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Unit 3: Life

Teaching Tools

Living organisms have evolved into billions of different species since life first emerged over 3 billion years ago. While the complexity of life has increased over time, many species are extinct, which tells us life on Earth is also fragile.

Lesson 3.1

Complexity of Life on Earth
What does the diversity of life on Earth have in common with many superheroes: mutations! Evolution is all about increasing complexity via tiny changes in DNA. But these mutations are a bit different from the ones you read about in comic books.

Lesson 3.2

Origins of Life
Did ancient meteors bring life to Earth or did organic chemicals form when lava mixed with water deep in the ocean? Hey now, there’s no need to fight about it! Let’s explore the theories about the origins of life on our planet.

Lesson 3.3

Evolution
Did you know that birds are descendants of dinosaurs? How is that possible? It has a lot to do with environmental changes and that complex molecule you’ve been hearing so much about called DNA.

Lesson 3.4

Extinction Events

The dinosaurs were wiped out 65 million years ago. Could you survive an extinction event? Time to use your Big History knowledge to put together a survival plan—and consider if we should bring some dinosaurs back to life!

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Teaching This Unit

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Unit 3 Guide External link

Everything you need to know about Unit 3.

Unit 3 Vocab Guide External link

Key Unit 3 vocabulary words and definitions.
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Activities Guide External link

How we approach classroom-based activities.
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OER Teaching Sensitive Topics in Social Studies Guide External link

Support for having discussions that are difficult, but meaningful.
Blog

Blog: Lesson Plan: Claim Testing External link

Equip students with the language and practice needed to analyze claims.
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Unit 3 Teaching Guide

All the lesson guides you need in one place.