“Evolution” MCQ with Answer Explanation : NEET 2025.

31. Which of the following processes can lead to adaptive radiation?
    A) Mass extinction events
    B) Stabilizing selection
    C) Genetic drift
    D) Artificial selection
    Answer: A) Mass extinction events

Explanation: Adaptive radiation often occurs after mass extinction events, where surviving species rapidly diversify to fill available ecological niches. The removal of dominant species creates opportunities for new species to evolve and adapt to different environments.

32. In Darwin’s theory of evolution, which factor primarily influences the process of natural selection?
    A) Genetic mutation
    B) Environmental pressures
    C) Human intervention
    D) Random mating
    Answer: B) Environmental pressures

Explanation: Environmental pressures, such as availability of resources, predation, and climate, influence which traits are favorable for survival and reproduction. Natural selection acts on individuals with advantageous traits that improve their fitness in a given environment.

33. Which of the following is an example of artificial selection?
    A) The development of antibiotic resistance in bacteria
    B) Breeding dogs for specific traits
    C) Evolution of the peppered moth
    D) Changes in plant traits due to climate change
    Answer: B) Breeding dogs for specific traits

Explanation: Artificial selection occurs when humans selectively breed individuals with desired traits to produce offspring with those traits. The breeding of dogs for specific characteristics, such as size, color, or behavior, is a prime example of artificial selection.

34. Which of the following statements is true about mutations?
    A) All mutations are harmful to organisms.
    B) Mutations are the only source of genetic variation.
    C) Most mutations have no effect on an organism’s fitness.
    D) Mutations only occur in reproductive cells.
    Answer: C) Most mutations have no effect on an organism’s fitness.

Explanation: While some mutations can be harmful or beneficial, many mutations are neutral and do not significantly impact an organism’s fitness. Mutations can occur in any cell, including somatic (non-reproductive) cells, although only mutations in germ cells can be passed to offspring.

35. Which type of isolation occurs when two populations breed at different times?
    A) Temporal isolation
    B) Behavioral isolation
    C) Mechanical isolation
    D) Geographic isolation
    Answer: A) Temporal isolation

Explanation: Temporal isolation occurs when two populations breed at different times, preventing them from mating even if they inhabit the same area. This can be due to differences in mating seasons or times of day.

36. Which of the following is NOT a prezygotic barrier to reproduction?
    A) Temporal isolation
    B) Mechanical isolation
    C) Gametic isolation
    D) Hybrid sterility
    Answer: D) Hybrid sterility

Explanation: Hybrid sterility is a postzygotic barrier, which occurs after fertilization, leading to offspring that are sterile (e.g., mules). In contrast, prezygotic barriers prevent mating or fertilization between species through mechanisms like temporal, mechanical, or gametic isolation.

37. Which of the following statements about fossils is true?
    A) Fossils can only be formed from hard body parts.
    B) Fossils provide direct evidence of the DNA of ancient organisms.
    C) Fossils can be dated using both absolute and relative dating techniques.
    D) Fossils are always preserved in sedimentary rock.
    Answer: C) Fossils can be dated using both absolute and relative dating techniques.

Explanation: Fossils can be dated using absolute dating (e.g., radiometric dating) to determine their age in years and relative dating to establish the order of layers in which fossils are found. Fossils can be found in various types of rock, but sedimentary rock is the most common.

38. What is the primary role of a mutation in evolution?
    A) To ensure species survival
    B) To create genetic diversity
    C) To enhance reproductive success
    D) To reduce competition
    Answer: B) To create genetic diversity

Explanation: Mutations introduce new genetic variations into a population’s gene pool, which is crucial for evolution. This genetic diversity provides raw material for natural selection to act upon, leading to the adaptation and evolution of species.

39. Which of the following is an example of a postzygotic barrier?
    A) Different mating calls of frogs
    B) Different blooming times of flowers
    C) Sperm unable to fertilize egg from another species
    D) Differences in mating rituals
    Answer: C) Sperm unable to fertilize egg from another species

Explanation: Postzygotic barriers occur after fertilization and prevent the development of viable or fertile offspring. An example is when sperm from one species cannot fertilize the eggs of another species, leading to unsuccessful reproduction.

40. The concept of “survival of the fittest” primarily refers to:
    A) The survival of the strongest individuals in a population
    B) The most intelligent individuals in a population
    C) The individuals best adapted to their environment
    D) The individuals with the most offspring
    Answer: C) The individuals best adapted to their environment

Explanation: “Survival of the fittest” means that individuals with traits best suited to their environment are more likely to survive and reproduce. It does not necessarily refer to physical strength or intelligence but rather to overall adaptability and reproductive success in a given environment.