Food Chains and Food Webs

Question 1

Food Chain…

Answer 1

a food chain shows what eats what in a habitat.

Food chains start with a green plant which is eaten by a primary consumer, which may be eaten by a secondary consumer and so on. (The only exception are food chains that start with chemosynthetic bacteria instead of plants, e.g. at hydrothermal vents.

Oak Tree ———-> Caterpillar ———–> Blue tit (type of bird) ————> Sparrowhawk

The oak tree is the producer – it converts light energy from the sun to chemical energy (food).
The oak tree leaves are eaten by the caterpillars (primary consumer).
The caterpillars are eaten by the blue tits (secondary consumer).
Finally, the sparrowhawk eats blue tits – it is a tertiary consumer.

The arrows show the direction of energy flow – from food to feeder.

Question 2

Food Web…

Answer 2

a food web is made up of all the individual food chains in a habitat, linked together.

All the food chains in this web start with the grass, e.g. grass -> rabbit -> fox

Question 3

Producer…

Answer 3

start of a food chain which is typically a green plant which converts light energy from the sun into chemical energy (food) by photosynthesis
all the energy in the food chain originally comes from this producer

Question 4

Primary consumer…

Answer 4

eats the producer - it is a herbivore.

Question 5

Secondary consumer…

Answer 5

eats the primary consumer – it is a carnivore (or omnivore)

Question 6

Territory consumer…

Answer 6

tertiary consumer eats the secondary consumer – it is a carnivore (or omnivore)

Question 7

Prey…

Answer 7

animal that is hunted, killed and eaten by another animal

Question 8

Predator…

Answer 8

animal that hunts, kills and eats another animal

Question 9

Herbivore…

Answer 9

animal that only eats plant material e.g. a rabbit

Question 10

Carnivore…

Answer 10

animal that only eats meat (other animals) e.g. a wolf

Question 11

Omnivore…

Answer 11

animal that eats plant and animal material e.g. a bear or a human

Question 12

Interdependence…

Answer 12

when different organisms in a particular habitat or food web depend on one another for survival

Question 13

Bioaccumulation…

Answer 13

when a toxin builds up in a food chain

A small amount of toxin may be present in the producer (e.g. from an insecticide being sprayed on it)
when the producer is eaten by a consumer the toxin accumulates (builds up) in its tissue.
The toxins are not broken down or excreted by the organism so the more the consumer eats the more toxin builds up.
The animals at the top of the food chain will have the largest amount of toxin bioaccumulated in their tissues – this can be very harmful and can be dangerous or life-threatening for the food chain.

Question 14

Toxin…

Answer 14

poisonous substance that can cause an organism harm

Question 15

Insecticide…

Answer 15

a chemical that is used by farmers or gardeners to kill insects that might eat the plants they are growing

Question 16

Ecosystem/community…

Answer 16

community of living organisms and the environment they live in / all the living organisms that interact (live together) in an environment

Question 17

Coexist…

Answer 17

living together

Question 18

Niche…

Answer 18

particular part of a habitat that an organism has adapted to live in and/or the way it has adapted to live in this habitat – it could be specially adapted to live in that niche.

For example, a beadlet anemone lives high up the rocky shore (at a beach) – no other anemones live there so they don’t have any competition for food, however twice a day the tide goes out and the anemones end up out of the water! To cope with living in this niche they have adapted to pull their tentacles inside their bodies and coat themselves with special mucus so that they don’t dry out.