EARTH’S HISTORY UNIT 1 BRIDGES TO SCIENCE DIFFERENTIATED INSTRUCTION Scaffold View the geologic time scale together. Ask questions to guide students toward comprehension. For example: What eon is shown? How long is it? What eras are shown? In what era did humans live? What kinds of animals lived in the XX period? The XX period? Amplify Tell students to reread the text closely and study the graphic. Then have them each write three questions about the content of the article and the geologic time scale that are answered on the page. Have students ask and answer their questions in pairs or small groups. Instructional Routine: Science p. Txxxii Earth’s Story Essential Question: How do scientists measure time in Earth’s history? • Preview Have students preview pages 30–31. Ask: What is the title of the lesson? (Earth’s Story) What is the title of the science text? (Understanding Earth’s History) What is the title of the graphic? (Geologic Time Scale) What is the research topic? (fossils) Ask students to make predictions about what they will learn in this lesson. • Participate in academic discussions Use the Essential Question to activate prior knowledge about Earth’s history. Encourage students to share what they know in pairs and then see if the class can come to a consensus on what they know. Tell students they can check their ideas when they read the text. ANSWERS Sample answer: Scientists study rock layers to find clues about what lived on Earth during different times. Then they order the layers by age. A • Read and comprehend science texts Play the audio as students read along. Play it again for them to whisper read. • Determine the meaning of domain-specific words as used in scientific context Point out the glossary terms at the bottom. Ask students to find the words in the text and study the context of the sentence to understand the meaning. • Determine meaning from context Have students work in pairs to analyze the text and identify any unfamiliar words. Write on the board: fossil, geologic time scale, eons, eras, periods. Ask students to find these words in the text and use the context to write a definition for each. (These words are defined within the text.) • View closely Ask students to study the graphic in pairs and discuss how the visual supports the information in the text. • Determine central ideas or conclusions of a text Ask questions to ensure that students comprehend the central ideas of the text and graphic. For example, ask: How old is Earth? How long have humans been on Earth? How do we know what happened on Earth before us? What kinds of life were on Earth before us? How do geologists divide Earth’s history? • Connect to theme Ask: How does this information in this text connect to the unit theme of identity? Elicit that just like people, Earth has its own story to tell. EXPLORE AND LEARN A Read about the history of Earth and the development of the geologic timeline. Earth is 4.6 billion years old. That’s 4,600,000,000 years! But how do we know about Earth’s history? Geologists are scientists who study Earth’s rocks. They study the layers of rock in the ground, which get older as you go farther down into Earth. Geologists also study fossils, which are the preserved remains or traces of living things. Geologists use fossils to determine what Earth was like in the past and how life has changed over time. Geologists have used what they learn from rock layers and fossils to make the geologic time scale. The scale is like a timeline that tells the story of Earth’s history. It is divided into very long intervals called eons. Eons are divided into shorter intervals of time called eras, and eras are divided into periods. What era and period of Earth’s history do we live in? Understanding Rise of man Rise of mammals First birds Cycads, First dinosaurs First reptiles First insects Many crinoids Earliest land animals Early bony fish Modern seed bearing plants Dinosaurs First seed plants Cartilage fish Invertebrate animals, Brachiopods, Trilobites Earth’s crust had cooled enough to allow the formation of continents and life started to form. Bacteria, Algae, Jellyfish Formation of the Earth layers things on top of one another fossils prints of dead animas in rock EARTH’S HISTORY GLOSSARY ESSENTIAL QUESTION How do scientists measure time in Earth’s history? ? BRIDGES TO SCIENCE Geologic Time Scale UNIT 1 30 Earth’s Story BLC23_SE_LB_U01_030-031_BS.indd 30 8/30/21 12:13 PM 30 | Teacher’s Edition • UNIT 1
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