AP BIO Chapter 21
1) If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average
homozygosity of the species should be
A) 23%.
B) 46%.
C) 54%.
D) There is not enough information to say.
54%.
Which variable is likely to undergo the largest change in value resulting from a mutation that
introduces a new allele into a population at a locus for which all individuals formerly had been
fully homozygous?
A) average heterozygosity
B) nucleotide variability
C) geographic variability
D) average number of loci
average heterozygosity
Which statement about the beak size of finches on the island of Daphne Major during
prolonged drought is true?
A) Each bird evolved a deeper, stronger beak as the drought persisted.
B) Each bird's survival was strongly influenced by the depth and strength of its beak as the
drought persisted.
C) Each bird that survived the drought produced only offspring with deeper, stronger beaks than
seen in the previous generation.
D) The frequency of the strong-beak alleles increased in each bird as the drought persisted.
Each bird's survival was strongly influenced by the depth and strength of its beak as the
drought persisted.
The higher the proportion of loci that are "fixed" in a population, the lower is that population's
A) nucleotide variability only.
B) chromosome number only.
C) average heterozygosity only.
D) nucleotide variability, average heterozygosity, and chromosome number.
E) nucleotide variability and average heterozygosity.
nucleotide variability and average heterozygosity.
Rank the following one-base-point mutations (from most likely to least likely) with respect to
their likelihood of affecting the structure of the corresponding polypeptide:
1. insertion mutation deep within an intron
2. substitution mutation at the third position of an exonic codon
3. substitution mutation at the second position of an exonic codon
4. deletion mutation within the first exon of the gene
A) 1, 2, 3, 4
B) 4, 3, 2, 1
C) 2, 1, 4, 3
D) 3, 1, 4, 2
E) 2, 3, 1, 4
4, 3, 2, 1