Difference Between Mutations and Darwinian Variations
Biology · Evolution · NEET
Mutations, proposed by Hugo de Vries, are large, sudden, random and directionless changes that appear in one step (called saltation). Darwinian variations are small, slow and directional changes that build up gradually. Memory hook: de Vries = "Directionless, big, one step" (D-B-O); Darwin = "Small, Slow, Steered" (S-S-S).
At a glance
Size of change
Large and sudden
Small and minor
Direction
Random and directionless
Directional
Speed / steps
Single step (saltation)
Slow and gradual
Proposed by
Hugo de Vries
Charles Darwin
Study material
Evening primrose plant
Variation seen across nature
Role in speciation
One big mutation causes new species
Small variations accumulate over time
Side-by-side NCERT contrast: de Vries mutations are large, sudden, random, directionless (saltation); Darwinian variations are small, directional and gradual.
Your doubts, answered
Are mutations and Darwinian variations the same thing?
No. They are opposite ideas about how new features appear. NCERT says mutations are random and directionless, while Darwinian variations are small and directional. Mutations are large and sudden; Darwinian variations are minor and build up slowly over many generations.
Why did de Vries say mutation causes evolution and not Darwin's variations?
Hugo de Vries worked on the evening primrose plant and saw large differences appear suddenly in the population. He believed such a big single change (not the small variations Darwin talked about) could create a new species. So he said mutation, not minor variation, drives evolution.
What is saltation in de Vries' mutation theory?
Saltation means a single-step large mutation. Darwin thought evolution was gradual (slow, many small steps). De Vries thought a new species could form in one big jump through a large mutation, and he called this jump saltation.
Are Darwinian variations directional or directionless?
Darwinian variations are directional. This means natural selection steers them toward useful traits over time. Mutations, in contrast, are directionless (random) — they happen without any aim to help the organism.
Did Darwin know about mutations?
No. Even though Mendel had spoken of inheritable factors, Darwin either ignored or stayed silent about them. The idea of mutation came later, in the first decade of the twentieth century, from Hugo de Vries.
⚠️ The NEET trap ✗ Mutations are small and directional; Darwinian variations are large and sudden. ✓ Mutations are large, sudden, random and directionless; Darwinian variations are small, slow and directional. 🧠 NTA swaps the two words. Remember: MUTATION = random + directionless (like a coin toss); DARWIN = directional (natural selection points the way).
Real NEET questions
NEET 2018
According to Hugo de Vries, the mechanism of evolution is
A · Phenotypic variations
B · Saltation ✓
C · Multiple step mutations
D · Minor mutations
Solution: De Vries believed a single large mutation could cause speciation, which he named saltation (single-step large mutation). It is not gradual phenotypic change or minor mutation. NCERT Ch 6 Evolution, p.119: 'deVries believed mutation caused speciation and hence called it saltation (single step large mutation).'
NEET 2019
Variations caused by mutation, as proposed by Hugo de Vries are
A · random and directional
B · random and directionless ✓
C · small and directional
D · small and directionless
Solution: NCERT states mutations are random and directionless, while Darwinian variations are small and directional. So mutation-caused variations are random and directionless. NCERT Ch 6 Evolution, p.119: 'Mutations are random and directionless while Darwinian variations are small and directional.'
Solved Evolution NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
What plant did Hugo de Vries use for his mutation work?
He worked on the evening primrose (Oenothera). Watching this plant, he saw large differences appear suddenly in a population and built his mutation theory from it.
Is mutation gradual or sudden?
Mutation is sudden. A large difference arises in a single step. This is opposite to Darwin's view of evolution, which he saw as slow and gradual.
What does 'directionless' mean for mutations?
It means a mutation happens randomly, with no aim to help the organism. It may be useful, harmful, or neutral. Darwinian variations are 'directional' because natural selection favours the useful ones over time.
Did population genetics settle the de Vries versus Darwin debate?
Later studies in population genetics brought clarity. Today we know both matter: mutation and recombination create variation, and natural selection acts on it in a directional way, so evolution uses both ideas together.
