The work of Darwin and WallaceSpec 4.1B
In short
The theory of evolution by natural selection was developed by two scientists working separately, each using their own observations and collections of plants and animals. Their observations included variation within species and organisms suited to their different environments. The theory gives a unifying explanation for the diversity of living things and helps explain antibiotic-resistant bacteria.
The theory of evolution by natural selection was developed by two scientists working separately: Charles Darwin and Alfred Wallace.
Charles Darwin
- Darwin collected observations and specimens on a long sea voyage, including studying plants and animals in different places.
- He noticed that individuals of the same species show variation, and that organisms in different places are suited to their different environments.
- He spent many years collecting evidence and developing his ideas before publishing them in his book On the Origin of Species in 1859.
Alfred Wallace
- Wallace independently developed a very similar theory of evolution by natural selection.
- His ideas were based on his own observations and collections of plants and animals in different parts of the world.
- His work encouraged Darwin to publish, and the two men's ideas were presented together.
Impact on modern biology
- Natural selection gave a unifying explanation for the huge diversity of living things and how species are related.
- When combined with later knowledge of genes, it explains how variation arises (through mutation) and how characteristics are inherited.
- It helps us understand the emergence of resistant organisms, such as antibiotic-resistant bacteria.
- It supports the idea that living things can be classified according to how they are related.
If asked about Wallace, say he developed the theory independently of Darwin. Do not say he copied or helped Darwin write the book.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026