Mutation Creates Variation
Understand how genetic mutations create new variation in populations for Grade 8 evolution science. Students learn that mutations are random gene changes that produce new proteins and new traits—like the first newt that developed stronger poison—introducing novel variation that natural selection can then act on.
Key Concepts
When a gene mutates, it gives instructions to build a different protein . This altered protein creates a new structure or function in the body—a new trait .
For example, long ago, a random mutation occurred in a single newt that caused it to produce slightly stronger poison. Before that moment, the trait did not exist. Mutations introduce new variation into a population.
Common Questions
What is a genetic mutation and how does it create new traits?
A mutation is a random change to the DNA instructions in a gene. The altered instructions build a different protein, which creates a different structure or function—a new trait. For example, a mutation in a newt produced a gene that built a stronger poison-producing protein.
Are mutations always harmful?
No—mutations are random and can be harmful, neutral, or beneficial depending on the environment. The poison-strength mutation in newts had no particular advantage until garter snakes began predating the population. Then the previously neutral trait became powerfully beneficial.
Why does natural selection depend on mutations to create new traits?
Natural selection can only work with variation that already exists in a population. Mutations are the ultimate source of new genetic variation—they introduce traits that have never existed before. Without mutation, selection would exhaust available variation and evolution would stall.