Download Use core knowledge to give reasons for genetic variation and change.

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Recognise evolution as a
process of change in allele
frequency within a population.
Description indicates there is a permanent change in the gene
pool of the population over a period of time.
Definitions include Gene, Allele, Species, Population, Gene Pool,
Gene Flow, Allele Frequency.
Describe the key ideas that are Key Darwinian ideas:
used to formulate the theory of
 Heritable variation in populations (genes/alleles)
evolution.
 Tendency of population to overproduce
 Competition in populations i.e. limited resources
 Survival linked to characteristics that are selected for
(Natural Selection)
Definitions including fitness / selection pressure / adaptation
 Increased reproductive success in individuals with favourable
characteristics.
Identify sources of variation in
Identified as genetic variation as a result of:
a gene pool.
sexual reproduction (meiosis) – crossing over; independent
assortment; mutation
Identify factors that lead to
Define Genetic Equilibrium.
change in a gene pool.
Identified as immigration; mutation; natural selection; population
size; genetic drift; mate selection AND environmental variation
leading to selection. The basic concept of barriers to gene flow
e.g. geographic, potentially leading to biological isolation and
speciation.
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In relation to genetic change,
define the term natural
selection and describe the
different types.
Definitions have following concepts:
Natural Selection: Survival and differential reproductive success
in individuals whose characteristics are best suited to the
environment at a given time.
Stabilising - favours middle range of adaptive phenotype
Directional – favours one extreme of adaptive phenotype
Disruptive – Favours both extremes of adaptive phenotype.
In relation to genetic change,
Definitions have following concepts:
define the terms genetic drift,
Genetic Drift: random change in allele frequency OR chance
the founder effect and the
loss of alleles from gene pool; most pronounced in small
bottleneck effect.
population.
Bottleneck: severe reduction in gene pool diversity, followed by
recovery of a population
Founder: development of a population from a small number of
individuals with a limited gene pool.
Causes/consequences of genetic drift, founder effect and the
bottleneck effect in relation to genetic biodiversity.
Use core knowledge to give
E.g. different selection pressures produce a change in allele
reasons for genetic variation frequency in the local gene pool, due to changed reproductive
and change.
success of individuals with particular genotype.
Show understanding of
E.g. if two populations are isolated i.e. no gene flow, and there
genetic variation and change are different selection pressures then the allele frequencies in
by using the core knowledge each gene pool will diverge. Reasoning includes an explanation
to link ideas e.g. in justifying, of survival of the fittest as appropriate to two different
relating, evaluating,
environments. e.g. Hedgehog qu (2004 exam).
comparing and contrasting
or analysing.