How Humans can affect the environment

Question 1

What is the problem with using up non-renewable resources?

What is there when goods are produced?

Answer 1

Non-renewable resources cannot be replaced.

When good are produced there is a lot of industrial waste.

Question 2

In what four ways do human reduce the amount of land available for animals and plants?

Answer 2

1) Building
2) Quarrying
3) Farmning
4) Dumping waste

Question 3

What is the continuing increase in the human population affecting?

Answer 3

The continuing increase in human population is affecting the ecology of the Earth.

Question 4

What three main things do humans pollute?

Answer 4

Humans Pollute:

1) Waterways with sewage, fertiliser and toxic chemicals.
2) Air with smoke and gases such as sulfur dioxide, which contributes to acid rain.
3) Land with toxic chemicals such as pesticides and herbicides and these can then be washed into the water.

Question 5

In what five ways can humans pollute the land?

Answer 5

People pollute land in many different ways:

1) Sewage contains human body waste and waste water from our homes. Sewage must be treated properly to remove gut parasites and toxic chemicals or these can get onto the land.
2) Household and industrial waste is placed in landfill and toxic chemicals leak out. Industrial waste such as radioactive waste can also be very hazardous.
3) Farming methods can pollute the land.
4) Herbicides and pesticides sprayed onto crops can get into the soil and food chain and eventually be washed into rivers.
5) Farmers also use chemical fertilisers, to keep the soil fertile which can be washed into rivers.

Question 6

In what three ways can water be polluted?

Answer 6

1) Herbicides, pesticides and chemical fertilisers all get washed into rivers and streams.
2) Fertilisers and untreated sewage can cause a high level of nitrates in water.
3) Toxic chemicals from landfill also leak into waterways and pollute the water, killing organisms such as fish.

Question 7

What can burning fuels release into the atmosphere?

Answer 7

Burning fuels can produce sulfur dioxide and other acidic gases, power stations and cars also release acidic gases.

Question 8

What environmental problems can sulfur dioxide cause?

What are the impacts of this? (2)

Answer 8

Sulfur dioxide dissolves in water in the atmosphere forming acidic solutions. The solutions the fall as acid rain sometimes a long way from where the gases were produced.

1) Acid rain kills organisms, trees can be damaged if the leaves are soaked in acid rain for long periods.
2) Acid rain can change the pH of the soil, which damages roots and may release toxic minerals. E.g. aluminium ions damage organisms in the soil and in waterways.

Question 9

What are enzymes sensitive to?

What are the impacts of trees being damaged?

Answer 9

Enzymes which control reactions are sensitive to pH.

When trees are damaged, food and habitats for many other organisms are lost.

Question 10

What is deforestation?

Answer 10

Deforestation is where many trees are cut down, large scale deforestation in tropical areas is due to the increased demand for timber to provide land for agriculture.

Question 11

What have been the impacts of deforestation? (3)

Answer 11

Deforestation has:

1) Increased the release of carbon dioxide into the atmosphere due to burning of the trees or decay of the wood by organisms.
2) Reduced the rate at which carbon dioxide is removed from the atmosphere, by photosynthesis.
3) Reduced biodiversity due to loss of food and habitats.

Question 12

Why has deforestation occurred? (2)

Answer 12

Deforestation has occurred so that:

1) Crops can be grown to produce ethanol-based biofuels
2) There can be an increase in cattle and rice fields for food.

Question 13

What are the impacts of cattle and rice growing?

Answer 13

Cattle and rice growing produce methane, which has led to an increase in methane in the atmosphere.

Question 14

What are the impacts of destruction of peat bogs?

Answer 14

The destruction of peat bogs, and other areas of peat, also results in the release of carbon dioxide into the atmosphere, this occurs because the peat is removed from the bogs and used for compost in gardens which is decayed by microorganisms.

Question 15

What is the benefit of using peat-free composts?

Answer 15

Peat bogs will not be destroyed.

Question 16

What processes release and remove carbon dioxide into the atmosphere?

Answer 16

Carbon dioxide is released into the air by respiration and removed by plants and algae in photosynthesis.

Question 17

In what three main places does carbon dioxide dissolve into?

What can we say about carbon dioxide?

Answer 17

1) Oceans
2) Rivers
3) Lakes and ponds.
Caron dioxide is sequestered by plants and water.

Question 18

What is happening to the levels of carbon dioxide and methane in the atmosphere, what are these two gases called and what do most scientists believe they are causing?

Answer 18

Levels of carbon dioxide and methane in the atmosphere increasing, they are called greenhouse gases and cause the greenhouse effect. Most scientists believe an increase in greenhouse gases contributes to global warming.

Question 19

What may be the impacts of an increase in the earth’s temperature of only a few degrees celsius? (5)

Answer 19

1) Big changes in the Earths climate.
2) Rise in sea level due to melting ice caps and glaciers
3) Reduced biodiversity
4) Change in migration patterns e.g. birds
5) Change in the distribution of species

Question 20

What are biofuels? Give two types of biofuel.

Answer 20

Biofuels are fuels made from natural products. Two types of biofuel are ethanol-based fuels and biogas.

Question 21

How can ethanol-based fuels be produced?

How can ethanol be extracted?

Answer 21

Ethanol-based fuels can be produced by fermentation, glucose and sugar can juices are fermented by yeast to produce ethanol.
Ethanol can be extracted by the process of distillation, and can then be used as a fuel in motor vehicles.

Question 22

How can microorganisms produce ethanol?

How can glucose be produced from maize starch?

Answer 22

Microorganisms respire anaerobically to produce the ethanol, using sugars from crops as the energy source.

Glucose is produced from maize starch by the action of carbohydrase.

Question 23

Give three benefits of using ethanol as a fuel.

Answer 23

Benefits of using ethanol as a fuel:

1) Ethanol can replace fossil fuels which are a limited resource.
2) Using ethanol is more carbon friendly than fossil fuels.
3) Ethanol is carbon neutral.

Question 24

How can biogas be produced, what is biogas mainly made from?

What can be broken down in biogas generators?

Answer 24

Biogas, mainly made from methane, can be produced during anaerobic fermentation by bacteria.
Plants and any waste material containing carbohydrate, e.g. cattle dung can be broken down in biogas generators.

Question 25

What are biogas generators?

What are some generators designed to do?
How are generators insulated?

Answer 25

Biogas generators provide the ideal conditions for bacteria to reproduce and ferment the carbohydrates, they must be maintained at a suitable temperature in oxygen-free conditions.
Some generators are designed to mix the contents.
Generators are either insulated underground or have insulating jackets.

Question 26

What do large scale, commercial biogas generators use?
Where can generators be used on a small scale?
What is the gas produced and what can it be used for?
How does the amount of methane in the mixture affect the quality of biogas?

Answer 26

Large scale generators use waste from sugar factories or sewage works.
On a small scale generators can be used by a home or farm. The gas produced is a fuel and provides energy for heating.
The more methane in the gas mixture, the better the quality of biogas.

Question 27

How does the size of the food chain affect energy wasted?

What does this mean about the efficiency for humans to eat plants and animals?

Answer 27

The shorter the food chain, the less energy will be wasted. It is therefore efficient for us to eat plants than it is to eat animals.

Question 28

In what two ways can we produce meat more efficiently?

Answer 28

1) Preventing animals from moving so they don’t waste energy on movement, but this is seen as cruelty by many people and so is controversial.
2) Keeping the animals in a warm shed so they don’t use as much energy from food to maintain it’s body temperature.

Question 29

What does sustainable food production involve?

Answer 29

Sustainable food production involves managing resources and finding new types of food such as mycoprotein. This ensure there is enough food for the current population and in the future.

Question 30

In what two ways are fish stocks in the oceans monitored?

Answer 30

Fisherman:

1) Can only remove a strict allocation of fish per year - a quota.
2) Must use certain sized nets to avoid catching samll, young fish.

Question 31

What is the fungus fusarium grown to produce?
What are the benefits of this product?
How is fusarium grown?

Answer 31

The fungus fusarium is grown tor produce mycoprotein. This is protein-rich and suitable for vegetarians.
Fusarium is grown aerobically on cheap sugar syrup made from waste starch and mycoprotein is harvested.

Question 32

Where can microorganisms be grown on a large scale?

Why must the conditions be controlled?

Answer 32

Microorganisms can be grown on a large scale in industrial fermenters.
The conditions in a fermenter must be controlled to ensure maximum growth of Fusarium.

Question 33

What are the four main conditions in industrial fermentors?

Answer 33

1) An air supply providing oxygen for respiration
2) A stirrer or gas bubbles used to keep microorganisms spread out and to provide an even temperature.
3) A water-cooled jacket around the outside, as the respiring microorganisms release energy which heats the contents.
4) Sensors to monitor pH and temperature.

Question 34

Give three human activities which can affect the global environment.

Answer 34

1) Deforestation which can cause increased levels of carbon dioxide in the atmosphere.
2) Increases in rice growing and rearing cattle resulting in more methane being released.
3) Building dams to store water in reservoirs, causing loss of habitats, rivers drying out below the dams and reduction in fertile land to grow the crops.

Question 35

What are the two main beliefs about why global temperatures have increased?

Answer 35

1) Some say the earth’s temperature has increased due to increases in greenhouse gases.
2) Others say the increase is part of a natural cycle.

Question 36

Why is it important to test environmental data? (2)

Answer 36

1) As lost of different scientists around the world produce environmental data, so it can be difficult so be sure if the data is valid or reliable.
2) Scientists often come to different conclusions when considering the same data, sometimes depending on the opinions of the scientist and can be biased.