Nat 5 - Life On Earth

Question 1

Define the term biodiversity

Answer 1

Biodiversity is the total variation that exists amongst all living things on Earth.

Question 2

Name three things that can affect biodiversity

Answer 2

Pollution, habitat destruction and overfishing

Question 3

Define the term biotic factor

Answer 3

Biotic factors are factors that are caused by living things

Question 4

Define the term abiotic factor

Answer 4

Abiotic factors are factors that are caused by non-living factors

Question 5

Name 4 biotic factors

Answer 5

Food availability, disease, grazing and predation

Question 6

Name 4 abiotic factors

Answer 6

Light intensity, pH, temperature and oxygen levels

Question 7

Define the term biome

Answer 7

A biome is a region of the plant that has similar climate, flora (plants) and fauna (animals). It is made up of many similar ecosystems

Question 8

Name 3 examples of biomes

Answer 8

Freshwater, tropical rainforest and grassland

Question 9

State 2 factors that can influence the global distribution of biomes

Answer 9

Temperature and rainfall

Question 10

Define the term ecosystem

Answer 10

An ecosystem is the entire community of living organisms in a habitat and the non-living components with which the organisms interact

Question 11

Define the term habitat

Answer 11

A habitat is the place where an organism lives

Question 12

Define the term community

Answer 12

A community is a group of organisms of one species in an ecosystem

Question 13

Define the term population

Answer 13

A population is all of the living organisms within a particular habitat

Question 14

Define the term niche

Answer 14

A niche is the role that an organism plays within a community

Question 15

Define the term food chain

Answer 15

A food chain shows feeding relationships of animals and plants in an ecosystem

Question 16

State what the arrows in a food chain show

Answer 16

The arrows in a food chain show the direction of energy flow through an ecosystem

Question 17

Define the term producer

Answer 17

A producer is a plant that produced its own food using light energy in photosynthesis

Question 18

Define the term consumer

Answer 18

A consumer is an organism which eats other organisms in a food chain

Question 19

Define the term decomposer

Answer 19

A decomposer is an organism that breaks down dead plant and animal material

Question 20

Define the term herbivore

Answer 20

A herbivore is an organism that only eats plants

Question 21

Define the term carnivore

Answer 21

A carnivore is an organism that only eats animals

Question 22

Define the term omnivore

Answer 22

An omnivore is an organism that eats plant and animal material

Question 23

Explain the difference between primary, secondary and tertiary consumers

Answer 23

The primary consumer is a herbivore which eats the plant, the secondary consumer eats the primary consumer and the tertiary consumer eats the secondary consumer

Question 24

State how much percent of energy is lost at each level of a food chain

Answer 24

90% lost, 10% passed on

Question 25

Name 3 ways that energy is lost

Answer 25

Heat, movement and undigested waste

Question 26

Define a pyramid of numbers

Answer 26

A pyramid of numbers shows the number of organisms at each level of a food chain in an area (m2)

Question 27

Explain why some pyramids of numbers are irregular in shape

Answer 27

Sometimes a tree is the producer or a flea is the tertiary consumer

Question 28

Define a pyramid of biomass

Answer 28

A pyramid of biomass shows the total mass of organisms at each stage of a food chain

Question 29

Define a pyramid of energy

Answer 29

A pyramid of energy shows the energy available at each stage of a food chain

Question 30

Discuss which of the 3 types of pyramid most accurately demonstrates a food chain

Answer 30

Pyramid of energy because it shows that 10% of energy is always passed on

Question 31

Define the term competition

Answer 31

Competition occurs in an ecosystem when two or more members of the community need a particular resource that is in short supply

Question 32

Name 3 resources that plants compete for

Answer 32

Light, water and nutrients

Question 33

Name 3 resources that animals compete for

Answer 33

Space, food, water and mates

Question 34

Define the term interspecific competition

Answer 34

When competition occurs between members of different species

Question 35

Define the term intraspecific competition

Answer 35

When competition occurs between members of the same species

Question 36

Describe the intensity of intraspecific competition compared to interspecific competition and explain why this is the case

Answer 36

Intraspecific competition is more intense because organisms compete for the exact same resources

Question 37

State the molecule needed by plants and animals that contains nitrogen

Answer 37

Protein

Question 38

State the form of nitrogen that plants can take up through their roots

Answer 38

Nitrates

Question 39

Name the 3 types of bacteria involved in the nitrogen cycle

Answer 39

Nitrifying bacteria, denitrifying bacteria and nitrogen fixing bacteria

Question 40

Describe the role of nitrifying bacteria

Answer 40

It causes ammonium compounds to be converted into nitrites and nitrates

Question 41

Describe the role of denitrifying bacteria

Answer 41

It removes nitrates from the soil by converting it to nitrogen gas

Question 42

Describe the role of nitrogen fixing bacteria

Answer 42

It absorbs nitrogen from the atmosphere and converts it into ammonium compounds