Mutations vs Variation in Evolution — NEET Biology
✅ Asked in NEET 2022Select the correct statement regarding mutation theory of evolution. (NEET 2022 Phase 2)
Select the correct statement regarding mutation theory of evolution. (NEET 2022 Phase 2)
Variations caused by mutation, as proposed by Hugo de Vries, are (NEET 2019)
According to Hugo de Vries, the mechanism of evolution is: (NEET 2018)
Answer & NCERT explanation
Correct answer: D — Single step large mutation is a cause of speciation
Hugo de Vries' mutation theory proposed that single large mutations (saltations) can cause immediate speciation, not gradual small changes. This contradicts Darwin's gradual evolution concept. De Vries studied evening primrose and suggested that new species arise suddenly through major genetic changes, making single-step large mutation a direct cause of speciation according to his theory.
Read more NCERT concept on the PYQ
What is the origin of this variation and how does speciation occur? Even though Mendel had talked of inheritable 'factors' influencing phenotype, Darwin either ignored these observations or kept silence. In the first decade of twentieth century, Hugo deVries based on his work on evening primrose brought forth the idea of mutations – large difference arising suddenly in a population. He believed that it is mutation which causes evolution and not the minor variations (heritable) that Darwin talked about. Mutations are random and directionless while Darwinian variations are small and directional. Evolution for Darwin was gradual while deVries believed mutation caused speciation and hence called it saltation (single step large mutation). Studies in population genetics, later, brought out some clarity.
NTA tests students on the key difference between Hugo deVries' mutation theory and Darwin's variation theory. Mutations are large, sudden, random changes that cause saltation (evolution in single steps), while Darwinian variations are small, gradual, and directional. Students often confuse these concepts or mix them up. The critical mistake is thinking all variations lead to speciation equally—they don't. Remember: deVries believed mutations alone drive evolution and speciation, whereas Darwin emphasized gradual change through natural selection of small variations. NTA repeatedly asks which scientist proposed which theory to test conceptual clarity on evolutionary mechanisms.
What does NCERT say about What origin this variation?
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Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.