Biodiversity Flashcards
(43 cards)
What is biodiversity?
The variety of living organisms present in an area
What different levels can biodiversity be studied at?
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
What is habitat biodiversity?
Refers to the number of different habitats found within an area
What are the 2 components of species biodiversity?
- Species richness
- Species evenness
What is species richness?
The number of different species living in a particular area
What is species evenness?
A comparison of the numbers of individuals of each species living in a community
What is genetic biodiversity?
Refers to the variety of genes that make up a species
How is species richness measured?
- Sample organism
- A list should be compiled of each speices identified
- Total number of species can be calculated
How is species evenness measured?
- Can be even or uneven based on the number of populations of each species
- Use frame quadrats
- Samples taken at a number of different points
- Calculate mean of individual qudrat
- Multiply mean value per m2 by the total area
How can an animal population size be estimated?
- Capture-mark-release-recapture
- Capture as many individuals of a species in an area as possible
- Organisms are marked and released back into community
- Time is allowed for organisms to redistribute themselves throughout the habitat before another sample of animals is collected
- The greater the number of marked individuals recaptured, the smaller the population
What are abiotic factors?
Non-living conditions in a habitat
Give 2 factors that increase genetic biodiversity
1- Mutations
2- Interbreeding
What is gene flow?
When an individual migrates from one population to another and breeds with a member of another population, alleles are transferred between the 2 populations
Give 8 factors that decrease genetic biodiversity
1- Selective breeding 2- Captive breeding programmes 3- Rare breeds 4- Artificial cloning 5- Natural selection 6- Genetic bottlenecks 7- Founder effect 8- Genetic drift
What is a genetic bottlenecks?
- A sharp reduction in the size of a population
- Could be due to a natural event, such as a flood
- Reduces gene pool
What is the founder effect?
Where a small number of individuals create a new colony, geographically isolated from the original
What is genetic drift?
Due to the random nature of alleles being passed on from parents to their offspring, the frequency of occurence of an allele will vary
What 3 human factors affect biodiversity?
- Human population growth
- Agriculture
- Climate change
How does human population growth affects biodiversity?
- Destruction of habitat, e.g. deforestation
- Separating populations, e.g. roads
- Unsustainable hunting/fishing, e.g. overfishing of cod
- Pollution
- Decreases habitat/species/genetic biodiversity
How does agriculture (monoculture) affect biodiversity?
- More land is needed to feed growing population
- Increased habitat destruction, e.g. deforestation
- Use of herbicides kills weeds
- Continuous monoculture causes soil depletion, reducing other plant species ability to survive
- Decreases habitat/species/genetic biodiversity
How does climate change affect biodiversity?
- Humans burn CO2, a greenhouse gas
- Weather patterns change
- Changes the abundance and distribution of species
- Some species will become extinct
- Decreases habitat/species/genetic biodiversity
Give 3 reasons why biodiversity should be maintained
1- Aesthetic reasons
2- Economic reasons
3- Ecological reasons
Describe the aesthetic reasons for why biodiversity should be maintained
- Enrich people’s lives
- Provides inspiration
- Recovery from stress and injury
Describe the economic reasons for why biodiversity should be maintained
- Resources for non-medical reasons (e.g. building materials)
- Ecotourism
- Continuous monoculture causes soil depletion, decreasing yields and requires more fertiliser
