4.1.2 biodiversity Flashcards
species diversity
number of different individuals within each species in a community
genetic diversity
variety of genes amongst all individuals in a population of one species
habitat diversity
range of different habitats
species richness
number of different species in a particular area at a particular time
species evenness
relative abundance of each different species within the community
polymorphic gene
more than one allele
how is genetic diversity investigated
examining polymorphic genes within isolated populations
what is the formula for calculating genetic diversity
proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
higher the proportion of polymorphic genes, larger the genetic diversity in population
what is the simpson’s index of biodiversity
way to look at biodiversity in different habitats
explain the simpsons index formula
N = total number of organisms of all species
n = total number of organisms of specific species
D = simpson’s diversity index
D = 1 - (sum of(n/N)^2)
what are the meanings of simpsons index results
calculated value always between 0 and 1
values closer to 0 have lower biodiversity, closer to 1 have higher biodiversity
opportunistic sampling
sampling organisms conveniently available - biased
stratified sampling
populations/habitats separated into groups to sample from
then take random samples from each group
systematic sampling
identifies different areas within habitat to sample from
often uses a belt transect to look at distributions of species within the habitat
quadrats
used to sample plants and slow-moving organisms
point quadrat
horizontal bar with holes along it at intervals, pins pushed through to touch ground and any species touching pin recorded
frame quadrat
square frame of known size, species at various coordinates recorded
density in recording data
counting all individuals present within quadrat
frequency in recording data
uses gridded frame quadrat with 100 squares
count how many squares out of 100 that species you’re investigating are present in
percentage cover
estimate percentage of entire quadrat covered by species
quick and subjective
sweeping nets
nets used to capture insects in long grass
pooters
used to capture small insects
two tubes connected to closed pot, investigator sucks on one tube and places other tube over insect, draws insect into pot
factors affecting biodiversity
human population
agriculture
climate change
how does human pop affect biodiversity
increasing at exponential rate
increased need for housing, farming and industry requiring deforestation
how does agriculture affect biodiversity
clearing land for agriculture destroys habitats and releases chemical pesticides or fertilisers into land
reduces number of habitats and range of food sources
how does climate change affect biodiversity
high global temperatures -
melting ice caps, habitats destroyed
sea level rising leads to flooding of habitats
lower rainfall means some species can’t survive
xerophytes outcompeting others as they can survive in harsher abiotic conditions
why is a reduction in biodiversity undesirable
ecological - interdependence is impacted
economical - soil erosion and monocultures mean less able to grow crops, tourism impacted, medicines production reduced
aesthetic - nature enriches people’s lives with creative inspiration and mental health
in situ conservation
happens within the habitat
genetic diversity maintained as individuals not bred captively
preventing extinction of one species positively impacts interdependent species
in situ examples
marine conservation zones
wildlife reserves
ex situ conservation
removing organisms from natural habitat to try and protect them
ex situ examples
botanical gardens
seed banks
captive breeding
CITES
Convention on International Trade in Endangered Species
- started in 1973
- 145 countries
- regulates trade of endangered animals, plants and products
- requires cooperation of countries, not always successful as it drives prices of banned substances up through illegal trading
CBD
Rio Convention on Biological Diversity
- started in 1992
- 172 nations
agreed that countries must:
- come up with strategies for sustainable development
- stabilise greenhouse gas emissions and concentrations
- prevent destruction of fertile land and reduce effects of drought
- share access to scientific knowledge and technology
CSS
Countryside Stewardship Scheme
- UK
- set up to protect and enhance natural environment
