What is the role of decomposers in the ecosystem?
Decomposition is the process of breaking down the substances into the smaller particles or the parts. Decomposition of the decay organic matter like plants, wastage of animals etc. , also known as putrefaction. In the process of decomposition mainly two decomposers are responsible, i.e, bacteria and the fungi. These two organisms breaks the dead organic matter into smaller organic molecules (utilized as nutrients by themselves) or into inorganic compounds which are released into the environment.
Decomposition involves some enzymes for the degradation of organic matter. Mainly 3 steps are involved in this process fragmentation (breakdown of the organic matter into smaller fragments), leaching (fragmented detritus particles like sugar and several nutrients get dissolved in water percolating through the soil and removed due to the leaching process) and the catabolism (release the extracellular enzymes to decompose decay particles into the simpler compounds which are carried out by the decomposers like bacteria and fungi) process occurs.
The decomposition process plays vital role in any ecosystem because it involves the release of the nutrients from the dead matter. If there is no decomposers, all the nutrients would remain locked in the dead remains of plants and the animals, so these will not be available for the indefinite recreation of the living matter.
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
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 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?
Explain the formation of scum when hard water is treated with soap.
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
What is the importance of DNA copying in reproduction?
Where should an object be placed in front of a convex lens to get a real image of the size of the object?
(a) At the principal focus of the lens
(b) At twice the focal length
(c) At infinity
(d) Between the optical centre of the lens and its principal focus.
Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?
How is the concentration of hydroxide ions (OH-) affected when excess base is dissolved in a solution of sodium hydroxide?
What do you mean by a precipitation reaction? Explain by giving examples.
State the rule to determine the direction of a (i) magnetic field produced around a straight conductor-carrying current, (ii) force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it, and (iii) current induced in a coil due to its rotation in a magnetic field.
Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.
Material medium |
Refractive index |
Material medium |
Refractive index |
Air | 1.0003 | Canada Balsam |
1.53 |
Ice | 1.31 | ||
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | ||
Kerosene | 1.44 | Carbon disulphide |
1.63 |
Fused quartz |
1.46 | ||
Turpentine oil |
1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
Table 10.3 Absolute refractive index of some material media
Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?