CUET UG Biology Booster Test 2 Adaptive Radiation and Population Genetics -

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CUET UG Biology Booster Test 2 Adaptive Radiation and Population Genetics

⏱️ 30 Minutes

❓ 20 Questions

📌 Answers are locked once submitted — results and explanations appear at the end.

CUET UG Biology Booster Test 2 Adaptive Radiation and Population Genetics

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QUESTION 1 OF 20

Consider the following statements regarding Darwin's finches:
Statement I: Darwin conjectured that all varieties of the finches evolved on the Galapagos island itself.
Statement II: Darwin's finches are considered one of the best examples of adaptive radiation.

Answer Review

1 Consider the following statements regarding Darwin's finches:
Statement I: Darwin conjectured that all varieties of the finches evolved on the Galapagos island itself.
Statement II: Darwin's finches are considered one of the best examples of adaptive radiation.

A Statement I is true, Statement II is false.

B Statement I is false, Statement II is true.

C Both Statement I and Statement II are true.

D Both Statement I and Statement II are false.

💡 Short Explanation

Darwin observed diverse finch species on the Galapagos archipelago. He hypothesized that these species diverged from a common ancestral stock after reaching the islands. This diversification is the classic textbook definition of adaptive radiation.

✅ Correct Answer Explanation

�� Darwin's study of the Galapagos finches led him to the conclusion that a single ancestral species migrated to the islands and then underwent rapid diversification (adaptive radiation) to exploit different niches. Both statements are accurate reflections of his observations and the evolutionary significance of these birds.

❓ Why Other Options Are Incorrect

Option A → Statement I is true, as the radiation occurred on the islands.
Option B → Statement I is true, not false.
Option D → Both statements are widely accepted evolutionary facts.

🎯 Strategy

Used: Contextual/Tonal Matching

Application: Verify both statements against standard evolutionary biology curriculum.

Final Logic: Both statements align perfectly with established evolutionary theory regarding Darwin's finches.

🧠 Memory Trick

"Finch radiation = Galapagos = Adaptive."

📚 Evolution – Topic: Adaptive Radiation

2 Which of the following features is NOT associated with the adaptive changes in the beak shapes of Darwin's finches?

A The origin from a seed-eating ancestor.

B An adaptation to identical diets across all islands.

C Enabling some birds to become insectivorous.

D A representation of adaptive radiation.

💡 Short Explanation

Adaptive radiation relies on dietary differences (niche exploitation). Identical diets would not drive beak specialization. Finch beaks are highly varied precisely because their diets are varied.

✅ Correct Answer Explanation

�� Adaptive radiation is driven by the exploitation of different resources. The beak shapes changed specifically because different island populations had to adapt to different diets (insects, seeds, cactus fruits), not identical ones. Option B contradicts the core mechanism of adaptive radiation.

❓ Why Other Options Are Incorrect

Option A → True, they descended from a common seed-eating ancestor.
Option C → True, niche specialization included insect-eating beaks.
Option D → True, this is the primary phenomenon these finches exemplify.

🎯 Strategy

Used: Elimination

Application: Eliminate statements that are "True" (A, C, D) to find the "NOT associated" statement (B).

Final Logic: Divergent diets drive radiation; identical diets would not.

🧠 Memory Trick

"Different diet = Different beak."

📚 Evolution – Topic: Adaptive Radiation

📄 Passage

"This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. Darwin's finches represent one of the best examples of this phenomenon. Another example is Australian marsupials."

According to the passage, the defining characteristic of adaptive radiation is that it:

A Involves species converging to one physical form.

B Starts from a single point and radiates to other geographic habitats.

C Ensures that identical species evolve on separate continents.

D Eliminates variation in a given geographic area.

💡 Short Explanation

The passage explicitly defines adaptive radiation as starting from a single point and radiating. It emphasizes the movement into different habitats. It is a process of diversification, not convergence.

✅ Correct Answer Explanation

�� The passage provides a direct definition: "This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation." Option B paraphrases this exactly.

❓ Why Other Options Are Incorrect

Option A → This describes convergent evolution.
Option C → Radiation results in different species, not identical ones.
Option D → Adaptive radiation increases variation.

🎯 Strategy

Used: Substitution

Application: Directly compare options to the passage text.

Final Logic: Option B is a restatement of the passage's definition.

🧠 Memory Trick

"Radiation = Spread from Point of Origin."

📚 Evolution – Topic: Adaptive Radiation

📄 Passage

Based on the passage, if more than one adaptive radiation appeared to have occurred in an isolated geographical area (representing different habitats), it is referred to as:

A Genetic drift

B Disruptive selection

C Convergent evolution

D Stabilizing selection

💡 Short Explanation

Different radiations in the same area often lead to similar features in unrelated groups. This pattern of independent groups arriving at similar adaptive traits is convergent evolution. Australia (Marsupials vs. Placentals) is the classic example cited in NCERT.

✅ Correct Answer Explanation

�� The passage establishes that adaptive radiation happened in Australia for marsupials. When a different adaptive radiation (placental mammals) occurs in the same region, their independent evolution of similar traits (e.g., the placental wolf and the Tasmanian wolf) is called convergent evolution.

❓ Why Other Options Are Incorrect

Option A, B, D → These are mechanisms of population change or selection, not the name for the pattern of multiple independent radiations in one area.

🎯 Strategy

Used: Contextual/Tonal Matching

Application: Recognize the pattern of "Different groups, same area, similar features" Convergent Evolution.

Final Logic: The text uses this specific terminology to describe the placental/marsupial relationship.

🧠 Memory Trick

"Convergent = Different Radiation, Same Geography."

📚 Evolution – Topic: Convergent Mammalian Forms

5 Arrange the conceptual sequence of Australian marsupial evolution accurately:
I. A number of different marsupials emerged.
II. All forms evolved within the Australian island continent.
III. An ancestral marsupial stock existed.

A III → I → II

B I → II → III

C III → II → I

D II → I → III

💡 Short Explanation

Ancestor (III) is always the starting point. Radiation (I) produces the variety. Isolation (II) is the geographical context that allowed it.

✅ Correct Answer Explanation

�� Evolutionary logic dictates starting with the ancestor (III), followed by the process of radiation/differentiation (I), all of which occurred within the specific geographical context of the Australian continent (II).

❓ Why Other Options Are Incorrect

Option B, C, D → All break the logical chain of ancestor-to-descendant-to-environment.

🎯 Strategy

Used: Substitution

Application: Ancestor -> Differentiation -> Location.

Final Logic: A is the only chronologically sound order.

🧠 Memory Trick

"Start with Ancestor, Diversify, Then Isolate."

📚 Evolution – Topic: Australian Marsupials

6 The lack of competition from any other mammal that allowed pouched mammals of Australia to survive was primarily due to:

A High rate of mutations

B Continental drift

C Volcanic storms

D Artificial selection

💡 Short Explanation

Australia drifted away from other landmasses. This separated marsupials from placental competitors. "Continental drift" is the geologic mechanism for this isolation.

✅ Correct Answer Explanation

�� Continental drift caused the separation of Australia from other landmasses, leaving the marsupials isolated. Without placental mammals crossing over to compete for resources, the marsupials were free to undergo adaptive radiation.

❓ Why Other Options Are Incorrect

Option A → Mutation rates are not the cause of geographic isolation.
Option C → Volcanic activity is not the reason for marsupial-specific success.
Option D → Artificial selection is human-driven.

🎯 Strategy

Used: Elimination

Application: Rule out non-geological factors (A, C, D).

Final Logic: Continental drift is the geologic reality that explains the isolation of Australian fauna.

🧠 Memory Trick

"Drift = Isolation = No Competition."

📚 Evolution – Topic: Isolated Geographical Development

7 Match the evolutionary concept with its corresponding description.

List I	List II
1. Similar isolated habitats selecting similar adaptive features	a. Adaptive Radiation
2. Radiation of a single ancestral stock to different habitats	b. Convergent Evolution
3. Darwin's finches	c. Diversification from a common ancestor into different ecological niches
4. Australian marsupials and placental mammals	d. Independent evolution of similar adaptations

A 1-b, 2-a, 3-c, 4-d

B 1-a, 2-b, 3-d, 4-c

C 1-c, 2-d, 3-a, 4-b

D 1-d, 2-c, 3-b, 4-a

💡 Short Explanation

Similar environmental conditions can produce similar adaptations in unrelated organisms. Adaptive radiation results from diversification of a common ancestor. Darwin's finches illustrate adaptive radiation. Australian marsupials and placental mammals demonstrate convergent evolution.

✅ Correct Answer Explanation

The correct matching is: List I — List II 1. Similar isolated habitats selecting similar adaptive features — b. Convergent Evolution 2. Radiation of a single ancestral stock to different habitats — a. Adaptive Radiation 3. Darwin's finches — c. Diversification from a common ancestor into different ecological niches 4. Australian marsupials and placental mammals — d. Independent evolution of similar adaptations According to NCERT, adaptive radiation is the evolution of multiple species from a common ancestor that occupy different ecological niches, as illustrated by Darwin's finches. Convergent evolution occurs when unrelated organisms living under similar environmental conditions independently evolve similar adaptations. The resemblance between Australian marsupials and placental mammals is a classic example of convergent evolution. Therefore, the correct matching is 1-b, 2-a, 3-c, 4-d.

❓ Why Other Options Are Incorrect

Option B → Reverses the definitions of adaptive radiation and convergent evolution.
Option C → Incorrectly matches Darwin's finches and Australian mammals with the wrong evolutionary concepts.
Option D → Misaligns all the evolutionary descriptions.

🎯 Strategy

Used: Concept Matching

Application: Match each evolutionary phenomenon with its defining characteristic and standard NCERT example.

Final Logic:

Similar habitats → Convergent Evolution
Single ancestral stock → Adaptive Radiation
Darwin's finches → Adaptive Radiation
Australian mammals → Convergent Evolution

🧠 Memory Trick

Convergence → Different ancestors, similar forms.

📚 Class XII – Biology – Chapter: Evolution – Topic: Adaptive Radiation and Convergent Evolution

8 Which of the following is NOT an accurate comparison drawn by convergent evolution in mammals?

A Placental wolf and Tasmanian wolf-marsupial

B Placental mammals and corresponding Australian marsupials

C Darwin's seed-eating finch and Placental mammals

D Independent evolutionary lines resulting in similar body forms

💡 Short Explanation

Convergent evolution involves similar body forms. Seed-eating finches are birds; Placental mammals are mammals. These are not a convergent pair in evolutionary biology.

✅ Correct Answer Explanation

�� Convergent evolution compares placental and marsupial versions of the same ecological niche (e.g., wolves, anteaters). Darwin's finch is an example of adaptive radiation, not a convergent pair with a placental mammal.

❓ Why Other Options Are Incorrect

Option A → This is a classic convergent pair.
Option B → This represents the entire group comparison for convergent study.
Option D → This is the definition of convergent evolution.

🎯 Strategy

Used: Odd One Out

Application: C relates to Adaptive Radiation (Finches), while A and B relate to Convergent Evolution.

Final Logic: C does not fit the category of Convergent Mammalian Forms.

🧠 Memory Trick

"Convergent = Placental + Marsupial."

📚 Evolution – Topic: Convergent Mammalian Forms

9 In the context of Hardy-Weinberg equilibrium, a disturbance or change in the frequency of alleles in a population is interpreted as resulting in:

A Spontaneous generation

B Genetic drift elimination

C Evolution

D Perfect stabilizing selection

💡 Short Explanation

H-W = No evolution. Change in allele frequency = Evolution. This is the definition of evolution at the population level.

✅ Correct Answer Explanation

�� Genetic equilibrium means the gene pool is stable. If allele frequencies change, the population is no longer in equilibrium, which is the definition of evolution at the population level.

❓ Why Other Options Are Incorrect

Option A → Spontaneous generation is irrelevant.
Option B → Change doesn't eliminate drift.
Option D → Stabilizing selection is one type of evolution, not the general interpretation of "any" change.

🎯 Strategy

Used: Substitution

Application: "Evolution = Change in allele frequency."

Final Logic: Allelic change IS evolution.

🧠 Memory Trick

"Frequency Change = Evolution."

📚 Evolution – Topic: Hardy-Weinberg Principle

10 Consider the following statements about allele frequencies:
Statement I: In a stable population, the probability that an allele A with a frequency of p appears on both chromosomes of a diploid individual is (p^2).
Statement II: The frequency of a recessive allele 'a' is represented by 2pq.

A Both statements are correct.

B Statement I is correct, but Statement II is incorrect.

C Statement I is incorrect, but Statement II is correct.

D Both statements Are Incorrect.

💡 Short Explanation

AA genotype freq = p^2 (Statement I is correct). Recessive allele freq = q (not 2pq). Aa freq = 2pq.

✅ Correct Answer Explanation

�� In the H-W formula: p = dominant allele freq, q = recessive allele freq. Statement I is correct because probability of AA is p × p = p^2. Statement II is incorrect because 2pq represents the frequency of the heterozygous genotype (AA), not the frequency of the allele 'a'.

❓ Why Other Options Are Incorrect

Option A → Statement II is definitely incorrect.
Option C → Statement I is definitely correct.
Option D → Statement I is correct.

🎯 Strategy

Used: Elimination

Application: Test Statement I (Correct) vs Statement II (False).

Final Logic: I is true, II is false.

🧠 Memory Trick

"Aa=2pq; a=q."

📚 Evolution – Topic: Hardy-Weinberg Genotype Frequencies

11 Arrange the logical steps to formulate the Hardy-Weinberg equation for a diploid organism:
I. The sum of all allelic frequencies is 1 ((p+q=1)).
II. Alleles A and a have frequencies p and q respectively.
III. The probabilities of genotypes (AA), (AA), and (A) become (p^2), (2pq), and (q^2).
IV. The binomial expansion results in (p^2 + 2pq + q^2 = 1).

A I → II → III → IV

B II → I → III → IV

C II → III → I → IV

D I → III → II → IV

💡 Short Explanation

Define alleles (II). Establish sum of frequencies (I). Expand to genotypes (III). Form the final equation (IV).

✅ Correct Answer Explanation

�� The formulation starts by defining the variables (allele frequencies p and q). Then, you apply the rule that the sum of these frequencies must be 1. Following this, you apply binomial probability to derive the genotype frequencies based on the random combination of alleles, leading to the final H-W equation.

❓ Why Other Options Are Incorrect

Option A, C, D → All attempt to place the allele frequency sum (I) either before the definition of p and q or out of its logical mathematical sequence.

🎯 Strategy

Used: Contextual/Tonal Matching

Application: Logical derivation flow: Definitions -> Rules -> Probabilities -> Expansion.

Final Logic: II (Defining variables) must precede I (Summing them).

🧠 Memory Trick

"Define -> Sum -> Expand."

📚 Evolution – Topic: Algebraic Foundations

12 Which of the following factors is NOT one of the five factors known to affect the Hardy-Weinberg equilibrium?

A Gene migration

B Genetic drift

C Artificial breeding

D Genetic recombination

💡 Short Explanation

The five factors are: Mutation, Recombination, Gene flow (migration), Genetic drift, and Natural selection. "Artificial breeding" (or artificial selection) is not one of the five primary factors listed in the Hardy-Weinberg equilibrium framework.

✅ Correct Answer Explanation

�� According to the Hardy-Weinberg principle, the five evolutionary forces that disrupt equilibrium are: gene migration, genetic drift, mutation, genetic recombination, and natural selection. Artificial breeding is a human-directed process and not listed as one of these fundamental natural evolutionary forces.

❓ Why Other Options Are Incorrect

Option A, B, D → These are all recognized factors that disrupt Hardy-Weinberg equilibrium.

🎯 Strategy

Used: Elimination

Application: Use the standard NCERT list of five factors to eliminate the one that doesn't belong.

Final Logic: C is an external/human-driven factor, not a primary evolutionary mechanism listed in the H-W chapter.

🧠 Memory Trick

"M-R-G-G-S (Mutation, Recombination, Gene flow, Genetic drift, Selection)."

📚 Evolution – Topic: Factors affecting Equilibrium

13 Match the evolutionary factor with its corresponding outcome.

List I	List II
1. Gene Migration	a. Heritable variations enabling better survival leave more progeny
2. Natural Selection	b. Alleles are transferred from one population to another
3. Genetic Drift	c. Random changes in allele frequency, especially in small populations
4. Mutation	d. Introduces new heritable variations into the gene pool

A 1-b, 2-a, 3-c, 4-d

B 1-a, 2-b, 3-d, 4-c

C 1-c, 2-d, 3-a, 4-b

D 1-d, 2-c, 3-b, 4-a

💡 Short Explanation

Gene migration transfers alleles between populations. Natural selection increases the frequency of favourable traits. Genetic drift causes random changes in allele frequencies. Mutation introduces new genetic variations.

✅ Correct Answer Explanation

The correct matching is: List I — List II 1. Gene Migration — b. Alleles are transferred from one population to another 2. Natural Selection — a. Heritable variations enabling better survival leave more progeny 3. Genetic Drift — c. Random changes in allele frequency, especially in small populations 4. Mutation — d. Introduces new heritable variations into the gene pool According to NCERT, gene migration (gene flow) introduces or removes alleles when individuals migrate between populations. Natural selection favours individuals with advantageous heritable variations, allowing them to leave more offspring. Genetic drift produces random fluctuations in allele frequencies, particularly in small populations, while mutations create new alleles and provide the raw material for evolution. Therefore, the correct matching is 1-b, 2-a, 3-c, 4-d.

❓ Why Other Options Are Incorrect

Option B → Incorrectly exchanges the roles of gene migration and natural selection.
Option C → Incorrectly matches genetic drift and mutation.
Option D → Misaligns all four evolutionary factors with their outcomes.

🎯 Strategy

Used: Concept Matching

Application: Match each evolutionary factor with its direct effect on the gene pool according to NCERT.

Final Logic:

Migration → Transfer of alleles
Selection → Survival of the fittest
Drift → Random allele changes
Mutation → New genetic variation

🧠 Memory Trick

Mutate → New Variation

📚 Class XII – Biology – Chapter: Evolution – Topic: Factors Affecting Hardy–Weinberg Equilibrium

14 If an initial migration event causes an allele frequency change, what transforms this isolated event into "gene flow"?

A The occurrence of a random chance mutation.

B The migration happening multiple times.

C The immediate stabilization of the gene pool.

D The disruption of the natural habitat.

💡 Short Explanation

A single event is just migration/drift. "Flow" implies a continuous or repeating process.

✅ Correct Answer Explanation

�� The term "gene flow" denotes the ongoing, repeated exchange of genetic material between populations. A single, isolated migration event is usually categorized differently (like the founder effect); continuous movement is the defining trait of gene flow.

❓ Why Other Options Are Incorrect

Option A → Mutation is unrelated to the volume of migration.
Option C → Stabilization is the opposite of gene flow (which changes frequencies).
Option D → Habitat disruption doesn't define the "flow" process.

🎯 Strategy

Used: Contextual/Tonal Matching

Application: Match the word "flow" with "continuous" or "multiple."

Final Logic: B is the definition of "flow" (continuous movement).

🧠 Memory Trick

"Flow = Multiple."

📚 Evolution – Topic: Migration and Flow

15 Which of the following statements is NOT a characteristic of genetic drift?

A It operates primarily through random chance events.

B It affects allele frequencies in a population.

C It guarantees an increase in the population's adaptive fitness.

D It can lead to the founder effect.

💡 Short Explanation

Genetic drift is random. Random processes do not guarantee adaptive fitness (which requires selection).

✅ Correct Answer Explanation

�� Genetic drift is a stochastic (random) process. It does not select for "fitness"; rather, it can even cause the loss of beneficial alleles by sheer coincidence. Therefore, it does not guarantee an increase in adaptive fitness.

❓ Why Other Options Are Incorrect

Option A → True, drift is random.
Option B → True, it shifts frequencies.
Option D → True, founder effect is a type of drift.

🎯 Strategy

Used: Extreme Word Filter

Application: "Guarantees" is an extreme word that contradicts the randomness of drift.

Final Logic: C is false.

🧠 Memory Trick

"Drift = Chance, NOT Guaranteed Fitness."

📚 Evolution – Topic: Genetic Drift

16 The founder effect occurs when a change in allele frequency in a new sample of population is so extreme that:

A They revert to their ancestral stock.

B They become a different species.

C They immediately achieve genetic equilibrium.

D They lose the ability to undergo mutations.

💡 Short Explanation

Founder effect leads to rapid, drastic changes. This divergence can result in speciation.

✅ Correct Answer Explanation

�� When a small group of founders establishes a new population, their allele frequencies are often vastly different from the source. This isolation and change can lead to significant divergence, eventually resulting in the formation of a new species.

❓ Why Other Options Are Incorrect

Option A → They cannot revert to the original; they are isolated.
Option C → Drift disrupts equilibrium.
Option D → They continue to mutate.

🎯 Strategy

Used: Substitution

Application: Define the outcome of the Founder Effect in NCERT context.

Final Logic: Divergence/Speciation is the established end-point of this process.

🧠 Memory Trick

"Founder = New Species."

📚 Evolution – Topic: Founder Effect

17 According to Figure (A), what happens to the population distribution curve when stabilizing selection operates?

A The peak shifts towards one extreme value.

B Two independent peaks form at the extremes.

C The peak gets higher and narrower as more individuals acquire the mean character value.

D The curve flattens completely.

💡 Short Explanation

Stabilizing = Favoring the mean. The "average" individuals survive better. The curve peaks higher at the center.

✅ Correct Answer Explanation

�� In stabilizing selection, the extremes are selected against. Consequently, the bell curve tightens and grows taller at the center (the mean), as a larger percentage of the population conforms to the average trait.

❓ Why Other Options Are Incorrect

Option A → This is directional selection.
Option B → This is disruptive selection.
Option D → This is not a standard selection mode.

🎯 Strategy

Used: Substitution

Application: "Stabilizing" means "Focusing on the center."

Final Logic: C describes the physical "narrowing/peaking" of the distribution.

🧠 Memory Trick

"Stabilizing = Mean Peak."

📚 Evolution – Topic: Natural Selection Modes

18 Based on Figure(C), disruptive selection is characterized by:

A More individuals acquiring the mean character value.

B More individuals acquiring peripheral character values at both ends of the curve.

C Elimination of variations entirely.

D Shifting the entire curve in one direction.

💡 Short Explanation

Disruptive selection = Favoring the extremes. The mean is selected against. Peaks form at both ends.

✅ Correct Answer Explanation

�� Disruptive selection happens when environmental conditions favor individuals at both ends of the phenotypic spectrum. This results in a bimodal distribution where the frequency of extreme traits increases significantly.

❓ Why Other Options Are Incorrect

Option A → This is stabilizing selection.
Option C → Selection typically maintains or redirects variation, not eliminates it.
Option D → This is directional selection.

🎯 Strategy

Used: Substitution

Application: "Disruptive" means "Breaking the middle."

Final Logic: B accurately identifies the "extreme" phenotype preference.

🧠 Memory Trick

"Disruptive = Extremes."

📚 Evolution – Topic: Natural Selection Modes

19 How does variation due to recombination during gametogenesis contribute to evolution under natural selection?

A It forces the population to remain in Hardy-Weinberg equilibrium.

B It results in changed gene frequencies which, when coupled with enhanced reproductive success, makes it look like a different population.

C It strictly prevents the formation of new alleles.

D It eliminates all mutations immediately.

💡 Short Explanation

Recombination shuffles alleles. Natural selection filters these new combinations. If successful, the population evolves.

✅ Correct Answer Explanation

�� Genetic recombination creates novel allelic combinations. Natural selection then acts on these combinations, favoring those that increase reproductive fitness. Over time, this shifts the population's gene pool, which we perceive as an evolutionary change.

❓ Why Other Options Are Incorrect

Option A → Recombination disrupts equilibrium.
Option C → Recombination rearranges alleles (though mutation creates new ones).
Option D → Recombination does not eliminate mutations; selection does.

🎯 Strategy

Used: Elimination

Application: Choose the only statement that describes the "Recombination + Selection = Evolution" sequence.

Final Logic: B is the accurate description of the evolutionary mechanism.

🧠 Memory Trick

"Recombination + Selection = Change."

📚 Evolution – Topic: Factors of Change

20 According to Hugo deVries' concept of mutation (saltation), how do mutations differ from Darwinian variations?

A Mutations are small and directional; Darwinian variations are random.

B Mutations are random and directionless; Darwinian variations are small and directional.

C Both are exactly the same and operate slowly.

D Mutations only affect somatic cells, while Darwinian variations affect germ cells.

💡 Short Explanation

De Vries: Large, random mutations (saltation). Darwin: Small, directional variations.

✅ Correct Answer Explanation

�� Hugo de Vries proposed that mutations are sudden, random, and directionless ("saltation"). In contrast, Darwin's theory was based on the premise that variations are small, gradual, and accumulate in a direction favored by natural selection.

❓ Why Other Options Are Incorrect

Option A → Contradicts the definitions.
Option C → De Vries explicitly argued they were not the same.
Option D → Both theories discuss germ-line transmission for evolutionary impact.

🎯 Strategy

Used: Contextual/Tonal Matching

Application: Match "De Vries" with "Saltation/Random" and "Darwin" with "Gradual/Directional."

Final Logic: B accurately contrasts the two schools of thought.

🧠 Memory Trick

"De Vries = Sudden; Darwin = Gradual."

📚 Evolution – Topic: Mutation Impacts

CUET UG Biology Booster Test 2 Adaptive Radiation and Population Genetics

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