Evolution MCQs set 3 for HEC USAT-M (Pre-Medical) Biology — 20 solved questions.
Q1. What is the term for the process by which organisms become better suited to their environments?
Answer: Natural selection
Explanation: Natural selection drives adaptation, others are random or genetic changes.
Q2. The evolution of the horse is an example of what type of evolutionary trend?
Answer: Cope's rule
Explanation: Cope's rule describes the trend towards increased body size, horse evolution is a classic example.
Q3. What is the term for the idea that evolution occurs in rapid bursts followed by long periods of stability?
Answer: Punctuated equilibrium
Explanation: Punctuated equilibrium describes rapid evolution followed by stability, others describe continuous change.
Q4. The fossil record shows that the evolution of whales from land-dwelling mammals occurred in a series of gradual steps. What type of evolution is this an example of?
Answer: Gradualism
Explanation: Gradualism describes continuous, slow evolution, whale evolution is a classic example.
Q5. What is the term for the idea that evolution is driven by the interaction between organisms and their environments?
Answer: Niche construction theory
Explanation: Niche construction theory describes the role of environment in evolution, others describe related concepts.
Q6. As populations evolve, genetic drift acts on variation through what mechanism?
Answer: Random sampling error
Explanation: Genetic drift occurs due to random sampling error
Q7. Which of the following types of speciation occurs when a new species emerges from an existing one without geographic isolation?
Answer: Sympatric speciation
Explanation: Sympatric speciation occurs without geographic isolation
Q8. A fossil record shows a sudden appearance of complex life forms. What is this phenomenon called?
Answer: Cambrian explosion
Explanation: Cambrian explosion refers to sudden appearance of complex life
Q9. A species has a high degree of genetic variation. What is the primary advantage of this variation?
Answer: Increased potential for evolution
Explanation: Genetic variation increases potential for evolution
Q10. Which of the following statements about homologous structures is true?
Answer: They have different functions but similar anatomy
Explanation: Homologous structures have similar anatomy but different functions
Q11. A population has a high frequency of a particular allele. What can be inferred about this allele?
Answer: It is beneficial and has been selected for
Explanation: High frequency allele is likely beneficial
Q12. Which of the following statements about analogous structures is true?
Answer: They have similar functions but different anatomy
Explanation: Analogous structures have similar functions but different anatomy
Q13. What is the term for the process by which a new species emerges from an existing one through geographic isolation?
Answer: Allopatric speciation
Explanation: Allopatric speciation occurs through geographic isolation
Q14. A fossil record shows a gradual change in the characteristics of a species over time. What is this phenomenon called?
Answer: Gradualism
Explanation: Gradualism refers to gradual change in characteristics
Q15. What is the term for the ability of an organism to survive and reproduce in a particular environment?
Answer: Fitness
Explanation: Fitness refers to ability to survive and reproduce
Q16. A population has a high degree of gene flow. What can be inferred about this population?
Answer: It is genetically uniform
Explanation: High gene flow leads to genetic uniformity
Q17. In a population of finches on an island, a severe drought leads to a scarcity of small seeds, resulting in the survival of finches with larger beaks. What is the primary mechanism driving this evolutionary change?
Answer: Natural selection acting on beak size
Explanation: Natural selection favors larger beaks, most tempting wrong option fails as genetic drift is random.
Q18. A species of bird undergoes a rapid evolutionary change in response to a change in its environment. Which of the following is the most likely reason for this rapid evolution?
Answer: Genetic variation already present in the population
Explanation: Pre-existing variation allows for quick adaptation, most tempting wrong option fails as mutation is rare.
Q19. In a study of the evolution of antibiotic resistance in bacteria, researchers find that resistance is more likely to develop in bacteria that are exposed to low levels of antibiotics. What is the primary mechanism driving this evolutionary change?
Answer: Natural selection acting on pre-existing genetic variation
Explanation: Natural selection favors resistant bacteria, most tempting wrong option fails as mutation is less common.
Q20. A group of scientists are studying the evolution of a particular trait in a population of animals. They find that the trait is influenced by multiple genes, each with a small effect. What is the most likely explanation for the evolution of this trait?
Answer: Polygenic inheritance with multiple genes contributing
Explanation: Polygenic inheritance explains small effect sizes, most tempting wrong option fails as single mutation is rare.