Short summary
The short answer is: partly, but not entirely. Some parts of evolution involve chance. Others do not. If you mix them together, the topic becomes confusing very quickly.
What is random
Two important parts of evolution involve chance.
Mutation
New DNA changes do not appear because an organism needs them. A bacterium does not “try” to create the exact mutation that would save it from an antibiotic. In that sense, mutation is random with respect to need.
Genetic drift
Genetic drift is also driven by chance. In small populations, some variants become more common or disappear simply because of random sampling.
What is not random in the same way
Natural selection is not random in that sense. If one inherited trait helps organisms survive or reproduce better in a certain environment, that trait tends to spread more often than a trait that hurts survival or reproduction.
The environment does not make choices consciously, but it does create a non-random filter.
A useful analogy
Imagine a deck of cards being shuffled. The deal is random. But now imagine a rule that says only red cards stay on the table. The arrival of cards was random, but the filtering was not.
Evolution is similar:
- new variation can appear without direction
- the spread of that variation can be shaped by non-random forces
Why this distinction matters
If people hear only the first part, they may think evolution is just chaos. But real populations show repeatable patterns when environments stay similar. Traits that improve success in those environments can repeatedly become more common.
That is why adaptation is possible.
A real-world example
In a population of bacteria, a resistant variant may already exist or arise by mutation. When an antibiotic is used, many non-resistant bacteria die. The resistant ones survive and multiply more often. The mutation was not planned, but the spread of resistance under antibiotic use is not random in the same sense.
Randomness does not mean “anything can happen”
Chance matters in biology, but it works within limits. Mutations affect real DNA. Selection acts in real environments. Organisms inherit traits from real parents. So evolution is not an unlimited free-for-all.
The best one-sentence answer
If you want a careful short answer, use this:
“Mutation and genetic drift involve chance, but natural selection makes evolutionary change partly non-random.”
That sentence is much closer to the scientific picture than saying evolution is either fully random or fully directed.