Unit 3B - Human And Their Environment Flashcards
What is the two biggest causes of the rate of the world population growth and why?
Modern medicine and farming methods as it has reduced the number of people dying from disease and hunger
How is the worlds population growing?
Very quickly, exponentially
An increasing population causes what on the demands of the environment?
The demands increase
The effects of human activity used to be small and local, what are they like now?
They have a far more widespread effect
Why are we taking more resources from the environment?
Increasing population means we need more resources to survive but also we demand a higher standard of living which use more resources and energy
As well as increasing the demand on the environment what else does a rapidly increasing population cause?
Us to produce more waste
As we are producing more waste what does this effect and why?
The water, land and air because of harmful population
What effect does more waste have on the water?
Sewage and toxic chemicals from industry can pollute lake, rivers and oceans which affects the plant and animals which rely on them for survival and chemicals used on land like fertilisers can be washed I to water
What effect does more waste have on the land?
We bury nuclear waste unground and we dump a lot of household waste into landfills
What effect does more waste have on the air?
Smoke and gases released into the atmosphere can pollute the air
What are the four main human activities the reduce the amount of land and resources available to other animals and plants?
Building, farming, dumping waste, quarrying for metal ores
Why isn’t the greenhouse effect all bad?
We need it to keep the earth a suitable temperature for living on
How is carbon present in the atmosphere?
As carbon dioxide
What does too much carbon dioxide in the atmosphere cause?
Global warming and the greenhouse effect
What are the five places that naturally stores carbon dioxide?
Oceans, lakes, seas, peat bogs and green plants
What’s another way for saying carbon dioxide is locked up in natural stores?
It is sequestered in natural stored
Why are the natural stores of carbon dioxide really important?
It means that carbon dioxide is removed from the atmosphere
What is the temperature of the earth a balance between?
The heat it gets from the sun and the heat it radiates back out into space
What makes the gases in the atmosphere like an insulating layer?
They absorb most if the heat that would normally be radiated out into space and re radiate it in all directions
Why is it important that we have some gases in our atmosphere to act as an insulating layer?
If it didn’t happen they’d be nothing to keep the heat in at night and so we would get very cold
What are the gases called in the atmosphere which help keep the heat in?
Greenhouse gases
What are the two main greenhouse gases which levels are rising very quickly?
Carbon dioxide and methane
What is the main cause of global warming?
The increasing greenhouse gases
What is another type of climate change that global warming can cause?
Changing rainfall patterns
What is deforestation?
The cutting down of forests
What are the main three reasons deforestation happens?
- ) It provide timber to use as building material
- ) to clear more land for farming
- ) to produce paper from wood
Why is it important to clear more land for farming?
It provides more food and more crops which can be used in biofuels
What are the four main problems caused by deforestation?
- ) more methane in the atmosphere
- ) more carbon dioxide in the atmosphere
- ) less carbon dioxide taken in
- ) less biodiversity
What two reasons are they for that deforestation leads to more Nathan in the atmosphere?
The land is cleared for farming, some of the fields have chattel which produce methane and rice which is grown on the fields is grown in warm, waterlogged conditions ideal for decomposers, these organism produce methane
What two reasons are there for that deforestation causes more carbon dioxide to be in the atmosphere?
Carbon dioxide is released when trees are burnt to clear land and the microorganism that feed on dead wood realises carbon dioxide as a waste product of respiration
Why does deforestation mean less carbon dioxide is taken in?
Cutting down trees means that less carbon dioxide is removed from the atmosphere during photosynthesis
What is biodiversity?
It is when a variety of different species live in a habitat, the more species the greater the biodiversity
Why does deforestation mean less diversity?
When rain forests are cut down habitats of huge number of different species are lost, this causes many species of become extinct and so biodiversity is reduced
Why is less biodiversity bad?
There are lots of useful products in the rainforest that we will probably never know about because the organism that produced them has become extinct, reducing our opportunities
What are bogs?
Areas of land that are acidic and waterlogged
Why does peat form in bogs?
Plants that live in bogs don’t fully decay because there isn’t enough oxygen, these partially rotted plants gradually build up to form peat
What happens to the carbon when a plant that lives in a bog decays?
Because the plants have only partially decayed to form peat there is some carbon stored in the peat
What are three reasons why peat bogs are often drained?
- ) so that the area can be used as farm land
- ) the peat can be cut up and dried to use as fuel
- ) it is used as compost
Why does destroying peat bogs add to the amount of carbon dioxide in the atmosphere?
As peat contains carbon as the bog is drained the peat starts to decompose releasing carbon dioxide
What is one way that people can help reduce the amount of peat bogs being drained?
Buy peat free compost to reduce the demand for peat
What are two reasons that global warming causes sea level rise?
- ) as the easy gets warmer it expands
2. ) higher temperature cause ice to melt and the water cause into the sea
What three places will be at risk if sea levels rise?
Netherlands, East Anglia and the Maldives
What has global warming done to the weather?
It has changed weather patterns and causes more extreme weather
How does global warming increase the amount of hurricanes?
Hurricanes from over warm water and so as the water warms up more hurricanes will happen
What three things can global warming change about animals?
- ) the distribution of many wild animals and plant species may change
- ) biodiversity could be reduced
- ) change in migration patterns
Why might global warming change the distribution of aniamls and plant species?
Some species might become more widely distributed if they like warmer temperature, other species may become less widely distributed if they prefer colder conditions
What do you need to weigh up before making judgements?
The evidence
What can you use to monitor snow and ice cover and the temperature and speed of the sea?
Satellites
Data for global warming is only useful is it is?
Covers a wide enough are and a long enough time scale
Give an example of why an observation in a small area isn’t much use.
If you notice that one glacier is melting very fast it doesn’t mean that ice everywhere is melting it might just be the one glacier and so it’s not valid to measure global temperature changed that way
What process can you make fuels with?
Fermentation
What us fermentation?
Fermentation is when bacteria or yeast break sugars down by anaerobic respiration
What is fermented to make ethanol?
Glucose with yeast
What’s the word equations of the fermentation of glucose to make ethanol?
Glucose ——–> ethanol + carbon dioxide + energy
What can you use as glucose when you are fermenting it to produce glucose?
Sugar cane juices, or glucose can be derived from maize starch by the action of carbohydrase
What is done to ethanol after fermentation before it is used?
It is distilled to separate it from the yeast and the remaining glucose
How is biogas made?
Anaerobic fermentation of waste material
What does biogas contain?
70% methane and 30% carbon dioxide
What is biogas made in?
A simple fermenter called a digester or generator
Why do biogas generators need to be kept at a constant temperature?
To keep the microorganisms respiring away
What are the two types of biogas generators called?
Batch generator and continuous generators
Why can’t biogas be stored as a liquid?
It needs too high a pressure
By products of producing biogas can be used for?
Fertilising crops and gardens
What can be digested by bacteria to produce biogas?
Human waste, waste from pigs and food waste
What is a batch generator?
It makes biogas in small batches, they’re manually loaded up with waste and the by products are cleared away at the end of each session
What is a continuous generator?
They make biogas all the time on a large scale, waste is continuously fed in and biogas is produced at a steady rate
What three things must a simple biogas generator have?
- ) an inlet for waste material to be put in
- ) an outlet for the digested material to be removed through
- ) an outlet is that the. Iona’s can be piped to where it is needed
What four factors so you need to consider when designing a generator?
Cost, convenience, efficiency and position
Why are continuous generators more expensive that batch generators?
Because more waste has to be pumped in and digested material mechanically removed all the time
Which generator for biogas are less convenient and why?
Batch generators are less convenient because they have to be continually loaded, emptied and cleaned
At which temperature is biogas produced most quickly at?
At about 35c
Why are some generator is insulated to keep warm?
Ah biogas produced happens the quickest at 35c so by insulating it it stops the temperature falling below this level and slowing down
Where do generators need to be positioned and why?
Sited away from homes and the waste will smell, but close to where the waste store is
Why is biogas production carbon neutral?
The carbon dioxide released into the atmosphere was taken in by the plants as they grew
What gases doesn’t biogas produce a lot of and why is this good?
Sulphur dioxide or nitrogen oxides which is good as this causes acid rain
How does methane reduce the amount of methane released into the atmosphere?
Methane is given off be untreated waste, which may be kept in farmyards or used as fertilisers, burning it to produce biogas doesn’t release the methane
What about the raw material is good about biofuel?
It is cheap and readily available
Why is biogas generators a good waste disposal system?
It gets rid off waste that would otherwise be left lying around
What are the main three reasons that make biogas really good?
- ) it gets rid off waste
- ) makes a great fertiliser
- ) provides energy
What three things can be done to increase the efficiency of food production?
- ) reducing the number of stages in the food chain
- ) restricting the energy lost by farm animals
- ) developing new food sources like mycoprotein
Why does reducing the number of stages in the food chain increase efficiency of food production?
There’s less energy and less biomass every time you go up a stage in the food chain, so my reducing the stages you get and save more energy
Why is it better to grow crops on land rather than letting animals growing on it?
You get more food by growing crops on land as you reduce the number of stages in the food chain
Although it is better to grow crops than let animals graze on land why are animals still allowed to graze?
People want a varied diet, and some land like hillsides aren’t suitable to grow crops on
What does it mean is animals like pigs and chickens are intensively farmed?
They are kept close together indoors in small pens, so that they are warm and can’t move about
Why does intensively farming animals restrict the amount of energy lost?
It saves them wasting energy on movement, and stops them giving out so much energy as heat, this makes the transfer of energy from the animal feed to the animal more efficient, so the animals grow faster on
less food. Making it cheaper so the farmers and reducing energy lost
What does mycoprotein mean?
Protein from fungi
What is mycoprotein used in?
Meat substitutes for vegetarians like quorn
What is the main source of mycoprotein?
A fungus called fusarium
How is fusarium grown?
In fermenters using glucose syrup as food
How to they prevent other microorganisms growing in the fermenter?
The fermenter is sterilised using steam, incoming nutrients are heat sterilised and the air supplied is filtered
Why is mycoprotein could to use in developing countries?
It difficult to find enough protein, animals need a lot of space to graze and plenty of nice grass however mycoprotein can grow quickly and doesn’t need much space and it can feed on waste material that would be no good for feeding animals with
What are the main three bad things about intensively farmed animals?
- ) it seen as cruel to force animals to live in unnatural small spaces
- ) the cramped conditions lead to the spread of disease
- ) animals need to be kept warm to reduce the energy they lose as heat and this uses fossil fuels which we wouldn’t be using if the animals were in their natural environment
To prevent disease spreading it intensively farmed animals what do they do and why?
The animals are given antibiotics, this can lass onto the human and it allows microbes that infect humans to develop immunity to those antibiotics meaning they become less effective in humans
Why can food distribution cause a problem?
If products have big food miles, the ships, planes and trucks used to transport the food releases carbon dioxide into the environment contributing to global warming
Are fish stocks inclining?
No they are declining
Why is over fishing bad?
There’s less fish to ear, and the oceans food chains are affected because some species of fish may disappear
What is sustainable food production?
Having enough food without using resources faster than they can renew
What two ways can fish sticks me maintained?
Fishing quotas and with net sizes
Why does fishing quotas help to maintain the fish stocks?
As there are limits to the number and size of fish that can be caught in certain areas it prevents certain fish from being over fished
How can net size help to maintain fish stocks?
There are different limits of the mesh size of the fish net depending on what is being fished this is to reduce the number of unwanted and discarded fish, it also allow younger fish to slip through the net allowing them to reach breeding age
