B7 Ecology

Question 1

Define the term ecosystem.

Answer 1

An ecosystem includes all of the living things interacting with each other, and also with their non-living environment.

Question 2

Give an Example of an Abiotic factor

Answer 2

Abiotic factors are the non living components of an ecosystem so things such as the soil pH, light levels, wind speed, water content etc.

Question 3

Define a ‘Community’

Answer 3

A group of organisms or a population of different species occupying a particular area.

Question 4

Name a producer on this food web

Answer 4

The Grass.

Question 5

Name a secondary consumer on this food web.

Answer 5

snake or lizard

Question 6

What are the mising labels on the water cycle? Starting with the arrows up from the sea to the sun and working clockwise.

Answer 6

Evaporation, Condensation, precipitation.

Question 7

What is a detritovore?

Answer 7

An organism that eats detritus (decaying matter).

Question 8

What is a saprophyte?

Answer 8

A fungus or plant which feeds on detritus by secreting enzymes which help digest the detritus.

Question 9

Name a process which locks carbon away.

Answer 9

Photosynthesis or sedimentation

Question 10

Name a process which adds carbon to the carbon cycle

Answer 10

Respiration or Combustion

Question 11

What does ‘biodiverse’ mean?

Answer 11

An area with a large number of different species living there.

Question 12

What is a pesticide?

Answer 12

A chemical which kills pests, used in farming methods.

Question 13

What is a herbicide?

Answer 13

A chemical used in agriculture which kills weeds.

Question 14

What can cause algal blooms in lakes and result in Eutrophication?

Answer 14

Fertilisers

Question 15

Name a gas responsible for causing acid rain.

Answer 15

Sulpher or nitrogen oxides.

Question 16

What produces sulphur dioxide responsible for acid rain?

Answer 16

Cars and factories.

Question 17

Name an effect of acid rain on the environment.

Answer 17

Limestone buildings and grave stones worn away, trees die, lakes too acidic for fish to survive.

Question 18

Name a fossil fuel

Answer 18

natural gas, coal, oil.

Question 19

What effect does the action of destroying peat bogs have on the gases in the atmosphere?

Answer 19

Increases the amount of carbon dioxide.

Question 20

Describe one effect of deforestation on the environment.

Answer 20

Destroys habitats

reduces biodiversity

disruption of food chains

Question 21

Name a gas responsible for Global warming.

Answer 21

Carbon dioxide, Methane.

Question 22

Biodiversity can be reduced by these things:

H

I

P

P

O

Answer 22

Habitat destruction

Invasive species

Pollution

Population Increase

Overharvesting

Question 23

What are Trophic Levels?

TRIPLE ONLY

Answer 23

They are the feeding levels within a food chain.

Question 24

What is a top or ‘Apex’ predator?

TRIPLE ONLY

Answer 24

A predator that has no predators of its own.

Question 25

Where is trophic level one found on a pyramid of biomass? TRIPLE ONLY

Answer 25

At the bottom.

Question 26

Approximately how much biomass is transferred from one trophic level to another? TRIPLE ONLY

Answer 26

10%

Question 27

How is the energy lost at each trophic level? TRIPLE ONLY

Answer 27

MRS GREN Movement, Respiration, Senses, Growth, Excretion, Nutrition

Question 28

Why is most energy lost between the transfer from producer to consumer? TRIPLE ONLY

Answer 28

Much of the plant material (cellulose) is indigestible and is simply excreted.

Question 29

Calculate the missing respiration value. TRIPLE ONLY

Answer 29

100-63-4 =33KJ

Question 30

Calculate the efficiency for this diagram. TRIPLE ONLY

Answer 30

Only 4 kJ of the original energy available to the bullock is available to the next stage, which might be humans. The efficiency of this energy transfer is: efficiency = 4⁄100 × 100 = 4%

Question 31

Give **two** possible negative effects of the decrease in forest cover on ecosystems.

Answer 31

any two from: * decreased biodiversity * loss of habitats * increased carbon dioxide (concentration) * global warming

Question 32

Define three biotic factors which affect an ecosystem.

Answer 32

Any three from availability of food • new predators arriving • new pathogens • one species outcompeting another so the numbers are no longer sufficient to breed.

Question 33

What are 'extremophiles'?

Answer 33

Some organisms live in environments that are very extreme, such as at high temperature, pressure, or salt concentration. Bacteria living in deep sea vents are extremophiles.

Question 34

What are the conditions needed for rapid decay? TRIPLE ONLY

Answer 34

Heat, Moisture and Oxygen.

Question 35

Which gas is produced in anaerobic decay? TRIPLE ONLY

Answer 35

Methane Gas

Question 36

How does a biogas generator work? TRIPLE ONLY

Answer 36

They canbe used to produce methane gas as a fuel.

Question 37

Why has large scale deforestation in tropical areas occured?

Answer 37

Large-scale deforestation in tropical areas has occurred to: provide land for cattle and rice fields grow crops for biofuels

Question 38

What is 'food security'? TRIPLE ONLY

Answer 38

Food security is having enough food to feed a population.

Question 39

Decsribe 2 factors which are affecting food security. TRIPLE ONLY

Answer 39

2 answers from here: Biological factors which are threatening food security include: the increasing birth rate has threatened food security in some countries * changing diets in developed countries means scarce food resources are transported around the world * new pests and pathogens that affect farming * environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail * the cost of agricultural inputs * conflicts that have arisen in some parts of the world which affect the availability of water or food.

Question 40

Describe one way in which the efficency of cattle farming could be improved. TRIPLE ONLY

Answer 40

The efficiency of food production can be improved by restricting energy transfer from food animals to the environment. This can be done by limiting their movement and by controlling the temperature of their surroundings

Question 41

Describe two methods which maintain fish stocks at sustainable levels. TRIPLE ONLY

Answer 41

Control of net size and the introduction of fishing quotas play important roles in conservation of fish stocks at a sustainable level.

Question 42

What is the name of the fungus used to produce mycoprotein? TRIPLE ONLY

Answer 42

The fungus Fusarium is useful for producing mycoprotein