Biology Test Biology Genetics & Evolution 3 — Questions and Answers
Question 1: What does the Hardy-Weinberg principle predict about allele frequencies in a population?
- They increase over time due to selection
- They remain constant in the absence of evolutionary forces (Correct answer)
- They decrease due to genetic drift
- They fluctuate randomly each generation
Correct answer: They remain constant in the absence of evolutionary forces
The Hardy-Weinberg principle states allele and genotype frequencies remain constant across generations in a non-evolving population.
Question 2: Which stage of meiosis results in genetic recombination via crossing over?
- Metaphase I
- Prophase I (Correct answer)
- Anaphase II
- Telophase II
Correct answer: Prophase I
Crossing over between homologous chromosomes occurs during Prophase I of meiosis, generating new allele combinations.
Question 3: A gene has two alleles with frequencies p = 0.6 and q = 0.4. Under Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes?
- 0.16
- 0.36
- 0.48 (Correct answer)
- 0.24
Correct answer: 0.48
Heterozygote frequency = 2pq = 2 × 0.6 × 0.4 = 0.48.
Question 4: What distinguishes microevolution from macroevolution?
- Microevolution involves large-scale changes; macroevolution involves small allele shifts
- Microevolution is changes in allele frequency within a species; macroevolution is species-level divergence and above (Correct answer)
- Microevolution only occurs in bacteria; macroevolution occurs in eukaryotes
- They are identical processes
Correct answer: Microevolution is changes in allele frequency within a species; macroevolution is species-level divergence and above
Microevolution refers to allele frequency changes within a population, while macroevolution encompasses speciation and higher-level evolutionary changes.
Question 5: Which mutation type results in an amino acid change that may or may not affect protein function?
- Silent mutation
- Nonsense mutation
- Missense mutation (Correct answer)
- Frameshift mutation
Correct answer: Missense mutation
Missense mutations change one codon to code for a different amino acid, which may or may not impact protein function depending on the change.
Question 6: What is the role of restriction enzymes in recombinant DNA technology?
- They copy DNA strands
- They cut DNA at specific sequences (Correct answer)
- They join DNA fragments together
- They transcribe DNA into RNA
Correct answer: They cut DNA at specific sequences
Restriction enzymes recognize specific DNA sequences and cleave the DNA at or near those sites, enabling gene cloning and manipulation.
Question 7: Which concept explains why islands often have unique species found nowhere else on Earth?
- Gene flow from mainland populations
- Convergent evolution replacing all species
- Geographic isolation leading to independent speciation (Correct answer)
- The founder effect preventing any evolution
Correct answer: Geographic isolation leading to independent speciation
Islands are geographically isolated, so colonizing populations evolve independently over time, producing endemic species through allopatric speciation.
Biology Test Biology Genetics & Evolution 3
What does the Hardy-Weinberg principle predict about allele frequencies in a population?