Home Subjects NEET Zoology Genetics & Evolution

NEET Zoology
Genetics & Evolution

Zoology questions for NEET UG — Animal Kingdom, Human Physiology, Genetics, Evolution.

100 Q 6 Topics Take Test
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Difficulty: All Easy Medium Hard 21–30 of 100
Topics in NEET Zoology
In a population, the allele frequency of 'a' is 0.4 and 'A' is 0.6. If the population is in Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes?
A 0.24
B 0.36
C 0.48
D 0.16
Correct Answer:  C. 0.48
EXPLANATION

Frequency of heterozygotes = 2pq = 2(0.6)(0.4) = 0.48 in Hardy-Weinberg equilibrium.

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Which statement about mutations is correct?
A Mutations are always harmful to organisms
B Mutations occur at predictable rates in all genes
C Mutations provide raw material for evolution but are not directed
D Mutations increase in frequency during environmental stress
Correct Answer:  C. Mutations provide raw material for evolution but are not directed
EXPLANATION

Mutations are random, non-directed changes in DNA that provide genetic variation for natural selection to act upon. They're not inherently harmful or beneficial.

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A population of beetles shows industrial melanism. Dark beetles increased from 5% to 95% in 50 years in polluted areas. What type of selection is most likely operating?
A Stabilizing selection
B Directional selection
C Disruptive selection
D Artificial selection
Correct Answer:  B. Directional selection
EXPLANATION

Industrial melanism is a classic example of directional selection where environmental change (pollution) favors one phenotype (dark color) over another.

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In Drosophila, if the coefficient of inbreeding (F) increases, what is the expected change in heterozygosity?
A Heterozygosity decreases proportionally to F
B Heterozygosity increases proportionally to F
C Heterozygosity remains constant
D Heterozygosity shows random fluctuations
Correct Answer:  A. Heterozygosity decreases proportionally to F
EXPLANATION

Inbreeding increases homozygosity and decreases heterozygosity. The relationship is: Ht = H0(1-F), where heterozygosity decreases with increasing F.

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Which mechanism of evolution is most likely responsible for the loss of eyes in blind cave fish?
A Directional selection against eye development
B Neutral evolution and genetic drift
C Mutation pressure
D Gene flow from surface populations
Correct Answer:  B. Neutral evolution and genetic drift
EXPLANATION

In cave environments, eyes provide no selective advantage. Neutral mutations affecting eye development accumulate through genetic drift, resulting in eye loss.

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A recessive genetic disorder appears in 1% of a population. What is the frequency of the recessive allele (q)?
A 0.01
B 0.1
C 0.9
D 0.99
Correct Answer:  B. 0.1
EXPLANATION

If q² = 0.01, then q = √0.01 = 0.1. This is the frequency of the recessive allele.

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Which of the following represents the correct sequence of speciation in peripatric speciation?
A Small population isolated → Genetic drift → Reproductive isolation → New species
B Large population → Natural selection → Polyploidy → New species
C Gene flow reduction → Mutation accumulation → Speciation
D Geographic isolation → Gene flow continues → Speciation
Correct Answer:  A. Small population isolated → Genetic drift → Reproductive isolation → New species
EXPLANATION

Peripatric speciation occurs when a small population is geographically isolated, genetic drift acts strongly, leading to reproductive isolation and speciation.

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In a test cross with a heterozygous individual (Aa), if 40% of offspring show the dominant phenotype, what might this indicate?
A The recessive allele is lethal
B Incomplete dominance is occurring
C The dominant allele is lethal in homozygous condition
D Codominance is present
Correct Answer:  C. The dominant allele is lethal in homozygous condition
EXPLANATION

In a normal test cross (Aa × aa), expected ratio is 1:1 (50% each). 40% dominant suggests some homozygous dominant (AA) offspring are dying, indicating lethal homozygous dominant allele.

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What is the term for the evolutionary relationship where two or more species share a common ancestor?
A Convergent evolution
B Homoplasy
C Common descent
D Divergent evolution
Correct Answer:  C. Common descent
EXPLANATION

Common descent refers to the principle that all organisms share evolutionary ancestry, a fundamental concept in evolutionary biology.

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Which type of natural selection favors both extreme phenotypes over the intermediate phenotype?
A Disruptive selection
B Directional selection
C Stabilizing selection
D Balancing selection
Correct Answer:  A. Disruptive selection
EXPLANATION

Disruptive selection eliminates intermediate phenotypes and favors both extreme phenotypes, increasing genetic variation.

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