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Complexity of Life on Earth

Driving Question: How did complexity increase as life on Earth emerged?

For about the first billion years, Earth was a fiery ball of lava—much too hot for anything to live. But about 3.8 billion years ago, things changed. The Earth cooled and life emerged and evolved.

Learning Objectives:

  1. Describe how life on Earth changed over time.
  2. Explain the differences between life and nonlife.
  3. Investigate how complexity increased as life evolved on Earth.

Vocab Terms:

  • DNA
  • energy
  • life
  • metabolism
  • reproduction
  • RNA
  • self-maintenance
STEP 1

Opener: Complexity of Life on Earth

Teaching Tools

To teach this lesson step, refer to page 2 of the Lesson 3.1 Teaching Guide Locked .

Our Openers and Closers Guide provides more information about these short activities at the beginning and end of each lesson.

You’re alive and you’re here on Earth, which makes you part of a proud 3.5-billion-year tradition. It’s time to learn about your very distant relatives.

STEP 3

Threshold 5: Life on Earth

Teaching Tools

To teach this lesson step, refer to page 4 of the Lesson 3.1 Teaching Guide Locked .

There are still some mysteries surrounding how life first appeared—watch this video and fill out the Threshold 5 card to do some investigating!

Threshold 5: Life External link

Take a diversity of chemical elements, mix in the perfect conditions on Earth, and abracadabra: life mysteriously appears.
STEP 4

Life and Nonlife

Teaching Tools

To teach this lesson step, refer to page 4 of the Lesson 3.1 Teaching Guide Locked .

OER Project’s Reading Overview provides valuable insight into why literacy practices are vital to success in social studies.

What does it mean to be alive? What’s the difference between something that’s alive and something that isn’t? You’re about to get some useful answers to questions you may have never thought of asking.

“Unknowns” Podcast Episode 2 Clip External link

There are many unsolved mysteries about life on Earth, but there’s one thing that scientists just can’t agree on—the definition of life.
STEP 5

Closer: Complexity of Life on Earth

Teaching Tools

To teach this lesson step, refer to page 6 of the Lesson 3.1 Teaching Guide Locked .

Check out this conversation External link in the OER Project community for some fun twists to add to this closer.

Your DNA is an index of all the unique things that make you...well, you. But did you know you share a lot of your DNA with many different organisms on Earth? Get ready to discover some surprising connections!