4.2.1 - Biodiversity Flashcards
What is biodiversity?
the variety of living organisms in an area
What is the relationship between biodiversity and the stability of an ecosystem?
proportional to eachother
-more biodiversity there is, the more stable the ecosystem is
What different levels can biodiversity be considered on?
- habitat biodiversity (e.g. sand dunes, woodland, meadows, streams)
- species biodiversity (species richness and species evenness)
- genetic biodiversity (e.g. different breeds within a species)
What is habitat biodiversity?
the number of different organisms in an area
What is species biodiversity?
species richness (number of different species living in an area) species evenness (abundance of each species -comparison between the number of each different species)
What is sampling?
taking measurements of individual organisms present in a particular area
What is random sampling?
selecting individuals by chance
-each individual in the population has an equal likelihood of being selected
What is non-random sampling?
sample is not chosen by random
- opportunistic: uses organisms that are available conveniently at the time
- stratified: population is divided into sub groups and then a random sample is taken from each sub group proportional to its size
- systematic: different areas within an overall habitat are sampled separately
What is opportunistic sampling?
a type of non-random sampling where organisms that are conveniently available at the time are used
What is stratified sampling?
a type of non-random sampling where populations are divided into strata (sub groups) based on a characteristic and then a random sample is take from each strata proportional to its size
What is systematic sampling?
a type of non-random sampling where different areas within an overall habitat are identified and then sampled separately
-usually carried out by using a line or belt transect (quadrat moved along line
Name some sampling techniques for animals
- pooter (insects)
- sweep nets (insects in areas of long grass)
- pitfall traps (small, crawling invertebrates)
- tree beating (invertebrates in trees/bushes)
- kick sampling (organisms living in water)
- tullgren funnel (organisms in soil)
Name some sampling techniques for plants
- point quadrats
- frame quadrats
How do you increase the reliability of sampling?
- taking a large number of samples at a number of different points
- use random sampling (to reduce bias)
What is Simpsons index of biodiversity?
a better measure of biodiversity that takes species richness and evenness into account
What does a low/high value from Simpsons index of biodiversity mean?
0 = no diversity
1 = infinite diversity
(closer to 0 = lower biodiversity, closer to 1 = higher biodiversity)
How does genetic biodiversity occur within a species?
- there is little variation of DNA within a species
- all members have the same gene but different alleles
- differences in alleles creates genetic biodiversity
- more alleles present, the more genetically biodiverse a population
proportion of polymorphic gene loci (%) =
number of polymorphic gene loci
__________________________
total number of loci
What factors decrease genetic biodiversity?
- artificial cloning
- selective breeding
- captive breeding programmes
- rare breeds
- natural selection
- genetic bottlenecks
- the founder effect
- genetic drift
What factors increase genetic biodiversity?
- interbreeding
- mutations
What are polymorphic genes?
genes that have more than one allele
-the more polymorphic genes a species has, the more genetically biodiverse the species is
What factors affect biodiversity?
- human population growth
- agriculture (monoculture, chemicals, etc)
- climate change
What is monoculture?
when a large amount of biodiverse land is cleared and a single crop is plants
- only one species present
- less animal species can be supported (less food sources)
What reasons are there for biodiversity to be maintained?
- ecological (eg. protecting keystone species, maintaining genetic resources)
- economic (eg. reducing soil depletion from continuous monoculture)
- aesthetic (eg. protecting landscapes)
What are keystone species?
species that have a disproportionately large effect on their environment relative to their abundance
- affect many other organisms in an ecosystem and help determine species richness and evenness
eg. sea star
What is conservation?
the preservation and careful management of the environment and natural resources
What are the two types of conservation?
- in situ (in natural habitat)
- ex situ (not in natural habitat)
What is in situ conservation?
conservation in natural habitat
eg. wildlife preserve
What is ex situ conservation?
conservation not in natural habitat
eg. zoo
Name some examples of in situ conservation
marine conservation zones
wildlife reserves
Name some examples of ex situ conservation
seed banks
botanic gardens
zoos
Name some conservation agreements
- the Convention on International Trade in Endangered Species (CITES)
- the Rio Convention on Biological Diversity (CBD)
- the Countryside Stewardship Scheme (CSS)
What does Convention on International Trade in Endangered Species (CITES) do?
- issues an annual red list (conservation status of threatened animals) -makes it illegal to kill endangered species
- regulates trade of plant and animals species and their products -limits trade through licensing
What does the Rio Convention on Biological Diversity do?
- aims to develop international strategies on the conservation of biodiversity and how to use plant and animal resources in a sustainable way
- develop strategies on sustainable development
- stabilises greenhouse gas concentrations in the atmosphere
- aims to prevent transformation of fertile land into desert and reduce the effects of drought
What does the Countryside Stewardship Scheme (CSS) do?
- government pays land managers (like farmers) to enhance and conserve the English landscape
- sustaining the beauty and diversity of the landscape
- improving, extending and creating wildlife habitats
- restoring neglected land
- conserving archaeological and historic features
- improving opportunities for countryside development
What are the advantages of conserving plants as seeds compared to as adult plants?
- can be collected with minimal damage to wild population
- takes up little space
- can store greater genetic diversity
- lower maintenance
- easy to transport
- viable for long periods
- less susceptible to disease/environmental change
- prevents fertilisation by undesired pollen
Why is sampling important in measuring the biodiversity of a habitat?
- it is difficult to count every individual so sampling provides an estimate
- sample is representative of whole area
