Humans and their Environment Flashcards
What are two reasons why the population is growing?
- Medicine
* Modern farming methods
How does waste affect our water supplies?
- Sewage and toxic chemicals from industry can pollute lakes, rivers and oceans.
- Fertilisers and pesticides can wash into rivers and lakes.
How does fertiliser getting into water dangerous?
It causes algal bloom which blocks out the light for other plants in the water.
How can we pollute land?
- Toxic chemicals for farming
- Nuclear waste is buried underground
- Lots of waste sent to landfill sites
How can we pollute the air?
- Sulphit dioxide mixes with clouds to for dilute sulphuric acid which falls as acid rain
- Carbon dioxide contributes to the accelerated greenhouse effect
What four human activities reduce the amount of land and resources available to animals and plants?
- Building
- Farming
- Dumping waste
- Quarrying for metal ores
What are three reasons why deforestation is happening?
- Provide timber
- To clear land for farming
- To produce paper
What four problems does deforestation cause?
- More methane in the atmosphere from rice and cattle
- Less biodiversity
- More carbon dioxide in atmosphere as stored carbon dioxide is released when trees are burnt
- Less carbon dioxide taken in - the forests are our green lungs
What is a peat bog?
An area of acidic and waterlogged land where plants don’t fully decay when they die so form peat.
Why do peat bogs help the environment?
Carbon dioxide from the dead plants is locked away in the peat and not released into the atmosphere.
Why are peat bogs being drained?
- So that the area can be used for farming
- Peat used as fuel
- Peat used as compost
What is one way that we can discourage the destruction of peat bogs?
Use peat-free compost
What does sequestered mean?
To lock carbon dioxide away
What are three natural stores of carbon dioxide?
- Bodies of water
- Green plants
- Peat bogs
Describe the accelerated greenhouse effect.
1) Energy from the sun is absorbed by the Earth
2) The Earth radiates this heat energy back into the atmosphere
3) Greenhouse gases in the atmosphere absorb the heat energy
4) The greenhouse gases re-radiate the get energy back towards the Earth
What are five consequences of climate change?
- Othrr types of climate change like water shortages
- Rising sea level as ice melts and releases previously stored water
- Changes in the distribution of organisms
- Changes to migration patterns
- Less biodiversity as some species are unable to cope with changes to the environment
When evaluating evidence on climate change, what questions should we ask?
- Does the data cover a wide enough area?
- Does the data cover a wide enough timescale?
- Has the data been reproduced by anyone else?
- Could the people collecting or presenting the data be biased?
What are biofuels?
Fuels made by the fermentation of natural products.
What is fermentation?
When bacteria or yeast break down sugars by anaerobic respiration.
What is the word equation for ethanol production?
Glucose -> ethanol + carbon dioxide + energy
What are two ways of getting glucose for ethanol production?
- Sugar cane juices
* Production from maize starch by the action of carbohydrase and then distillation
What gases make up biogas?
70% is methane and 30% is carbon dioxide.
Why does biogas need to be used straight away?
Because it needs too high a pressure to be stored as a liquid.
What three features are required in a standard biogas generator?
- An inlet for waste material to be put in
- An outlet for the digested material to be removed through
- An outlet so that the biogas can be piped to where it’s needed
How is biogas made?
Microorganisms ferment plant material and pang waste containing carbohydrates.
How does biogas generation happen on a large scale?
Suitable waste is collected separately from other types of household rubbish and sent to biogas plants.
How can biogas generation be used on a small scale?
To make enough gas for a village or a family to use in cooking stoves or heating and lighting.
What are batch generators?
Generators that make biogas in small batches. They’re manually loaded with waste which is left to digest and the by products are cleared away at the end of each session.
What are two advantages and one disadvantage of batch generators?
+Cheapest to make
+Don’t need to be filled up often
-Don’t provide a regular supply of biogas
What is a continuous generator?
A biogas generator in which waste is continuously fed in and biogas is produced at a steady rate.
What four factors should be considered when designing biogas generators?
- Cost
- Convenience
- Efficiency
- Position
At what temperature is biogas most quickly produced?
35 degrees
What are four socioeconomic benefits of biogas?
- Raw material required is cheap and read it available
- Digested material is a better fertiliser than undigested dung
- Biogas saves women having to spend hours collecting wood for fuel
- Generators act as a waste disposal system
What are four environmental benefits of biogas?
- Burning methane as biogas stops it being released into the atmosphere
- Biogas doesn’t produce much sulphur dioxide or nitrogen oxide which cause acid rain
- Stops waste going to land fill
- Biogas is considered carbon neutral - the carbon they take in is equal to the carbon they give out
What are two ways of increasing the efficiency of food production?
1) Reducing the number of stages in a food chain
•Reduce the energy lost at each stage of the food chain
How does reducing the number of stages in a food chain increase efficiency in food production?
Because biomass is lost at each level of a food chain, if you cut out some trophic levels you lose less biomass.
How are animals in factory farms kept and why?
They are kept close together indoors to save them energy on movement and keeping warm. This means that animals will grow faster on less food.
What are two ways of preventing overfishing?
- Fishing quotas - limits on the numbers and sizes of fish that can be caught in certain areas
- Controlling net size to stop unwanted species being caught
What is mycoprotein?
Protein from fungi
What is the main source of mycoprotein?
Fusarium
How is fusarium used to make mycoprotein?
The fungus is grown in big containers full of liquid culture medium using glucose syrup as food.
How is the glucose used in mycoprotein production made?
By gmdigesting maize starch with enzymes.
What is added to the fermenter during mycoprotein production?
- Oxygen and ammonia to allow for respiration
* Steam to sterilise the fermenter
What two conditions are carefully maintained during mycoprotein production?
Temperature and pH.
What are four advantages of mycoprotein?
- Gives people in the developing world protein
- Grows very quickly
- Space efficient
- Can use waste which animals can’t use
What are three disadvantages of intensive farming?
- Considered unnatural and cruel
- Conditions encourage disease like avian flu and foot-and-mouth disease
- Animals need to be kept warm to reduce heat loss which uses energy
What are food miles?
How far the food has had to travel before it reaches the consumer.
What are two problems with food distribution?
Expensive and bad for the environment
