Ecosystem quiz

The vertical distribution of different species occupying different levels in an ecosystem is called:

Net primary productivity equals:

The process by which water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts is:

Humus is:

The ten percent law of energy transfer was given by:

A pyramid of biomass in a sea is generally inverted because:

Which pyramid is always upright?

Earthworm is called a farmer's friend because it is a:

In a grazing food chain, the first trophic level is occupied by:

Decomposition is faster when conditions are:

Why is a pond considered a self-sustainable ecosystem? Name its abiotic and biotic components. (2 marks)

Distinguish between the grazing food chain and the detritus food chain. (2 marks)

What are the four basic functional aspects of an ecosystem? (2 marks)

Why is the flow of energy in an ecosystem unidirectional? (2 marks)

What is secondary productivity? (2 marks)

What is mineralisation? Why is it important? (2 marks)

Why are food chains in nature generally limited to 3 or 4 trophic levels? (2 marks)

Give two reasons why a man-made ecosystem like a crop field has lower diversity than a forest. (2 marks)

Why does the primary productivity of an ecosystem vary? State two factors. (2 marks)

What is a food web? How does it help ecosystem stability? (2 marks)

If a lion (tertiary consumer) gets 25 J of energy, calculate the energy present at the producer level according to the ten percent law. (3 marks)

A crop field has a GPP of 18,000 kcal per square metre per year and an NPP of 12,000 kcal per square metre per year. Calculate the energy lost in respiration, and the percentage of GPP that is NPP. (3 marks)

A pond receives 8,00,000 J of sunlight. Phytoplankton capture 1.5% of it. Calculate the energy fixed by phytoplankton and the energy reaching small fishes that eat zooplankton (second consumer level). (3 marks)

In a grassland the dry biomass is: producers 1,000 g per square metre, herbivores 100 g, primary carnivores 10 g and secondary carnivores 1 g. Calculate the ratio of biomass at successive levels and state the type of pyramid formed. (3 marks)

The annual NPP of the biosphere is about 170 billion tonnes and that of oceans about 55 billion tonnes. Calculate the NPP of land and the ratio of land to ocean productivity. (3 marks)

Read the passage and answer the questions. A class visited a village pond and found algae, water plants, zooplankton, small fish, frogs and snails. The bottom was covered with dead leaves and mud rich in bacteria and fungi. The pond water received sunlight and nutrients from runoff. (i) Identify the producers, consumers and decomposers. (ii) Write one grazing food chain from the pond. (iii) Name the abiotic components that drive the pond ecosystem. (5 marks)

Read the passage and answer the questions. A student placed equal masses of dry leaves in nylon mesh bags in two places: one in a moist, warm forest floor in Kerala and one on a dry, cold hillside in Ladakh. After three months, most of the Kerala leaves had broken down. (i) Explain why decomposition was faster in Kerala. (ii) Name the steps of decomposition. (iii) How would the result change if the leaves were rich in lignin? (5 marks)

Read the passage and answer the questions. A deer eats 1,000 J of grass energy in a day but stores only about 100 J in its body tissue. A tiger that eats the deer stores about 10 J from that energy. (i) Which law is illustrated? (ii) Where does the remaining energy go? (iii) Why are there fewer tigers than deer in a forest? (5 marks)

Read the passage and answer the questions. Marine biologists measured biomass at one time and found phytoplankton biomass of 4 g per square metre, while zooplankton and fishes together had 21 g per square metre. Yet phytoplankton have a very high turnover rate. (i) Draw the pyramid of biomass described. (ii) Why is it inverted? (iii) Would the pyramid of energy also be inverted? Explain. (5 marks)

Read the passage and answer the questions. A tropical rainforest has many layers of vegetation, from tall emergent trees to shrubs and herbs, while a desert has sparse vegetation. The rainforest also has higher primary productivity. (i) What is the vertical layering called? (ii) Give two reasons for higher productivity in the rainforest. (iii) What happens to the productivity of a forest when it is cleared for farming? (5 marks)

Draw a labelled diagram of the energy flow through trophic levels. Explain the ten percent law, the unidirectional nature of energy flow and the role of decomposers. (6 marks)

Describe the process of decomposition, explaining each step. Draw a labelled diagram of the decomposition cycle and explain the factors affecting the rate of decomposition. (6 marks)

Explain the pyramids of number, biomass and energy with labelled diagrams. Give one example each of an upright and an inverted pyramid, and state limitations of ecological pyramids. (6 marks)

Explain primary productivity, GPP, NPP and secondary productivity. Draw a flowchart showing how solar energy is converted into NPP and passed to consumers, with typical efficiencies. (6 marks)

Describe the pond as an ecosystem, explaining its structure and functions. Draw a labelled diagram of a pond ecosystem showing producers, consumers and decomposers. (6 marks)