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Odyssey of Life, Part I—The Ultimate Journey
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Viewing Ideas
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Before Watching
Distinguishing fact from theory can prove challenging. It is, for example, a fact that life on Earth has changed over geologic time. There are many
theories concerning precisely how life began, by what mechanism or mechanisms life evolves, through what stages evolving life forms may have passed
and how quickly evolution takes place. Discuss with students what makes something a fact and what makes it a theory. Have students work in groups to collect resources about evolution. Then have each group create two lists: one enumerating facts about the history of life on Earth, and the other describing theories that attempt to explain those facts. Review students' findings and facilitate a discussion in which they debate and defend their reasoning for why something is a fact or a theory.
After Watching
Have students use a piece of string to represent the Earth's geologic history. Have them devise a scale to
calculate the length of string they will need to represent the planet's entire geologic history and the length of each geologic period. (If they use a scale of
1 inch = 10 million years, for example, the string would be 41.7 feet long.) Then have them measure out the string and mark each period to scale, noting how much string represents the periods that include the evolution of life.
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