CLEP Biology Genetics & Biological Diversity 5 — Questions and Answers
Question 1: Which of the following is an example of allopatric speciation?
- Two populations of fish in the same lake evolving reproductive barriers
- A polyploid plant species arising within a single population
- A mountain range separating two populations of squirrels that diverge over time (Correct answer)
- A single bird population splitting by mating season preference
Correct answer: A mountain range separating two populations of squirrels that diverge over time
Allopatric speciation occurs when a physical geographic barrier separates populations, allowing them to diverge independently.
Question 2: Restriction fragment length polymorphisms (RFLPs) are useful in genetics because they:
- Directly mutate specific genes
- Serve as molecular markers to track inherited DNA regions (Correct answer)
- Synthesize new DNA strands
- Encode proteins that cut DNA at specific sites
Correct answer: Serve as molecular markers to track inherited DNA regions
RFLPs are DNA sequence variations that are detected as different-sized fragments after restriction enzyme digestion and can be used as genetic markers in linkage studies.
Question 3: What is the primary characteristic that distinguishes mosses (bryophytes) from ferns (pteridophytes)?
- Mosses are heterosporous while ferns are homosporous
- Mosses lack vascular tissue while ferns possess it (Correct answer)
- Mosses produce seeds while ferns do not
- Mosses are diploid-dominant while ferns are haploid-dominant
Correct answer: Mosses lack vascular tissue while ferns possess it
Bryophytes lack vascular tissue (xylem and phloem) and are non-vascular, while pteridophytes (ferns) possess vascular tissue.
Question 4: In population genetics, genetic drift has the greatest effect on:
- Large populations with high gene flow
- Small, isolated populations (Correct answer)
- Populations under strong directional selection
- Populations with high mutation rates
Correct answer: Small, isolated populations
Genetic drift (random changes in allele frequencies) has a disproportionately large effect in small populations, where chance events can significantly alter allele frequencies.
Question 5: Which of the following characteristics is shared by both gymnosperms and angiosperms?
- Production of flowers
- Enclosed seeds within a fruit
- Production of seeds (Correct answer)
- Double fertilization
Correct answer: Production of seeds
Both gymnosperms and angiosperms are seed-producing plants; the key difference is that angiosperm seeds are enclosed in fruit while gymnosperm seeds are naked.
Question 6: A frameshift mutation is caused by:
- Substitution of one nucleotide for another
- Insertion or deletion of a nucleotide not in multiples of three (Correct answer)
- A change in the start codon only
- Inversion of a large chromosome segment
Correct answer: Insertion or deletion of a nucleotide not in multiples of three
Frameshift mutations result from insertions or deletions of nucleotides in numbers that are not multiples of three, shifting the reading frame of all downstream codons.
Question 7: Which evolutionary mechanism involves the preferential survival and reproduction of individuals with traits better suited to their environment?
- Genetic drift
- Gene flow
- Natural selection (Correct answer)
- Mutation pressure
Correct answer: Natural selection
Natural selection is the process by which heritable traits that increase reproductive success become more common in a population over successive generations.
CLEP Biology Genetics & Biological Diversity 5
Which of the following is an example of allopatric speciation?