Observe the following food-chain and answer the questions that follow:
Grass - Grasshopper- Frogs - Snakes.
i) Work out the energy flow in the above food chain - if the grass gets 1000
K.cal. of energy. How much energy will the snake receive?
ii) What is each step of the food chain known as?
iii) What is the ideal number of steps in a food chain and why?
fo:1
Answers
i) 1k.cal
according to energy rule,only 10% energy passes to next level in a food Chain..and 90% is lost in form of heat.
If grass is 1000 kcal then
grasshopper 100
frog 10
snake 1k.cal
ii) trophic levels
iii) max 4 or 5 because at every trophic level energy decreases as disscussed above.so at the end of 4 to 5 trophic levels no more energy is left to pass on
Answer:
(i) - 1 K.cal
(ii) - Trophic level
(iii) - 3-5 steps
Explanation:
(i) - Because of the 10% Rule of energy transfer. The 10% Rule means that when energy is passed in an ecosystem from one trophic level to the next, only ten percent of the energy will be passed on. A trophic level is the position of an organism in a food chain or energy pyramid.
(ii) - Each step in a food chain or web is called a trophic level. It refers to the mode of nutrition at that level. For example, a producer or autotroph is an organism capable of converting simple inorganic compounds into organic compounds like glucose that can be used by other organisms as food.
(iii) - Eventually there is so little energy remaining in the top trophic level i.e. 3rd to 5th level, that no higher trophic level can be supported. Hence most food chains have 3-5 steps.