Natural selection and evolution (B5.2) | OCR GCSE Biology A (Gateway Science) — Foundation (J247)

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
$B5.2a state that there is usually extensive genetic variation within a population of a species$

B5.2a 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

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

Learning outcomes	To include	Maths	Working scientifically	Practical suggestions
$B5.2f describe the work of Darwin and Wallace in the ☑ development of the theory of evolution by natural selection and explain the impact of these ideas on modern biology$	$seedbanks being used as a store of biodiversity$		$WS1.1a, WS1.1d, WS1.1g, WS1.1h, WS1.3i$

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

Natural selection and evolution

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Learning Objectives