Summary:
- Every organism is different from every other organism.
- Every organism's genes are different, too.
- Mutations are natural.
- Some are harmful, but many are neutral.
- If a mutation is harmful, the organism may not live to reproduce.
- If the mutation is beneficial, that organism may have a better chance to survive.
- An organism that survives is likely to have offspring.
- If it does, it may pass the mutation on to its offspring.
- Traits that help an organism survive become more common.
- Over time, traits that hinder survival eventually disappear.