Humans and the Environment Flashcards

(24 cards)

1
Q

What commonly pollutes water?

A

Sewage, fertilisers from farms or toxic chemicals from industry.

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2
Q

What commonly pollutes air?

A

Smoke and poisonous gases from industry or vehicle fumes.

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3
Q

What commonly pollutes land?

A

Pesticides/herbicides from farming or industrial waste such as heavy metals.

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4
Q

Why is more waste being produced?

A

The population has grown and the standard of living increases.

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5
Q

How is acid rain formed and what are its effects?

A

Acid rain is formed when sulphur and nitrous oxides dissolve in the water vapour in the air and fall as rain; its effects are the damage of trees and the increased acidity of the soil.

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6
Q

What are the reasons for deforestation?

A

To use the timber for building work; to use the land cleared for agriculture; to use the space to grow crops for ethanol-based biofuels; to grow rice crops or keep cattle for food.

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7
Q

Why does deforestation release carbon dioxide?

A

The combustion of the trees releases carbon dioxide; the respiration of microorganisms decaying the trees releases carbon dioxide; the removal of trees reduces the rate at which they can remove carbon dioxide from the atmosphere through photosynthesis.

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8
Q

What is biodiversity and why do we need it?

A

Biodiversity is the wide range of organisms, plants and animals, that live in a habitat; it is important because species that have not yet been discovered or studied could be a source of medicine or food for the future.

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9
Q

Where is carbon dioxide sequestered?

A

Peat bogs, forests, oceans and rivers where it dissolves.

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10
Q

What is the greenhouse effect?

A

The buildup of greenhouse gases in the atmosphere which form a thicker layer around the earth; energy from the sun is trapped in this this thick gaseous layer and is reradiated back to earth, causing the temperature to rise.

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11
Q

What are the effects of global warming?

A

Increased unpredictability to the earth’s climate; a rise in sea levels as the ice caps melt, leading to increased flooding; reduced biodiversity as the climate changes; changes in migration patterns to species; changes in distribution of certain species.

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12
Q

How are ethanol-based biofuels produced?

A

Glucose from maize ferments anaerobically with yeast to produce ethanol and carbon dioxide; the ethanol is extracted by distillation.

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13
Q

What are the advantages / disadvantages of using ethanol as a fuel?

A

It is an efficient fuel; it doesn’t produce toxic gases when burnt; it is a carbon neutral process and isn’t very polluting; it requires large amounts of crops to be grown to produce ethanol; there are ethical issues when there is world hunger but crops are grown to produce fuel for developed countries.

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14
Q

What is biogas?

A

A biofuel that is a flammable mixture of gases, formed when bacteria decompose plant material in anaerobic conditions.

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15
Q

What is the main gas present in biogas?

A

Methane.

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16
Q

What is put into a biogas generator?

A

Dung from humans and animals, farm waste, garden rubbish.

17
Q

What comes out of a biogas generator?

A

Methane for cooking or heating; slurry, which can be used as a fertiliser.

18
Q

What temperature will the production of biogas work best at?

A

Around 30°C.

19
Q

How can food production be made more efficient?

A

By reducing the number of stages in the food chain to prevent loss of energy and biomass; by restricting the movement of animals and keeping them in a warm temperature to prevent waste of energy.

20
Q

How can overfishing be prevented?

A

Enforcement of fishing quotas so there is a limit as to how many and what type of fish can be caught; controlling the size of nets so that smaller fish can escape to breed; restricting fishing during breeding season so the species can reproduce.

21
Q

What is mycoprotein?

A

A protein made from the fungus Fusarium; grown in fermenters; suitable for vegetarians and a suitable substitute for meat.

22
Q

What are the features of mycoprotein fermenters?

A

They have an air supply to provide oxygen for the respiration of the fungi; they have stirrers to keep the microorganisms in suspension and to maintain an even temperature; they have a water-cooled jacket to remove any excess energy; they have sensors which constantly monitor the pH and temperature.

23
Q

What are the effects of building dams for reservoirs?

A

Habitats for humans, plants and animals are lost; river ecosystems are destroyed as they dry up; flood plains disappear along with the fertile soil they provide.

24
Q

What is eutrophication?

A

The process by which oxygen levels in a stream or pond fall so low that the aquatic animals die and the water becomes “dead”.