1. Look at the illustration of a trophic level pyramid. For each trophic level, write one or two sentences explaining the role of that type of organism. You should include those organisms that fall outside the normal pyramid. Give an example of each type of organism. Your examples do not have to belong to the same food chain in real life. Why does the pyramid get narrower at each higher level?

2. What is an environmental sphere or earth system sphere? Name the earth’s five major environmental spheres and state the defining characteristics of each. Give one example of a way in which two or more earth system spheres interact.

3. What is biogeochemical cycling? For each of the following five cycles, state two processes in which matter changes its form: carbon, phosphorus, nitrogen, oxygen, and sulfur.

1) In trophic levels, producer are organisms which has the ability to make their own food e.g plants and algae. Primary consumers are the organisms which feed on producers e. g deer and zebra etc. Secondary consumers are those which feed on primary consumers and tertiary consumers are those organisms which take energy by feeding on secondary consumers e. g tiger and lions. The pyramid get narrower at each higher level because when we moves upward, the population of organisms decreases.

2) Environmental sphere refers to all the materials that are present in the environment. There are five sphere which are given below.

1) Lithosphere: This sphere comprise of land on which all living organisms lives.

2) hydrosphere: It refers to water bodies.

3) biosphere: It is the living part of the environment.

4) atmosphere: This sphere contains gaese which are necessary for survival.

5) cryosphere: This sphere contains water in stored form.

3) A cycle in which chemical moves from living and non living things to the atmosphere.

1)carbon goes to the atmosphere through respiration and burning of fuel.

2) phosphorus is released after the burning of plant body.

3) nitrogen is released in denitrification process and industries.

4) oxygen is released in the atmosphere through photosynthesis.

5) sulfur is released in the atmosphere through volcanic eruptions.

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