What are the different levels of biodiversity?
- habitat biodiversity
- species biodiversity
- genetic biodiversity
What is biodiversity?
- the variety of living organisms present in an area
Why is biodiversity important?
- maintains a balanced ecosystem for all organsims as they are all interdependent
- maintains the interconnected ecosystem
Why are ecosystems important?
- vital for human wellbeing, provides us with invaluable services e.g food, medicine, fuel
What areas have the most and least biodiversity
- tropical regions have the most biodiversity
- cold areas have the least biodiversity
What is an EIA?
- environmental impact assessment
- used to determine how major projects e.g. buildings will affect biodiversity in the area
What is habitat diversity?
- the number of different habitats found within an area
What are examples of habitat biodiversity?
- in the UK there is large habitat biodiversity as it contains many habitats including meadows, woodlands, streams, and sand dunes.
What is species biodiversity?
- the range of organisms found in a habitat
What is species richness?
- the number of different species living in a particular area
What is species evenness?
- a comparison of individuals of each species living in an area
What is genetic biodiversity?
- the variety of genes that make up a species
How do you measure biodiversity
- using Simpson’s index of diversity
What effect does high biodiversity have on an ecosystem?
- leads to a more stable ecosystem
How can genetic biodiversity be measured?
- no. of polymorphic gene loci / total number of loci
Why might low genetic biodiversity be harmful?
- can lead to inbreeding
How can the number of alleles increase, leading to increased genetic variation?
- mutations in DNA leading to new alleles interbreeding between different populations
What is gene flow?
- where an individual from one population breeds with another from a different population, transferring alleles
How can genetic variation be decreased?
- selective breeding - e.g pedigree animals
- captive breeding e.g zoos
- artificial cloning - asexual production in plants
- natural selection - only advantageous alleles are passed down
- in a genetic bottleneck where few individuals within a population survive an event or change so they are the only ones to pass on their alleles - gene flow is reduced
- founder effect - small number of individuals create a new colony, geographically isolated from the original - gene flow is reduced
- genetic drift - specific genes don’t get passed onto offspring due to chance
What is a polymorphic gene?
- a gene with 2 or more alleles
What are the human factors that affect human biodiversity?
- human population growth
- agriculture (monoculture)
- climate change
What are the three reasons for maintaining biodiversity?
- ecological
- economic
- aesthetic
What are the ecological reasons for maintaining biodiversity?
- interdependence e.g protecting keystone species
(disproportionately large effect on their environment in comparison to their abundance) - either modifiers (beavers) or hosts (cacti) - maintains genetic resource bank- important for gene flow
What are the economic reasons for maintaining biodiversity?
- loss of species with potential economic importance e.g medical
- continuous monoculture results in soil depletion - increased spending on fertiliser / decreased yield
- high biodiversity protects against abiotic stresses + disease
- ecotourism - economic advantages e.g coral reefs
- sustainable use of food and timber production - causes soil erosion and desertification
