Biodiversity = the variety of different species in an ecosystem.
high biodiversity = ensures the stability of an ecosystem and the survival of species
levels of carbon dioxide and methane in the atmopshere are increasing due to human activity which contributes to global warming and climate change
global warming = gradual increase in the averagetemperature of the earth
global warming has resulted in:
extreme weather and sea level changes
large scale habitat change
threats to security and availability of food
migration of species to different parts of the world
Food security = having enough food to feed a population
Factors threatening food security:
rapid population growth
environmental changes
conflict
new pests and pathogens
changing diets
increasing costs of agricultural inputs
intensive farming techniques - make food production more efficient by restricting energy transfer from food animals to their environment
intensive farming methods:
limiting movement of the animals
controlling the temperature of their surroundings
How to maximise yield:
feed animals highprotein foods
give animals antibiotics to prevent disease
regularly use fertilisers , herbicides and pesticides on crops
Sustainable fisheries - use net sizes and fishing quotas to ensure that fish stocks are not overfished
Advantages of Intensive Farming:
high yield + quicker growth of crops and animals
efficient use of food with less waste produced
can meet demand for food
Disadvantages of Instensive Farming:
increased risk of antibiotic resistant bacteria strains
large carbon dioxide and methane emissions
Ethical issues
pesticides and herbicides may kill beneficial organisms
Deforestation = the removal of trees from an area, usually for agriculture or to make space for housing
Large scale deforestation - has been used to provide land for cattle and rice fields and to grow crops for biofuels
Result of large scale deforestation:
large amounts of carbon dioxide being released into the atmosphere
extinctions and reductions in biodiversity
climate changes
Eutrophication: excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.
Process of Eutrophication:
farmer puts fertiliser on crops
rain causes run-off
increased nitrates and phospates in the water (from fertiliser)
overgrowth of algae 'algalbloom'
nolight = no photosynthesis , lots of decay = oxygen is used up