B3.4 Humans and their environment Flashcards
What may waste pollute?
WATER- with sewage, fertiliser, toxic chemicals
AIR–with smoke, gases such as sulfur dioxide which contributes to acid rain
LAND- with toxic chemicals such as pesticides and herbicides, which may be washed off the land into water ways
What 4 ways do humans reduce the amount of land available for other animals and plants?
by building
quarrying
farming
dumping waste
Why is deforestation happening?
to provide timber
to provide land for agriculture- Crops can be grow from which biofuels, based on ethanol can be produced. There is an increase in cattle and in rice fields to provide more food.
What has deforestation caused?
An increase in the release of carbon dioxide into the atmosphere (because of burning and the activities of microorganisms)
A reduction in the rate at which carbon dioxide is removed from the atmosphere and ‘locked up’ for many years as wood
A reduction in biodiversity
What has led to an increase in methane in the atmosphere?
The increase in the numbers of cattle and rice fields.
These organisms produce methane
What 2 organisms produce a lot of methane?
cattle, rice fields
What is an impact of the destruction of peat bogs?
Increase in carbon dioxide in the atmosphere
This is because peat bogs store carbon dioxide. When the peat is drained it starts to decompose as CO2 is released
What are peat bogs?
Areas of land that are acidic and waterlogged.
Plants that live in peat bogs do not fully decay when they die because there is not enough oxygen for microorganisms.
The partly-rotted plants gradually build up to form peat
why are ‘peat free’ composts increasing in importance?
As using peat releases carbon dioxide into the atmosphere
Using peat free composts (bark chippings, manure, ect) reduces the demand for peat
so less carbon dioxide is being added to the atmosphere
What is global warming?
an increase in the Earth’s temperature of only a few degrees Celsius
What are some predicted impacts of global warming?
- May cause big changes in the Earth’s climate
- May cause a rise in sea level
- May reduce biodiversity
- May cause changes in migration patterns, eg in birds
- May result in changes in the distribution of species
What does ‘sequestered’ mean?
locked up
What is an important factor in removing carbon dioxide from the atmosphere?
CO2 can be sequestered (locked up) in oceans, lakes and ponds
How are biofuels made?
from natural products by fermentation
Biogas, mainly methane, can be produced by anaerobic fermentation of a wide range of plant products or waste material containing carbohydrates
How can the efficiency of food production be improved?
- By reducing the number of stages in food chains
(As at each stage in the food chain, less material and less energy are contained in the biomass of organisms)
- By restricting energy loss from food animals by limiting their movement and controlling the temperature of their surrounding
- By developing new food sources like mycoprotein
Why is more waste being produced?
due to rapid growth in the human population and an increase in the standard of living
What is an example of sustainable food production?
Fish stocks in the oceans are declining
It is important to maintain fish stocks at a level where breeding continues or certain species may disappear altogether in some areas
Net size and fishing quotas play an important role in the conservation of fish stocks
What are fishing quotas and how do they play an important role in the conservation of fish stocks?
they are limits on the number and size of fish that can be caught in certain areas
This prevents certain species from being overfished
How does the limit of net size play an important role in conservation of fish stocks?
There are different limits of the mesh size of the fish net depending on what’s being fished
This is to reduce the number of ‘unwanted’ fish- ones ones that are accidentally caught. The bigger mesh size will let the ‘unwanted’ fish escape
Also means that younger fish will slip through the net, allowing them to reach breeding age
What fungus is used to produce mycoprotein?
Fusarium
How is Fusarium used to produced mycoprotein?
The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified
What is mycoprotein?
a protein rich food, suitable for vegetarians
grown using the fungus Fusarium
What are the 2 main factors in the conservation of fish stocks?
Net size
Fishing quotas
What are the 2 main types of biogas generators?
Batch generators- make biogas in small batches. They’re manually loaded up with waste, which is left to digest, and the by products are cleared away at the end of each session- eg used in third world countries, supplying a single family
Continuous generators- make biogas all the time. Waste in continually fed in, and biogas is produced at a steady rate- eg used in large scale biogas projects- commercial generators
Describe the basic structure of a biogas generator
- INLET- for waste material to be put in
- OUTLET- for digested material to be removed through
- BIOGAS OUTLET- so that biogas can be piped where it is needed
What is fermentation?
When bacteria or yeast break down sugars by anaerobic respiration
In what ways is energy lost in an organism?
- heat
- respiration
- movement
- waste products- faeces
Suggest why chickens kept in cages produce more eggs than free range chickens
- less movement
- less heat loss
- More feeding
Therefore energy can be used instead to produce more eggs
Why are the animals we raise for food usually herbivores
less steps in the food chain
so less losses of biomass and energy
cheaper to feed herbivores
What are 4 factors to consider when designing a generator?
Cost-continuous generators are more expensive than batch ones
Convenience- Batch generators are less convenient as they continually have to be loaded, emptied and cleaned
Efficiency- Gas is produced most quickly at about 35 degrees
Position- The waste will smell so bio generators should be situated away from homes
What are some economic and environmental effects of using biofuels?
- carbon neutral
- does not produce significant amounts of sulfur dioxide
- Methane is normally given off from untreated waste but burning it as biogas means that it is not released into the atmosphere
- The raw material is cheap and readily available
- The digested material afterwards can be used as fertiliser
- They act as a waste disposal system, getting rid of human and animal waste that’d otherwise lie around causing disease and polluting water supplies
Why are some people against factory farming animals?
- some people think that forcing animals to live in unnatural and crowded conditions is cruel- there’s a growing demand for organic meat
- The crowded conditions in an animal factory creates a favourable environment for the spread of disease
- To try to prevent disease, animals are given antibiotics. When the animals are eaten they can enter humans- antibiotics become less effective on humans
-Animals need to be kept warm to reduce the energy lost as heat
. This means using fossil fuels
What are some impications of ‘food miles’?
Some foods have a lot of ‘food miles’ which means that they are transported a long way from where they’re produced to where they’re sold
This can be expensive and it’s bad for the environment as fossil fuels are used to transport the food- contributing to global warming
What evidence is there for global warming?
we are using satellites to monitor snow and ice cover- which are decreasing
Automatic weather stations are constantly recording atmospheric temperature
Over the last 100 years sea levels have risen
Convincing data for climate change is only useful if…..
it covers a wide enough area and a long enough time scale
What do humans rely on ecosystems for?
food, water and shelter
Name 3 things that can pollute water
fertilisers
toxic chemicals from factories
sewage
Explain how acid rain is caused
sulfur dioxide and nitrogen oxides are released when fossil fuels are burnt
they dissolve in rain water
What is eutrophication?
Excess fertilisers are washed into rivers and lakes
They encourage the growth of algal blooms
These use up all the oxygen available in the water so aquatic organisms die
What is meant by biodiversity?
range of different species in a habitat
How is biogas made?
fermentation (anaerobic respiration) of biological matter by microbes
How is carbon dioxide naturally removed from the atmosphere?
photosynthesis
dissolved in oceans and lake
trapped in rocks
Why are most biogas generators kept underground?
so they are warm enough to provide the optimum temperature for microbial enzymes
What is biofuel?
fuel made from animal or plant matter
What conditions are needed for producing mycoprotein?
glucose syrup
oxygen
Why is mycoprotein considered to be a healthy food?
high in protein
low in fat
Why are outlets in biogas generators sealed with oil?
to prevent oxygen from entering
Give an advantage of using invertebrates rather than chemical tests to monitor pollution
more sensitive
less equipment needed
Give some methods of factory farming animals and the advantages and disadvantages
kept in cramped conditions- increased efficiency and profit as less energy used in movement- overcrowding is inhumane spread of disease- antibiotics used- increase antibiotic resistance in humans when eat animals
controlled temperature-less energy used to keep warm-use of fossil fuel for electricity
control feeding-animals will grow faster
Why are biogas generators in the UK built with thick concrete walls?
as temperatures in the UK are usually below optimum processes
heat from fermentation is retained in the digester to increase the rate of reaction
Give 3 ways in which the efficiency of food production is increased
reduce the number of stages in the food chain- as energy is loss at each stage in the food chain
keep animals indoors and warm- so that less energy is used in maintaining body temperature
restrict the movement of animals- so that less energy is used in movement
Why is it important to conserve biodiversity?
as organisms may have future uses
Give ways in which global warming might affect species on a worldwide scale
change migration patterns
cause changes in the distribution of organisms
cause a loss of habitat
What type of organ is fusarium?
fungus
What are some advantages of getting more food from mycoprotein instead of factory farming
quicker
cheaper
suitable for vegetarians
more efficient
What effect does the destruction of peat bogs have on the gases in the atmosphere?
increases carbon dioxide
give 2 reasons why the mass of household waste is increasing each year
growth in population
increase in standard of living
Suggest why the percentage of fish caught from sustainable sources is increasing
public awareness
Give 2 methods of maintaining fish stocks at a sustainable level
fishing quotas
limiting net size
Why do fish in cages grow faster than the same species of fish that are free?
cannot move as much
so less energy loss from the fish
more food available
so more energy for growth
Suggest why gas produced in a biogas generator released after a day does not burn
initially there is oxygen in the generator
so aerobic respiration by microorganisms
produces carbon dioxide, which does not burn
Suggest why potato peelings produce a lot of biogas
as they contain lots of carbohydrate
