Unit 3

Question 0

What factors may increase or decrease biodiversity?

Answer 0

Human activities
Biotic factor
Abiotic factor

Question 1

What is biodiversity?

Answer 1

Biodiversity is the total variation that exists amoung all living things on earth

Question 2

What are the Biotic Factors?

Answer 2

Living factors including:
Competition
Disease
Predation
Grazing
Good availability

Question 3

What are Abiotic factors?

Answer 3

Non-living factors including:
Temperature
pH
Light intensity
Moisture

Question 4

What is predation?

Answer 4

Predation is the feeding of one organism on another.

Question 5

What is a niche?

Answer 5

A niche is a role that an organism plays in a community. It includes:
Use of resources
Interaction with other organisms (competition)

Question 6

What is an ecosystem?

Answer 6

An ecosystem consists of all living organisms in a particular area and the non-living components with which the organisms interact

Question 7

Describe what is meant by ‘population’

Answer 7

The number of one type of living organisms in an area

Question 8

Describe what is meant by a ‘community’

Answer 8

The number of different types of living organisms in an area

Question 9

What is meant by the term ‘species’

Answer 9

A species is a group of organisms which can interbreed to produce fertile offspring

Question 10

What is at the beginning of a food chain and why?

Answer 10

Producers because they can make their own food (self-dependant)

Question 11

What do plants compete for?

Answer 11

Soil nutrients
Sunlight
Water

Question 12

What do animals compete for?

Answer 12

Water
Shelter
Mates
Territories
Food

Question 13

What is the deference between inter-specific and intra-specific?

Answer 13

inter specific competition is competition between all living organisms as they require similar resources

Intra specific competition is competition between specific living organisms as they require the same resources therefore making it more intense

Question 14

What is a mutation?

Answer 14

A mutation is a permanent change in the DNA of an organism that occurs randomly

Question 15

What is this chromosome XX

Answer 15

Female

Question 16

What is this chromosome XY

Answer 16

Male

Question 17

How does variation occur?

Answer 17

Overtime advantageous mutations result in variation within a population

Question 18

What do the arrows represent on a food chain?

Answer 18

The flow of energy

Question 19

How much energy is lost in ecosystems and why?

Answer 19

90% of energy is lost as heat, movement or undigested material

Question 20

Why is nitrogen requires in the nitrogen cycle?

Answer 20

Nitrogen (N2) is required to make protines

Question 21

What is nitrification?

Answer 21

Ammonium compounds are converted into nitrites and then nitrates

Question 22

What is denitrification?

Answer 22

Bacteria breaks down nitrates in the solid and releases nitrogen into the air

Question 23

What is nitrogen fixation?

Answer 23

Soil bacteria absorb nitrogen from the air and ‘fix’ it onto ammonium compounds and then into nitrites

Question 24

Why is lightening important in the nitrogen cycle?

Answer 24

Lightening converts nitrogen in the air to nitrites. This then dissolves into the rain which falls to the ground and is absorbed by the soil

Question 25

What are types of mutations?

Answer 25

Neutral Advantage Disadvantage

Question 26

Give 3 examples of disadvantageous mutations

Answer 26

Cystic Fibrosis Sickle cell Anaemia Down syndrome (extra chromosome)

Question 27

Why is variation important?

Answer 27

To allow a population to evolve over time in response to changing environmental conditions

Question 28

Give three examples of mutagenic agents

Answer 28

X-rays Mustard Gas UV light

Question 29

What are the 3 types of adaptations?

Answer 29

Behavioural Physiological Anatomical

Question 30

What is speciation?

Answer 30

The appearance of a new species

Question 31

What is natural selection?

Answer 31

Nature produces more offspring than the environment can support. Nature selects those organisms which are best suited to their environment and 'weeds out those who are not. This is sometimes called survival of the fittest

Question 32

What do pyramids of numbers represent?

Answer 32

The number of organisms at each stage in the food chain

Question 33

What do pyramids of energy represent?

Answer 33

The quantity of energy at each stage in the food chain

Question 34

What so pyramids of biomass represent?

Answer 34

The total mass of living material at each stage in the food chain

Question 35

Why do plants need fertilisers?

Answer 35

To provide nutrients which the plant needs to be able to grow properly

Question 36

How can nitrogen be replaced when harvesting crops?

Answer 36

Nitrite fertilisers Manure Composts

Question 37

What are indicator species?

Answer 37

Species that indicate levels of pollution by their presence or absence

Question 38

What are the three types of pest control?

Answer 38

Biological- ladybugs Chemical- pesticides Physical- soapy water

Question 39

What are pesticides?

Answer 39

Pesticide is a broad term covering a range of products that are used to control pests

Question 40

Give three examples of pesticides

Answer 40

Slug pellets Insecticides Herbicides

Question 41

Give the advantages of using pesticides

Answer 41

Advantages- protects crops from disease Protects from contamination when stored Safeguards human health as it prevents the contamination of fungi

Question 42

Give the disadvantages of using pesticides

Answer 42

Harms people, wildlife and the environment

Question 43

What are GM crops?

Answer 43

Genetically modified crops are crops which have specific genes inserted into them which give them desirable characteristics

Question 44

Name three methods of sampling

Answer 44

Pitfall traps Quadrats Tree beating

Question 45

How to you measure moisture?

Answer 45

A moisture meter

Question 46

How do you measure light intensity?

Answer 46

Use a light meter

Question 47

What is natural selection?

Answer 47

Nature produces more offspring than the environment can support. Nature select those organisms that are best suited to their environment and weeds out those that are not. This is sometimes referred to as survival of the fittest.

Question 48

What is speciation?

Answer 48

Speciation is the appearance of new species. A new species is the end product of evolution

Question 49

Describe the role of nitrogen fixing bacteria in the nitrogen cycle

Answer 49

To convert nitrogen to nitrate