Ecosystems And Material Cycles

Question 1

What is symbiosis?

Answer 1

The ecological relationship between two or more organisms living closely together with some sort of feeding relationship involved

Question 2

What is mutualism?

Answer 2

Symbiosis when both organisms benefit

Question 3

What is commensalism?

Answer 3

Symbiosis when one organism benefits and the other is not harmed

Question 4

What is parasitism?

Answer 4

Symbiosis where one organism benefits and the other is harmed

Question 5

What is an ecosystem?

Answer 5

A community of organisms and the physical environment they live in

Question 6

What is a habitat?

Answer 6

A place where an organism lives

Question 7

What is a population?

Answer 7

All the organisms of a particular species living in the same area

Question 8

What is a community?

Answer 8

Populations of different species that live and interact with each other

Question 9

What is interdependence?

Answer 9

When organisms in an area need each other for resources to survive

Question 10

What are abiotic factors?

Answer 10

Non living factors that affect the distribution of organisms

Question 11

What are biotic factors?

Answer 11

Living factors that affect the distribution of organisms

Question 12

Name some abiotic factors that could affect the distribution of organisms

Answer 12

• Temperature
• Water availability
• Light avalibility
• Pollutants

Question 13

Name some biotic factors that could affect the distribution of organisms

Answer 13

• Competition
• Predation

Question 14

What is a belt transect?

Answer 14

A line created (eg. with a tape measure) where quadrants are placed along

Question 15

What is a quadrat?

Answer 15

Frame placed on the ground where sampling can take place

Question 16

What is a pyramid of biomass?

Answer 16

Pyramid where each level shows the relative biomass of each organism

Question 17

How much biomass is typically transferred to the next trophic level?

Answer 17

10%

Question 18

How do you calculate the efficiency of energy transfers between trophic levels?

Answer 18

Biomass transferred to the next level
—————————————————— x100
Biomass from the previous level

Question 19

What calculation is used to estimate a population size based on data obtained from quadrats?

Answer 19

Number of organisms in all quadrats x total area where the organism lives
———————————————————————————————————
Total area of quadrats

Question 20

Describe the role of bacteria in the nitrogen cycle

Answer 20

• Nitrogen fixing bacteria converts nitrogen into nitrates
• Decomposing bacteria breaks down waste products and dead organisms into ammonia
• Nitrifying bacteria converts ammonia into nitrates
• Denitrifying bacteria converts nitrates to nitrogen

Question 21

What is eutrophication?

Answer 21

When lots of nutrients are added to water, resulting in too much plant growth eg. Due to adding too much fertiliser to crops

Question 22

How does eutrophication cause a negative impact on biodiversity?

Answer 22

• Crops sprayed with too much water before heavy rain causes the fertiliser to run into nearby streams
• This causes algae and other plants to increase in number on the surface of the water
• This prevents sunlight from reaching plants at the bottom of the water
• These plants will begin to decompose as they won’t be able to photosynthesise
• The microorganisms decomposing the bacteria will respire, removing oxygen from the water
• This will cause other respiring organisms to die, reducing biodiversity

Question 23

What impact can fish farming have on biodiversity?

Answer 23

Overfishing can lead to species becoming endangered

Question 24

What impact can introducing a non-indigenous species have on an ecosystem?

Answer 24

They could prey on native species, reducing biodiversity