Biological Evolution - Mechanisms - Unsolved Practice Set
Chapter: Evolution | Topic: Biological Evolution Mechanisms
BIOLOGICAL EVOLUTION - MECHANISMS - UNSOLVED PRACTICE SET
Topic: Biological Evolution Mechanisms
Multiple Choice Questions
Q1. Which of the following is considered the ultimate source of new genetic variation in a population?
- Natural selection
- Mutation
- Genetic drift
- Gene flow
Q2. Evolution, at its most basic genetic level, can be defined as:
- A change in the physical appearance of an individual organism during its lifetime
- A change in allele frequencies in a population over successive generations
- The formation of new organs in an organism
- The extinction of a species
Q3. Random changes in allele frequencies, especially significant in small populations, is referred to as:
- Natural selection
- Genetic drift
- Gene flow
- Mutation
Q4. The "founder effect" refers to a special case of genetic drift that occurs when:
- A large population undergoes selection
- A small group of individuals establishes a new, isolated population, carrying only a fraction of the original population's genetic variation
- Two populations merge completely
- Mutation rates suddenly increase
Q5. The movement of alleles between populations due to migration of individuals is called:
- Gene flow
- Genetic drift
- Natural selection
- Adaptive radiation
Short Answer Questions
Q6. What is the ultimate source of variation upon which evolution depends?
Q7. Define genetic drift, and explain why it has a more significant effect in small populations.
Q8. What is the founder effect? Give a brief example if you can.
Q9. Differentiate between gene flow and genetic drift as mechanisms of evolution.
Long Answer Questions
Q10. Discuss the different mechanisms of evolution - mutation, gene flow, genetic drift, and natural selection - explaining how each contributes to changes in a population's genetic makeup over time.
Q11. Explain, using a suitable example, how the development of resistance to a chemical (like DDT resistance in insects) illustrates evolution occurring at a population level.
APPLICATION / ANALYSIS
Q12. A small group of animals gets isolated on a remote island after a natural event separates them from the mainland population. Over many generations, this island population shows noticeably different allele frequencies compared to the original mainland population, despite no strong environmental pressure. Explain, using your understanding of evolutionary mechanisms, which process is most likely responsible for this rapid genetic change.
Q13. In a population of insects repeatedly exposed to a pesticide, a small number of individuals carrying a resistance-conferring mutation survive and reproduce, while most others die. Over several generations, the resistant form becomes dominant in the population. Explain how this scenario demonstrates evolution driven by natural selection acting on existing genetic variation.