Ecology, Cycles and Human Influences

Question 1

Define the term population

Answer 1

The number of organisms of a particular species in a habitat

Question 2

Define the term community

Answer 2

Multiple populations interacting within a particular habitat

Question 3

Define the term habitat

Answer 3

The place where an organism lives

Question 4

Define the term ecosystem

Answer 4

All interactions between groups of organisms in a habitat as well as the abiotic factors involved

Question 5

In the food chain, identify the producer and the secondary consumer: Grass –> Centipede –>Wren –> Kestrel

Answer 5

Producer = Grass
Secondary Consumer = Wren

Question 6

In a food chain, what do the arrows indicate?

Answer 6

Direction of energy transfer

Question 7

Producer, primary consumer, secondary consumer etc are examples of t__________ levels

Answer 7

trophic

Question 8

Roughly, what percentage of energy is transferred from one trophic level to the next?

Answer 8

10 %

Question 9

Why are food chains not likely to have more than 4/5 trophic levels?

Answer 9

Not enough energy can be obtained by top predators as too much is lost in the food chain

Question 10

What is the process by which CO2 in the atmosphere is transferred into plants?

Answer 10

Photosynthesis

Question 11

Give 3 reasons why energy is lost between tropic levels in a food chain

Answer 11

Energy is lost by: movement (respiration), excretion, egestion, growth,

Question 12

What is the process by which CO2 is released into the atmosphere by animals

Answer 12

aerobic respiration

Question 13

What is the process by which carbon is converted into fossil fuels?

Answer 13

Death
Decay
Fossilisation

Question 14

By which process is nitrogen gas converted into ammonium ions?

Answer 14

Nitrogen fixation

Question 15

By what process are nitrates converted into nitrates by plants?

Answer 15

Nitrification

Question 16

What organisms convert nitrates back into nitrogen gas in the air?

Answer 16

Denitrifying bacteria

Question 17

By what process will nitrate ions be taken up by root hair cells of plants?

Answer 17

Active transport

Question 18

By what process will dead plant matter be broken down into ammonium ions in the soil?

Answer 18

Decomposition

Question 19

Name two pollutant gases and describe their effects

Answer 19

Sulfur dioxide: dissolves in rain water to form acid rain; can acidify lakes/ponds and kill marine life; can corrode marble/limestone statues
Carbon monoxide: binds irreversibly to haemoglobin

Question 20

Name 4 greenhouse gases

Answer 20

Carbon dioxide
Nitrous oxides
CFCs
Methane
Water vapour

Question 21

Name 2 human activities that can contribute to enhanced greenhouse effect

Answer 21

Burning fossil fuels
Deforestation
Cattle ranching

Question 22

What name is given to the pollution of lakes and rivers by leached minerals from fertilisers

Answer 22

Eutrophication

Question 23

State 3 consequences of an enhanced greenhouse effect

Answer 23

Global warming
Melting of polar icecaps
Habitat destruction
Extreme weather events

Question 24

State 3 ways in which humans could reduce their carbon footprint

Answer 24

Walking
Electric/hybrid cars
Public transport
Re-forestation
Burning fewer fossil fuels
Renewable energy sources

Question 25

State 3 consequences of deforestation

Answer 25

Leaching
Soil erosion
Disturbance of evapotranspiration and the carbon cycle
Disturbance in balance of atmospheric gases

Question 26

Define the term biodiversity

Answer 26

The variety of different species of organisms on earth, or within an ecosystem. It includes variation within ecosystems, habitats and within/between species.

Question 27

Give 3 human activities that may decrease biodiversity

Answer 27

Pollution
Deforestation
Global Warming

Question 28

What square piece of apparatus can be used to take a sample?

Answer 28

Quadrat

Question 29

Describe how you would study the population size of a small organisms using random sampling?

Answer 29

Set up grids in 2 areas
Randomly select coordinates to sample using random number generator
Count all organisms within quadrat
Repeat for 9 more pairs of co-ordinates and count up each grid
Scale up your mean values so they are representative of the whole area.

Question 29

What method of sampling would you use to measure distribution across a habitat?

Answer 29

Belt transect (systematic sampling)

Question 30

What is meant by the term abiotic factors? Give 3 examples

Answer 30

Non-living factors that affect communities:
Temperature
Light intensity
Soil PH levels
Carbon Dioxide concentration
Soil Moisture
Humidity

Question 31

What is meant by the term biotic factors? Give 3 examples

Answer 31

Living factors that affect communities:
Predation
Disease
Competition for - (food/mineral ions/water/mates/space/
shelter)