Charles Darwin in 1840. Watercolour by George Richmond.
	Illustration in Darwin and the Beagle by Alan Moorehead (1969)

SO WHO WAS CHARLES DARWIN?

Charles Darwin was an English naturalist who travelled thousands of miles to obtain factual evidence to support the theory of evolution.

Charles Darwin came from a prosperous family. His father, Robert Darwin was a doctor in Shrewsbury. His grandfathers were Erasmus Darwin, who was an author, philosopher and scientist and Josiah Wedgwood the famous potter.

He was educated at Shrewsbury School and Edinburgh University where he read medicine. Darwin did not complete his studies at Edinburgh and went to Cambridge to read theology. While he was at Edinburgh he developed an interest in natural history which was to continue during his time at Cambridge and for the rest of his life.

In 1831 he obtained his degree from Cambridge and in the same year set out as a naturalist on a survey ship called the Beagle. He did not return home until 1836.

WHAT EXACTLY DID CHARLES DARWIN DO?

The theory of evolution was not new, in fact it had been around since the time of the ancient Greeks, but Charles Darwin is seen as the scientist who developed the modern theory of evolution and together with Alfred Russel Wallace proposed the principle of natural selection. Darwin eventually published his findings in, The Origin of the Species by Natural Selection.

WHAT IS NATURAL SELECTION?

According to Charles Darwin animals with variations better suited to their environment would have a better chance of survival and ability to breed. They would then pass on the favourable characteristics to their offspring.

This publication caused a great deal of controversy at the time, because it disagreed with the literal interpretation of the Book of Genesis in the Bible.

HOW DID CHARLES DARWIN FIND OUT ABOUT NATURAL SELECTION?

Charles Darwin sailed from Plymouth on the 27 December 1831 on a journey that was to take him many thousands of miles. He sailed in a ship called the Beagle. The Beagle was not a big ship, it was only about 28 metres long and had to be home to 74 people for the whole voyage.

	The Beagle at Sydney Harbour, 1841. Watercolour by Owen Stanley.
	Illustration in Darwin and the Beagle by Alan Moorehead (1969)

Darwin took with him a copy of the bible and books by Milton, Humboldt as well as a copy of Lyell's first volume on Principles Of Geology. He also took binoculars, a geological magnifying glass and jars of spirit for preserving specimens.

For many of the early weeks at sea, Darwin was extremely sea-sick and could eat nothing but raisins. When they landed at Cape Verde he began to feel better, as he was able to go ashore and start noting, collecting, recording and observing the bird life, the natives, the plants and the landscape.

Darwin's Journey

Their voyage continued down the Atlantic coast of South America stopping often for Darwin to carry out important inland excursions, where he would carry out his detailed observations.

They eventually rounded Cape Horn which is the southern most point on the mainland of South America, after battling for one month against mountainous seas.

They reached the Galapagos Islands in September 1835 and stayed for two months. These isolated islands had only a very small human population and life had stayed unchanged for thousands of years. On the islands Darwin found huge turtles, tortoises and lizards. The animals were not afraid of people and so Darwin was able to study them very closely.

This was when Darwin made an extremely interesting observation. He discovered that the animals on the Galapagos Islands were not quite like the animals he had seen in South America. In some ways the lizards were the same as those in South America but were different in others. Darwin also observed this to be the same with the many different types of finches on the islands. They were different from the finches he had seen in South America. Darwin then found out something even more important. A tortoise or finch on one island was not quite like a tortoise or a finch on another island. By looking at the shell of a tortoise or the beak of a finch you could tell which island it had come from. All the finches had dull coloured feathers and short tails. They all laid four pink and white eggs in nests with small roofs. The difference was they all had different beaks. On one island they had strong thick beaks for cracking open nuts and seeds. On another island eighty kilometres away they had long thin beaks for catching insects.

This raised many puzzles for Darwin; he knew that the animals of the Galapagos Islands had come from South America thousands of years ago, but he wanted to know how they had arrived at the islands. He also wanted to know how the plants and seeds had come all the way from the mainland and importantly why the animals were different on each island.

Darwin did not find the answers easily; in fact it took him a long time. He decided the birds had originally flown from South America and landed on the Galapagos Islands. Some finches landed on one island and some on others. They ate the food available on the island. Some islands were rich in seeds which the finches ate. Other islands had many insects and so the finches ate them. Gradually over thousands of years the finches slowly changed to suit the food available on the island on which they lived.

This explained why some finches had developed short strong beaks to crack open seeds and why other finches had long thin beaks to catch insects.

The next question was where had the food originally come from.

Darwin felt that seeds must have floated across the sea from Equador. It would have taken the seeds a month to travel and some scientists of the day felt that seeds could not live for so long in cold salt water.

Darwin carried out tests and found that seeds could stand being in cold salt water for over four months and still grow into plants.

He had now confirmed that the seeds had come from Equador.

Charles Darwin made his discoveries through detailed studies of his subject and by testing his findings until he was satisfied they were accurate.