IGCSE BIOLOGY – TOPIC 5
BIOLOGICAL RESOURCES
a) FOOD PRODUCTION
CONTROLLING CLIMATES:
• Controlling climates allows farmers to control temperature, light
intensity and carbon dioxide to increase growth of plants
• There are two main ways of controlling climate:
o GLASSHOUSES – allows artificial heating, artificial lighting, increasing
carbon dioxide content of air and regular watering – however there is
also an extra cost of providing these things
o POLYTHENE TUNNELS – large enough for machines to work inside
them, they can protect crops grown outside from weather (e.g. wind,
rain, extreme temperature), prevents the entry of pests, increase in
temperature outside the tunnel too
• Farmers can benefit from increasing carbon dioxide/temperature levels
as long as temperature/carbon dioxide and light are optimal – MORE
GLUCOSE is made and therefore there is more energy for crops = faster
growth and a HIGHER YIELD
USE OF FERTILISER:
• FERTILISERS provide elements needed for plants to grow well such as
nitrogen, phosphorus and potassium – they make crops grow faster and
bigger so yields are increased
o The compounds must be water-soluble so the plant can absorb them
through their roots
PEST CONTROL:
• There are two types of pest control. They are easily accessibly, have an
immediate effect and kill the entire population of pests – but the
organism they are meant to be killing may develop resistance to them
and also can sometimes kill beneficial organisms
o Using PESTICIDE - insecticide, herbicide, fungicide
o Using BIOLOGICAL CONTROL – when you introduce another species
to get rid of pests. These both are to:
69
, § Protect the crops from PESTS eating them
§ Reduce weeds which can take up space/water/soil nutrients
for crop plants
MICROORGANISMS:
• Microorganisms can be used by humans to produce food and other
useful things. They can GROW RAPIDLY and have SIMPLE NUTRIENT
REQUIREMENTS
• We can use YEAST, a type of single-celled fungus, to make bread and
beer - when it anaerobically respires ethanol and carbon dioxide (causing
the bread to rise and beer to fizz) are made
• BEER PRODUCTION:
o Sugar is extracted from plants, yeast is added and kept warm, air
and other microorganisms are kept out of fermentation container
using an air lock, fermentation is allowed to continue, mixture is
clarified by settling and filtration, drink is pasteurized then stored
This is a fermenter, which can
make beer and yoghurt – it
must have specific conditions
70
BIOLOGICAL RESOURCES
a) FOOD PRODUCTION
CONTROLLING CLIMATES:
• Controlling climates allows farmers to control temperature, light
intensity and carbon dioxide to increase growth of plants
• There are two main ways of controlling climate:
o GLASSHOUSES – allows artificial heating, artificial lighting, increasing
carbon dioxide content of air and regular watering – however there is
also an extra cost of providing these things
o POLYTHENE TUNNELS – large enough for machines to work inside
them, they can protect crops grown outside from weather (e.g. wind,
rain, extreme temperature), prevents the entry of pests, increase in
temperature outside the tunnel too
• Farmers can benefit from increasing carbon dioxide/temperature levels
as long as temperature/carbon dioxide and light are optimal – MORE
GLUCOSE is made and therefore there is more energy for crops = faster
growth and a HIGHER YIELD
USE OF FERTILISER:
• FERTILISERS provide elements needed for plants to grow well such as
nitrogen, phosphorus and potassium – they make crops grow faster and
bigger so yields are increased
o The compounds must be water-soluble so the plant can absorb them
through their roots
PEST CONTROL:
• There are two types of pest control. They are easily accessibly, have an
immediate effect and kill the entire population of pests – but the
organism they are meant to be killing may develop resistance to them
and also can sometimes kill beneficial organisms
o Using PESTICIDE - insecticide, herbicide, fungicide
o Using BIOLOGICAL CONTROL – when you introduce another species
to get rid of pests. These both are to:
69
, § Protect the crops from PESTS eating them
§ Reduce weeds which can take up space/water/soil nutrients
for crop plants
MICROORGANISMS:
• Microorganisms can be used by humans to produce food and other
useful things. They can GROW RAPIDLY and have SIMPLE NUTRIENT
REQUIREMENTS
• We can use YEAST, a type of single-celled fungus, to make bread and
beer - when it anaerobically respires ethanol and carbon dioxide (causing
the bread to rise and beer to fizz) are made
• BEER PRODUCTION:
o Sugar is extracted from plants, yeast is added and kept warm, air
and other microorganisms are kept out of fermentation container
using an air lock, fermentation is allowed to continue, mixture is
clarified by settling and filtration, drink is pasteurized then stored
This is a fermenter, which can
make beer and yoghurt – it
must have specific conditions
70
