Back to AI Flashcard MakerBiology /OCR Biology A - 4.2.1 - Biodiversity Part 1
Biodiversity
Measure of how varied life on earth is
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Key Terms
Term
Definition
Biodiversity
Measure of how varied life on earth is
3 types of biodiversity
Habitat Species Genetic
Genetic diversity
Measure of how many variations that are in the genetic code between individuals in spp. or diff spp
Species diversity
Measure of how many diff species are present
Species
Share common physiological, anatomical and behavioural characteristics Can interbreed to produce fertile offspring
Hybrid
Produced by diff species but are infertile
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| Term | Definition |
|---|---|
Biodiversity | Measure of how varied life on earth is |
3 types of biodiversity | Habitat Species Genetic |
Genetic diversity | Measure of how many variations that are in the genetic code between individuals in spp. or diff spp |
Species diversity | Measure of how many diff species are present |
Species | Share common physiological, anatomical and behavioural characteristics Can interbreed to produce fertile offspring |
Hybrid | Produced by diff species but are infertile |
Community | Several populations of diff spp living in a habitat at a certain time |
Habitat | Place where organisms live at a certain time |
Population | The amount of spp living in a habitat at a certain time |
Endemism | Group of organisms unique to one particular habitat (geographically discrete) |
Things to consider when sampling | Size of samples No. of samples Sampling technique used Ways to not disturb the habitat |
Random sampling | Uses a calculator to generate random numbers which can be used as coordinates on an imaginary grid |
Opportunistic sampling | Involves using prior knowledge to select sample sites or changing the sampling strategy on site |
Stratified sampling | Involves carrying out samples in each recognisable sub-habitat |
Systematic sampling | Involves carrying out sampling at fixed intervals in each distance |
Methods of using quadrats | Point sampling - counting species touching quadrat Grid sampling - estimating how many smaller squares are occupied by each species |
Methods to sample animals | Longworth trap (mark, release, recapture) Observation Pitfall trap Tullgreen funnel (invertebrates living in leaf litter) Sweep net and kick sampling Pooters Tree beating |
Measures of species diversity | Species richness Species evenness |
Species richness | No. of diff types of species in a particular area. The greater the number of spp, the ‘richer’ the area |
Species evenness | How evenly each species is represented throughout a habitat |
What does a high Simpson’s index indicate | Habitat with high diversity High species evenness and richness May survive disruption (introduction of new disease or competition) Should be conserved |
When is genetic diversity increased | When there is more than one gene variant (allele) for a particular locus |
Factors affecting biodiversity | Human population growth Increasing use of agriculture (monoculture) Climate change |
Reasons for maintaining biodiversity | Ecological Economic Aesthetic |
Ecological reasons for maintaining biodiversity | Regulation of O2 and CO2 in the atmosphere Soil formation and retention Protecting keystone species Maintaining genetic resource |
Economic reasons for maintaining biodiversity | Pollination of crops depends on bees Unknown species may be effective medicines Growth of food and timber relies on correct functioning of ecosystem To avoid soil depletion (continuous monoculture) Natural predators to pests reduce the need for pesticides |