CBSE Class 7 Science Advanced Biology Our Ecosystem Very Short Answer Questions Set 01

Very Short Answer Questions

Question 1. ______ covers 0.78% of earth's surface.
Answer:
Freshwater ecosystem
In simple words: Freshwater covers a very small part of the earth.

Teacher's Note:
1. Learn the two numbers: freshwater 0.78 percent, marine about two-thirds.
2. This ecosystem still holds 41 percent of the world's fish.

Question 2. The type of the natural biomes which lack tree is ______.
Answer:
Alpine tundra
In simple words: High mountains are too cold and windy for trees to grow.

Teacher's Note:
1. Altitude, cold and wind together stop tree growth.
2. Only dwarf shrubs survive in this biome.

Question 3. Desert-like areas that has cold winters with snowfall throughout the long winter season is ______.
Answer:
Cold desert
In simple words: A desert with snowy winters is a cold desert.

Teacher's Note:
1. Gobi and Taklamakan are examples.
2. Its plants are mainly deciduous and shed leaves in winter.

Question 4. ______ is a mixed of woodland and grassland ecosystem.
Answer:
Savannah
In simple words: Savannah has both grass and scattered trees.

Teacher's Note:
1. Savannah is a tropical grassland of Africa, India and Australia.
2. It supports big herbivores and predators like lions.

Question 5. Biggest predator as seen in pampas region is ______.
Answer:
Puma
In simple words: The puma is the top hunter of the pampas.

Teacher's Note:
1. Pampas are temperate grasslands of South America.
2. Foxes, maned wolves and Geoffroy's cats come next.

Question 6. ______ is the largest desert in the world.
Answer:
Sahara (in Africa)
In simple words: The Sahara in Africa is the biggest desert.

Teacher's Note:
1. Link desert names with continents: Sahara in Africa, Thar in Asia, Atacama in South America.
2. The Sahara is a hot and dry desert.

Question 7. The wastes that can be degraded naturally are called ______.
Answer:
Biodegradable wastes
In simple words: Wastes that rot naturally are biodegradable.

Teacher's Note:
1. Kitchen waste and paper are biodegradable.
2. Plastic and metal are non-biodegradable and cause soil pollution.

Question 8. Creating forest manually or artificially is called ______.
Answer:
Afforestation
In simple words: Planting a new forest on purpose is afforestation.

Teacher's Note:
1. Do not mix it with reforestation, which replants cut forest.
2. Both help to restore green cover.

Question 9. Producers help in converting energy from sunlight to ______ energy.
Answer:
Chemical energy (stored as glucose)
In simple words: Plants store sunlight as chemical energy in food.

Teacher's Note:
1. This happens through photosynthesis.
2. All other organisms depend on this stored energy.

Question 10. The amount of energy ______ as it flows from lower trophic level to higher trophic level.
Answer:
Reduces
In simple words: Energy becomes less at every step up the food chain.

Teacher's Note:
1. Each organism uses part of its energy for its own life activities and loses some as heat.
2. This is why food chains are short.

Question 11. ______ comes in the first trophic level.
Answer:
Producers
In simple words: Plants make food, so they are the first level.

Teacher's Note:
1. Remember the order: producers, herbivores, carnivores, top carnivores.
2. Decomposers act on all levels.

Question 12. What is permafrost?
Answer:
A layer of permanently frozen soil is called permafrost.
It is found mostly in the Arctic tundra region.
In simple words: Permafrost is soil that stays frozen all year.

Teacher's Note:
1. It contains gravel and little fine material and traps methane.
2. It is a key feature of the Arctic tundra.

Question 13. What is Arctic tundra?
Answer:
Arctic tundra is the cold, desert-like region that circles the northern pole.
Its soil is permanently frozen below the surface.
Plants are short and grow in groups to resist cold, and animals like arctic hares and arctic foxes live there.
In simple words: It is the frozen treeless land around the North Pole.

Teacher's Note:
1. Examples: Alaska, northern Canada and Greenland.
2. Do not confuse it with the alpine tundra of mountains.

Question 14. What is tundra? Write the names of different types of tundra.
Answer:
Tundra is the coldest of all biomes, with a frost-moulded landscape, very low temperature and little rainfall.
Its vegetation is scarce: shrubs, mosses and grasses.
Types: Arctic tundra (around the northern pole) and Alpine tundra (on high mountains worldwide).
In simple words: Tundra is a very cold biome of two kinds: Arctic and alpine.

Teacher's Note:
1. Both types are cold, but alpine tundra depends on height.
2. Few living organisms survive here.

Question 15. What are the types of freshwater ecosystem?
Answer:
Freshwater ecosystems are of three types.
Lentic (lacustrine) ecosystem: still or slow-moving water, such as pools and ponds.
Lotic (riverine) ecosystem: flowing water, such as streams and rivers.
Wetlands: marshy or swampy lands, such as Loktak Lake in Manipur.
In simple words: Freshwater can be still, flowing or marshy.

Teacher's Note:
1. Lentic means still; lotic means flowing.
2. Lakes hold still water, so they are lentic; give streams and rivers as lotic examples.

Question 16. What are the main components of a forest ecosystem?
Answer:
Producers, consumers and decomposers form the main components.
Producer: makes food, for example plants.
Consumer: depends on plants directly or indirectly for food, for example deer, rabbit and lion.
Decomposer: breaks down dead and decaying matter, for example fungi and bacteria.
In simple words: A forest has food makers, food eaters and recyclers.

Teacher's Note:
1. Give one example for each group in the exam.
2. Decomposers return nutrients to the soil.

Question 17. Write a short note on snow forest.
Answer:
Snow forest is another name for the taiga or boreal forest.
It encircles a large part of the northern hemisphere and is the largest land biome of the world.
It mainly has conifers such as pines and spruce, and lies between the tundra in the north and temperate forests in the south.
In simple words: The taiga is a cold forest of cone-bearing trees.

Teacher's Note:
1. It is found in Alaska, Canada, Scandinavia and Siberia.
2. Remember it lies between the tundra and the temperate forest.

Question 18. What are the threats which a forest face?
Answer:
Commercial exploitation causing mass destruction of forest.
Clearing forest for buildings, industries and factories as cities grow.
Clearing land for agriculture.
Wild forest fires.
Cutting trees for timber, firewood and similar uses.
In simple words: Human needs and fires are the main dangers to forests.

Teacher's Note:
1. Most threats are caused by people.
2. The cure is conservation, afforestation and reforestation.

Question 19. Mention the names of four types of grasslands.
Answer:
Prairies: flat fertile grasslands of North America.
Savannah: mixed woodland and grassland of Africa, India and Australia.
Steppes: dry temperate grass plains of Europe and Asia.
Pampas: temperate grasslands of Argentina and Brazil in South America.
In simple words: The four grasslands are prairies, savannah, steppes and pampas.

Teacher's Note:
1. Learn each with its continent.
2. Savannah and pampas support herbivores and big predators.

Question 20. What are the types of desert ecosystem?
Answer:
There are four types of deserts.
Hot and dry: warm all year, very hot summer and scanty rain, for example the Sahara.
Semi-arid: moderately long dry summer, for example the Thar.
Coastal: moderately cold winter and long warm summer, for example the Atacama.
Cold: snowy winters, for example the Gobi and Taklamakan.
In simple words: Deserts are hot and dry, semi-arid, coastal and cold.

Teacher's Note:
1. Pair each type with its example desert.
2. Animals live in burrows and come out at night.

Question 21. Complete the diagram with missing words.

Answer:
A — Dead and decaying organisms
B — Respiration
C — Producers
Producers take CO₂ from the atmosphere (photosynthesis), pass carbon to consumers and then to dead matter; respiration returns CO₂ to the air, and decomposers act on dead organisms; burning of fossil fuels also returns CO₂.
In simple words: A is dead matter, B is respiration and C is producers.

Teacher's Note:
1. Use the carbon cycle arrows: air to producers by photosynthesis, producers to B by respiration.
2. Check each arrow direction before filling a box.