Where Did Everybody Go?

Something strange happened around 245 million years ago. Almost 90 percent of all ocean-living species became extinct. Gone, for example, were all the trilobites and all but a handful of cephalopod species. Land plants and animals were reduced, too, although not as severely. An entire planet’s life was changed forever.

Where did everything go? As you remember from page 4, extinction is a normal part of Earth’s life. One species disappears and others evolve in its place. But at least five times in the past 500 million years, mass extinctions occurred at enormous rates over very short periods of time (in a few hours on our “year-long calendar of life” on page 6). Imagine! From 20 to 90 percent of all living things disappeared! These periods of extinction were followed by millions of years of recovery, then periods of rapid new evolution.

What was the cause of these mass extinctions? Scientists have come up with many ideas, but have proven none. Perhaps ocean levels or water temperatures changed. Maybe air temperatures or amounts of oxygen around the Earth dropped. (You can read about other ideas on page 22.) Whatever the causes, they must have been terrible, Earth-wide disasters.

EXTINCTION GAME. Is your time running out? Can you and a group of related species survive a wave of mass extinctions as you go through 300,000 years of time? Play alone or with a friend. You’ll need:

• This playing board. Each circle equals 10,000 years.
• Fifteen counters for each player. One counter equals 1 species. Counters can be coins, pebbles, buttons, or squares of paper.
• One of the dice from another game.

How to Play: Each player puts one counter at “Start.” Then flip a coin to see who goes first. To move, roll the die and move that many spaces. Discard the number of counters printed in the circle you land on. Take turns. Continue, subtracting 1, 2, or 3 counters at the end of each turn as you are directed. If you run out of counters before you reach “Finish,” your entire group of species is extinct. If you have counters left, you survived the mass extinction—happy evolution!

 

Extra Challenge: How many times can you survive in 10 rounds?

What’s the smallest number of species (counters) you can begin with and still survive?