Explain how environmental factors can act as stabilising, disruptive and directional forces of natural selection
Explain how environmental factors can act as stabilising, disruptive and directional forces of natural selection

Explain how environmental factors can act as stabilising, disruptive and directional forces of natural selection
How does natural selection lead to adaptation in populations?
Explain that natural selection occurs because populations have the capacity to produce many offspring that compete for resources; in the ‘struggle for existence’, individuals that are best adapted are most likely to survive to reproduce and pass on their alleles to the next generation
Use the t-test to compare the means of two different samples (the formula for the t-test will be provided, as shown in the Mathematical requirements)
Explain the genetic basis of discontinuous variation and continuous variation
Explain what is meant by discontinuous variation and continuous variation
Explain, with examples, that phenotypic variation is due to genetic factors or environmental factors or a combination of genetic and environmental factors
Explain how gibberellin activates genes by causing the breakdown of DELLA protein repressors, which normally inhibit factors that promote transcription
State that transcription factors are proteins that bind to DNA and are involved in the control of gene expression in eukaryotes by decreasing or increasing the rate of transcription
Explain genetic control of protein production in a prokaryote using the lac operon (knowledge of the role of cAMP is not expected)