Q.Which of the following was the contribution of Hugo de Vries? a) Theory of mutation b) Theory of natural Selection c) Theory of inheritance of acquired characters d) Germplasm theory

Hugo de Vries proposed the mutation theory after observing sudden, striking variations in the Evening Primrose (Oenothera lamarckiana). Unlike Lamarck and Darwin, who held that new species arise from the gradual accumulation of small variations, de Vries argued that new species arise abruptly, through large, discontinuous mutations. Salient features: mutations are heritable and transmitted to future generations; they arise spontaneously and recurrently in natural populations; mutant forms appear fully formed, with no intermediate stages linking them to the parent type; and mutants remain fully subject to natural selection like any other variant. The theory's core contribution — that discrete, heritable jumps in variation exist and matter for evolution — was later incorporated, alongside Darwinian gradualism, into the Modern Synthesis.

Searches for "mutation theory de Vries Oenothera lamarckiana" and "mutation theory vs Darwinism class 12 biology" are common around the Evolution chapter of the NCERT/CBSE Class 12 Biology curriculum, a comparative-theories topic that appears regularly in NEET biology. Distinguishing de Vries's abrupt, discontinuous mutations from Darwin's gradual variation is one of the most frequently asked conceptual contrasts in competitive-exam evolution questions.