Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Sexual selection wikipedia , lookup
Natural selection wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Theistic evolution wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
Saltation (biology) wikipedia , lookup
On the Origin of Species wikipedia , lookup
The Expression of the Emotions in Man and Animals wikipedia , lookup
Name Date Class Changes Over Time ■ Adapted Reading and Study Darwin’s Theory (pages 172–179) Darwin’s Observations (page 173) Key Concept: Charles Darwin’s important observations included the diversity of living things and the remains of ancient organisms. • In 1831, Charles Darwin left from England on a ship that made many stops along the coast of South America. Darwin’s job was to learn about the living things he saw. • Darwin saw many plants and animals that he had never seen before. The living things he saw in South America were all very different from those in England. • A species is a group of similar living things that can mate with each other and produce offspring. • Darwin saw fossils in South America. A fossil is the preserved remains of an organism that lived long ago. Answer the following questions. Use your textbook and the ideas above. 1. Is the following sentence true or false? Darwin saw that living things in South America were just like those in England. 2. Read each word in the box. In each sentence below, fill in the correct word or words. fossil living thing species a. The preserved remains of an organism that lived long ago is a b. A group of similar living things that can mate and produce offspring is a © Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. 80 . Name Date Class Changes Over Time ■ Adapted Reading and Study Galápagos Organisms (pages 174–175) Key Concept: Darwin’s important observations included the characteristics of organisms on the Galápagos Islands. • Darwin saw that the plants and animals on the Galápagos Islands were much like those on the mainland of South America. • The Galápagos plants and animals did have some very important differences from those on the mainland. For example, Galápagos iguanas had larger claws than mainland iguanas. • Darwin thought that some plants and animals came to the Galápagos Islands from the mainland. Eventually, the offspring of these plants and animals became different from their mainland relatives. • Darwin also saw that tortoises and finches were different from one Galápagos island to the next. Finches, for example, had different beak shapes. • Beak shape is an example of an adaptation. An adaptation is a trait that helps an organism survive and reproduce. Answer the following questions. Use your textbook and the ideas above. 3. Is the following sentence true or false? Darwin thought that some plants and animals came to the Galápagos Islands from the mainland. 4. What is an adaptation? Circle the letter of the correct answer. a. a difference between two animals b. a trait that helps an organism survive and reproduce c. a way for plants and animals to get to an island © Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. 81 Name Date Class Changes Over Time ■ Adapted Reading and Study Evolution (page 176) Key Concept: Darwin reasoned that plants or animals that arrived on the Galápagos Islands faced conditions that were different from those on the mainland. Perhaps, Darwin hypothesized, the species gradually changed over many generations and became better adapted to the new conditions. • The gradual change in a species over time is called evolution. • Darwin concluded that the living things that came to the Galápagos Islands from the mainland had changed over time. The living things changed so that they could live better in the island environment. • Darwin’s ideas are often called the theory of evolution. A scientific theory is a well-tested idea. Answer the following questions. Use your textbook and the ideas above. 5. Is the following sentence true or false? The Galápagos plants and animals changed over time so that they could live better in the island environment. 6. Read each word in the box. In each sentence below, fill in the correct word or words. adaptation evolution scientific theory a. A well-tested idea is a(an) b. The gradual change in a species over time is called © Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. 82 Name Date Class Changes Over Time ■ Adapted Reading and Study Natural Selection (pages 177–179) Key Concept: Darwin proposed that, over a long time, natural selection can lead to change. Helpful variations may gradually accumulate in a species, while unfavorable ones may disappear. • Darwin suggested that evolution happens because of natural selection. In natural selection, individuals that are better adapted to their environment are more likely to survive and reproduce. • Factors that affect natural selection are overproduction, competition, and variation. • Most species produce far more offspring than can possibly survive. Overproduction makes it more likely that some offspring will survive. • Food and other resources are limited. Members of a species must compete with each other for these resources. Some members of a species may not find enough to eat, so they do not survive. • Any difference between individuals of the same species is called a variation. • Some variations make individuals better adapted to their environment. Individuals that are better adapted are more likely to live and produce more offspring. Their offspring may inherit these helpful variations. After many generations, more members of the species will have the helpful variations. • Variations in characteristics are caused by mutations and the shuffling of alleles during meiosis. Answer the following questions. Use your textbook and the ideas above. 7. Evolution happens because of ©PearsonEducation,Inc., publishingas PearsonPrenticeHall. All rights reserved. 83 Name Date Class Changes Over Time ■ Adapted Reading and Study 8. Look at the picture of the turtle eggs above. Circle the letter of the factor affecting natural selection that the picture shows. a. competition b. overproduction c. variation 9. Draw a line from each factor that affects natural selection to its meaning. Factor Meaning competition overproduction variation a. difference between individuals of the same species b. caused by limited food and other resources c. produce more offspring than can survive © Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. 84