What is ozone and how does it affect any ecosystem?
Ozone is a clear, blue gas layer which is also known as the layer of protection of the environment. Ozone is the form of oxygen and the molecules of ozone contains three oxygen atoms (O3) It is present in the stratosphere which protects the earth from the ultraviolet (UV) radiations that came from the sun. Stratosphere is present at the altitude of 15-50 km above the earth’s surface and at the lower altitude it has thick sheet of ozone known as ozonosphere. The amount of atmospheric ozone is measured by the Dobson Spectrometer. Reaction:- O2 + O → O3 (Ozone)
Ozone affects the environment in following ways:-
Ozone is very poisonous at the ground level but at the higher altitude it is a layer of protection present in the stratosphere which protects the earth’s surface from the ultraviolet radiations, specially UV- B rays (290- 320 nm). Increase in the amount of UV rays reaches the earth surface when ozone depletion occurs, it can affect the ecosystem like it can cause skin cancer, dimming of the eye sight, herpes and diminishing the functioning of immune system in human beings.
It can cause death (mortality) of the young ones of the human beings and the animals.
It can cause mutation and blindness of the land animals.
All food chains can get disturbed.
The main cause of the ozone depletion is chlorofluorocarbon (CFCs).
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 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?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
When does an electric short circuit occur?
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
(a) Na (b) Mg (c) AI (d) Si
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
(a) Between the principal focus and the centre of curvature
(b) At the centre of curvature
(c) Beyond the centre of curvature
(d) Between the pole of the mirror and its principal focus.
How do auxins promote the growth of a tendril around a support?
How are the alveoli designed to maximise the exchange of gases?
How do we detect the smell of an agarbatti (incense stick)?
How is the small intestine designed to absorb digested food?
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?