Darwin and Wallace: Developing the Theory of Evolution Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Explore how Charles Darwin and Alfred Russell Wallace independently developed the theory of evolution by natural selection, their collaboration in 1858,...

• Describe the work of Charles Darwin in developing the theory of evolution by natural selection
• Explain the contribution of Alfred Russel Wallace to evolutionary theory
• Compare the approaches taken by Darwin and Wallace in their research
• Evaluate the impact of their joint publication in 1858 on scientific understanding

Key ideas to keep in view

Use this lesson to stay inside B5.2 Natural selection and evolution while connecting the detail back to the wider B5: Genes, inheritance and selection topic.

• B5: Genes, inheritance and selection
• B5.2 Natural selection and evolution
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Darwin and Wallace: Developing the Theory of Evolution before testing yourself from memory.

• Before 1858, most people believed species never changed. Then two British naturalists proposed something radical: all life forms gradually change over time through a process called natural selection. This wasn't just another scientific theory - it revolutionised how we understand life itself.
• What makes this story fascinating is that Charles Darwin and Alfred Russel Wallace developed virtually identical theories independently. Darwin had been working on his ideas for over 20 years when Wallace's letter arrived, forcing Darwin to finally publish his groundbreaking work.
• Charles Darwin began developing his theory during his voyage on HMS Beagle (1831-1836). As the ship's naturalist, he observed finches on the Galápagos Islands with different beak shapes perfectly suited to their food sources. This sparked a crucial question: why were closely related species so perfectly adapted to t...
• A characteristic that helps an organism survive and reproduce in its environment, developed through natural selection over many generations
• Darwin spent decades collecting evidence. He studied domestic breeding, noting how farmers selected animals with desirable traits. If humans could change species through artificial selection, perhaps nature did something similar through natural selection.
• The key insight came from Thomas Malthus's essay on population growth. Malthus argued that populations grow faster than food supplies, creating competition for resources. Darwin realised this competition would favour individuals with advantageous traits - they would be more likely to survive and reproduce.
• Alfred Russel Wallace was collecting specimens in the Malay Archipelago (modern-day Indonesia and Malaysia) when he independently developed the same theory. Unlike Darwin's gradual realisation, Wallace's breakthrough came suddenly during a fever in 1858.
• Wallace was studying the geographical distribution of species when he noticed a pattern: closely related species were often separated by geographical barriers like mountains or seas. This suggested species changed over time as they adapted to different environments.
• Like Darwin, Wallace was influenced by Malthus's ideas about population pressure. During his fever, Wallace suddenly realised that in the struggle for survival, those with favourable variations would survive while others would perish. This was natural selection.
• In June 1858, Wallace sent Darwin a manuscript outlining his theory. Darwin was shocked - Wallace had described almost exactly the same mechanism Darwin had been developing for decades. This created a dilemma: who should get credit for the discovery?

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.