Module 4.2.1 - Biodiversity Flashcards
What is biodiversity?
The number of different ecosystems and habitats in an area, the number of species within those ecosystems and the genetic variation within each species
What are the 3 levels of biodiversity?
- habitat
- species
- genetic
What is habitat biodiversity?
The number of different habitats in an area, includes both abiotic and biotic factors
What are abiotic factors?
- air
- soil
- salinity
- temperature
- humidity
- light
- water
- minerals
- pH
What are biotic factors?
- food webs
- competition
- availability of food
- predators
- parasitism
What is species biodiversity?
Number of different species (species richness) and abundance of each species (species evenness) in an area#
- 2 habitats may have equal number of different species but representation in 1 may be dominated by 1 or 2 species
What is genetic biodiversity?
Variation of alleles within species/population of species
- greater genetic biodiversity within species allows for better adaptation to a changing environment and more likely result in individuals who are resistant to disease
- often limited in small populations where there are more chance of inbreeding
What is sampling?
Taking measurements of a limited number of individual organisms present in a particular area
What must sampling be a representive of?
- size of area or length of transect
- incorporation of repeat measurements
- accounting for different times of year
What ways are quadrats used to assess abundance?
- species frequency
- species density
- percentage cover
What is species frequency?
Calculates % of quadrats that include each species
What is species density?
Number of individual organisms within a quadrat
What is random sampling?
Taken to avoid bias in locations for sampling, dividing area into gird and using random number generator to determine coordinated for sampling. Ensures each sample site has some probability of being chosen
What is percentage cover?
% of area of quadrat in which plant or animal occur, ideal for species such as grass high in abundance
What are 3 types of non-random sampling?
- opportunistic
- stratified
- systematic
What is opportunistic (non-random sampling)?
- weakest form of sampling
- researcher makes decisions from prior knowledge
- may deliberately sample an area they know contains particular species
- quicker/easier
What is stratified (non-random sampling)?
Habitat divided into areas and sample from each area separately
What is systematic (non-random sampling)?
- samples are taken at fixed intervals across habitat
- used to investigate effect of a changing factor on biodiversity (such as soil, pH, moisture)
- other species may be missed
- clear gradient in environmental factor
e.g. belt transect, interrupted belt transect, line transect
What ca be used to sample animals?
- beating tray
- pooter
- sweep net
- pond net
- pitfall traps
What is the process of the capture-mark-release-recapture method?
- capture certain number of animal species and mark them, this is the first sample (S1)
- release animals back into environment
- after suitable length of time to allow the mixing of population, repeat same sample technique
- some individuals caught in second sample (S2) will be marked individuals and others unmarked
- smaller the number of marked individuals, the larger the population size
What can be used to estimate population using capture-mark-release-recapture method?
The Lincoln Index:
Population size = (S1) x (S2)
—————-
(S2)
What is the Lincoln Index?
Population size = (S1) x (S2)
—————-
(S2)
What does the Index being closer to 1 mean?
More diverse the habitat and greater ability to cope with change
What equation is used to calculate biodiversity?
D = 1 - Σ n^2
—-
N^2
What does low Index values (closer to 0) mean?
Habitat is less stable and more likely to be damages by change
What is the types of food webs in low and high biodiversity?
Low - relatively simple
High - complex
What is the number of successful species in low and high biodiversity?
Low - relatively few
High - large number
What is the nature of the environment in low and high biodiversity?
Low - stressful/extreme with few ecological niches
High - benign/not stressful, more ecological niches
What is the adaptation of species to the environment in low and high biodiversity?
Low - few species live there. very specific adaptations for environment
High - many species live there, few specific adaptations to environment
What is the effect of a change to environment on ecosystem as a whole in low and high biodiversity?
Low - major effects on ecosystem
High - often relatively small