investigating biodiversity Flashcards
What is intraspecific variation?
Differences in characteristics between individuals, within a species
What is interspecific variation?
Differences in characteristics between different species
What could variation within a species could be the result of? [3]
- Genetic factors (i.e. different alleles)
- Environmental factors
- A combination of both
What is Continuous Variation? [5]
- No distinct categories
- Data teds to be quantitative
- Controlled by many genes
- Strongly influenced by the environment
- Example: height
What is Discontinuous Variation? [5]
- Distinct, discrete categories
- Data tends to be qualitative
- Controlled by a single gene or a few genes
- Unaffected / not strongly influenced by the environment
- Example: blood groups
What is the difference between Quantitative & Qualitative data?
Quantitative > Is measurable, telling us how many, how much, or how often in calculations.
Qualitative > Qualitative data is interpretation-based, helping us to understand why, how, or what happened behind certain behaviours
How can Genetic Diversity be determined? [3]
By comparing…
- The frequency of measurable / observable characteristics
- The base sequence of DNA and mRNA
- The amino acid sequence of the proteins encoded by DNA and mRNA
How were early estimates of genetic diversity made?
Early estimates of genetic diversity were made by looking at the frequency of measurable / observable characteristics in a population
What were the limitations of early methods of estimating genetic diversity? [2]
- Many observable characteristics are coded for by more than one gene (polygenic) → difficult to distinguish one from another
- Characteristics could be modified by the environment → differences may be as a result of different environmental conditions rather than different alleles
Mark-Release-Recapture Method [6]
- Capture a large number of sample organism, count them
- Mark using a suitable method that will not endanger their chances of survival (nail polish, UV pen)
- Release and allow to mix back amongst the population
- After a day or 2 recapture another large sample
- Count the total number caught and how many of those are marked
- Use the formula to calculate population size:
(total of first captured population X total of second captured population) / number of marked individuals recaptured
How can a representative sample be taken? [2]
Random Sample
- eliminates bias
- e.g. using grid co-ordinates and a quadrat
Large sample size
- Minimise effects of chance
- Anomalies have less influence and can be identified
Species Diversity
The number of different species present in a
community (including the number of individuals of
each species)
Species Richness
The number of different species in a community
(this doesn’t consider the number of individuals of
each species within an area)
Simpson’s diversity index [4]
D = Simpson’s diversity index
Σ = the sum of
N = the total number of individuals recorded in a sample
n = the number of individuals of each species
Removal of Hedgerows - advantages [3]
- Increases space for crop growth
- Removes shading
- No hedge maintenance
