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
How can you help in reducing the problem of waste disposal? Give any two methods.
What is ozone and how does it affect any ecosystem?
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 amount of urine produced regulated?
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Explain the following.
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?
You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?
Find the focal length of a lens of power – 2.0 D. What type of lens is this?
Write an equation to show the reaction between Plaster of Paris and water.
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron(II) sulphate | Cooper(II) sulphate | Zinc sulphate | Silver nitrate |
A | No reaction | Displacement | ||
B | Displacement | No reaction | Displacement | |
C | No reaction | No reaction | No reaction | No reaction |
How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?