Biodiversity Flashcards
What is species richness?
number of species in an area
What is the definition for genetic diversity?
variety of alleles of different genes within a population
What is the definition for species diversity?
number of different species in a community and number of individuals of each species
What is species evenness?
number of individuals of each species
What is Simpsons index of biodiversity?
takes into account species richness and evenness
What is biodiversity?
the variety of living organisms in an area
How can genetic diversity be assesed?
sequence DNA and compare
What factors affect biodiversity?
temperature, nutrient content of soil, rainfall, sunlight, competition, fertilisers
What are direct impacts of farming on biodiversity?
removal of hedgerows (habitats)
filling in ponds or draining marshlands (habitats)
overgrazing of land (variety of nutrients in soil)
What are the indirect impacts of farming on biodiversity?
pesticides/fertilisers (eutrophication)
absence of crop rotation and lack of intercropping (soil can’t replenish)
What is the impact of agriculture on biodiversity?
number of species and genetic variation is decreased
What is the effect of reducing the diversity of plants?
less food/habitats for animals, so animal diversity is reduced
How can ecosystem diversity be increased?
replanting or maintaining hedgerows
digging ponds
producing hay from natural meadows
How can species diversity be increased?
biological control rather than pesticides
crop rotations
natural fertilisers (reduced risk of eutrophication)
Why is it more useful to calculate index of diversity rather than recording only one number of species present?
measures no. of individuals and species
some species are only present in small numbers
