This Environment & Ecology quiz on Ecosystem and Food Chains puts 11 multiple-choice questions to you, the verified MCQs published with GK24's note on the topic. Every question carries a full explanation of why the correct option is right and why the other options are wrong, so you learn the fact behind the answer rather than the letter. Attempt it right after reading the note, keep to the timer, and use the explanations at the end to mark what needs another look. Sit it again before the exam as a quick revision of the topic.
11 questions with answers and explanations
The term ecosystem was coined by which scientist?
The British botanist Arthur George Tansley used the word ecosystem in 1935 for a unit in which living organisms and their non-living surroundings are treated together as one system exchanging energy and matter.
Read the full explanation →In a food chain, green plants are called
Green plants make their own food from carbon dioxide and water by photosynthesis, using the energy of sunlight, so they are also called autotrophs.
Read the full explanation →The ten per cent law of energy transfer in a food chain was given by
It says that only about ten per cent of the energy present at one trophic level is passed on to the next, since the rest is used in respiration and other life processes and is lost to the surroundings as heat.
Read the full explanation →Which of the following ecological pyramids is always upright?
Energy is lost as heat at every transfer from one trophic level to the next, so a higher level can never hold more energy than the level below it.
Read the full explanation →Bacteria and fungi that break down dead plants and animals are known as
They feed on dead bodies, fallen leaves and waste matter, break the complex organic substances into simple ones and release nutrients back into the soil, water and air, where plants can take them up again.
Read the full explanation →The flow of energy in an ecosystem is
Energy enters an ecosystem as sunlight, is fixed by green plants, and then moves from producers to herbivores, to carnivores and finally to decomposers.
Read the full explanation →A food chain that begins with dead organic matter is called
Detritus is dead organic matter such as fallen leaves, dead bodies and animal waste. Organisms like earthworms, termites, bacteria and fungi feed on it, and they in turn are eaten by small birds and other animals.
Read the full explanation →Animals that feed on both plants and animals are called
Bears, crows, pigs and human beings eat both plant and animal food, which allows them to occupy more than one trophic level at the same time and makes them a good example of why food webs, rather than single food chains, describe nature better.
Read the full explanation →The pyramid of biomass in a pond ecosystem is
In a pond the producers are phytoplankton, tiny floating plants whose total weight at any one moment is small. They multiply very rapidly, however, so over time they can feed a far greater mass of zooplankton and fish.
Read the full explanation →Net primary productivity of an ecosystem is equal to
Gross primary productivity is the total amount of energy that producers fix by photosynthesis. Plants use a part of it for their own respiration, and what remains stored in plant bodies is the net primary productivity.
Read the full explanation →The concentration of pesticides such as DDT increases at each higher trophic level of a food chain. This phenomenon is called
DDT and mercury compounds are not broken down in the body and are not excreted, so they build up in the tissues of every organism that takes them in and are passed on to whatever eats it.
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