Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
The impact of removing all the organisms in the trophic level will be the same at each independent trophic level. When we remove or kill the organism of any trophic level it will be an damage to the ecosystem.
For example, in a pond food chain:-
Phytoplanktons ← Zooplanktons ← Small fishes ← Large fishes ← Snakes, birds
In this food chain phytoplanktons are eaten by zooplanktons and then zooplanktons get eaten by the small fishes; small fishes are eaten by the large fishes in the pond and then at the last trophic level large fishes get caught and eaten by the snake or the birds. So, we can see that all the trophic levels in the ecosystem are dependent on each other. If we remove any one trophic level population like we remove zooplanktons in the food chain then the lower trophic level, i.e, phytoplanktons population will get increase in number which will disturb the entire 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?