Overview

In your lab group, you will be assigned one of six imaginary exoplanets. You will come up with five major stages of evolution for this planet, beginning with the emergence of life, and ending with the development of a sentient civilization.

Science Question

How might evolution have proceeded differently on a geologically different Earth?

Materials:

• Paper
• Loose rice grains or beans
• Pen/pencil
• Play-doh or clay (one per student)

Biology

Darwinian evolution states three things:

1. Individuals are born with genetic variations
2. More individuals are born than will survive
3. Individuals better suited for their environment will live to pass on their genes

The environment a species lives in is fundamental to its development. Life on Earth has adapted to a number of things: Different amounts of radiation across different energy levels from the sun, the amount of gravity inherent to the planet, the changing temperatures and compositions of our oceans and atmospheres, and many more. On a planet with stronger radiation, evolution could proceed more quickly (if more radiation means more disturbances to cells and more chances for genetic variation), or slower (if the radiation is too harmful to the creatures). On one with high gravity, the structures we use for support (shells, bones, etc) would have to be far stronger. A thick atmosphere might favor avian life. A planet outside the habitable zone might foster life which is based in ammonia, methane, or ethane instead of water. You get the idea.

Planet 1:

• Gravity is 2.5x that of Earth
• Outside the habitable zone
• Receives 80% less UV radiation than the Earth
• Atmosphere is very thick
• 75% land, 25% ocean (not water!!)

Planet 2:

• Gravity is 10% that of Earth
• Inside edge of the habitable zone but tidally locked in a 2:3 resonance
• Receives 150% UV radiation of Earth
• Thick, cloudy atmosphere (high surface pressure)
• 90% land, 10% water ocean

Planet 3:

• Gravity is the same as Earth
• Far outside the habitable zone
• Atmosphere is thinner than Earth
• Receives 200% as much UV radiation as Earth
• Planet is 80% ocean, 20% land

Planet 4:

• Gravity is 40% that of Earth
• Solidly in the middle of the habitable zone
• Receives 5% UV radiation of Earth
• Atmosphere is similar to Earth
• Planet is 100% covered in ocean

Planet 5:

• Gravity is 5% that of Earth (it’s a moon)
• Outer edge of habitable zone + erratic sunlight
• Receives 130% the UV radiation of Earth
• Atmosphere 50% as thick as Earth’s
• Planet is 50% land 50% ocean

Planet 6:

• Gravity is 85% that of Earth

• Planet is in the habitable zone but tidally locked to its star
• Receives 1000% the UV radiation of Earth
• Atmosphere much thicker than Earth’s
• Planet is 30% land and 70% ocean

Instructions

Your professor will assign you one of six planets. Create a detailed timeline of life on your planet by following the below instructions.

1. On the Map 1 page, if your planet has land, use a fistful of rice to randomly drop rice around the paper according to the percentage of land you have. When you are done, use a pencil to draw around the clusters of rice, creating continents. If you have the ocean planet, do the same thing, but use less rice. These locations will correspond to underwater mountains and rifts.
2. Using your knowledge of land and oceanic plates, create 10-20 tectonic plates on your world.
3. Decide how long it takes for life to evolve from the Last Common Universal Ancestor (LUCA) to macroscopic creatures.
4. Decide on three unique creatures which represent different fauna of your world (i.e. something that walks, something that swims, something that flies, etc). Make one from clay at its earliest stage of evolution, then draw it.
5. Create a second map from your first. Assume 1 billion years has passed, and so the existing continents have moved around, or merged, or subducted in the mantle.
6. For each creature, create and draw two further stages of evolution. It could have to adapt to: a colder/hotter climate, predators, changes in the atmosphere, etc.
7. Choose one of your three species to become intelligent. We will use “able to create and use tools” to define intelligence here. How does your creature adapt to be able to use tools?
8. Your intelligent species is now sentient. Answer these questions: how does it treat natural resources? [is it careful about resource depletion? Is nature sacred?] What celestial objects does it find religiously significant? [does it worship the sun or moon? A different philosophy? A person?] What kind of economy does it develop? [Bartering? Currency? Important trade items?]
9. What kind of spaceships would have to be designed to accommodate your species’ newfound desire to explore the solar system? Come up with three specific accessible design features that consider the physical abilities of your species.
10. Describe how does your species handle first contact with:
    1. A technologically superior, warlike species?
    2. A technologically superior, peaceful species?
    3. A technologically less advanced species?