Standard 5: Earth and Life

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Objective 5.2: Geologic Time Scale

Describe how evidence from geologic layers, rocks, fossils and radioactive dating indicate the Earth is approximately 4.6 billion years old, and that life began more than 3 billion years ago.

□ I can compare the four major geologic eras in Earth’s history.

□ I can explain how life and environmental conditions may have changed over time.

□ I can list the major extinctions.

□ I know the impacts that humans have on the environment.

□ I can calculate radioactive decay

□ I know one theory about how life may have started on Earth

Evidence of Mastery

□ Geologic Timeline

□ Vocabulary

□ Objective 5.2 Study Guide

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Vocabulary for Objective 5.2 Copy BETWEEN the lines only

Objective 5.2: Geologic Time Scale

Describe how evidence from geologic layers, rocks, fossils and radioactive dating indicate the Earth is approximately 4.6 billion years old, and that life began more than 3 billion years ago.

Vocabulary: CHAPTER 9 SECTIONs 1 and 2 (Life Science, Holt)

Define these words in common language.

1. Ice Age

2. relative dating

3. absolute dating

4. half-life

5. ozone

6. mass extinction

7. geologic time scale

8. extinct

9. anaerobic

10. Precambrian time

11. Cenozoic era

12. Mesozoic era

13. Paleozoic era

Add extra credit vocabulary words!

Study Guide for Objective 5.2 Copy BETWEEN the lines only

Objective 5.2: Geologic Time Scale

Describe how evidence from geologic layers, rocks, fossils and radioactive dating indicate the Earth is approximately 4.6 billion years old, and that life began more than 3 billion years ago.

Study Guide: CHAPTER 9 SECTIONs 1 and 2 (Life Science, Holt)

Explain each concept

□ Relative dating is an estimate based on the age of the sediment layer where a fossil is found.

□ Absolute dating measures the rate of decay of elements found in rock surrounding a fossil.

□ Scientists use the geologic time scale as a calendar of the history of Earth and life on Earth.

□ Many species existed for a few million years and then became extinct.

□ Mass extinctions have occurred several times in Earth’s history.

□ Precambrian includes the beginning of life, and evolution of simple organisms.

□ The Earth is about 4.6 billion years old.

□ Life formed from nonliving matter on the turbulent early Earth.

□ The first cells, prokaryotes, were anaerobic.

□ Multicellular photosynthetic cyanobacteria evolved and oxygen to entered the atmosphere.

□ In the Paleozoic era, plants and animals appeared in the oceans, and colonized the land.

□ In the Mesozoic, dinosaurs, reptiles, flowering plants, birds, and mammals appeared.

□ Primates evolved during the Cenozoic era, which extends to the present day.