OCR Biology Evolution Revision Notes
Master OCR Biology Evolution using simple revision notes, key facts and practice questions — all generated by AI for your exam.
Evolution is the process by which species change over time through mechanisms such as natural selection, genetic drift, and mutation. It explains the diversity of life on Earth and how organisms adapt to their environments.
Key Concepts
- 1Natural selection is the mechanism proposed by Charles Darwin that explains how advantageous traits become more common in a population.
- 2Genetic drift refers to random changes in allele frequencies in a population, which can lead to significant evolutionary changes over time.
- 3Mutations are changes in the DNA sequence that can introduce new traits into a population, potentially leading to evolutionary change.
- 4Speciation occurs when populations of the same species become isolated and evolve independently, leading to the formation of new species.
- 5Evidence for evolution includes fossil records, comparative anatomy, and molecular biology.
Simple Explanation
Evolution is how living things change over time. It happens when some traits help organisms survive better than others, so those traits get passed on to the next generation. Changes in DNA can also create new traits. Over a long time, these changes can lead to new species forming.
Memory Trick
“Remember 'N-G-M-S' for 'Natural selection, Genetic drift, Mutation, Speciation' to recall the key mechanisms of evolution.”
Flashcards
What is natural selection?
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Exam Questions
Describe and explain the process of natural selection. [6 marks]
6 marksView mark scheme hint▾
Define natural selection, explain variation, survival of the fittest, and reproduction.
Explain how mutations can lead to evolutionary change. [4 marks]
4 marksView mark scheme hint▾
Discuss how mutations introduce genetic variation and their potential effects on fitness.
What is meant by the term 'speciation'? [2 marks]
2 marksView mark scheme hint▾
Define speciation and give an example of how it occurs.
Practice Quiz
What is the main mechanism of evolution proposed by Charles Darwin?
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