Under what condition does natural selection occur?
Individuals with different heritable phenotypes differ in survival or reproductive success.
AQA GCSE Combined Science: Trilogy (8464) — Biology — Higher · 4.6.2.2
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Under what condition does natural selection occur?
Individuals with different heritable phenotypes differ in survival or reproductive success.
How can selection pressures such as predation, disease and competition affect phenotypes?
They can favour phenotypes that provide an advantage in the prevailing conditions.
How are favourable alleles passed on through natural selection?
Individuals with advantageous phenotypes are more likely to reproduce and pass their favourable alleles to offspring.
How can natural selection cause evolution over generations?
Favourable alleles can increase in frequency in the population’s gene pool.
What is evolution?
A change in allele frequencies in a population over time.
What is evolution?
Change in the inherited characteristics of populations over generations.
What process can contribute to evolution?
Natural selection.
How can diverging populations descended from shared ancestors contribute to biodiversity?
They can give rise to different species.
What connects living organisms through their evolutionary history?
Common ancestry.
How does the recency of a common ancestor relate to how closely organisms are related?
Organisms with a more recent common ancestor are more closely related.
What is speciation?
The formation of new species as populations diverge over generations.
How can natural selection contribute to divergence between populations?
It can contribute to differences in their inherited characteristics and phenotypes.
When are two populations regarded as separate species?
When they are reproductively isolated and can no longer interbreed to produce fertile offspring.
What effect does reproductive isolation have on gene flow between populations?
It prevents gene flow between them.
How have repeated evolutionary divergence and speciation affected life on Earth?
They have contributed to the diversity of life.
What are all present-day species descended from?
Simple life forms that first developed more than three billion years ago.