Which of the following statements is not Lamarck's postulate on evolution?

Analyze the question: We need the statement that is not part of Lamarck's theory. Three options are Lamarckian ideas, and one belongs to someone else (Darwin).

Concept: Lamarck's theory (Lamarckism) Jean-Baptiste Lamarck proposed that:

1. Environmental change creates new needs in organisms, leading to changes in species.
2. Use and disuse: organs used often become well developed, while those not used degenerate (become vestigial).
3. Inheritance of acquired characters: features developed during an organism's lifetime are passed to offspring.

Darwin's theory (Natural Selection) is different. It says:

• Organisms produce more offspring than can survive.
• There is variation and a struggle for existence.
• Those with useful inherited traits survive and reproduce ("survival of the fittest").

Checking each option:

• A. Environmental changes cause corresponding changes in species. This is Lamarckian.
• B. Use and disuse of organs. This is Lamarckian.
• C. Acquired characters are inheritable. This is Lamarckian.
• D. Survivors in a competitive community must have inherited useful traits. This is Darwinian natural selection, based on competition and survival of the fittest, not Lamarck.

Answer: D

Tip: Link the names to keywords:

• Lamarck = use and disuse and acquired characters inherited (think of the giraffe stretching its neck).
• Darwin = competition, variation, survival of the fittest, natural selection.

If you see "competition" or "fittest," think Darwin, not Lamarck.