human influences on ecosystems

substance that contains important nutrients for plant growth, such as magnesium and nitrates

substances that kill insectsand, in doing so, protect the crop plants from damage

substances that kill plants by disrupting their growth in some way

growing only one variety of crop in an area at a given time

• Simplicity • Higher yields • Reduced costs • Larger land and machinery

• Negative impacts on the environment, such as: • Land clearance • Deforestation • Reduced biodiversity • Soil damage • Water pollution • Air pollution

diversity of living organisms in an ecosystem

place where an organism lives

• using more land for food crops, livestock production and housing • the extraction of natural resources • freshwater and marine pollution

• pollution is created by fuels when they are burned • the search for oil or gas damages natural habitats • drilling and mining operations need wells, roads, pipelines and other facilities

• oil spills • untreated sewage • careless disposal of rubbish • mining waste • nitrates entering rivers from fertiliser use • herbicides and pesticides • heavy metal runoff (this can carry toxic metals such as mercury that pose a danger to water life and human health

• reduced biodiversity • flooding • loss of soil • extinction of species • an increase in carbon dioxide in the atmosphere

the release of any substance that has an undesired, unexpected, harmful or toxic effect on the environment

how and where the pollutant enters the environment

the harm that the pollutant does when it is in the environment

human and animal waste released without passing through sewage treatment plants

may carry harmful pathogens that cause disease; uses up oxygen when it rots; hormones affect reproduction of some organisms

runoff from farmland

algal blooms and eutrophication

something that is produced as rapidly as it is removed from the environment, so that it does not run out

resources that are used up faster than they are being formed

• destruction of habitat • pollution • climate change • hunting • introduced species • overharvesting.

• monitoring and protecting species and habitats • education • seed banks • captive breeding programmes

• Artificial insemination • In-vitro fertilisation