Pearson Edexcel · GCSE · Biology
Course version: 1BI0 · Version from Sept 2016
State that there is usually extensive genetic variation within a…
Full specification wording
Topic 3 – Genetics: 3.22 State that there is usually extensive genetic variation within a population of a species and that these arise through mutations
A population is the group of individuals of one species living in a habitat.
Checked against the Pearson Edexcel 1BI0 specification (opens in a new tab) on .
- Point 19 of 20
Study notes
From the checked teaching notes for this specification point.
The idea
A population is the group of individuals of one species living in a habitat. Within such a group there is usually extensive genetic variation: individuals differ in their alleles, so they differ in features such as blood group, eye colour or disease resistance. First, genetic variation within a population is usually extensive. Second, this variation arises through mutations — changes in the base sequence of DNA that produce new alleles. Mutation is the original source of new alleles; sexual reproduction then shuffles existing alleles into new combinations. A mutation in a body cell affects only that individual, whereas a mutation in a gamete can be passed to offspring and so enter the population's gene pool.
What earns the marks
- States that there is usually extensive genetic variation within a population of a species.
- States that this genetic variation arises through mutations.
- Recognises mutation as a change in DNA base sequence producing new alleles.
- Distinguishes mutation (source of new alleles) from sexual reproduction (reshuffling of existing alleles).
- Recognises that a mutation in a gamete can be inherited and so spread through a population.
Common mistakes and how to put them right
Thinking variation arises mainly from mutation occurring in body cells.
Put it right: Only mutations in gametes can be passed on and contribute to variation in the next generation.
Confusing mutation with sexual reproduction as the origin of new alleles.
Put it right: Mutation creates new alleles; sexual reproduction only recombines alleles already present.
Exam tips
- Read the stem carefully to see whether it asks for the source of variation (mutation) or the reshuffling of alleles (sexual reproduction).
- Eliminate options that describe body-cell mutation as inherited, since these cannot increase variation in offspring.
- Check that the chosen option mentions both extensive variation and mutation, because the statement contains both clauses.
Try the lesson
The start of the Topic 3 – Genetics: 3.22 State that there is usually extensive genetic variation within a population of a species and that these arise through mutations lesson, made from checked teaching notes for this specification point.
Have a go first
Within a population of the same species, where does the genetic variation originally come from?
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Topic 3 – Genetics: 3.22 State that there is usually extensive genetic variation within a population of a species and that these arise through mutations
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge