Use the words, given in the box, to make a ‘food chain’. Also, identify the nature (terrestrial/aquatic) of the food chain.

dolphin

snail

tuna

plankton

_____ → _____ → _____ → _____

An illustration of a pyramid of a number of an aquatic ecosystem is given.

The pyramid of energy for the same ecosystem would be:

The following figure represents the flow of energy in a pyramid of food. If this ecosystem receives 100000 kcal of sunlight energy of the energy finally available to Tertiary Consumer (TC) is:

Give reason:

Food chains generally consist of only three or four steps.

a) Given below are some organisms. Arrange all of them in a food chain and show the direction of the flow of energy.

Eagle, grasshopper, frog, grass, snake.

b) Which of the organism in the above food chain has maximum amount of energy ?
c) Give an example of artificial ecosystem.

A food chain in a polluted aquatic ecosystem is given. Observe it and answer the following questions.
Freshwater $\to$ Algae $\to$ Fishes $\to$ Birds.

(i) Which organisms are disturbed more due to biomagnification? Why?

(ii) This ecosystem will be destroyed gradually due to biomagnification. Why? 

Attempt the following:

(i) Construct a Food Chain with the help of the organisms given below:

Hawk, Grass, Snake, Hen.

(ii) Why is it not advisable to have a six-step food chain?

(iii) If Pesticides enter the above food chain.
(a) In which organism will it be found in the maximum amount?
(b) What is this phenomenon called?