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Flashcards in 22. Humans And The Environment Deck (20)
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How has modern technology increased food supply?

Agricultural machinery
Chemicals fertilizers improve yields
Insecticides and herbicides
Selective breeding


How has agricultural machinery increased food supply?

It has replaced humans, improved efficiency due to the ability to form much larger areas of land then manual labour can do


How has chemical fertilizers improved yields?

Fertilisers increase the amount of nutrients in the soil for plant, meaning that they can grow larger and produce more fruit.


What is monoculture?

Growing only one type of crop in a large area


What is a sustainable resource ?

one which can be removed from the environment without it running out


What is sustainable development?

Providing for the needs of an increasing human population without harming the environment


What is a greenhouse effect ?

The warming effect of carbon-dioxide, methane and other green houses gases on earth.


What are the greenhouse gases ?

- methane
- carbon-dioxide
- water vapour
- nitrous dioxide
- CFCs


What are the problems caused by monocultures?

- biodiversity is low
- increase of populations of organisms that are pests of the crop


What is enhanced greenhouse?

Increased greenhouse effect caused by the addiction effect of more greenhouse gases into the atmosphere


What causes acid rain ?

Sulfur dioxides
Nitrogen oxides


Write the process of Eutrophication?

Runoff of fertiliser from farmland enters the water and causes increased growth of algae
resulting ‘algal bloom’ blocks sunlight so water plants on the bottom start to die
As water plants and algae die in greater numbers, decomposing bacteria increase in number and use up the dissolved oxygen
As a result there is less oxygen dissolved in water, so aquatic organisms such as fish and insects may be unable to survive


What are the effects of acid rain?

- damages the leaves which kills the plants
-acidification of lakes- kills animals
-increased risk of asthma attacks
-corrosion of stonework and buildings
-release of aluminium from the soil which is toxic for fish


Solutions for acid rain?

- using scrubbers in power stations
- using catalytic converters in the exhaust system of the cars
-changing power stations to renewable energy sources


Explain the greenhouse effect?

The Sun emits rays that enters the Earth’s atmosphere
The heat bounces back from the Earth’s surface
Some heat is reflected back out into space
Some heat is absorbed by greenhouse gases and is trapped within the Earth’s atmosphere – this is normal
However, as the levels of greenhouse gases in the atmosphere rise due to human activities the Earth’s average temperature rises beyond normal (an enhanced greenhouse effect), causing global warming or climate change


Consequences of global warming due to an enhanced greenhouse effect

Ocean temperatures increase which causes rising sea levels
Increasing temperatures can cause extreme weather
These extreme weather events can lead to changes in or loss of habitats
decrease in biodiversity
There could also be increases in migration of species to new places, increased spread of pests and disease


Explain the sewage treatment?

Crude sewage flows through a screen in which large materials like paper and sticks are trapped so they can be removed and burned
The sewage is passed slowly through channels where grit and other heavy particles picked up along the way settle to the bottom
The channels lead into sedimentation tanks where the solid material settles on the bottom as sludge and the liquid part, called effluent, remains on top
The sludge is removed by pumping it into tanks where anaerobic bacteria decompose it – often the bacteria produce methane which can be collected and used as an energy source for the plant
The effluent (liquid) is treated with aerobic bacteria to remove any organic waste in it, before being treated with chlorine to kill the bacteria
At this point it is clean enough to return to natural water systems or be passed on to a second treatment plant where it is processed further to make it pure enough to reuse as drinking water


What are reasons why a species can become endangered?

climate change
loss of habitat
introduction of non-native species that outcompete native species


Endangered species can be helped by conservation measures such as:

education programmes
captive breeding programmes
monitoring and legal protection of the species and of their habitats
seed banks as a conservation measure for plants


Managing fish stocks sustainably includes:

Controlling the number of fish caught each year
Controlling the size of fish caught
Controlling the time of year that certain fish can be caught
Restocking-breeding and keeping offspring until they are large enough to survive in their natural habitat then releasing.
Educating fishermen as to local and international laws and consumers so they are aware of types of fish which are not produced sustainably