Humans and the environment Flashcards
How modern technology has resulted in increased food production
- Agricultural machinery (tractors) to be used in larger areas of land and improve efficiency
- Chemical fertilizers to increase yield
- Insecticides sprayed on crops to improve quality and yield
- Herbicides are sprayed to reduce competition with weeds
- selective breeding to improve production by crop plants and livestock, e.g. cattle, fish and poultry
negative impacts to an ecosystem of large-scale monocultures of crop plants
- there is a low biodiversity as only few species can live where crop is growing.
- Lead to increase in population of organism that are pests of the crop
- Spraying chemicals such as insecticides will kill pests however also kill predatory insects and spiders that help reduce population of pest.
negative impacts to an ecosystem of intensive livestock production
- Welfare issues for livestock, diseases can be easily spread amongst livestock as are crowded together.
- Reduction in biodiversity in areas where large amounts of land are used to graze cattle (as only grass is grown so in effect it becomes a monoculture)
- overgrazing can lead to soil erosion
- waste from intensive farming unit can pollute land and waterways
social implications of providing sufficient food for an increasing human global population
-Unemployment due to reduced labour force in rural area
environmental implications of providing sufficient food for an increasing human global population
- Increased carbon emissions cause global warming
- Air pollution from factories as countries industrialise and exploit resources
economic implications of providing sufficient food for an increasing human global population
- Higher energy prices as sources are depleted
- The gap between rich and poor becomes more evident.
problems which contribute to famine
- unequal distribution of food
- drought and flooding
- increasing population and poverty
reasons for habitat destruction
– increased area for food crop growth, livestock production and housing
– Damage habitats due to extraction of natural resources
– marine pollution
How can humans have a negative impact on habitats
through altering food webs and food chains, humans can have a negative impact on habitats
Undesirable effects of deforestation
- extinction
- loss of soil
- flooding
- increase of carbon dioxide in the atmosphere (trees take Co2 for photosynthesis, if trees are cut down less Co2 is taken and more Co2 give into atmosphere when trees are burnt.
undesirable effects of deforestation on the environment
- Loss of biodiversity
- Loss of habitat
- Loss of hiding place for prey from predators
- Soil erosion ( Tree roots hold soil in place, without them rain can easily wash soil away, Trees intercept rain drops as they fall, without them rain hits harder on ground and soil is loosened and washed away, Trees absorb water from soil without trees less water is absorbed and more runs off surface of land causing soil erosion and flooding)
- Global warming
sources and effects of pollution of land and water
rivers, lakes and the sea are affected by:
- insecticides
- herbicides
- nuclear fall-out
sources and effects of pollution of water
rivers, lakes and the sea are affected by:
- chemical waste
- discarded rubbish
- untreated sewage
- fertilisers
sources and effects of pollution of the air by methane and carbon dioxide
- Source of methane is cattle farming, rice fields. Methane is a greenhouse gas that contributes to enhanced green house effect (increase in greenhouse effect caused by increase in Co2 and Methane in atmosphere), causing climate change.
- Sources of Co2 are When fossil fuels are burnt or trees are burnt. Co2 is a greenhouse gas that contributes to enhanced green house effect, causing climate change.
process of eutrophication of water
- increased availability of nitrate and other ions (Excessive nutrients from fertilizers, run of from land to water, and untreated sewage)
- increased growth of producers (Aquatic plants grow rapidly)
- increased decomposition after death of producers (rapid growth of Algae)
- increased aerobic respiration by decomposers (Growth of Algae prevents sunlight from entering water, thus oxygen levels fall)
- reduction in dissolved oxygen (As decomposition rate increases due to aerobic respiration of decomposers reducing dissolved oxygen)
- death of organisms requiring dissolved oxygen in water ( as there is a reduction in dissolved oxygen in water)