficient recycling of nutrients from dead bodies into living things is done by?

  1. Producers

  2. Consumers

  3. Decomposers

  4. Predators


Correct Option: C
Explanation:
  • Decomposer are feed on the decaying organic matter and convert this matter into nitrogen and carbon dioxide. 
  • Decomposers are the fungi and bacteria, which are the saprophytes.
  • The saprophytes play a vital role in recycling the nutrients so that the producers i.e. plants can use them once again.

Which of the following can convert organic substance into inorganic substance?

  1. Producers

  2. Decomposers

  3. Primary consumers

  4. Secondary consumers


Correct Option: B
Explanation:
  • Decomposers are organisms that break down the dead organic matter into carbon dioxide, water, minerals and other simple chemicals called inorganic substances.
  • These inorganic substances are utilized by green plants. 
  • Leaf litter, dead wood, animal carcasses and faeces are the organic matter present in the soil.
  • So, the correct answer is 'Decomposers'.

The breakdown of dead and decaying organisms is carried out by

  1. Decomposers

  2. Humans

  3. Insects

  4. Rodents


Correct Option: A
Explanation:

Decomposers are organisms that break down dead or decaying organisms, and in doing so they carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. 

Which of the following helps in maintaining the supply of nutrients to the growing plants?

  1. Herbivores

  2. Carnivores

  3. Decomposers

  4. Omnivores


Correct Option: C
Explanation:

The food chain is comprised of different species which depend on each other for energy. The producers are which can prepare the food. The consumers feed on the producers. The dead plants and animals are degraded due to the microbial activity of the decomposers. The decomposers include the microbes which are involved in the breaking down of the organic complexes and recycling of the nutrients. They help in maintaining the continuous supply of the nutrients for the producers. 

Thus, the correct answer is option C. 

Decomposers are otherwise called as

  1. Detritivores

  2. Primary consumers

  3. Organic matter

  4. Secondary consumers


Correct Option: A

Which of the following are nature's cleaners?

  1. Producers

  2. Consumers

  3. Symbionts

  4. Decomposers and scavengers


Correct Option: D
Explanation:

Scavengers are organisms, that consume remains of other dead organisms or their waste products. The scavenger's role in the ecosystem is to prepare bodies for decomposition. They open up the bodies so that others can share the food. Scavengers include large animals. For example, crow and vulture. Many large carnivores, such as hyena and lion, which hunt regularly, will scavenge if given a chance. 

Decomposers are organisms that transform the bodies of both plants and animals back into the basic constituents they were made from. Decomposers are mostly bacteria and fungi. Hence, decomposers and scavengers are nature's cleaners.

Which one of the following is genetically improved bacteria for pollution control.

  1. Pseudomonas

  2. Rhlzobium

  3. N!trobacter

  4. Nttrosomonas


Correct Option: A

For recycling of materials, which of the following is most necessary?

  1. Producers

  2. Consumers

  3. Decomposers

  4. None of the above


Correct Option: C
Explanation:

Biogeochemical cycle mainly involves the exchange of materials between biotic and abiotic components of the biosphere. The bio - genetic nutrients are essential elements required by organisms for their body building and metabolism which are provided by earth and returned to earth after the death of organisms and/or through excreta of animals. The decay of excreta and dead bodies of organisms is carried out be decomposers. The activity of decomposers releases the bio - genetic nutrients from excreta and dead bodies of organisms. Hence decomposition activity is most important part of biogeochemical cycles. Else all the nutrients will slowly become trapped in excreta and dead bodies of organisms.

So, the correct answer is option C.

Which one of the following is a decomposer?

  1. Fungi

  2. Algae

  3. Protozoa

  4. Insect


Correct Option: A
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'.

Maintenance of soil fertility without addition of nutrition is due to

  1. Floods

  2. Crop residue

  3. Favourable temperature

  4. Microbial activity


Correct Option: D
Explanation:

Soil fertility is the ability of a soil to sustain agricultural plant growth. It is maintained without addition of nutrition due to microbial activity. Microbes increase the amount of nutrients in soil available for plants. Maintaining soil fertility naturally using microbes can reduce the need for synthetic fertilizers and pesticides.

Thus, the correct answer is 'Microbial activity.' 

Most animals that live in deep oceanic water are 

  1. Primary consumers

  2. Secondary consumers

  3. Tertiary consumers

  4. Detritivores


Correct Option: D
Explanation:

Most animals that live in deep oceanic water are detritivores. They are also called as scavengers. Most of them living in deep ocean include crustaceans and polychaetes.

Thus, the correct answer is option D.

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


Correct Option: C
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.'

Decomposers of an ecosystem include

  1. Microscopic animals

  2. Bacteria and fungi

  3. Both A and B

  4. Bacteria, fungi and macroscopic animals


Correct Option: B
Explanation:
An ecosystem is made up of living things and nonliving things. Living things include plants, animals and decomosers. Nonliving things include air, water, land. Plants are producers. They synthesize their own food. Animals are consumers. They are either herbivores or carnivores. Decomposers include bacteria and fungi. They decompose the waster organic matter from animals and plants and release energy back in the environment.
Thus, the correct answer is 'Bacteria and fungi.'

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


Correct Option: D

Exlusively scavenger bird is

  1. Vulture

  2. Own

  3. Kite

  4. Duck


Correct Option: A
Explanation:
A scavenger is an organism that mostly consumes decaying biomass such as meat or rotting plant material. They usually consume animals that have died of natural cause or been killed by another carnivore. Vultures are the scavengers that only eat the bodies of dead animals. They have excellent eyesight and a strong sense of smell. They use these keen senses to locate rotting carrion while they are soaring high over land.
So, the correct answer is 'Vulture'.

In food web, hyenas and vultures are

  1. Primary consumers

  2. Predators

  3. Scavengers

  4. Decomposers


Correct Option: C
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.'

Decomposers occupy a trophic level

  1. $T _1$

  2. $T _2$

  3. $T _3$

  4. $T _6$


Correct Option: D
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$.' 

What will happen if all the bacteria and fungi are destroyed?

  1. There will be no disease and death.

  2. No antibiotics would become available.

  3. Dead bodies and excretions will pile up.

  4. Soil will become depleted of all nutrients.


Correct Option: C
Explanation:

A food chain is series of plants/animals which are interrelated in the form of organism being eaten as food by the other. It consists of producers, consumers and decomposers. The plants are producers. The animals eating plants are called as primary consumers and animals eating primary consumers are called as secondary consumers. Decomposers like bacteria and fungi are those which decomposes the waster organic matter like dead bodies and excretions and release energy back in the environment. Hence, if all the bacteria and fungi are destroyed, dead bodies and excretions will pie up.

Thus, the correct answer is 'Dead bodies and excretions will pile up.'

 What are decomposers?

  1. Decomposers break down the complex organic substances of garbage, dead animals and plants into simpler inorganic substances.

  2. Decomposers synthesise the complex organic substances of garbage, dead animals and plants into simpler inorganic substances.

  3. Decomposers break down the complex inorganic substances of garbage, dead animals and plants into simpler inorganic substances.

  4. Decomposers break down the complex organic substances of garbage, dead animals and plants into simpler organic substances.


Correct Option: A
Explanation:

Decomposers are organisms that break down dead or decaying organisms and in doing so, carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development.

Decomposers and scavengers break down dead plants and animals. They also break down the waste (poop) of other organisms. Decomposers are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients and dead matter and waste would pile up.
Therefore, the correct answer is option A.

Choose the correct from the alternatives given.
Hyena that lives on left over food of the lion is called a

  1. scavenger

  2. parasite

  3. predator

  4. antibiosis


Correct Option: A
Explanation:
A.Scavengers are animals that consume dead organisms that have died from causes other than predation. . For example, hyena eats the leftover food of the lion. Hence hyena is a scavenger. 
B.Parasite - relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism.
C.Predator -  an animal that lives by killing and eating other animals : an animal that preys on other animals. 
D.Antibiosis - an antagonistic association between two organisms (especially microorganisms), in which one is adversely affected.

So the correct option is 'scavenger'.

The decomposers in an ecosystem

  1. Convert inorganic material to simpler forms.

  2. Convert organic material to inorganic forms.

  3. Convert inorganic materials into organic compounds.

  4. Do not breakdown organic compounds.


Correct Option: B
Explanation:

Most important characteristics of an ecosystem are unidirectional flow of energy and cycling of material. The cycling of material is directly dependent on the activity of decomposers. These organisms, also called as detritivores, feed on detritus ie dead and decaying matter and release the nutrients locked up in dead bodies of plants and animals and excreta of animals. Thus, converting organic material into inorganic nutrients.

Therefore, the correct answer is option B.

If the decomposers become extinct, the most severely affected would be

  1. Non-cycling of minerals

  2. Damage to nitrogen fixation

  3. Biomagnification

  4. Carnivores will be starved


Correct Option: A
Explanation:

Decomposers are microorganisms which decomposes organic matter. These include bacteria and fungi. They break down the organic matter of dead animals and plants and releases essential minerals back to the environment. If the decomposers become extinct, the most severely affected would be noncycling of minerals. Due to this, the essential minerals would not be released back in the environment and could not be used by plants for next cycle.

Thus, the correct answer is 'Noncycling of minerals.'

Organisms in all trophic levels may be consumed by decomposers

  1. True

  2. False


Correct Option: A
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.

In an ecosystem, bacteria are

  1. Microconsumers

  2. Macroconsumers

  3. Primary consumers

  4. Secondary consumers


Correct Option: A
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.'

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


Correct Option: C
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.

Which of the following is not an example of pray predator relationship?

  1. Tiger eating a deer

  2. Plant Nepenthes trapping an insect

  3. Bacteria decomposing organic matter

  4. Crocodile killing a man


Correct Option: C
Explanation:

Bacteria decompose the organic matter which is not really living. hence, it cannot be considered as a pray-predator relationship.

Read the following statements and select the incorrect one.

  1. Little decomposition occurs during the formation of primary sludge

  2. formation of primary sludge requires ample aeration.

  3. Activated sludge possess flocs of decomposer microbes

  4. Formation of activated sludge requires aeration.


Correct Option: B
Explanation:

Little decomposition occurs during the formation of primary sludge. Activated sludge possess flocs of decomposer microbes. Formation of activated sludge requires aeration. But formation of primary sludge does not requir ample aeration. So, the correct option is 'Formation of primary sludge requires ample aeration'

State whether the following statements are true or false.
A food relation in which an animal feeds on a dead animal or one killed by anothr animal is known as predation 

  1. True

  2. False


Correct Option: B
Explanation:

Predation is the biological interaction where an organism called predator feeds on the other living organism called prey. It plays an important role in the distribution and diversity of the species in the ecosystem.

So, the correct option is 'True'.

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


Correct Option: B
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.

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


Correct Option: A

In the food chain, the saprophytic organisms are

  1. Producers

  2. Consumers

  3. Predators

  4. Decomposers


Correct Option: D
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. 

Which of the following is not true for reducers ? 

  1. Reduces inorganic remains of earth

  2. Essential component of an ecosystem

  3. Help in cycling of nutrients

  4. Also called natural scavengers


Correct Option: A
Explanation:

There are four components of the ecosystem namely, abiotic substances, producers, consumers, and reducers also called as decomposers. 

The reducers are an essential component of the ecosystem as they help in the cycling of the nutrients by breaking down the dead organic matter (animal and waste matter) and therefore also called as natural scavengers. Eg- fungi and certain bacteria species.
So, the incorrect statement from the given statements is 'Reduces inorganic remains of the earth'.

Decomposers helps in ______

  1. Breaking dead waste

  2. Recycle nutrients

  3. Both A and B

  4. Spreading decay


Correct Option: C
Explanation:

Decomposers are also unable to make their own food. Hence, they break down waste products and dead organisms for food. These broken down materials are returned to the soil to be recycled and used by plants again.

Most important group of decomposers includes

  1. Bacteria

  2. Fungi

  3. Both A and B

  4. Virus


Correct Option: C
Explanation:

Explanation: Bacteria and fungi are decomposers. They break down waste products and dead organisms for food.

Which statement is correct about the role of decomposers in the environment?

  1. Decomposers break down the dead and decaying organic matter.

  2. Decomposers return the nutrients to the soil.

  3. Decomposers play a very important role in the nutrient re-cycling.

  4. All of the above.


Correct Option: D
Explanation:

Decomposers are organisms such as bacteria and fungi that break down the organic matter in the dead bodies of plants and animals. As the decomposers feed on the dead animals, they break down the organic compounds into simple nutrients to the soil. Organic matter is recycled in an ecosystem by decomposers.

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