Key Idea.
Section 1
Mutation is Random
It is critical to understand that mutations are random.
Organisms cannot "try" to mutate because they need a new trait. A newt didn't get a poison mutation because snakes were eating it. The mutation happened by accident.
Section 2
Selection is Non-Random
While the arrival of a trait is random, its survival is not.
Once a mutation introduces a new trait, the environment decides its fate. If the mutation makes the newt more poisonous (Adaptive), it spreads. If the mutation makes the newt slower (Non-Adaptive), it disappears. This explains how random changes can lead to perfect adaptations.
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Section 1
Mutation is Random
It is critical to understand that mutations are random.
Organisms cannot "try" to mutate because they need a new trait. A newt didn't get a poison mutation because snakes were eating it. The mutation happened by accident.
Section 2
Selection is Non-Random
While the arrival of a trait is random, its survival is not.
Once a mutation introduces a new trait, the environment decides its fate. If the mutation makes the newt more poisonous (Adaptive), it spreads. If the mutation makes the newt slower (Non-Adaptive), it disappears. This explains how random changes can lead to perfect adaptations.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter