13 Darwin's Finches-Mid

Darwin's Finches FOCUS Question What can small differences in finch species teach us about adaptations?

达尔文的雀类焦点问题雀类之间的微小差异能教会我们什么关于适应性的知识?

Setting Sail In 1831, a ship called the Beagle sailed from England to South America. Some people on board made maps of the continent's coastlines. But a naturalist named Charles Darwin spent his time taking notes about the plants and animals he saw. He visited the Galapagos Islands during the trip. After the journey, he published his notes as a book called The Voyage of the Beagle. Years later, the ideas from his first book led Darwin to write a book called The Origin of Species. This book stated that species evolve—they change over time by passing down certain traits to offspring.

1831年，一艘名为“小猎犬号”的船从英国驶往南美洲。 船上的一些人绘制了欧洲大陆的海岸线地图。 但是一位名叫查尔斯·达尔文的博物学家花时间记录他所看到的植物和动物。 在这次旅行中，他参观了加拉帕戈斯群岛。 旅行结束后，他把他的笔记写成了《小猎犬号航行》一书出版。 多年后，他的第一本书中的思想促使达尔文写了一本书，名为《物种起源》。 这本书指出，物种是进化的——它们通过将某些特征遗传给后代而随着时间而改变。

A Living Laboratory The Galapagos Islands, are a group of islands or an archipelago (ar-kih-PEH-luh-go). There are eighteen main islands. and three small islands The islands are 965 kilometers (600 mi.) off the coast of South America. The great distance from the mainland has caused island isolation. The habitats on the islands are different from the habitats on the mainland. When new species arrive on an island, they must find new food sources. They may face unknown predators. As a result, plants and animals can change quickly on isolated islands. For this reason, the Galapagos Islands are a great place to study evolution—how living organisms change over time.

加拉帕戈斯群岛是一群岛屿或群岛(ar-kih-PEH-luh-go)。 有十八个主要岛屿。 这些岛屿距离南美洲海岸965公里(600英里)。 与大陆的遥远距离造成了岛屿的孤立。 岛屿上的栖息地与大陆上的栖息地不同。 当新物种到达一个岛屿时，它们必须找到新的食物来源。 它们可能会面临未知的捕食者。 因此，孤岛上的动植物变化很快。 因此，加拉帕戈斯群岛是一个研究进化的好地方——生物体如何随时间变化。

A Bunch of Beaks Among the unique animals on the Galapagos Islands are finches, a type of bird. Fourteen finch species are found only on these islands. Seven of the species live in trees and mainly eat insects. One species lives in trees and eats seeds. Three live in cactuses and eat seeds or nectar. The final three species live on the ground and mainly eat seeds. The beaks of these finches are different sizes and shapes to match their food sources. These birds are often called "Darwin's Finches" because Darwin studied them. He used the ideas he developed from studying these birds to help explain his theory of evolution.

加拉帕戈斯群岛上独特的动物之一是雀，一种鸟类。 有14种雀类只在这些岛屿上发现。 其中7种生活在树上，主要以昆虫为食。 一种生活在树上，以种子为食。 有三种住在仙人掌里，吃仙人掌的种子或花蜜。 最后三个物种生活在地面上，主要吃种子。 这些雀的喙有不同的大小和形状来匹配它们的食物来源。 这些鸟通常被称为“达尔文的雀”，因为达尔文研究过它们。 他用他从研究这些鸟类中得到的想法来帮助解释他的进化论。

The First Finch How did all those different finches get on the Galapagos Islands? They actually started off as just one species! A few million years ago, a single type of finch reached one of the islands. That finch species is called the ancestral (an-SES-truhl) finch. It lived on the ground and ate seeds. Ancestral finches quickly spread to all the other Galapagos Islands. On each new island, the birds had to compete for different types of food. Those finches whose beak shape and size helped them find and eat food were able to survive and reproduce. This process is called natural selection. Over millions of years, the ancestral finch species became fourteen different species of finch.

所有这些不同的雀是如何来到加拉帕戈斯群岛的? 它们实际上一开始只是一个物种!几百万年前，一种雀类到达了其中一个岛屿。 这种雀被称为祖先雀(an-SES-truhl)。 它住在地上，吃种子。 雀类祖先迅速传播到加拉帕戈斯群岛的其他岛屿。 在每一个新的岛屿上，这些鸟都必须争夺不同类型的食物。 那些喙的形状和大小有助于它们寻找和进食食物的雀能够生存和繁殖。 这个过程被称为自然选择。 经过数百万年，祖先的雀类变成了14种不同的雀类。

Seeking Seeds Many of the islands' finch species mainly eat seeds. But seeds come in different sizes and shapes, and they're found in different places. The small ground finch has a small beak suited to eating tiny seeds. It forages on the ground for the seeds of plants such as the Galapagos carpetweed. A different finch eats larger and harder seeds. The large ground finch has an enormous beak. Snapping open the woody seeds of plants, like the puncture vine, is a cinch for this finch! A third bird, the cactus finch, eats seeds from cactus fruit. It uses its longer, more pointed beak to carefully pull seeds out of the fruit.

许多岛上的雀类主要吃种子。 但是种子的大小和形状各不相同，它们分布在不同的地方。 小地雀有适合吃小种子的小喙。 它在地面上觅食加拉帕戈斯地毯草等植物的种子。 另一种雀吃更大更硬的种子。 大地雀有一个巨大的喙。 咬开植物的木质种子，比如刺藤，对这种雀来说很容易!第三种鸟，仙人掌雀，吃仙人掌果实的种子。 它用更长更尖的喙小心地把种子从水果中拔出来。