Two closely related nocturnal species of frogs in the same marsh sometimes mate, but the embryos almost always fail to complete development. The mechanism maintaining these frog species is __________.

a. reduced hybrid fertility
b. gametic isolation
c. reduced hybrid viability
d. temporal isolation
e. habitat isolation


Answer: c. reduced hybrid viability

Biology & Microbiology

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Imagine that you are searching for the gene associated with nail-patella syndrome, a dominant genetic disorder that causes developmental abnormalities. In a large pedigree you discover an association between nail-patella syndrome and a genetic marker that

occurs in two different alleles, A and B. Fifteen individuals within this pedigree have nail-patella syndrome and are A/B heterozygotes for the marker. Thirty individuals within this pedigree don't suffer from nail-patella syndrome and are homozygous for the A marker allele. One individual within this pedigree has nail-patella syndrome and is also homozygous for the A marker allele. The most likely explanation for this exceptional individual is that _____. A) a new mutation converted the disease-causing allele to the wild-type form B) a new mutation converted the B allele of the marker to the A form C) the exceptional nail-patella individual is haploid D) recombination occurred between the nail-patella gene and marker locus in one of the parents of the exceptional individual

Biology & Microbiology

If a fungus encountered a particularly rich food source, what would be the expected result?

A. Hyphae would branch and extend rapidly to form a mycelium. B. Hyphae would stop growing in length, but increase in diameter. C. Individual hyphae would begin to produce spores. D. Hyphae would stop growing and a fruiting body would form to exploit the food source. E. The mycelium would break down into widely separated hyphae.

Biology & Microbiology

The most numerous cells carried in the plasma

are

a. erythrocytes. b. leukocytes. c. platelets. d. thrombocytes. e. cyanocytes

Biology & Microbiology

Neisseria gonorrhoeae circumvents our iron-sequestering defenses by

A) breaking down red blood cells to get to the iron-rich hemoglobin inside. B) capturing our iron-binding proteins and pulling the iron out of them for their own use. C) making siderophores that pull iron from our iron-binding proteins. D) using manganese in their metal-requiring enzymes instead of iron. E) releasing lytic enzymes and then scavenging the debris for iron.

Biology & Microbiology