Darwin & Wallace

Darwin & Wallace 🧭

You already know HOW natural selection works. This module is about the two people who worked it out, and why almost nobody believed them at first. Remarkably, two naturalists on opposite sides of the world reached the same conclusion at almost the same time, without either one copying the other.

Darwin and the Beagle ⛵

**Charles Darwin** spent five years as a naturalist aboard **HMS Beagle**, collecting specimens and observations from around the world. On the **Galapagos Islands** he noticed that finches on different islands had **different beaks**, each suited to the food available there. Observations like these, gathered over roughly **20 years** of thinking and testing, led him to evolution by natural selection.

What the finches showed

Darwin found that finches on different Galapagos islands had differently shaped beaks. What did this suggest to him?

• Birds with beaks suited to the food on their island survived and reproduced, so the populations diverged
• Each finch grew a new beak shape to match its island during its lifetime
• Finches simply flew to whichever island matched the beak they already had
• Nothing about evolution, since beak shape is not inherited

Wallace writes a letter ✉️

Meanwhile **Alfred Russel Wallace** was working in the Malay archipelago (present-day Indonesia and Malaysia). Studying the wildlife there, he reached the **same conclusion independently**: species change through natural selection. In 1858 he wrote to Darwin describing his idea. Wallace also did important work on **warning colouration** in animals and on **speciation**.

Published at last 📖

Wallace's letter forced Darwin's hand. Their work was presented **jointly in 1858**, giving both men credit for the idea. The following year, in **1859**, Darwin published **On the Origin of Species**, setting out the theory with the mass of evidence he had spent two decades gathering.

How the theory emerged

An interactive activity.

Wallace's role

How did Alfred Russel Wallace contribute to the theory of evolution by natural selection?

• He reached the same conclusion independently, and their work was presented jointly in 1858
• He worked as Darwin's assistant on board HMS Beagle
• He tried to disprove Darwin's theory
• He discovered genes, which explained how characteristics are inherited

Why the slow acceptance?

Select ALL THREE reasons the theory of evolution was accepted only slowly.

• It conflicted with religious beliefs about how life was created
• There was not enough evidence at first to convince many scientists
• The mechanism of inheritance was not yet known
• The theory has since been shown to be wrong
• Darwin kept the theory completely secret and never published it
• No fossils had ever been discovered at the time

Match each to its part in the story

Story summary

Darwin collected evidence aboard HMS _____, including finches with beaks suited to different foods. _____ reached the same conclusion independently, and their work was presented jointly in 1858. Darwin published On the Origin of Species in _____. Acceptance was slow, above all because the mechanism of _____ was not yet known.