4.2.1 Trophic Levels & Food Chains

Question 1

What are Trophic Levels used to describe?

Answer 1

Trophic levels are used to describe the feeding relationships between organisms

Question 2

Energy flows from the sun to, where?

Answer 2

the first trophic level (producers) in the form of light

Question 3

What do producers convert light energy into?

Answer 3

chemical energy and it flows in this form from one consumer to the next

Question 4

Eventually, all energy is transferred to, where?

Answer 4

to the environment – energy is passed on from one level to the next with some being used and lost at each stage

Question 5

What type of process is Energy Flow

Answer 5

Energy flow is a non-cyclical process – once the energy gets to the top of the food chain or web, it is not recycled but ‘lost’ to the environment

Question 6

(Trophic Levels) Producers

Answer 6

They produce their own organic nutrients usually using energy from sunlight

Question 7

(Trophic Levels) Primary Consumers

Answer 7

Herbivores - They feed on producers (Plants)

Question 8

(Trophic Levels) Secondary Consumers

Answer 8

Predators that feed on primary consumers

Question 9

(Trophic Levels) Tertiary Consumers

Answer 9

Predators that feed on Secondary Consumers

Question 10

(Trophic Levels) Quaternary Consumers

Answer 10

Predators that feed on Tertiary Consumers

Question 11

Animals (known as consumers) can be at different, what?

Answer 11

trophic levels within the same food web as they may eat both primary, secondary and/or tertiary consumers

Question 12

A simple way to illustrate the feeding interactions between the organisms in a community is with a, what?

Answer 12

food chain

Question 13

Give each step of a food chain

Answer 13

1. Producer: food chains always begin with a producer

Question 14

What does a food chain show?

Answer 14

A food chain shows the transfer of energy from one organism to the next

Question 15

What is the source of all energy In a food chain?

Answer 15

light energy from the sun

Question 16

What do the arrows in a food chain show?

Answer 16

The arrows in a food chain show the transfer of energy from one trophic level of the food chain to the next

Question 17

Give an example of 5 Levels (with animals) of a food chain

Answer 17

Trophic (Level 1 Producer) : Grass

Trophic (Level 2 Primary Consumer) : Grasshopper

Trophic (Level 3 Secondary Consumer) : Frog

Trophic (Level 4 Tertiary Consumer) : Python

Trophic (Level 5 Quaternary Consumer) : Eagle; Apex Predator

Question 18

In order for the energy to be passed on, what has to happen?

Answer 18

it has to be consumed (eaten)

Question 19

not all of the energy grass plants receive goes into, what?

Answer 19

making new cells that can be eaten

Question 20

Only the energy that is made into new cells remains with, what?

Answer 20

with the organism to be passed on

Question 21

The majority of the energy an organism receives gets ‘lost’ (or ‘used’) through, what?

Answer 21

1. Making waste products eg (urine) that get removed from the organism

Question 22

inefficient loss of energy at each trophic level explains, what?

Answer 22

why food chains are rarely more than 5 organisms long

Question 23

10% of energy available to the organism at the next level to make, what?

Answer 23

New biomass

Question 24

Exam Tip

Answer 24

This is a complicated concept but by learning the main ways in which energy is lost between trophic levels, you will be able to answer most questions on this topic.

Make sure you read the question carefully and tailor your answer to the specific organism you are being asked about – e.g. plants do not produce urine or faeces so you could not give this as one of the ways in which they use energy that cannot be passed on!