Human Influences on the Environment (Edexcel IGCSE Science (Double Award): Biology): Flashcards
Exam code: 4SD0
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How does carbon monoxide affect the body?
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How does carbon monoxide affect the body?
It binds to haemoglobin, reducing oxygen transport in the blood.
In high concentrations it can cause suffocation and death.
What are the biological consequences of sulfur dioxide pollution?
It combines with water vapour to form acid rain, which damages plants, aquatic life and soil.
It also causes respiratory problems in humans.
How is acid rain produced?
Sulfur dioxide released into the air combines with water vapour in the atmosphere.
Which three things does acid rain damage?
Plants
Aquatic life
Soil
Why is carbon monoxide so dangerous even in small amounts?
Because it binds to haemoglobin, so the blood can carry less oxygen to respiring cells.
Which human health problem does sulfur dioxide cause directly?
Respiratory problems.
Carbon monoxide binds to ＿＿＿＿＿＿＿＿, reducing oxygen transport in the blood.
Carbon monoxide binds to haemoglobin, reducing oxygen transport in the blood.
Sulfur dioxide combines with water vapour in the atmosphere to form ＿＿＿＿＿＿＿＿.
Sulfur dioxide combines with water vapour in the atmosphere to form acid rain.
True or False?
Carbon monoxide causes acid rain.
False.
It is sulfur dioxide that forms acid rain. Carbon monoxide binds to haemoglobin and reduces oxygen transport.
True or False?
Acid rain can damage aquatic ecosystems.
True.
It harms aquatic life as well as plants and soil.
Which two air pollutants have biological consequences?
Carbon monoxide
Sulfur dioxide
Why can high carbon monoxide levels be fatal?
Because so little oxygen can be carried by the blood that the body effectively suffocates.
Define greenhouse gas.
A gas that absorbs infrared radiation from the Sun so that it remains trapped in the Earth's atmosphere.
Name the five most important greenhouse gases.
Water vapour
Carbon dioxide
Methane
Nitrous oxides
CFCs
Why are greenhouse gases important to life on Earth?
They keep the Earth warm enough for life. Without them the planet would be too cold.
What happens if greenhouse gas levels increase?
The greenhouse effect increases, causing the Earth's average temperature to rise.
Which human activity increases atmospheric carbon dioxide?
The combustion of fossil fuels.
Which two human activities increase atmospheric methane?
Cattle, which produce methane as they digest grass
Rice paddy fields, which release it
Which two greenhouse gases have risen most from human activity?
Carbon dioxide
Methane
Greenhouse gases absorb ＿＿＿＿＿＿＿＿ radiation and trap it in the Earth's atmosphere.
Greenhouse gases absorb infrared radiation and trap it in the Earth's atmosphere.
＿＿＿＿＿＿＿＿ is produced by cattle digesting grass and released by rice paddy fields.
Methane is produced by cattle digesting grass and released by rice paddy fields.
True or False?
Water vapour is a greenhouse gas.
True.
It is one of the five most important greenhouse gases, along with carbon dioxide, methane, nitrous oxides and CFCs.
True or False?
Greenhouse gases are entirely harmful and serve no useful purpose.
False.
They are essential — they keep the Earth warm enough for life. The problem is the increase in their levels.
Where does the infrared radiation absorbed by these gases come from?
From the Sun, and from heat re-emitted by the Earth's surface.
Describe the four steps of the natural greenhouse effect.
The Sun emits radiation that enters the Earth's atmosphere.
The Earth's surface absorbs some of it and re-emits it as heat (infrared radiation).
Some of that heat is reflected back into space.
Some is absorbed by greenhouse gases and trapped in the atmosphere.
Why is the natural greenhouse effect essential?
It keeps the Earth warm enough to support life.
Define enhanced greenhouse effect.
When increasing levels of greenhouse gases from human activities trap more heat in the atmosphere, so the Earth's average temperature rises above normal.
Name three human activities that enhance the greenhouse effect.
Burning fossil fuels, releasing carbon dioxide
Farming cattle, which release methane
Growing rice in paddy fields, which also releases methane
What does the enhanced greenhouse effect lead to?
Global warming and climate change.
Give four consequences of rising ocean temperatures.
Melting of polar ice caps
Rising sea levels
Flooding
Coral bleaching
Which extreme weather events result from increasing temperatures?
Super storms, flooding and droughts.
How does global warming reduce the number of species in a habitat?
Food chains are disrupted and extinction rates rise.
Habitats are also changed or lost through extreme weather events.
How does global warming affect the movement of species?
It increases migration of species to new places, including the increased spread of pests and disease.
The Earth's surface absorbs radiation from the Sun and re-emits it as ＿＿＿＿＿＿＿＿.
The Earth's surface absorbs radiation from the Sun and re-emits it as heat.
Rising ocean temperatures cause the melting of ＿＿＿＿＿＿＿＿ and a rise in sea levels.
Rising ocean temperatures cause the melting of polar ice caps and a rise in sea levels.
True or False?
The greenhouse effect is entirely caused by human activity.
False.
The greenhouse effect is a natural and essential process. Human activity enhances it by increasing greenhouse gas levels.
True or False?
Global warming can increase the spread of pests and disease.
True.
As species migrate to new places in response to changing conditions, pests and diseases spread with them.
Define eutrophication.
The process that follows when minerals from agricultural fertilisers are leached into water bodies such as lakes and streams.
Describe the stages of eutrophication.
Fertilisers are high in nitrates, causing overgrowth of aquatic plants and algae at the water surface.
Plants below the surface die from reduced light and are broken down by decomposers.
Decomposers increase in number, and their increased respiration uses up oxygen.
The water no longer holds enough oxygen, so many aquatic organisms die.
Why do plants below the water surface die during eutrophication?
Because the overgrowth of algae at the surface blocks the light, so light levels below are reduced.
Which mineral in fertiliser drives eutrophication?
Nitrate, an essential mineral for plant growth.
Why does an increase in decomposers kill aquatic animals?
Their increased respiration uses up the dissolved oxygen in the water, leaving too little to support other organisms.
How does sewage get into waterways?
When sewers overflow, or when agricultural waste is washed off fields during heavy rain.
Describe the biological consequences of sewage pollution.
Sewage causes an increase in aerobic bacteria, which feed on the biological waste.
These bacteria reduce the dissolved oxygen in the water.
Oxygen-sensitive organisms die, leaving only those that tolerate low oxygen.
The ecosystem ends up supporting far fewer species.
What additional health risk does sewage in waterways create?
An increase in the number of pathogenic bacteria present.
What do eutrophication and sewage pollution have in common?
Both cause a rise in bacteria numbers whose respiration reduces dissolved oxygen, so oxygen-sensitive aquatic organisms die.
Fertilisers are high in ＿＿＿＿＿＿＿＿, which cause the overgrowth of algae during eutrophication.
Fertilisers are high in nitrates, which cause the overgrowth of algae during eutrophication.
Sewage pollution reduces the ＿＿＿＿＿＿＿＿ of the water, so sensitive organisms die.
Sewage pollution reduces the dissolved oxygen of the water, so sensitive organisms die.
True or False?
Eutrophication kills fish because the fertiliser itself is toxic.
False.
The fish die because the decomposers' respiration uses up the dissolved oxygen in the water.
True or False?
Sewage pollution reduces the number of species living in a river.
True.
Only organisms that can survive at low oxygen concentrations remain.
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