Biology (Separate Science) · GCSE · OCR · OCR GCSE Biology A (Gateway Science) — Higher (J247) · Specification point · B5.2 · Genes, inheritance and selection
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B5.2 Natural selection and evolution
Summary Variation in the genome and changes in the environment drive the process of natural selection, leading to changes in the characteristics of populations. Evolution accounts for both biodiversity and how organisms are all related to varying degrees. Key individuals have played important roles in the development of our understanding of genetics. Underlying knowledge and understanding Learners should appreciate that changes in the environment can leave some individuals, or even some entire species, unable to compete and reproduce leading to extinction.
Common misconceptions Learners are used to hearing the term evolution in everyday life but it is often used for items that have been designed and gradually improved in order to fit a purpose. They therefore find it difficult to grasp the idea that evolution by natural selection relies on random mutations. Learners also tend to imply that individuals change by natural selection. Statements such as ‘a moth will change by natural selection in order to become better camouflaged’ include both of these common misconceptions.
| Learning outcomes | To include | Maths | Working scientifically | Practical suggestions |
|---|---|---|---|---|
B5.2a state that there is usually extensive genetic variation within a population of a species |
B5.2b describe the impact of developments in biology on classification systems | natural and artificial classification systems and use of molecular phylogenetics based on DNA sequencing | WS1.1b |
B5.2c explain how evolution occurs through the natural selection of variants that have given rise to phenotypes best suited to their environment | the concept of mutation |
B5.2d describe evolution as a change in the inherited characteristics of a population over time, through a process of natural selection, which may result in the formation of new species |
B5.2e describe the evidence for evolution | fossils and antibiotic resistance in bacteria | WS1.1c, WS1.1d, WS1.1g |
B5.2f describe the work of Darwin and Wallace in the ☑ development of the theory of evolution by natural selection and explain the impact of these ideas on modern biology | seedbanks being used as a store of biodiversity | WS1.1a, WS1.1d, WS1.1g, WS1.1h, WS1.3i |