What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Some toxic substances chemicals and large number of pesticides like D.D.T (Dichloro- diphenyl- trichloroethane) are non- biodegradable. When the concentration of these chemicals and pesticides increases at each trophic level of the food chain, this phenomenon is known as biological magnification or biomagnifications. They are non- biodegradable substances, so they do not decompose then they get accumulated in the environment and affect each of the trophic level. And, our body get directly affected at some stage of trophic level or mostly human beings are on the top level because we consume most of the chemicals in our body.
The level of biological magnification will be different at the different trophic levels. The concentration of the biomagnification got increased with the increase in trophic levels. For example:- biomagnification of pesticide D.D.T in aquatic food chain;
Water ← Zooplankton ← Small fishes ← Large fishes ← Fish eating birds
(DDT 0.003ppm) (DDT 0.04 ppm) (DDT 0.5 ppm) (DDT 2 ppm) (DDT 5 ppm)
In the above example, when the pesticides are sprayed on the agricultural fields then they are carried out by running off water into the aquatic bodies in the pond or lakes etc. The pesticide DDT get accumulate into the water and then in the zooplanktons, the concentration of DDT goes on increasing with each trophic level in the food chain. The fish eating birds have the higher concentration of biomagnification, which affects the egg shells due to the effect on calcium metabolism. Egg shell becomes thin and breaks at the premature stage. Then mercury discharge into the ponds, rivers or lakes that is changed by the bacteria into the toxic forms which is very harmful, absorbes by the fishes and they may get killed.
Give any two ways in which biodegradable substances would affect the environment.
Which of the following constitute a food-chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat
If all the waste we generate is biodegradable, will this have no impact on the environment?
Why are some substances biodegradable and some non-biodegradable?
Which of the following groups contain only biodegradable items?
(a) Grass, flowers and leather
(b) Grass, wood and plastic
(c) Fruit-peels, cake and lime-juice
(d) Cake, wood and grass
What is ozone and how does it affect any ecosystem?
How can you help in reducing the problem of waste disposal? Give any two methods.
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What is the role of decomposers in the ecosystem?
What will happen if we kill all the organisms in one trophic level?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
How is the small intestine designed to absorb digested food?
What are alloys?
What changes can you make in your habits to become more environment-friendly?
What are the components of the transport system in human beings? What are the functions of these components?
How do Mendel’s experiments show that traits are inherited independently?
What type of oxides are formed when non-metals combine with oxygen?
Give an example of a double displacement reaction other than the one given in activity 1.10.
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Design an experiment to demonstrate hydrotropism.
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?