A-Level Biology Evolution Revision Notes
Master A-Level Biology Evolution using simple revision notes, key facts and practice questions — all generated by AI for your exam.
Evolution is the process by which populations of organisms change over generations through mechanisms such as natural selection, genetic drift, and gene flow. It explains the diversity of life on Earth and how species adapt to their environments.
Key Concepts
- 1Natural selection leads to adaptive evolution.
- 2Genetic drift causes random changes in allele frequencies.
- 3Gene flow introduces new genetic material into populations.
- 4Speciation occurs when populations become reproductively isolated.
- 5Fossil records provide evidence for evolutionary change over time.
Simple Explanation
Evolution is how living things change and adapt over time. It happens because some traits help organisms survive better in their environment, leading to those traits being passed on to future generations. This process can create new species and explain the variety of life we see today.
Memory Trick
“Remember 'Nasty Giraffes Get Special Food' to recall Natural selection, Genetic drift, Gene flow, Speciation, and Fossil records.”
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 in traits, survival of the fittest, and reproduction of advantageous traits.
Explain how genetic drift can affect small populations. [4 marks]
4 marksView mark scheme hint▾
Discuss random changes in allele frequencies and the impact of small population size.
What is meant by speciation? [2 marks]
2 marksView mark scheme hint▾
Define speciation and explain the concept of reproductive isolation.
Practice Quiz
What is the main mechanism of evolution proposed by Darwin?
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