Human Impact Flashcards
What is the definition of biodiversity?
Variety of species present in an ecosystem this can be calculated as the number of species in a specific area
What is extinction?
A natural process that has been taking place since life originated however currently the rate of extinction has increased rapidly due to human impact
Why does natural selection cause extinction?
When individuals less suited to prevailing conditions reproduce less successfully which cause numbers to decrease.
Human activities are causing habitats to change faster than new mutations allow species to adapt
What are examples of habitat destruction and how does this cause extinction?
Deforestation, drainage of wetlands, hedgerow loss
By reducing habitable areas populations decline as more species must compete over less
What are examples of overhunting that cause extinction?
Trophy hunting, traditional medicine practices, bush meat industry (where primates are killed for food), overfishing, agricultural exploitation
What examples of their competition from introduced species has caused extinction?
The dodo due to rats, North American crayfish has killed native UK crayfish and red squirrels have declined due to outcompeting by grey squirrels
How has pollution caused extinction?
Oil is sometimes accidentally discharged into the sea
Oil floats and prevents oxygenation of surface water and animals that breakthrough are covered by film of oil for example birds. These die due to their feathers clumping together and cannot provide insulation and oil washed up on beaches is ingested by shore animals which are poisoned by it
PCBs are ingested with food but they are neurotoxins carcinogens and home-made and disruptors and were banned in the UK however the waste was dumped in a quarry and not disposed of properly they are still detected in waste water from the site which animals eat
What is conservation?
Protection, preservation, management and restoration of natural habitats and that ecological community is to enhance biodiversity while allowing for suitable human activity
The sensible management of the biosphere and enhancement of biodiversity locally
What are examples of conservation techniques?
Habitat protection - nature reserves SSSI Restricting trade Breeding programmes and gene banks Education Legislation Ecotourism
How are habitats protected?
This protect species that live there and communities then active living gene banks.
These can be recognised as local nature reserve, National nature reserves, SACs (special areas of conservation), SSSIs (sites of special scientific interest) and these have legal protection and are managed and monitored
How is international cooperation conservation?
This is restricting trade in ivory or whaling
What example of gene banks are there?
Breeding programs in zoos and botanic Gardens, sperm banks which doesn’t need moving animals, seed banks, rare breeds societies, species re-introduction
What is involved in eco-tourism?
Recognising that mass travel is harmful globally and to specific habitats
Eco-tourism contributes to conservation efforts, employs locals to give money back to communities, educate visitors about the local environment and culture, cooperates with local people to manage and maintain natural areas
Why is it important to conserve species?
To conserve the existing gene pools
What are four reasons to conserve?
Ethical reasons
Agriculture and horticulture
Prevention of extinction
Potential medical uses
What are the ethical reasons behind conserving?
Each species represents a particular combination of genes and alleles adapted a particular environment and the uniqueness must be saved
What are the agriculture and horticulture reasons for conserving?
Selective breeding increases genetic uniformity and loses many alleles which might have had important qualities with resistance to certain weather or diseases and must be bread back into plants
Why is it important to conserve lots of different alleles?
If there is a change in environment certain alleles may provide an advantage to individuals and prevent the extinction of species
What are the potential medical reasons behind conservation?
Antibiotics and a lot of medicine are from fungi and synthesised from plants by conserving plants we may find a cure to more diseases
What is agricultural exploitation?
Agriculture is needed to produce food to feed the increasing human population however the way agricultural land is used cause conflicts with maintaining habitats and biodiversity
What does removing hedgerows do?
This makes larger fields enabling machinery different pet soil and harvest crops
However
It destroys habitats for birds and produces larger fields which are used for monoculture which reduces species diversity
What happens if the same crop is grown on the same plot year after year?
Yield progressively declines
Roots are always the same length and extract the same minerals from the same depth of salt which means that there is a huge increase in in organic fertilisers
Same species are always susceptible to the same pass which increases number of insecticide herbicides and fungicide is used
What is overgrazing by cattle unsustainable?
There hooves is compact soil driving out air and prevent water drainage and roots cannot penetrate the soil and grass cannot grow
Why is it bad to use a lot of pesticides?
Can kill pollinators and natural predators of bees
Can spread to other areas leading to contamination and poisoning
Why are natural fertiliser is not good for the environment?
Wash into water causing eutrophication
Fossil fuels are required to manufacture and transport them
Alter soil pH and reduce quality of the soil
What are the reasons for deforestation?
Timber is used for building material and feel
Land is cleared for farming to produce both use or grazing for cattle
New roads about to provide transport and infrastructure for these activities
Why is soil erosion a consequence of deforestation?
Tree roots bind soil together and deforestation allows heavy rain to sweep exposed topsoil to floodplains below topsoil is the fertile soil and what remains isn’t suitable for crop growth
What can deforestation of uplands cause on low lands?
Flooding
Why is non fertile soil a consequence of deforestation?
With no plants and water evaporates from the soil which returns as water vapour to the atmosphere more slowly than transpiration
Soil on deforested land becomes wetter
Water fills soil’s airspaces and oxygen is less available
It takes longer for wet soil to warm up then a dry so soils are also cold
Germination and root activity are reduced
Cold damp soil favours the growth of denitrifying bacteria so soil loses its fertility
Why is less rainfall a consequence of deforestation?
Water only returns to the atmosphere by evaporation and not transpiration which is faster this accelerates desertification
What are the effects on the atmosphere from deforestation?
As photosynthesising trees are cut down the removal of CO2 is decreased and burnt or left to decay release CO2
How does deforestation affect biodiversity?
It causes a lot of loss in habitat and this causes extinction which reduces biodiversity
What are three ways of forest management?
Coppicing
Selective cutting
Slash and burn
What is slash and burn?
A small forest area is cutting burnt and the ash is then used to fertilise the soil where crops are grown when it is no longer fertile the area is left to regenerate
What is coppicing?
A tree trunk is cut leaving a stall a few centimetres high
New shoots emerge from buds in the stall and grow into poles over years
Poles can be cut on rotation to produce timber of different widths
What is selective cutting?
This can be used to prevent soil erosion by filling only some trees and leaving others in place
What is overfishing?
The rate of which fish are harvested exceeding the rate at which they reproduce
What are the effects of overfishing on other wildlife?
When trawlers catch fish called capelin which are not eaten by humans but are an important prey species for cod which has contributed to the decline of cod stocks
Six countries have harvested Atlantic krill which are primary consumers eating phytoplankton and also the main diet of whales and seals penguins squid and fish affecting a wide variety of the food web
What are five methods which regulate fishing and allow breeding stocks to recover?
Controlling mesh size – allows young fish to swim through and survive and reproduce
Quotas – only a certain mass of fish can be bought to land however this means some trawlers are discarding excess
Exclusion zones – prohibiting fishing in certain times of the year to allowed for breeding and spawning
Legislations – controlling size of fishing fleet, number of days spent at sea and selling fish below a certain size
Fishfarming
What are the benefits of fish farming?
Fish convert their food into protein more efficiently than pork and beef
A greater portion of fish bodies are edible
Fish farming has a lower carbon footprint
Doesn’t deplete from wild fish stocks
What are the negative affects of fish farming?
Diseased fish – large doses of antibiotics and pesticides are used to keep fish healthy as they are have a high population density this can harm marine invertebrates
Pollution – eutrophication can be caused due to the large number of fish waste food excreta and fertiliser
Escape fish – found fish can outcompete wild fish for food habitats and mates they also transmit parasites and other infections and also deplete gene banks
Resource use – farm salmon eat three times that bodyweight fish feed which is made from other fish which are trawled
What is environmental monitoring?
It is establishes current status and is used for conservation
What is monitored?
Air quality monitoring
Soil monitoring
Water quality monitoring (chemical, biological, microbiological)
What are planetary boundaries?
Limits between which global systems must operate to prevent abrupt and irreversible environmental change
They are a safe operating space for humanity
What are the nine planetary boundaries and have they been crossed or not?
Crossed: Biodiversity boundary Climate change boundary (two core boundaries) Nitrogen boundary
Avoidable:
Land use boundary
Freshwater boundary
Ocean acidification boundary
Not quantified:
Chemical pollution boundary
Aerosol boundary
Avoided:
Ozone boundary
What is the climate change boundary?
This is from the addition of greenhouse gases affecting wind ocean currents rainfall patterns and temperature. This is causing a large change in habitats cause an animal extinction and also causing diseases to humans. The biofuel industry has been developed to reduce fossil fuel consumption
What are the disadvantages of biofuels?
The land could be used to grow food instead of producing biofuels which often monocultures
Stainable biofuel production relies on sustainable Ponting inefficient technical systems
Deforestation to grow biofuel crops causing soil erosion and biodiversity loss
Reduction water availability because biofuel crops require a large volume
Combustion of biofuel produces more nitrous oxide a greenhouse gas than fossil fuels
What are the three types of biofuels?
Bioethanol
Biodiesel
Biogas
