Genetic Survivor

There are lots of traits that differ from one person to the next. Most of them aren’t good or bad—they’re just different. But what if something changed, and a trait that’s neutral now suddenly became helpful or harmful?

In an imaginary future with killer grandmas or face-eating bacteria, how likely would you be to pass your genes to future generations?

Remember: natural selection can act only on existing trait variations!

When it comes to surviving and reproducing, genes are only part of the equation. People are clever, and you may be able to engineer a solution that will keep you (and your genes) from being wiped off the face of the earth. You might use platform shoes or stilts to keep your head above the deadly permasmog. And luck matters, too. Maybe you never run into any blind desert stalkers. So an unlucky combination of traits doesn’t doom you to an early death.

On the flip side, it isn’t enough just to survive. For your genes to live on, you must also reproduce. You may have a helpful trait combination, but If you don't have kids, your genes will still die out.

If you do survive and reproduce, there’s no guarantee your kids will share your traits. It will depend in part on your kids' other parent. If they have the same helpful traits as you, the chances are greater that your kids will too. But there’s a good chance that you and your partner will carry alleles that, through random allele shuffling, will give your kids some traits that are different from yours.

Plus there’s always the chance that the environment could change again. If that happens, a helpful trait might suddenly become neutral or even harmful.