4.2.1 - BIODIVERSITY Flashcards
Define Biodiversity
The variety of living organisms in an area
Define Species
A group of similar organisms able to reproduce to give fertile offspring
Define Habitat
The area inhabited by a species. It included the physical factors, like the soil and temperature range, and the living (biotic) factors, like availability of food or the presence of predators
Define Habitat Diversity
The number of different habitats in an area.
e.g. a particular area could contain many different habitats - sand dunes, woodland, meadows, streams, etc..
Define Species Diversity
The number of different species (species richness) and the abundance of each species (species evenness) in an area
e.g. a woodland could contain many different species of plants, insects, birds and mammals
Define Genetic Diversity
The variation of alleles within a species (or a population of a species)
e.g. the variation of alleles within the dog species gives rise to different breeds, such as a Labrador or poodle
Define Species Richness
The number of different species in an area. The higher the number of species, the greater the species richness. It is measured nu taking random samples of a habitat + counting the number of different species
Define Species Evenness
A measure of the relative abundance of each species in an area. The more similar the population size of each species, the greater the species evenness. Measured by taking random samples of a habitat, and counting the number of individuals of each different species
What are the three types of non-random samples?
- Systematic sampling
- Opportunistic sampling
- Stratified sampling
What is systematic sampling?
Samples are taken at fixed intervals, often a long a line (every nth specimen). E.g. if you were counting plant species in a field, quadrats could be placed along a line (transect) from an area of shade in the corner to the middle of the field. Each quadrant would be a sample site
What is opportunistic sampling?
Samples are chosen by the investigator. Simple but biased
What is stratified sampling?
When different areas in a habitat are identified and sampled separately in proportion to their part of the habitat as a whole. E.g. a heathland may have patches of gorse in it - the heath and gorse areas would be sampled separately according to how much of each there was in the habitat
What are the different types of sampling techniques?
Pitfall trap
Pooter
Tullgren funnel
Kick sampling
Sweep net
What is a pitfall trap?
A small pit that insects can’t get out of
What is a pooter?
A device that allows you to safely suck small insect through a tube into a jar
What is a Tullgren funnel?
Soil or leaf litter sample is put on a mesh filter at the top of a funnel and a light is shone down onto it. Organisms move away from the heat created by the light and fall out of the funnel and into a collecting beaker
What is kick sampling?
Gently kick the bottom of a stream then use a net to collect the organisms that have been disturbed
What is a sweep net?
A net lined with a strong cloth on a pole
When would random sampling be used?
To avoid bias in results
E.g. looking at a plant species in a field, you could pick random sample sites by dividing the field into a grid using measuring tapes and using a random number generator to select coordinates
When would non-random sampling be used?
When there’s a lot of variety in the distribution of species in the habitat and you want to make sure all the different areas are sampled
How to calculate Simpson’s Index of Diversity?
D = 1 - (∑(n/N) ²)
n - total number of individuals of one species
N - total number of organisms of all species
∑ - ‘sum of’ (i.e. added together)
What is a locus?
Alleles of the same gene are found art the same point on a chromosome
What is polymorphism?
A locus that has two or more alleles
What is the calculation for proportion of polymorphic gene loci?
Proportion of polymorphic gene loci = number of polymorphic gene loci/total number of loci
What are factors affecting global biodiversity?
- Human population growth
- Increased use of monoculture in agriculture
- Climate change
How does human population growth affect global biodiversity?
- Habitat loss - human development is destroying habitats (e.g. deforestation in the Amazon for grazing and agriculture). Decreases habitat diversity
- Over-exploitation - A greater demand for resources (e.g. food, water + energy) means resources used up faster than replenished
- Urbanisation - Sprawling cities are major road developments can isolate species, meaning populations are unable to interbreed and genetic diversity is decreased
- Pollution - High amounts of pollutants can kill species or destroy habitats, e.g. high levels of fertiliser flowing into a river can lead to a decrease in fish species in that river
How does increased use of monoculture in agriculture affect global biodiversity?
- Habitats are lost as land is cleared to make way for large fields, reducing habitat diversity
- Local and naturally occurring plants and animals are seen as week and pests, and so are destroyed with pesticides and herbicides, reducing species diversity
- Heritage (traditional) varieties of crops are lost because they don’t make enough money + so are not planted anymore - reduces species diversity
How does climate change affect global biodiversity?
- Climate change is the variation in the Earth’s climate, e.g. things like changes in temperature and rainfall patterns
- Occurs naturally, but the scientific consensus is that the climate change we’re experiencing at the moment is caused by humans increasing emissions of greenhouse gases (e.g. carbon dioxide)
- Greenhouse gases cause global warming (increased global average temperature) which causes other types of climate change, e.g. changing rainfall patterns
- Climate change will affect different areas of the world in different ways - some places will get warmer, some colder, some wetter and other drier. All of these may affect global diversity
Changes in climate may mean that areas that were previously inhabitable become uninhabitable (or vice versa). May increase or decrease range of some species (e.g. southern range limit of Sooty Copper Butterfly moved 60 miles north in recent decades)
Species may be forced to migrate, changing species distribution + decreasing biodiversity in the areas the species migrate from
If there is no suitable habitat to migrate, the species is a plant and can’t migrate, or the change is too fast, the species may become extinct (e.g. corals - they die if water temp changes by 1 or 2 degrees)
Define interdependence
Species depend on each other to survive
What is a genetic resource?
Any material from plants, animals or microorganisms, containing genes, that we find valuable
Give and explain ecological reasons for the conservation of biodiversity
- To protect species, including keystone species - Loss of a keystone species may disrupt food chains (some bear species feed on salmon, which feed on herring. If herring decline, salmon and bear populations are affected) and may disrupt nutrient cycles (e.g. decomposes like worms improve the quality of soil by recycling nutrients. If worm numbers decline, soil quality is affected, affecting plant growth
- To maintain genetic resources - they provide us with resources such as food, drink, clothing, drugs, fuels and other industrial materials. Genetic materials also allow us to adapt to changes in the environment (e.g. climate change may mean spoke crops can’t grow in areas there are now droughts. But can genetically engineer from crop that is resistant to droughts
Give and explain economic reasons for the conservation of biodiversity
- Reduce soil depletion - monoculture is growing a single variety of a single crop. If continued, involves planting the same crop in the same field without interruption. Causes soil depletion because nutrients required by the crop are gradually used up.
Give and explain aesthetic reasons for the conservation of biodiversity
- Areas rich in biodiversity provide pleasant, attractive landscapes that people can enjoy, by maintaining biodiversity we protect these landscapes
- The more biodiversity in an area, the more visitors the area is likely to attract - this has economic advantages
What are some methods of in situ conservation?
- Establishing protected areas such as natural parks and wildlife reserves
- Controlling or preventing the introduction of species that threaten local biodiversity
- Protecting habitats
- Promting particular species
- Giving legal protection to endangered species
What are some methods of ex situ conservation?
- Relocating an organism to a safer area
- Breeding organisms in captivity then reintroducing them to the wild when strong enough
- Botanic garden
- Seed banks
What are advantages of in situ conservation?
- Both the species and their habitat are conserved
- Larger populations can be protected and it’s less disruptive than removing organisms from their habitats
- The chances of a population recovering are greater than with ex situ methods
- Cheaper than ex situ methods
What are advantages of ex situ conservation?
- Can be used to protect animals in a controlled environment (hunting and predators can be managed)
- Can be used to reintroduce species that have left an area
What are disadvantages of in situ conservation?
- Can be difficult to control some factors that are threatening a species (e.g. poaching, predators, disease _ climate change
What are disadvantages of ex situ conservation?
- Usually only a small number of individuals can be cared for
- It can be difficult and expensive to create and sustain the right environment (animals that are used to human contact may be less likely to exhibit natural behaviour and more likely to catch a disease from humans
- Usually less successful than in situ methods - many species can’t breed successfully in captivity, or don’t adapt to their new environment
Describe how botanic garden help in the conservation of biodiversity.
Controlled environment sued to grow a variety if rare koans for the purposes of conservation, research, display, and education. They are watered a healthy amount and fertilised
Describe how seed banks help in the conservation of biodiversity.
Seeds can be frozen and stored in seed banks for over a century without losing fertility. Seed banks provide a useful source of seeds if natural reserves are destroyed (e.g. by disease or natural disasters)
Describe how protecting habitats helps in the conservation of biodiversity.
Allows organisms to continue living in their natural habitat (e.g. controlling water levels to conserve wetlands and coppicing (trimming trees) to conserve woodlands
Describe how promoting particular species helps in the conservation of biodiversity.
Could be protecting food sources or nesting sites
Give 2 examples of international conservation agreements made to protect species + habitats
- Rio Convention on Biological Diversity (CBD)
- Convention on International Trade in Endangered Species (CITES)
Give 1 example of a local conservation agreement made to protect species + habitats
The Countryside Stewardship Scheme (CSS)
What is CBD + how does it help top conserve endangered species?
- Aims to develop international strategies on the conservation of biodiversity + how to use animal and plant resources in a sustainable way
- Made it part of international law that conserving biodiversity is everyone’s responsibility
- Provides guidance to governments on how to conserve biodiversity
What is CITES + how does it help top conserve endangered species?
- An agreement designed to increase international cooperation in regulating trade in wild animals + plant specimens
- Member countries all agree to make it illegal to kill endangered species
- Helps to conserve species by limiting trade through licensing + making it illegal to trade in products made from endangered animals (e.g. rhino ivory)
- Raises awareness of threats to biodiversity through education
What is CSS + how does it help top conserve endangered species?
- Introduced in 1991
- Aimed to conserve wildlife + biodiversity, + improve & extend wildlife habitats by promoting specific management techniques to landowners
- Government offered 10-year agreements to pay landowners who followed management techniques they suggested
^— e.g. to regenerate hedgerows, to leave grassy margins around the edges of fields where wildflowers could grow + to graze upland areas to keep down bracken - Year 2000, there were 10000 agreements in England
- Since introduction, various species have begun to rebuild in numbers (incl. birds: stone curlew, black grouse, bittern)
