What's that big red pouch? The Frigate bird of the Galápagos Islands. This bird can be found throughout the tropical Atlantic down to the Galápagos Islands and Ecuador,
but not in Europe or South America, so Darwin may never have come across one until he landed on the Galápagos. Such a unique creature was bound to make a naturalist such as Darwin wonder why. Why do they look the way they do? What's that big red pouch? What are the advantages? The Englishman
Charles Darwin is one of the most famous scientists who ever lived. His place in the history of science is well deserved. Darwin’s theory of evolution represents a giant leap in human understanding. It explains and unifies all of biology. An overview of evolution can be seen at
http://www.youtube.com/watch?v=GcjgWov7mTM(17:39). As you view Introduction to Evolution and Natural Selection,focus on the following concepts:
Darwin’s theory of evolution actually contains two major ideas:
In Darwin’s day, most people believed that all species were created at the same time and remained unchanged thereafter. They also believed that Earth was only about 6,000 years old. Therefore, Darwin’s ideas revolutionized biology. How did Darwin come up with these important ideas? It all started when he went on a voyage. The Voyage of the BeagleIn 1831, when Darwin was just 22 years old, he set sail on a scientific expedition on a ship called the HMS Beagle. He was the naturalist on the voyage. As a naturalist, it was his job to observe and collect specimens of plants, animals, rocks, and fossils wherever the expedition went ashore. The route the ship took and the stops they made are shown in the Figure below. You can learn more about Darwin’s voyage at this link:www.aboutdarwin.com/voyage/voyage03.html. Voyage of the Beagle. This map shows the route of Darwin’s 5-year voyage on the HMS Beagle. Each stop along the way is labeled. Darwin and the others on board eventually circled the globe. Darwin was fascinated by nature, so he loved his job on the Beagle. He spent more than 3 years of the 5-year trip exploring nature on distant continents and islands. While he was away, a former teacher published Darwin’s accounts of his observations. By the time Darwin finally returned to England, he had become famous as a naturalist. Darwin’s ObservationsDuring the long voyage, Darwin made many observations that helped him form his theory of evolution. For example:
On his voyage, Darwin saw giant marine iguanas and blue-footed boobies. He also dug up the fossil skeleton of a giant ground sloth like the one shown here. From left: Giant Marine Iguana, Blue-Footed Boobies, and Fossil Skeleton of a Giant Ground Sloth The Galápagos IslandsDarwin’s most important observations were made on the Galápagos Islands (see map in Figure below). This is a group of 16 small volcanic islands 966 kilometers (600 miles) off the west coast of Ecuador, South America. Galápagos Islands. This map shows the location of the Galápagos Islands that Darwin visited on his voyage. Individual Galápagos islands differ from one another in important ways. Some are rocky and dry. Others have better soil and more rainfall. Darwin noticed that the plants and animals on the different islands also differed. For example, the giant tortoises on one island had saddle-shaped shells, while those on another island had dome-shaped shells (see Figure below). People who lived on the islands could even tell the island a turtle came from by its shell. This started Darwin thinking about the origin of species. He wondered how each island came to have its own type of tortoise. Galápagos Tortoises. Galápagos tortoises have differently shaped shells depending on which island they inhabit. Tortoises with saddle-shaped shells can reach up to eat plant leaves above their head. Tortoises with dome-shaped shells cannot reach up in this way. These two types of tortoises live on islands with different environments and food sources. How might this explain the differences in their shells? The Farallon Islands – "California's Galapagos"One of the most productive marine food webs on the planet is located on the Farallon Islands, just 28 miles off the San Francisco, California coast. These islands also host the largest seabird breeding colony in the continental United States, with over 300,000 breeding seabirds. The islands are known as the Galapagos of California. Why? Find out at http://science.kqed.org/quest/video/...ias-galapagos/ . Summary
Explore MoreUse this resource to answer the questions that follow.
Review
What did Darwin observe during his voyage on the Beagle?During the long voyage, Darwin made many observations that helped him form his theory of evolution. For example: He visited tropical rainforests and other new habitats where he saw many plants and animals he had never seen before (see Figure below). This impressed him with the great diversity of life.
Why did Darwin travel on the Beagle?In 1831, Charles Darwin received an astounding invitation: to join the HMS Beagle as ship's naturalist for a trip around the world. For most of the next five years, the Beagle surveyed the coast of South America, leaving Darwin free to explore the continent and islands, including the Galápagos.
What did Charles Darwin discover on his voyage?In South America, Darwin found fossils of extinct animals that were similar to modern species. Furthermore, on the Galapagos Islands he noticed many variations of plants and animals that were similar to those he found in South America, suggesting that species adapted over time and to their environment.
What did Darwin accomplish during his voyage on the HMS Beagle quizlet?Charles Darwin joined the Beagle as a naturalist and it was on this trip that he made many of the observations that contributed to his invention of the theory of evolution by natural selection.
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