Our Environment

A Food chain shows the relationship between plants and animals. Grass (plants) are the producers, grass hoppers act as the primary consumers which feed on grass and are in turn eaten by Frog that are secondary consumers. Snake, the tertiary consumers feed on frogs and are in turn eaten by Eagle which is a quaternary consumer. The food energy gets transferred from one trophic level to another in this process.

Decomposers are organisms that eat dead plants and animals i.e., organic matter and obtain energy. They break down the organic matter of plants and animals to get energy. Fungi are decomposers.

The crust of the earth is called lithosphere.

Explanation-It is the solid outer (top) surface/layer of the earth and includes mountains, oceans and lands.

The basic unit of environmental study is an ecosystem.

Explanation- Ecosystem is the area where living organisms interact with other living organisms and with non-living things (water, soil, sunlight etc) in that area.

A group of individuals belonging to the same species is population.

Explanation- It can also be defined as group of organisms of same species occupying a specific area.

Different kinds of ecosystem together constitute biosphere.

Explanation-Biosphere is a part of the earth that supports all the kinds of ecosystems and thus all the different kinds of organisms. All the living things and the places they exist in form of the Biosphere.

In a parasitic food chain, the pyramid of the number will be inverted.

Explanation- Here one primary producer supports numerous secondary consumers which support tertiary consumers. The number of individuals at the successive levels keeps on increasing in the parasitic food chain.

Life exists only on Earth out of all the other planets of the Solar system. The factors which have made life exist on earth are

a. Water- Water, with its unique physical and chemical properties supports life on earth.

b. Atmosphere- it consists of gases that protect from radiations of sun and also acts as a layer surrounding us.

c. Temperature- the distance of earth from the sun provides ideal temperature conditions for life to exist.

a. The lithosphere is the solid outer (top) surface/layer of the earth and includes mountains, oceans, and lands. The lithosphere is also called the crust of the earth.

b. The population is defined as a group of organisms of same species that occupy a specific area.

c. Populations of different species of plants and animals of an area together form the biotic community. Biotic community is basically made up of all the living things in an ecosystem.

d. Food web is a complex network of several food chains that are interconnected at various trophic levels.

e. Trophic levels- A trophic level is the representation of an organism’s specific feeding stage in an ecosystem. The producers and the consumers exist at different levels of eating an being eaten in an ecosystem, these levels are described as trophic levels.

Ecosystem is the area where living organisms interact with other living organisms and with non-living things (water, soil, sunlight etc) in that area.

Dichlorodiphenyltrichloroethane is a pesticide. A pesticide is used to destroy harmful insects of plants and animals. The use of DDT is not advisable because once it enters the food chain its concentration keeps on increasing as it passes to higher trophic levels and disturbs the organisms at those levels. The process is known as biomagnification.

Grass → Grass hopper → Frog → Snake → Eagle

A Food chain shows the relationship between plants and animals wherein food energy gets transferred from one trophic level to the another. Grass (plants) are the producers, grass hoppers act as the primary consumers which feed on grass and are in turn eaten by Frog that is secondary consumers. Snake, the tertiary consumers feed on frogs and are in turn eaten by Eagle which is a quaternary consumer.

Herbivores are the organisms that depend on producers (plants) to obtain food and are themselves a source of food to the carnivores. If all the herbivores of a terrestrial ecosystem get killed, all the life form on earth will die because there will be no food available for consumers. Also, the growth of producers (with zero consumption) will result in forests all over the earth. Since all the life forms on earth will die due to no availability of food (herbivores), the life on earth will come to an end.

In any food chain trophic level-1 is occupied by green plants. This is because all living beings need food energy and green plants are the only producers. They make their own food and are not dependent on any other organism for food. Animals cannot make their own food and depend on plants for food energy to survive. For this reason, green plants occupy the first trophic level in every food chain.