How have humans increased food production?
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How have humans increased food production?
Food production has been increased using:
agricultural machinery
chemical fertilisers
insecticides
herbicides
selective breeding
Define the term monoculture.
Monoculture is the practice of growing a single crop species on an area of land.
What are the advantages of large scale crop monocultures?
Advantages of crop monocultures include:
farmers can choose the right crop to suit the specific growing conditions
higher yield
the same chemicals can be used to treat the entire field
True or False?
Monocultures are beneficial to wildlife.
False.
Monocultures can harm wildlife as they lead to reduced biodiversity.
What are the disadvantages of crop monocultures?
Disadvantages of monocultures include:
reduced biodiversity
all of the crop is susceptible to the same diseases / pests
specific soil nutrients can become depleted over time
Define the phrase intensive farming
Intensive farming is a method of farming that aims to maximise production within a limited land area. An example is the raising of livestock in confined spaces.
True or False?
Allowing livestock to move freely increases food production efficiency.
False.
Limiting livestock movement increases food production efficiency by reducing energy used for movement; this energy can instead be used to fuel growth.
What is a potential drawback of keeping livestock in confined spaces?
Drawbacks of keeping livestock in confined spaces include:
disease can spread easily among the animals
animals may be distressed, resulting in poor welfare
animals may become aggressive and injure each other
Define the term biodiversity.
Biodiversity is the number of different species found in a habitat.
How do humans cause habitat destruction?
Humans cause habitat destruction by:
increasing land use for development and agriculture
resource extraction, e.g. mining and deforestation
releasing pollution into freshwater habitats or the ocean
True or False?
Human activities can alter food chains and food webs.
True.
Human activities can remove species from food chains, disrupting food webs and having harmful effects on habitats.
What are the harmful effects of deforestation?
Harmful effects of deforestation include:
biodiversity loss
extinction of species
loss of soil
flooding
increased atmospheric carbon dioxide
What human activities can result in water pollution?
Human activities that result in water pollution are:
Release of untreated sewage into waterways
Allowing agricultural chemicals to run off fields into waterways
Describe the consequences of untreated sewage runoff into water systems.
Consequences of untreated sewage runoff into water systems include:
Aerobic microorganisms use nutrients in sewage to fuel respiration, depleting dissolved oxygen levels in the water and leading to the death of aquatic organisms
Toxic chemicals in sewage can kill aquatic organisms
Dangerous microorganisms can be harmful to human health
Define the term eutrophication. (Extended Tier Only)
Eutrophication is the process by which increased nutrient availability in a body of water leads to a decrease in dissolved oxygen levels.
Describe the process of eutrophication. (Extended Tier Only)
The process of eutrophication is as follows:
Nutrient runoff results in increased plant growth at the water surface
Many aquatic plants die because new plants block the light and plants growing in deeper water cannot photosynthesise
Bacteria feed on dead plants and algae, using the dead matter to fuel respiration
High rates of aerobic respiration depletes oxygen levels in the water
Other aquatic organisms die due to a lack of oxygen
How can plastic pollution affect terrestrial and aquatic environments?
Plastic pollution can affect the environment as follows:
it can injure wildlife
it can break apart into microplastics which enter the food chain
it can degrade and release toxins into the environment
What human activities increase atmospheric carbon dioxide levels?
Carbon dioxide is released by human activities such as:
Burning fossil fuels
Burning organic matter, e.g. wood and other plant materials
True or False?
Methane is a greenhouse gas.
True.
Methane traps more radiation per molecule than carbon dioxide, so is a powerful greenhouse gas.
What human activities result in increased atmospheric methane?
Human activities that increase atmospheric methane are:
Farming cattle, which release methane as they digest grass
Growing rice in paddy fields
Disposing of waste in landfill
How does the release of methane and carbon dioxide into the atmosphere affect the environment?
Methane and carbon dioxide are greenhouse gases, so their release causes an enhanced greenhouse effect, leading to climate change.
What makes a resource sustainable?
A sustainable resource is one that can be produced as rapidly as it is harvested; this means that it will not run out.
What are some examples of natural resources that can be managed sustainably?
Examples of resources that can be managed sustainably include:
forests
fish stocks
How can forests be conserved? (Extended Tier Only)
Forests can be conserved as follows:
educating the public
assigning forests protected area status
introducing harvesting quotas
replanting trees
How can fish stocks be conserved? (Extended Tier Only)
Fish stocks can be conserved as follows:
educating the public
limiting the times of year during which fish can be harvested
assigning marine habitats protected area status
controlling the net types and mesh size used
introducing fishing quotas
monitoring fishing procedures and fish populations
What is an endangered species?
Endangered species are plants or animals at risk of extinction.
What are some of the factors that contribute to species becoming endangered?
Factors that contribute to species becoming endangered include:
climate change
habitat destruction
hunting
overharvesting
pollution
introduced species
What are some of the methods by which endangered species can be conserved?
Conservation methods include:
monitoring populations
protecting habitats
educating the public
captive breeding programmes
seed banks
How can breeding programmes be used to conserve endangered species?
Breeding programmes can be used to increase the reproductive success of endangered species in captivity; this can help to increase their population size and genetic diversity.
True or False?
A seed bank is a location where many plant species are grown in captivity.
False.
A seed bank is a collection of seeds from many plant species.
Why is conservation important?
Conservation is importance because it:
maintains or increases biodiversity
reduces extinction
protects vulnerable ecosystems
maintains ecosystem functions
What are ecosystem functions?
Ecosystem functions are the natural ecosystem processes and features that benefit humans, e.g.
nutrient cycling, e.g. locking up carbon in the soil and maintaining soil nutrient content
resource provision, including food, drugs, fuel and genes
True or False?
Artificial insemination and IVF are important for the conservation of endangered species.
True.
Artificial insemination and IVF are important processes in captive breeding programmes.
Why is maintaining population size essential in reducing the risk of extinction?
Maintaining population size is important because a large population is more likely to be genetically diverse. Genetically diverse populations are more likely to be able to respond to change and so are less likely to go extinct.