Zusammenfassung der Ressource
Variation
- Sampling
- Large sample size
- More reliable data
- smaller probability of
chance occurring and
influencing the results
- Data analysis
- statistical tests to determine the extent
to which chance may affect the data
- Chance
- pure chance that the
individuals are not
representative
- Sampling bias
- random sampling is the best
way to prevent sampling bias
- unrepresentative
choices either
deliberately or unwittingly
- Genetic factors
- Mutations
- sudden changes in the
genes may be passed on to
offspring
- Meiosis
- mixes genetic
material before
fertilisation so all
gametes are
different
- Fusion of gametes
- offspring inherit some
characteristics from each
parent, therefore are different
- which gametes fuse is a random process,
further adding to the variety of offspring that
two parents produce
- Environmental influences
- affect the way that the organism's genes
are expressed
- Classification of
characteristics
- Due to genetic factors
- a few distinct forms - no intermediate types
- Due to
environmental influences
- form a continuum. e.g.
height and weight
- can be plotted on a normal
distribution curve (bell-shaped)
- Normal distribution
- Mean
- measurement at the
maximum height of the
curve
- Standard deviation
- measure of the width of the curve
- Types of variation
- IntERspecific variation
- the difference between species - a giraffe isn't the same
as a sloth
- IntRAspecific variation
- the difference within a
species - no two humans
are the same