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Biology
Cambridge A-LevelA2Chapter 17

Selection and evolution

This chapter explores the mechanisms of selection and evolution, beginning with the sources of phenotypic variation, distinguishing between…

Lessons
MCQs
149
Exam questions
161
Flashcards
47

What you'll learn

  • Explain that genetic and environmental factors affect phenotypic variation.
  • Explain the differences between continuous and discontinuous variation.
  • Explain how natural selection takes place, including reference to the development of antibiotic resistance in bacteria.
  • Explain the differences between stabilising, disruptive and directional selection.
  • Explain how the founder effect and genetic drift may affect allele frequencies.
  • Use the Hardy–Weinberg equations.
  • Describe the principles of selective breeding, including examples.
  • Outline the theory of evolution in terms of changes to gene pools.
  • Discuss the use of DNA sequencing to determine relationships between species.
  • Explain how new species can be formed by allopatric and sympatric processes.

Study tools for this chapter

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About Selection and evolution on Nexelia Academy

Selection and evolution is chapter 17 of Nexelia Academy's Cambridge A-Level Biology course. This chapter explores the mechanisms of selection and evolution, beginning with the sources of phenotypic variation, distinguishing between…

This chapter is mapped to the official Cambridge International AS & A Level Biology syllabus and includes 149 multiple-choice questions, 161 structured exam questions with full mark schemes, 47 spaced-repetition flashcards, guided lesson slides and access to an AI tutor trained on the Cambridge specification.

Frequently asked questions about Selection and evolution

How do I revise Selection and evolution for Cambridge A-Level Biology?

Work through the guided lesson slides first to build a mental model, then drill the 149 MCQs for quick recall, attempt the 161 exam questions with mark schemes for technique, and use flashcards for spaced repetition. The AI tutor is available throughout if you get stuck.

How many practice questions does Selection and evolution include?

Selection and evolution on Nexelia Academy includes 149 multiple-choice questions, 161 structured exam questions with full mark schemes, and 47 flashcards.

Is Selection and evolution free?

Yes — Biology on Nexelia Academy is entirely free for all registered users, including Selection and evolution.

Does Nexelia Academy cover Selection and evolution for Cambridge A-Level Biology?

Yes. Selection and evolution is fully mapped to the official Cambridge International AS & A Level Biology syllabus and is one of Nexelia Academy's published chapters for this course.