6.2.1: Variation
Not started yet — this one needs some love.
Differences in the characteristics of individuals in a population is called variation.
Variation may be due to genes inherited, conditions during development, or a combination of genes and the environment.
There is usually extensive genetic variation within a population of a species.
All variants arise from mutations.
Most mutations have no effect on the phenotype; some influence phenotype; very few determine phenotype.
Mutations occur continuously.
Very rarely a mutation will lead to a new phenotype.
If the new phenotype is suited to an environmental change it can lead to a relatively rapid change in the species.
Common exam mistakes
Variation can be genetic, environmental, or caused by both genes and the environment.
Mutations create new variants, but most mutations have no effect on phenotype.
Mutations occur randomly; the environment selects useful variants rather than causing useful mutations on purpose.
Do not call every unusual value an anomaly; use the data pattern and the scale on the graph.