What will happen if we kill all the organisms in one trophic level?
Tropic levels in the food chain are interlinked with one to another level in the sequential manner. If we kill all the organisms in one trophic level, the flow of energy at each tropic level is reduced 10 percent and the food chain get disturbed that creates an imbalance in the ecosystem.
For example, food chain is:- crops ← Rats ← Owls
In this food chain, crops are eaten by rats and then rats are eaten by owl population. If all the owls in the one trophic level get killed, there will be increase in the rats population and will lead to the overeating of the crops will happen. And, due to the overeating can lead to barren land which will affect the another trophic levels due to the soil erosion. So, as a result if we kill one trophic level, the lower trophic level will reproduce and population will get increases that disturbs the ecosystem.
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
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?
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?
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
What is a good source of energy?
Compare the power used in the 2 Ω resistor in each of the following circuits:
(i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and (ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
Outline a project which aims to find the dominant coat colour in dogs.
State two ways to prevent the rusting of iron.
What would be the consequences of a deficiency of haemoglobin in our bodies?
Why do we apply paint on iron articles?
How is the equal genetic contribution of male and female parents ensured in the progeny?
What are the disadvantages of fossil fuels?
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?