One of the following is not the theory of natural selection stated by Charles Dawin

Analyze the question: We need the statement that is NOT part of Darwin's theory of natural selection.

Concept: Darwin's theory of natural selection rests on these ideas:

1. Variation exists naturally within a population (individuals differ).
2. Overproduction: more offspring are produced than can survive.
3. Struggle for existence: individuals compete for limited resources.
4. Survival of the fittest: individuals best suited to the environment survive and reproduce more.
5. Inheritance: favourable heritable variations are passed to offspring, so the population changes gradually over generations.

The idea of use and disuse with inheritance of acquired characteristics belongs to Jean-Baptiste Lamarck, not Darwin.

Checking each option:

• A. Acquired characteristics through use or disuse being transmitted to offspring is Lamarckism, so it is not Darwin's theory.
• B. Variations appear naturally in a population. Darwin accepted this (he did not know the cause, but he recognised that variation exists).
• C. Heritable variations are passed to offspring. This is part of Darwin's theory.
• D. The fittest are better adapted and leave more offspring. This is the core of natural selection.

Answer: A. It describes Lamarck's theory, not Darwin's.

Exam tip: Link the names to the ideas:

• Lamarck = Use and disuse + acquired traits (think "Lamarck = Lazy giraffe stretching its neck").
• Darwin = Natural selection / survival of the fittest.

Whenever you see "acquired characteristics are inherited" in an option for a "which is NOT Darwin" question, it is almost always the answer.