Biodiversity 2 Flashcards
Why maintain biodiversity
Provide resources such as food and medical uses
Protect food webs maintain ecosystem
Aesthetic reasons
Reduce ability to grow crops - soil erosion from deforestation
High biodiversity protects against abiotic stresses
Why are monocultures bad
1 species same field lacking biodiversity more susceptible to disease
Leach off soil for nutrients and minerals
Efficient
Must rotate to improve quality of soil
CSS
Farmers have a grant from government to make land more biodiverse
CITES
Prevention of trade of exotic animals or those at risk of extinction
Rio convention
All development requires an environmental impact assessment
Ways biodiversity can be studied
Habitat biodiversity
Species biodiversity
Genetic biodiversity
Habitat biodiversity
No of different habitats that can be found within an area - greater the habitat biodiversity greater species biodiversity
Species biodiversity
-species richness - number of different species in an area
- species evenness - comparison of the numbers of individuals of each species living in a community
Genetic biodiversity
Variety of genes that make up a species
Species have the same number of genes however different alleles leads to genetic biodiversity within a species
More biodiverse better adapted to changing environment
Sampling techniques
Random - at chance (mark out grid random number generator coordinates)
Opportunistic - organisms conveniently available
Stratified - population divided into subgroups and random sample of these proportion to size
Systematic - line transect or belt transect - studland bay
Reliability of samples
Never entirely representative
Sampling bias - selection process may be bias - use random sampling
Chance - organism selected may not be representative of whole population - minimised by using a large sample size
Sampling animal techniques
Pooter - catch small insects
Sweep nets - catch insects in long grass
Pitfall traps - catch small crawling invertebrates
Tree beating - samples of invertebrates in tree
Kick sampling- river bank and bed kicked to disrupt substrate and organisms
Estimating animal population size
Capture mark release recapture
Greater the number of marked recaptured smaller the population size
Measuring abiotic factors
Can be measured quickly and accurately with specialised equipment eg pH probe
Human error is reduced
High level of precision
Data can be stored and tracked on a computer
How to calculate biodiversity
Simpsons index= 1-sum of (total no of a particular species/total number of all organism of all species)^2
Simpsons index value
0 represents no diversity and 1 represents infinite biodiversity
The higher the value the more diverse the habitat
Low biodiversity values
Low biodiversity habitats may not be able to support many species the ones present may be highly adapted to extreme environment
Important to conserve these habitats in order to conserve rare species that may not cope elsewhere
Importance of genetic biodiversity
Greater genetic biodiversity likely to adapt to changes in their environment less likely to become extinct
More likely some organisms carry an advantageous allele which enables them to survive
Factors that increase genetic biodiversity
Mutation in dna creating new alleles
Interbreeding between different populations- gene flow
Factors that decrease genetic biodiversity
Selective breeding
Captive breeding programs
Artificial cloning
Natural selection
Genetic bottlenecks - pop died reducing gene pool only survivors able to pass on genes
Founder effect - geographically isolated small gene pool
Genetic drift
Polymorphic genes
More than one allele
Proportion = no of poly gene loci/ total No of loci
Greater proportion greater genetic biodiv
Human influence on biodiversity
Deforestation - permanent removal of trees to provide wood and make space for building etc
Agriculture - land cleared and planted with monoculture
Climate change - release of CO2 and other greenhouse gases incr temp of planet damaging habitats
Positive human activity
Grazing animals planting hedges and managing woodland sheep grazing on down lands - maintains species survivals grass low level allows insects to survive
Maintaining biodiversity
In situ conservation - within natural
Ex situ conservation - out of natural
In situ
Wildlife reserves- control grazing human activity poaching halting succession removal of invasive species
Marine conservation zones prevent fishing in the area and build up populations
Ex situ
Botanic gardens
Seed banks - gene banks
Captive breeding programmes
(Some can’t be released into wild due to lack of resistance to disease behaviour genetic differences and habitat change)
