11 - Biodiversity Flashcards
What are the different levels of biodiveristy?
habitat biodiversity
species biodiversity
genetic biodiversity
What is habitat diversity?
the number of different habitats in an area
- e.g one area could contains lots of habitats
- sand dunes
- woodlands
- meadows
- streams
What is species diversity?
the number of different species (species richness) and abundance of each species (species evenness) in an area.
what is species richness?
the number of different species in an area.
what is species evennness?
the relative abundance of each species in an area.
what is genetic diversity?
the variation of alleles within a species (or a population of species).
How can sampling be used to measure biodiveristy?
- choose an area to sample (small area within a habitat).
- count the number of individuals of each species.
- repeat the process many times to get have a better representative of the whole habitat.
- use the results to estimate the total number of species and individuals in the habitat.
What tools do you use to sample different organisms for when measuring biodiversity?
plants: quadrat flying insects: sweep net ground insects: pitfall trap insects: pooter aquatic animals: net
Why are samples taken to measure biodiversity in a habitat?
- too time consuming to count every individual in a habitat.
- samples provide an estimate about the whole habitat.
what is random sampling?
- random sampling means selecting individuals by chance.
- each individual has an equal chance of selection.
- avoids bias
- measuring tapes to divide area into a grid.
- random number generator to generate random coordinates.
what is non-random sampling?
sample is not chosen at random.
systematic sampling
opportunity sampling
stratified sampling
what is systematic sampling?
- samples are taken at fixed intervals.
what is opportunistic sampling?
- samples are chosen by the investigator.
- bias
- simple to carry out
what is stratified sampling?
when different areas within a habitat are identified and sampled separately in proportion to their part of the habitat as a whole.
- different sub groups are called strata based on a particular characteristic.
reliability of sampling
never 100% reliable or representative
there may be bias or by chance the may not be representative.
Simpson’s index of diversity
used to calculate the biodiversity of a habitat
- takes into account both species richness and evenness.
- value between 0 and 1.
- 0 no diversity
- 1 infinite diversity.
- the greater the species evenness and richness, the higher the value.
genetic polymorphism
- used to measure genetic diversity.
- polymorphism describes a locus that has two or more alleles.
proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci.
examples of suitable populations
low genetic diversity
zoos (captive breeding)
rare breeds
pedigree animals
Factors affecting biodiversity
- human population growth
- agriculture (monoculture)
- climate change
factors that affect genetic biodiversity?
- mutations in DNA of an organism
- interbreeding between different populations
- selective breeding
- captive breeding
- natural selection
How does human population growth affect biodiversity?
- deforestation, destroying habitats
- over exploitation of resources
- urbanisation, can isolate species
- pollution can kill species or destroy habitats.
How does agriculture (monoculture) affect biodiversity?
- deforestation to increase land available for growing crops.
- use of chemicals such as insecticides/herbicides
- monoculture: growing a single variety of a single crop. Greatly lowers biodiversity as only one type of plant is present.
How does climate change affect biodiversity?
pollutants caused by human activity.
- greenhouse gases can cause global warming, which causes other types of climate change such as changing rainfall patterns.
- climate changes affect different areas of world in different ways: warmer, colder, wetter, drier. All have an affect on global biodiversity.
- climate change can make an area uninhabitable or inhabitable.
- can cause increase or decrease in range of some species in the area.
- increase/decrease diversity.
- can cause migration. Decreases biodiversity in original location, increases biodiversity in new location.
- if climate change occurs too fast or organisms cannot migrate, this can cause a species to become extinct. Decreases biodiversity.
Why do we maintain biodiversity?
ecological reasons:
- protecting keystone species (often predators).
- maintaining genetic resources (e.g plants for medicine)
economic reasons:
- to reduce soil depletion caused by continuous monoculture.
aesthetic reasons:
- protecting landscapes
- protecting exotic animals
- because they are nice to look at.
- attracts tourism / increases tourism
ecotourism
Why does a change in one organism in an ecosystem have drastic effects on the ecosystem?
- organisms in an ecosystem are interdependent.
- disruption of food chains
- disruption of nutrient cycles.
What is in-situ conservation
protecting species in their natural habitat.
e.g marine conservation zones, wildlife reserves
What is ex-situ conservation
protecting a species by removing them from their natural habitat and placing them in a new location
e.g zoos, seed banks, botanic gardens.
what are captive breeding programmes?
they produce offspring of species in a human-controlled environment.
Rio convention on biological diversity (CBD)
- develop international strategies on the conservation of biodiversity and how to use animal/plant resources in a sustainable way.
- international law that conserving biodiversity is everybody’s responsibility.
- guidance to governments on how to conserve biodiversity.
Convention on international trade in endangered species (CITES agreement)
- increase international cooperation in regulating trade in wild animals and plant specimens.
- illegal to kill endangered species in all countries.
- illegal to trade in products made from endangered animals.
- raises awareness of threats to biodiversity through education.
the countryside stewardship scheme (CSS)
- aim to conserve wildlife and biodiversity.
- 10 year agreements to pay landowners who followed management techniques.
- since 2000, 10000 agreements. Populations of various species have begun to regrow.
