Investigating diversity (3.4.7)
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Random sampling is a technique used to measure biodiversity in an area, where every part of the habitat has an equal chance of being sampled.
Random sampling reduces bias and provides a more representative sample of the habitat, because the investigator does not choose the sampling locations or the organisms to be sampled.
Genetic diversity within or between species can be assessed by comparing:
- Observable characteristics.
- DNA and mRNA base sequences.
- Amino acid sequences.
The greater the similarity between these features, the more closely related the organisms are and the lower the genetic diversity between them. Conversely, greater differences indicate higher genetic diversity and more distant evolutionary relationships.
To study variation within a species, scientists collect quantitative data, allowing objective comparison between individuals or populations.
The mean is calculated by adding all the values and dividing by the number of observations. It provides the average value (the central tendency) of the data and allows comparisons between different groups or populations.
Standard deviation measures the spread of data around the mean.
A small standard deviation indicates that data values are close to the mean (low variation). A large standard deviation indicates greater variability.
Standard deviation can be used to compare datasets and assess whether differences between their means are likely to be significant.
Means that are very different, with standard deviations that do not overlap, suggest a significant difference. If standard deviations overlap, the difference may be due to chance or natural variation.