3.1.1 - Biodiversity Flashcards
Biodiversity
what is biodiversity?
the variety of living organisms in an area including the genetic diversity, species diversity and ecosystem diversity
Biodiversity
what is genetic diversity?
the diversity of genetic characteristics (expressed or recessive) within a species allowing populations to adapt to environmental changes through the survival and reproduction of those that can withstand these changes
Biodiversity
what is species diversity?
the number and relative abundance of species found in a given biological organisation
Biodiversity
what is ecosystem diversity?
A variety of different habitats, communities and ecological processes and the interactions between them in its associated physical environment
Biodiversity
what are the 5 ways of measuring species diversity?
- species richness
- species evenness (relative species abundance)
- Simpson’s diversity index
- percentage cover
- percentage frequency
Biodiversity
what is species richness and how do you measure it?
- the number of different species in an ecosystem (no notice of how many of each species)
- measure by counting the number of types of animals/plants in the ecosystem
- e.g. beaver, frog, lizard = 3 species
Biodiversity
what is species evenness and how do you measure it?
- a measure of the relative abundance of the different species (how many individuals there are of each species)
- measuring diversity of community: a community dominated by one or two species is considered to be less diverse than one in which several different species have a similar abundance.
- measure by counting how many animals/plants there are of each type (the population of each species).
- e.g. 5 beavers, 2 frogs and 1 lizards = beavers are domaining community
Biodiversity
what is the simpson’s diversity index and how do we calculate it?
- a calculation measuring diversity that takes into account both richness and evenness.
- The probability that two individuals randomly selected from a sample will belong to the same species
- values range between 0 and 1, closer to 1 = greater diversity
what is the formula for SDI?
- SDI = 1 - (sum of n(n-1)/N(N-1))
- n = number of individuals
- N = total number of individuals
what is the significance of an SDI value close to 0?
number close to 0 = low species diversity:
- few successful species in the habitat
- stressful environment, few ecological niches, few organisms well adapted to environment
- simple food webs
- change in environment would have drastic effects
what is the significance of an SDI value close to 1?
number close to 1 = high species diversity:
- greater successful species and more stable ecosystem
- more ecological niches, less hostile environment
- complex food webs
- change in environment is less damaging
what is percentage cover and how do you measure it?
- an estimation of what percentage of the area enclosed by a quadrat is occupied by each species
- measure by counting number of squares species is present in (according to counting criteria)
what is percentage frequency and how do we measure it?
- the probability that a species will be found within a single quadrant
-the number of quadrant samples taken affects the reliability of results
what does spatial mean
the extent of the area being studied
what does temporal mean?
the duration of time being studied
- e.g. seasonally, annually
define the types of species interactions and there effect on each species involved:
1. mutualism
2. competition
3. predation
4. commensalism
5. amensalism
6. neutralism
Temporal Habitat Data
compare these ecosystems
- similarities
- differeces
- significance of any trend identified
Similarity: in both forests, soil respiration is lowest in Jan and highest in July. Also, in both forests, litterfall is lowest in Dec and highest in Oct.
Difference: There is less biomass in the soil of the secondary forest (SF) than the primary forest (PF).
Significance: Meaning soil respiration in the secondary forest (SF) is lower compared to the primary forest (PF).
Temporal Habitat Data Exam Style Q
Exploitation of the Great Artesian Basin, a water source that underlies 22% of Australia, has led to water shortages. From the given data, predict the speed of ecosystem change along in the basin.
a) Look at the x axis. Identify if the question is working at a local, national or global scale
b) The Great Artesian Basin is a national issue as it covers such a large area of the country.
c) The biggest driver here is located at the slow level of the y axis, therefore the speed of ecosystem change must be slow.
ANS = Slow
