Human Influences on the Environment Flashcards
How has modern technology resulted in increased food production?
- Modern technology such as harvesters means more land can be covered, so crops can be bigger and have a larger yield
- Fertilisers increase the plant quality by giving them all the nutrients they need
- Pesticides, insecticides and herbicides get rid of primary consumers that feed on the monoculture and other comperting species
- Greenhouses can control conditions to get the optimal conditions for plants to grow
- Selective breeding programmes to consistently produce high yields
What are the negative impacts on an ecosystem of large-scale monocultures?
- Damages the soil because the same nutrient is leached out of the ground constantly
- Lack of biodiversity
- Easy spread of disease
- Increase in specific pest populations – if a particular pest feeds on a crop, farming it in large areas repeatedly means there is an ample supply of food for the pest, causing the population to increase
- High input of chemical fertilisers and pesticides, which damage the environment, and may cause biomagnification. This can also cause resistence from the target, kill innocent animals or simply pollute water or soil.
What are the negative impacts on an ecosystem of intensive livestock production?
- High cost of production
- Labour intensive
- May lead to types of pollution such as high levels of waste being released into the water
- Increase in methane released
- Increased spread of disease
- Antibiotics must be used, leading to antibiotic resistance
What are the social, environmental and economic implications of providing sufficient food for an increasing human global population?
- Waste of foods in some areas, and lack of food in others
- Deforestation , extinction of species and decrease in biodiversity
- Profit for workers, economic growth
- Unequal distribution of wealth
Def. Monoculture
Given area of agricultural land only one type of crop is grown
Def. Selective breeding
The selection of plants and animals for breeding due to their useful characteristics, eg. High yield
(Synonym: Artificial Selection)
Def. Chemical fertilisers
An artificially made chemical used to increase crop growth or crop yield (eg: Nitrate, Phosphate, Potassium, Magnesium)
Def. Crop plants
Plants which are farmed by humans
Def. Land pollution
Presence in a terrestrial environment of a substance that has harmful or poisonous effects
What are the reasons for habitat destruction?
- Housing
- Agriculture
- Transport
- Natural resources
- Dams
State how humans can negatively impact habitats?
- Water pollution
- Air pollution
- Altering food webs via biomagnification, extinction, and invasive species
- Deforestation
What are the undesirable effects of deforestation on the environment?
- Decrease in biodiversity
- Increase in CO2 levels —> Greenhouse effect
- Flooding
- Soil erosion
- Extinction
- Air and Water Pollution (from transport of trees)
Explain the stages of the process of eutrophication
- Fertilisers are leached from farmland (aka agricultural runoff) into the water when they are in excess
- Plants start to grow more since they get nitrates, letting them create protein and therefore the majority of the plant structure, and photosynthesise normally
- Bacteria darts to bloom, covering the surface in a greenish sludge
- Sunlight from the sun is blocked, causing plants in the water to be starved of sunlight, rendering them unable to photosynthesise
- The bacteria increase in number, taking up all of the oxygen in the water, meaning it becomes anoxic
- All other non-bacterial forms of life die from lack of oxygen
What causes an increase in carbon dioxide and methane level in the atmosphere?
- Intensive livestock production
- Burning of fuelwood in homes
- Deforestation
- Energy production by burning fossil fules, e.g. coal, oil and natural gas
How has increasing the carbon dioxide and methane concentrations in the atmosphere caused an enhanced greenhouse effect?
The particles in greenhouse gases reflect heat (in form of infrared) back towards the earth
What are the consequences of global warming?
- Melting of glaciers, leading to rising sea levels
- Drought and lack of water, and drying up of lakes and rivers
- More extreme and unpredictable weather events
- Decrease in crop yields
What do we call resources that can not be replaced? Give some examples
Non-renewable resources
e.g.plastics made from petrol, petrol itself, natural gas, and coal
Fossil fuels are the raw material for what resources?
Plastics, petrol, gasoline, kerosene, bitumen, naphtha etc.
Some resources can easily be disposed of but can’t be reused or recycled. Give an example and explain why this is beneficial.
E.g. plastics - This is beneficial as it does not take much effort to get rid of the materials, gaining time
Some resources have the potential to be sustainable but aren’t always. Give examples.
- Wood - if used moderately, grows back at a steady and reliable rate - this does not work if resource is overexploited
- Water - It takes time for water to be purified and sent back into freshwater form - the entire water cycle - so if used too excessively, it can run out
- Animals e.g. fish - If over fishing occurs, fish populations decrease and eventually become extinct
What is bioaccumulation?
Across the different trophic levels, pesticides increase in concentration as organisms need to eat mor at higher levels, due to low energy efficiency of the transfer from trophic level to trophic level.
With increasing plastic pollution, what is the impact of bioaccumulation?
The microplastics that can be found in nature in low concentrations are picked up by small organisms, which then get eaten. The animal that ate it also ate many others, meaning there is more plastic in the same organism. As this continues, the plastic concentration increases until it becomes lethal.
