biodiversity Flashcards
what is biodiversity
the variety of life which is split into
1) genetic diversity= genetic variation in a species which often underlies behavioural and phenotypic diversity
2) species diversity = variety of species which comprise a biological community
3) community and ecosystem diversity= different biological communites and their associated ecoystems that comprise whole landscapes
how is genetic diversity brought about
1) DNA mutations cause different alleles which form different proteins causing different phenotype
what are the different concepts which underpin species diversity
1) biological species concept- a group of individuals which can potentially breed with other groups
2) morphological species concept- group of individuals that is morphologically, physiologically and biochemically distinct
3)evolutionary species concept- individuals that share unqiue similarities of their DNA and hence evolutionary past
- all definitons have benefits and difficultues e.g. morphology not alwasy good as different polymorphisms or some species looking very similar
discuss how many species there are
1.24 million eukaryotic species
- 1.05 on land and 0.19 in oceans
bias exists towards larger and more abundant/ widespread species
many new to science species have been long known by locals
small and cryptic species underrepresented
how is species diversity measured
1) some populations have the same number of species but different evenness
- simpsons diversity index = lower diversity is higher number
- shannons diversity index= higher diversity is a higher number
what do conservationists try to preserve
1) trophic structure, describe the amount of energy and biomass at each trophic level
- if disturbed = trophic cascade where loss of single species results in extinction of multiple species
2) food web complexity= to conserve species we also need to conserve those that they rely on
3) species composition
what is functional diversity
the variety of ecological functions that species perform in ecosystems
what is linkage density and connectance and how is it linked to food web complexity
1) linage density= average number of interactions between species
2) connectance = the proportion of all possible links between species that are realized
why is it important to maintain species composition
‘all species are the same but some species are more equal than others’
- some species more important to community/ecosystem
e.g.
ecosystem engineers which from habitats e.g. beavers
keystone species which have high impact on other species through their interactions with other species
there is an argument that people shoudl focus on species with higher impacts on the communties
define a biogeographic realm
large regions across the globe where organisms share common geologic and evolutionary histories and composed of biomes which are identified by dominant vegetation type or dominant physical processes
what are ecoregions
realms which are further divided down into units of land containing distinct assemblage of natural communtiies and species
what are the most diverse biomes
1) tropical forests= contain over 50% of world species
2) coral reefs= home to around 25% of world species
3) tropical lakes and rivers
4) mediterranean communties
why is biodiversity higher in tropical regions
- evolves through mutation, migration, natural selection and genetic drift which result in speciation and extinction
tropics have a greater area, greater productivity and more time (more stable climate)
what are the two different types of values which are needed in increase efforts to save species
1) intrinstic
2) extrinstic
3) instrumental
4) relational
outline intrinsic values
1) moral- value based on sense of right and wrong
2) ethical- value based on social norms and codes of conduct
3) religious- value based in belief of higher powers
