investigating diversity

Question 1

what is variation

Answer 1

differences in characteristics between individuals within a species (intraspecific competition) or between different species (interspecific competition)

could be result if
genetic factors
environmental factors
or combination

Question 2

what is continuous variation

Answer 2

no distinct categories
data tends to be quantitative
controlled by many genes
strongly influenced by environment
eg. height

Question 3

what is discontinuous variation

Answer 3

distinct discrete categories
data tends to be qualitative
controlled by a single or few genes
unaffected by environment
eg. blood group

Question 4

how can genetic diversity with or between species be measured

Answer 4

the frequency of measurable or observable characteristics
- indicated genetic diversity because it is based on the fact different alleles determine different characteristics
- so higher the variety of characteristics the higher the variation of alleles of that gene so higher genetic diversity

the base sequence is DNA and mRNA

the amino acid sequence is the proteins encoded by DNA and mRNA

Question 5

how and why has gene technology caused a change in methods of investigating genetic diversity

Answer 5

limitations with looking at observable characteristics
- many observable characteristics coded for by more than one genes -> vary continuously-> difficult to distinguish one from another
- characteristics can be modified by the environment so differences may be as a result of environmental conditions not alleles

gene technology has made it possible to directly obtain DNA sequences
more accurate
- different alleles of the same gene have slightly different gene base sequences —> comparing DNA base sequence of same gene in different organisms in a population—> find out how may alleles is that gene in population
- different alleles transcribed into slightly different mRNA base sequences and may produce polypeptides with slightly different amino acid sequences which can also be compared

Question 6

what do quantitative investigations of variation within a species involve

Answer 6

taking representative sample
- random sample, removes bias
divide area into a grid, use random number generator to generate coordinates, take samples at coordinates using quadrat

large sample size
- minimise effect of chance
- anomalies have less influence and can be identified

analyse with stats test
- see if variation observed is due to chance

calculate mean and standard deviation
- shows spread of values around mean
-68% is +- 1 SD
- 95% is +- 2SD

interpretation of mean and SD
- mean provides no info on range but shows if there is variation in samples
- SD the higher the value the higher the variation
- if any SD overlap differences may be due to chance