Biodiversity, Preservation and Conservation - Biodiversity Flashcards
(36 cards)
define biodiversity
- refers to the variety of complexity of life
- a measure of variety of genes and habitats, and the number of different species of organisms
what are the three aspects of biodiversity
- habitat biodiversity
- species biodiversity
- genetic biodiversity
define habitat biodiversity
the number of different habitats found within an area
each habitat can support a number of different species
define habitat
the place where an organism lives
give examples of habitat biodiversity in the UK
- meadow
- woodland
- sand dunes
- stream
define species biodiversity
a measure of diversity within the community
it takes into account both species richness and species evenness
define species richness
the number of species found in a habitat
define species evenness
the number of individuals of each of the different species in a habitat
what does a high species diversity index indicate
large numbers of species with a relatively even spread of individuals
define genetic biodiversity
the variety of genes that make up a species
the more alleles present in a population, the more genetically biodiverse it is
what can genetic biodiversity lead to
different characteristics
why is genetic biodiversity important for the survival of a species
- change in environment
- greater variety of alleles in a species
- more chance that some individuals have an advantageous allele
- those individuals are more likely to survive and reproduce, passing on advantageous alleles
what are the factors affecting biodiversity
- human population growth
- deforestation
- agriculture
- invasive species
- over-exploitation
- pollution
- climate change
- disease
how does human population growth affect biodiversity
- human population is growing at a dramatic rate
- demand for food, houses, transport and goods has led to the destruction and fragmentation of habitats, pollution, climate change and extinction
how does deforestation affect biodiversity
- occurs for timber, fuel and land
- reduction of overall biodiversity when clear felling rainforest or reduction of species diversity is harvesting for just one type of tree
how does agriculture (monoculture) affect biodiversity
natural vegetation is clear and may be replaced with monoculture, destroying habitats and greatly reducing biodiversity
how does agriculture (fragmentation) affect biodiversity
natural habitats may be fragmented, leaving some populations too small to survive
how does agriculture (insecticides) affect biodiversity
use of insecticides and herbicides to improve crop yield directly kills species and has a knock-on effect along the food chain
how does agriculture (hedgerows and selective breeding) affect biodiversity
- larger fields have led to loss of hedgerows, reducing plant species diversity and habitats
- selective breeding reduces genetic diversity
how do invasive species affect biodiversity
introduced species may increase rapidly in number and reduce native populations due to predation and competition
how does over-exploitation affect biodiversity
species are harvested faster than they can replenish themselves
how does pollution affect biodiversity
- fertilisers and sewage
- litter
- plastics
- oil
how does climate change affect biodiversity
- species with low genetic variation may be unable to evolve to adapt to the changes in temperature and rainfall
- melting ice caps and rising sea levels could lead to habitat loss and extinction
how does climate change (xerophytes) affect biodiversity
higher temperatures and lower rainfall may lead to xerophytes becoming more dominant, causing changes to the whole ecosystem
