What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
The sequential inter- linking of organisms involves the transfer of food in the form of energy from producers by the series of organisms with repeated eating and being eaten is referred to as the food chain. And, these sequential steps in the food chain are referred as different tropic levels.
Example:- Grassland ecosystem food chain and their different tropic levels
Grasses ← Insects ← Frogs ← Snake ← Predatory birds
Producers Herbivores Primary Secondary Tertiary carnivores
carnivores carnivores
Trophic levels are the nutritional levels in which food energy is transferred from one level to another level. In this above example, producers are the green plant (grasses) which is first trophic level; herbivores (insects) are the secondary trophic levels which are the plant eaters also called primary consumers belongs to secondary trophic level; then came primary carnivores (frogs) also called secondary consumers which feeds on primary consumers. And, then secondary carnivores (snake) which are the flesh eaters as like primary carnivores also called tertiary consumers; And then quaternary consumer (predatory birds) level came which are the tertiary carnivores. The maximum step in the food chain is 4 or 5.
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 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?
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
An atom has electronic configuration 2, 8, 7.
(a) What is the atomic number of this element?
(b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)
N(7) F(9) P(15) Ar(18)
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Judge the equivalent resistance when the following are connected in parallel – (a) 1 Ω and 106 Ω, (b) 1 Ω and 103 Ω, and 106 Ω.
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?
How do Mendel’s experiments show that traits are inherited independently?
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be –
(a) 1:2 (b) 2:1 (c) 1:4 (d) 4:1
Define the unit of current.
A concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located?
Why is sodium kept immersed in kerosene oil?