Feeding Relationships

Question 1

What are trophic levels used for?

Answer 1

Trophic levels are used to describe the feeding relationships between organisms.

Question 2

Where does energy in the food web come from and in what form?

Answer 2

Energy flows from the sun to the first trophic level (producers) in the form of light.

Question 3

What happens when producers gain energy from the sun?

Answer 3

Producers convert light energy into chemical energy and it flows in this form from one consumer to the next.

Question 4

Explain the energy transfer in the food web.

Answer 4

Energy flows from the sun to the first trophic level (producers) in the form of light. Producers convert light energy into chemical energy and it flows in this form from one consumer to the next. Eventually, all energy is transferred to the environment – energy is passed on from one level to the next with some being used and lost at each stage.
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 5

Explain a producer’s role in a food web

Answer 5

THEY PRODUCE THEIR OWN ORGANIC NUTRIENTS USUALLY USING ENERGY FROM SUNLIGHT. Food chains always begin with a producer.

Question 6

Explain a primary consumer’s role in a food web

Answer 6

HERBIVORES - THEY FEED ON PRODUCERS (PLANTS).

Question 7

Explain a secondary consumer’s role in a food web

Answer 7

CARNIVORES/OMNIVORED - PREDATORS THAT FEED ON PRIMARY CONSUMERS.

Question 8

Explain a tertiary consumer’s role in a food web

Answer 8

CARNIVORES/OMNIVORES - PREDATORS THAT FEED ON SECONDARY CONSUMERS.

Question 9

Explain a quaternary consumer’s role in a food web

Answer 9

PREDATORS THAT FEED ON TERTIARY CONSUMERS.

Question 10

What does it mean if a consumer may eat both primary, secondary and/or tertiary consumers?

Answer 10

This means that they can be at different trophic levels within the same food web.

Question 11

What does it mean if a consumer is at different trophic levels within the same food web?

Answer 11

This means that they may eat both primary, secondary and/or tertiary consumers.

Question 12

What is the purpose of a food chain?

Answer 12

To illustrate the feeding interactions between the organisms in a community.

Question 13

What does a food chain represent?

Answer 13

It represents the transfer of energy from one organism to the next.

Question 14

Where does the source of all energy in a food chain originate from?

Answer 14

The source of all energy in a food chain originates from light energy from the sun.

Question 15

What do the arrows in a food chain represent?

Answer 15

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

Question 16

How does energy get passed on in a food chain?

Answer 16

In order for the energy to be passed on, it has to be consumed.

Question 17

What is the disadvantage of energy transfer in a food chain?

Answer 17

Not all of the energy producers receive goes into making new cells that can be eaten and only the energy that is made into new cells remains with the organism to be passed on.

Question 18

Which part of the energy remains with the organism to be passed on?

Answer 18

Only the energy that is made into new cells remains with the organism to be passed on.

Question 19

If an organism eats an entire organism, including the roots of plants of bones of animals how does some of the energy not get consumed.

Answer 19

Energy is still stored in these parts (roots of plants or bones of animals) and so it does not get passed on

Question 20

How does the majority of the energy an organism receives gets ‘lost’ (or ‘used’) ?

Answer 20

Organisms rarely eat every part of the organism they are consuming, making waste products (urine), Movement, Heat, metabolic processes and Undigested waste (faeces)

Question 21

Why are food chains rarely more than 5 organisms long?

Answer 21

The inefficient loss of energy at each trophic level explains why food chains are rarely more than 5 organisms long.

Question 22

HOW MUCH PERCENTAGE OF ENERGY IS AVAILABLE TO THE ORGANISMS AT THE NEXT LEVEL TO MAKE NEW BIOMASS?

Answer 22

10%

Question 23

HOW MUCH PERCENTAGE OF ENERGY LOST AS HEAT AND IN UNDIGESTED MATERIALS?

Answer 23

90%

Question 24

What is a food web?

Answer 24

A food web is a network of interconnected food chains.

Question 25

Why are food webs better than food chains?

Answer 25

Food webs are more realistic ways of showing connections between organisms within an ecosystem as organisms rarely exist on just one type of food source, give us a lot more information about the transfer of energy in an ecosystem and show interdependence.

Question 26

Define the word ‘decomposers’

Answer 26

BACTERIA AND FUNGI THAT GET THEIR ENERGY FROM FEEDING OFF DEAD AND DECAYING ORGANISMS AND UNDIGESTED WASTE (SUCH ASFAECES) BY SECRETINGENZYMES TO BREAK THEM DOWN.

Question 27

What is a pyramid of numbers?

Answer 27

The pyramid of numbers is a food pyramid that shows how many organisms at each trophic level of a food chain.

Question 28

What does the width of the box in a pyramid of numbers indicate?

Answer 28

The width of the box indicates the number of organisms at that trophic level.

Question 29

What don’t pyramid of numbers doesn’t always have to be pyramid-shaped?

Answer 29

Pyramid of numbers doesn’t always have to be pyramid-shaped because the size of the organism is also important - one large organism contains enough energy to support many smaller organisms.

Question 30

What are some rules to remeber when drawing a pyramid of numbers?

Answer 30

1. You cannot change the trophic level of the organisms - they must stay in the same order as in the food chain. 2. Generally, the larger an individual organism is, the fewer of them there are.

Question 31

What is a pyramid of biomass?

Answer 31

A pyramid of biomass is a food pyramid that shows how much mass the creatures at each level would have without including all the water that is in the organisms (their ‘dry mass’).

Question 32

What is the definition of the term ‘dry mass’ in an organism?

Answer 32

The mass of an organism wthout including all the water that is in the organism.

Question 33

What is important to remember about the shape of a pyramid of biomass?

Answer 33

Pyramids of biomass are ALWAYS pyramid-shaped, regardless of what the pyramid of numbers for that food chain looks like.

Question 34

Explain the shape of the a pyramid of biomass

Answer 34

Pyramids of biomass are ALWAYS pyramid-shaped, regardless of what the pyramid of numbers for that food chain looks like, as the mass of organisms has to decrease as you go up a food chain.

Question 35

Why are pyramids of biomass a better way of representing interdependence within the food chain?

Answer 35

Pyramids of biomass provide a much better idea of the quantity of the plant or animal material at each level of a food chain.

Question 36

What does a pyramid of energy illustrate?

Answer 36

Pyramids of energy illustrate the amount of energy contained within the biomass of individuals within different trophic levels.

Question 37

What does the area of each box represent in a pyramid of energy?

Answer 37

The area of each box represents the amount of energy present.

Question 38

What sort of base do pyramids of energy have and why?

Answer 38

Pyramids of energy always have a wide base due to the large amount of energy contained within the biomass of producers.

Question 39

What happens to the quantity of energy as you move up the pyramid to higher trophic levels?

Answer 39

As you move up the pyramid to higher trophic levels the quantity of energy decreases as not all energy is transferred to the biomass of the next trophic level.

Question 40

How many food pyramids are there?

Answer 40

There are three food pyraids.

Question 41

What is the definition of the term ‘biomass’?

Answer 41

Biomass is a store of chemical energy.

Question 42

What happens when primary consumers consume producers (in terms of biomass)?

Answer 42

When primary consumers consume producers, they break down the biomass of the producer ( by digestion) and use the chemical energy to increase or sustain their own biomass.

Question 43

What things are transferred from one trophic level to the next?

Answer 43

Chemical energy and biomass are transferred.

Question 44

How can we calculate the efficiency of energy and biomass transfers between to trophic levels?

Answer 44

Calculate the efficiency of biomass transfer from the first to the second trophic level, give your answer to 3 significant figures and use the equation: Perentage efficiency transfer = biomass in higher trophic level/biomass in lower trophoc level X 100

Question 45

Explain the loses of energy in a food chain

Answer 45

Not all energy is transferred from one trophic level to the next. Approximately only 10% of the energy of each trophic level is passed on to the next. This is why food chains are rarely made up of more than six trophic levels, the total amount of energy available eventually becomes too small to support another trophic level.

Question 46

Explain why trophic levels are rarely made up of more than six trophic levels.

Answer 46

Not all energy is transferred from one trophic level to the next. Approximately only 10% of the energy of each trophic level is passed on to the next. Therefore, the total amount of energy available eventually becomes too small to support another trophic level.

Question 47

Loses of energy are due to:

Answer 47

- Organisms rarely eat every part of the organism they are consuming (some of the biological material of plants and animals may be inedible, not all the ingested material is digested and absorbed (some is egested as faeces), Energy is used for movement, Energy is used to generate heat, Energy is used for metabolic processes, Some absorbed material is lost as waste

Question 48

What are the waste products of respiration?

Answer 48

Carbon dioxide and water

Question 49

What are the waste products in urine? And when are they produced?

Answer 49

Water and urea which are produced when proteins are broken down