The Earth is approximately 4.6 billion years old. Modern humans have only been around for .0002 percent of that time, and recorded history covers only a fraction of that. How do we know what the early Earth looked like? How do we know how living things evolve?

The evolution of complex organisms, such as humans, is so gradual that no one can watch it. But evolution does leave evidence. Scientists search for clues embedded in rock, encoded in DNA, and in the shape and structure of living things. In these activities, you will learn how scientists collect evidence for evolution.

	Activity 1: Evolution and Time Investigate geologic time scale, create a journal entry that describes the geologic ecosystem of a particular time period, and make a birthday card for the Earth at a specific point in time.
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	Activity 2: Evidence for Evolution WebQuest Surf the Web to find evidence for evolution from three different areas of science -- paleontology, molecular biology, and anatomy and physiology.
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