What Observations Did Darwin Make

5.13: Darwin'southward Voyage of the Beagle

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What'due south that large crimson pouch?

The Frigate bird of the Galápagos Islands. This bird can be found throughout the tropical Atlantic downward to the Galápagos Islands and Republic of ecuador, but not in Europe or South America, so Darwin may never have come up across ane until he landed on the Galápagos. Such a unique creature was bound to make a naturalist such equally Darwin wonder why. Why practise they wait the way they do? What's that big red pouch? What are the advantages?

Darwin's Theory

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'southward theory of evolution represents a giant bound in human understanding. It explains and unifies all of biology.

An overview of development can exist seen at http://www.youtube.com/watch?v=GcjgWov7mTM(17:39).

As you view Introduction to Evolution and Natural Pick,focus on the following concepts:

1. the meaning of "evolution,"
2. the human relationship between development and natural pick,
3. the human relationship between natural choice and variation,
4. the evolution of the peppered moth.

Darwin's theory of evolution really contains two major ideas:

1. Ane idea is that development occurs. In other words, organisms change over fourth dimension. Life on Earth has changed as descendants diverged from common ancestors in the past.
2. The other idea is that evolution occurs by natural selection. Natural selection is the process that results in living things with beneficial traits producing more offspring than others. This results in changes in the traits of living things over fourth dimension.

In Darwin'due south day, most people believed that all species were created at the same time and remained unchanged thereafter. They also believed that Globe was just nearly 6,000 years erstwhile. Therefore, Darwin's ideas revolutionized biology. How did Darwin come upwardly with these important ideas? Information technology all started when he went on a voyage.

The Voyage of the Beagle

In 1831, when Darwin was merely 22 years erstwhile, 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 chore 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 beneath. Yous can learn more than about Darwin's voyage at this link:www.aboutdarwin.com/voyage/voyage03.html.

Voyage of the Beagle. This map shows the route of Darwin'south 5-twelvemonth 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 iii years of the 5-twelvemonth trip exploring nature on distant continents and islands. While he was away, a onetime teacher published Darwin's accounts of his observations. By the fourth dimension Darwin finally returned to England, he had become famous every bit a naturalist.

Darwin's Observations

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 earlier (see Effigy below). This impressed him with the great diversity of life.
• He experienced an earthquake that lifted the ocean flooring 2.7 meters (9 feet) above sea level. He also found rocks containing fossil sea shells in mountains loftier above sea level. These observations suggested that continents and oceans had inverse dramatically over time and continue to change in dramatic means.
• He visited rock ledges that had clearly once been beaches that had gradually built up over fourth dimension. This suggested that ho-hum, steady processes likewise change Earth's surface.
• He dug up fossils of gigantic extinct mammals, such as the footing sloth (run across Effigy below). This was hard evidence that organisms looked very unlike in the by. It suggested that living things—similar Earth's surface—change over fourth dimension.

On his voyage, Darwin saw giant marine iguanas and bluish-footed boobies. He also dug up the fossil skeleton of a giant ground sloth like the one shown here. From left: Giant Marine Iguana, Bluish-Footed Boobies, and Fossil Skeleton of a Giant Ground Sloth

The Galápagos Islands

Darwin's near important observations were made on the Galápagos Islands (encounter map in Figure below). This is a group of 16 small volcanic islands 966 kilometers (600 miles) off the west declension 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 1 another in important means. Some are rocky and dry. Others have better soil and more rainfall. Darwin noticed that the plants and animals on the dissimilar islands as well differed. For instance, the giant tortoises on 1 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 isle a turtle came from by its vanquish. This started Darwin thinking about the origin of species. He wondered how each island came to have its own blazon of tortoise.

Galápagos Tortoises. Galápagos tortoises take 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 upwards in this manner. 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://scientific discipline.kqed.org/quest/video/...ias-galapagos/ .

Summary

• Darwin's theory of evolution by natural option states that living things with beneficial traits produce more than offspring than others do. This produces changes in the traits of living things over time.
• During his voyage on the Beagle, Darwin made many observations that helped him develop his theory of evolution.
• Darwin's most important observations were made on the Galápagos Islands.

Explore More than

Use this resource to respond the questions that follow.

• Beagle Voyage at http://www.nhm.ac.uk/nature-online/s...beagle-voyage/.

1. Describe Darwin'southward role on the Beagle.
2. Describe what Darwin encountered in the following places:
   1. Salvador, Brazil,
   2. Punta Alta, Argentina,
   3. Chiloe Island, Chile,
   4. Galapagos Islands,
   5. Sydney, Australia.

Review

1. Land the two main ideas in Darwin's theory.
2. What was Darwin's role on the Beagle?
3. Draw two observations Darwin made on his voyage on the Beagle that helped him develop his theory of development.
4. Why did Darwin'due south observations of Galápagos tortoises crusade him to wonder how species originate?

What Observations Did Darwin Make,

Source: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Introductory_Biology_(CK-12)/05%3A_Evolution/5.13%3A_Darwin's_Voyage_of_the_Beagle

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