Our Environment - Class 10 Biology - Extra Questions

In a food chain, producers produce their own food through photosynthesis. There are plant-eating organisms called herbivores like grasshoppers. Such animals are called primary consumers (they eat producers).
Animals like frogs eat the primary consumers (grasshoppers). These animals are called secondary consumers. Animals like snakes, eat the secondary consumers and are called tertiary consumers. Some animals like hawks eat tertiary consumers (snakes) and are known as the top carnivores. So, it is a quaternary consumer.

The differences are as follows:

Producers	Consumers
1.They do not produce their own food using energy from the Sun	1. They do not produce their own food, depend on producers for their nutritional requirements
2.Example: Green plants	2.Example: Herbivores

The correct food chain will be: 
Grass $$\to$$ Insects $$\to$$ Frog $$\to$$ Snake $$\to$$ Eagle. 

Carnivores occupy the third trophic level in the food chain because the second level is occupied by herbivores. Herbivores are organisms that feed on plants. Carnivores occupy the next level after herbivores.

(a) Desert ecosystem 
(b) Bushes, cactus, acacia, etc. 

Substances that are not broken down by biological processes are said to be non-biodegradable. These substances may be inert and simply persist in the environment for a long period of time or may harm the various members of the ecosystem, e.g. plastic.

Natural Ecosystem

Producers are those living organisms which can produce their own food by the process of photosynthesis. This includes green plants and blue-green algae. 

Bacteria and fungi break-down dead remains of living into simple substances hence are called decomposers.

(i)Insects, Bats, Squirrels
(ii)Flowers, Leaves, Fruits
(iii) Spiders, Swallows, Vole

The biotic components of an ecosystem are linked by food chains.

The term ecosystem is used for both small and large ecological systems. For example- A pond is a small ecological system. A grassland or forest or ocean or the whole earth are large ecological systems.

Food chain is the flow of energy from one trophic level to another. This flow of energy occurs as one organism depends on other organism for food. Flow of energy is unidirectional and it follows the particular series of:

• Interdependence is a consistent relationship between organisms that lead a way of life together. 

• Plants depend on animals for CO2, (during photosynthesis), animals like bees & butterflies help in pollination. Earthworms & other microorganisms make the soil fertile for plant growth. Grazing and other big animals help with seed dispersal. 
• Animals depend on plants for food, medicines, supply of O2, removal of CO2, shelter plants are homes for a variety of animals & provide material for construction, furniture, clothing, etc.

The organism found as secondary carnivore in an aquatic ecosystem is Shark.

The producer in the ecosystem capture light energy and produce energy-rich compounds (carbohydrates). From the producers, the energy flow in the food chain in the form of food. The producers are green plants, lichens, and algae.

According to 10% law, only 10% of energy gets transferred from one trophic level to the next.

Food web is a network of food chains which become inter- connected at various trophic levels so as to form a number of feeding connections amongst different organisms of a biotic community.

According to natural disposal, the pollutants may be biodegradable or nonbiodegradable.

In the given food chain, the grass is the producer, which forms the first trophic level. 

If all the lions from the given food chain are removed, the population of deer will increase exponentially. Thus, deers and other plant-eaters will be present in abundance which will lead to overgrazing of grass and no grass will left. And if no grass will be left, then deer will automatically die which will eventually destroy the complete food chain.

Humans are the dominant species in the biosphere. They modified the ecosystems to suit the social and economic needs. They even created new ecosystems. These man-made, or artificial ecosystems are terrestrial as well as aquatic. The terrestrial ones include rural and urban settlements, plantations, orchards, gardens, parks, croplands and animal farms. The man-made aquatic ecosystems include dams, reservoirs, lakes, canals, fishery tanks, ponds and aquaria.

Many interconnected food chains make up a food web. Sometimes, a single organism gets eaten by many predators or it eats many other organisms. This is when a food chain doesn’t represent the energy flow in a proper manner because there are many trophic levels that interconnect. This is where a food web comes into place. It shows the interactions between different organisms in an ecosystem.

The chemicals consumed by the autotrophs multiply in concentration as the trophic levels go up. The phenomenon of increase in concentration of toxic substances with the increase in trophic level is known as biomagnification. Hence, the organism at the highest trophic level in a food chain will have the accumulation of such substances in maximum concentration.

In the above scheme, the 10% law of transfer of energy is depicted from one trophic level to another.

Correct Answer: A-3,B-4,C-1,D-2

Depending on how organisms acquire their nutrients, we can categorize them into three categories.

1. Producers: Organisms that can make their own food (autotrophs), like plants.
2. Consumers: Organisms that consume producers and other animals.
3. Decomposers: Organisms that break down dead organic matter for food.

So, the correct answer is ‘decomposers’.

If we generate only degradable waste, it will have a positive impact on the environment as the waste could be recycled again and again. Also, no harmful chemicals will be liberated by the waste which will keep our water bodies, ground water as well as atmosphere clean and pure.

Each step or level of the food chain forms a trophic level. The autotrophs or the producers are at the first trophic level. They fix up the solar energy and make it available for heterotrophs or the consumers. The herbivores or the primary consumers come at the second, small carnivores or the secondary consumers at the third and larger carnivores or the tertiary consumers form the fourth trophic level.

Each step of a food chain is termed trophic level.
Grass $$\rightarrow$$ Insect $$\rightarrow$$ Frog $$\rightarrow$$ Snake.
The above food chain has four trophic level :
(i) Grass (Producer)
(ii) Insect (Primary consumer)
(iii) Frog (Secondary consumer)
(iv) Snake (Tertiary consumer). 

Decomposers are essential because they recycle nutrients from dead organisms to the physical environment, where the nutrients may again be used by another organism.

Characters	Biodegradable pollutants	Non biodegradable pollutants
Degradation	These pollutants can be degraded by microbial action in waste treatment plants.	These pollutants cannot be degraded by any biological actions
Cause pollution	These pollutants cause pollution when it is added more than their rate of degradation	These pollutants generally undergo biomagnification.
Examples	Domestic sewage	Pesticides.

Food chain	Food web
The sequence of living organisms that show inter-dependency of organisms.	The network of interconnected food chains in an ecosystem is called the food web.
It shows only one path of transfer of energy/food from producer to the ultimate consumer.	It shows several paths of transfer of energy/food from producer to the ultimate consumer.
The position of an organism is fixed.	The position of an organism may change.

The non-biodegradable wastes generally generated by human beings are metallic cans, bottles, cartons, polythene pouch and bags, plastic broken items, chemicals in the form of medicines, insecticides, pesticides, chemical fertilizers, wrappers etc.

Wastes
(i) Vegetable and fruit peels and rind, stale food, food leftovers, used tea leaves.
(ii) Milk pouches, polythene bags, empty cartons.
(iii) Waste paper (newspaper, bags, envelopes), packing paper, empty bottles, tom cloth pieces, etc.
(iv) Dust and other sweepings.
Disposal :
(i) Separation into biodegradable and non-biodegradable, recyclable and non-recyclable wastes.
(ii) Recyclable wastes (waste paper, cloth, polythene or plastic bags, cartons, bottles, cans, etc.) can be given to rag pickers for recycling.
(iii) Preparation of compost or vermicompost from kitchen wastes for home garden (kitchen garden).
(iv) In the absence of kitchen garden, the household garbage and other wastes can be given to waste collectors for disposal.

The fundamental purpose of food webs is to describe feeding relationship among species in a community.

Non-biodegradable waste is waste that degenerates the environment to zero level of tolerance in the entire ecosystem. Everything which nature cannot recycle on its own is a non-biodegradable waste. It is decomposed by the soil bacteria into humus which increases the fertility of the soil.

An ecosystem is made up of two components biotic and abiotic. It includes the interaction of the living things which are the biotic components in a given area with the non-living environment which are the abiotic factors such as temperature, weather, rainfall, earth, sun, soil, wind, and minerals. Hence, abiotic components form the physical factors of the ecosystem. 

Non-biodegradable substances affect the environment in the following ways:
→ They contaminate soil and water resources as they cannot be decomposed by micro-organisms.
→ These substances, when accidentally eaten by stray animals, can harm them and can even cause their death.

Answer:

• The ozone layer is a gaseous blanket that surrounds the Earth. The ozone layer serves as a protective shield for the planet's living creatures. The ozone layer's primary job is to block the Sun's dangerous ultra-violet rays.
• The ozone layer's depletion is a reason for concern because it will be unable to filter out ultra-violet radiation effectively, resulting in a variety of skin issues such as skin discoloration and skin cancer.
• The ozone layer keeps the planet's temperature constant. Damage to the layer could lead to the death of a large number of phytoplanktons, resulting in increased global warming.
• CFCs (chlorofluorocarbons) are chemicals that deplete the ozone layer. The release of CFCs into the atmosphere must be curtailed to limit the harm to the ozone layer. CFCs should be replaced with environmentally friendly replacements in refrigerants and fire extinguishers. In addition, the release of CFCs from industrial processes should be regulated.

a) An ecosystem is defined as a place where living and nonliving things live together interacting with each other for the sustenance of life. The two main components of an ecosystem include- biotic (living) and abiotic (nonliving) components. 

The food chain of the given organisms will be is as follows:
Plant $$\rightarrow$$ Insect $$\rightarrow$$ Frog $$\rightarrow$$ Snake $$\rightarrow$$ Hawk
Insect belongs to second trophic level and snakes belong to fourth trophic level in this food chain.

The food chain is the sequence of organisms through which food and energy pass in an ecosystem with the members of each trophic level. The grass is the producer on which grasshopper is dependent and thus is the primary consumer, frog feeds on grasshopper and snake feed on frog whereas eagle is at the apex of the trophic level and derives its nutrients from the snake. Thus the food chain is depicted as

Biomagnification is defined as the accumulation of a particular substance in the body of the organisms at different trophic levels of a food chain. One example of biomagnification is the accumulation of insecticide DDT which gets accumulated in zooplanktons. Small fishes consume these zooplanktons. Small fishes are consumed by large fish which are finally consumed by fish-eating bird present at the highest position in tropic level. Hence, the organism at the highest trophic level has the maximum accumulation of toxic substances.

When the plants and animals die in the forest, this is considered as waste. When they die, the microorganisms present in the soil helps to convert the waste into hummus or nutrients for the soil which in turn used by plants. And, therefore forest doesn't contain any waste materials.

 An ecosystem is composed of organisms (biotic) and abiotic factors which interact with each other. Hence, the ecosystem of the organisms is the basic unit of study in the environment. 

a) False - Snakes are secondary consumers as they generally prey on primary consumers like rats.

i) Grass $$\to$$ Rat $$\to$$ Snake $$\to$$ Hawk
ii) Corn $$\to$$ Mouse $$\to$$ Snake $$\to$$ Peacock

Man is an omnivore. He can consume plants and be called as a primary consumer or consume animals like goat and chickens which consume plants and be called as a secondary consumer.

The energy content is maximum in producers. The energy decreases at each trophic level of food chain, as part of energy is lost as heat and the major part of energy is liberated during respiration for use in various activities. 

The food web is a network of food chains that are interconnected at various trophic levels so as to form a number of feeding connections amongst members of a biotic community. A food chain is a linear sequence of organisms through which food and its contained energy pass, with earlier members of the sequence, becoming food of the later member of the sequence. A secluded food chain is always at a risk of being damaged with a major effect on the ecosystem as well. Suppose the tiger population increases. Its prey population of say deer will decrease rapidly resulting in the non-availability of food to tigers, their starvation, and hence, death. However, in a food web, each predator has a choice to feed on different types of prey. 
The concept of the food web or non-dependence on a single source helps in case of adversity.

All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem. Thus, an ecosystem consists of biotic components comprising living organisms and abiotic components comprising physical factors like temperature, rainfall, wind, soil and minerals.

Consumers are those organisms that obtain energy by either consuming the food prepared by plants or by consuming other consumers of autotrophs.

Decomposers have a very significant role in a food web. In their absence, dead organic matter will pile up and nutrient recycling will be inhibited. This will reduce the nutrient availability to the producers and subsequently, to the consumers. This will disrupt the functioning of the whole food web and also the ecosystem.

Wheat grains -----> Mouse -----> Snake -----> Hawk

Explanation:

The following are the issues caused by non-biodegradable waste: 

• Non-biodegradable waste does not decompose. They accumulate in the environment and cause biomagnification; as a result of this accumulation, they pollute soil and water; they pollute the environment. 
• If such wastes are burned, they pollute the air. 
• Non-biodegradable wastes, such as pesticides, deplete soil fertility as they penetrate it. The soil's pH level becomes unsuitable for plant growth. 
• Some substances contaminate the environment, causing harm to living organisms.

Yes, it is possible for one species to occupy more than one trophic level at the same time. The best examples are omnivores such as humans and bears.

Omnivore are the kind of animals that eats other animals or plants for their survival. It hunts and eats other carnivores and omnivores and also ears herbivores.

• Ecosystem can be defined as a system composed of biotic and abiotic components and the interactions between them
• The energy flow in an ecosystem is always from producers to consumers moving in the upward direction, that is from
•  producers$$\rightarrow$$ primary consumers$$\rightarrow$$ secondary consumers $$\rightarrow$$ tertiary consumers

A trophic level is the group of organisms within an ecosystem which occupy the same level in a food chain. 

(i) We can avoid the usage of chemical pesticides.

A food web having three food chains.

(a) If all producers are removed from an ecosystem. then there will be no food for the primary consumers. All the primary consumers will be wiped out because of starvation. This will leave no food (or secondary and tertiary consumers and they will also be finished in due course of time. This will be the end of the ecosystem. 
(b) If all herbivores are eliminated from an ecosystem, there will be no food for the carnivores. Eventually, all the carnivores would be finished because of lack of food. Absence of herbivores will also result in exponential growth in plant population. But lack of other biotic factors will stop biogeochemical cycle. This will finally finish the ecosystem. 
(c) If all the top carnivores are eliminated, then population of herbivores will become manifold. This will put the existence of green plants in danger because of overgrazing. Loss of green plants will force the herbivores to die because of starvation. 

The Swachh Bharat Abhiyan is a significant cleanliness campaign started by the Government of India. It was officially launched on 2nd October 2014 by our Prime Minister Shri Narendra Modi.

$$\textbf{Explanation:}$$

If all the grazers are removed from grassland, grass will grow unchecked. It may help the growth of some organisms harmful to the animals and the animals which feed on the grazers will die of starvation. The biogeochemical cycle will stop and the whole biosphere will get disturbed.

If all the carnivores are removed from the earth, the population of herbivores, will increase. Large population of herbivores will overgraze. As a result, all plants will disappear from the earth surface and ultimately the earth may become a desert. The biosphere will get disturbed which will lead to end of life on earth.

The odd term is styrofoam.
The category is a biodegradable waste.
Styrofoam is an expanded polystyrene and is a non-biodegradable waste while the other three (newspaper, sewage and hay) are a biodegradable waste. 

a) The phenomenon represented above is the food chain. A food chain is a linear sequence of organisms through which nutrients and energy pass when one organism eats another.
b) The organism that could be shown at 5, is the hawk. Hawks eat snakes.
c) Oxygen is the element which all the organisms 2-4 and even 5 are getting from 1 for their survival.

a) The food chain is the sequence of population or organisms through which food and its contained energy pass in an ecosystem with members at one step becoming the food of later step of the sequence. 

The improvement in our lifestyle have lead to greater amounts of waste generation. Increased use of paper plates, plastic, polythene, etc. and aluminium foil in packaging industries has resulted large amount of waste accumulation which is increasing day by day.

Every animal is a link in the food chain and a repository of a particular genome. The food chains are built up in such a way that there is a biological control at every step. If the chain is broken, the biological control is lifted resulting in large scale disturbance and destruction of foodweb. For example, President Roosevalt of U.S.A. ordered killing of carnivores of a national park so that deer could live peacefully. However, within a decade, the national park changed into a desert with no deer.

It starts with acorns, which are eaten by mice. The mice are eaten by snakes, and then finally the snakes are eaten by hawks. At each link in the chain, energy is being transferred from one animal to another where the hawk being the predator