Homologous structures like bat wings, whale flippers, and human arms demonstrate evolutionary relationship through:
AConvergent evolution
BDivergent evolution and common ancestry
CArtificial selection
DGenetic drift alone
Correct Answer:
B. Divergent evolution and common ancestry
EXPLANATION
These structures share similar bone arrangements despite different functions, indicating descent from a common ancestor with modification—evidence for divergent evolution.
A population of 500 individuals has allele frequencies of A = 0.7 and a = 0.3. If the population follows Hardy-Weinberg equilibrium, what will be the frequency of heterozygotes in the next generation?
A0.21
B0.42
C0.49
D0.09
Correct Answer:
B. 0.42
EXPLANATION
Using Hardy-Weinberg equation: frequency of Aa = 2pq = 2(0.7)(0.3) = 0.42. This remains constant across generations in equilibrium.
Correct Answer:
A. Geographic isolation → Genetic drift → Reproductive isolation → New species
EXPLANATION
Allopatric speciation begins with geographic isolation, followed by independent genetic drift and mutations in isolated populations, leading to reproductive isolation and eventually new species formation.
In Drosophila, the white eye mutation is X-linked recessive. If a heterozygous female is crossed with a normal male, what percentage of female offspring will have white eyes?
A0%
B25%
C50%
D100%
Correct Answer:
A. 0%
EXPLANATION
Heterozygous female (X^W X^w) × normal male (X^W Y) produces X^W X^W and X^W X^w females, both with normal eyes. White eyes appear only in males (X^w Y) at 50%.
Which of the following best describes the Hardy-Weinberg equilibrium principle?
AAllele frequencies remain constant across generations in the absence of evolutionary forces
BAll populations evolve at the same rate regardless of selection pressure
CDominant alleles always increase in frequency over time
DRecessive traits disappear from populations within few generations
Correct Answer:
A. Allele frequencies remain constant across generations in the absence of evolutionary forces
EXPLANATION
Hardy-Weinberg equilibrium states that allele frequencies remain constant when no evolutionary forces (mutation, selection, migration, genetic drift) act on a population.
