Mechanisms of Evolution

What is the change in allele frequencies in a population known as?

• Selective breeding

• Natural selection

• Evolution

• Random mating

Recall that sickle-cell is recessive. Who has an advantage where there is no malaria? Homozygous dominant, heterozygous, or homozygous recessive?

• Homozygous dominant

• Heterozygous

• Homozygous recessive

• None of the above

The "Blue People of Kentucky," have a rare recessive disorder called methemoglobinemia which turns their skin blue. Martin Fugate and his wife came to Troublesome Creek from France and had four children who were blue. Without railroads, their descendants stayed in a small, isolated community. Alva Stacy remarked "If you'll notice -- I'm kin to myself." What is the cause of this pattern?

• Genetic bottleneck

• Founder effect

• Natural selection

• Artificial selection

After the last ice age, 75% of large mammals from North America went extinct abruptly (approximately 40 species disappeared: saber-tooth tigers, mastodons, mammoths, dire wolves, short-faced bears, American lions and cheetahs). Cheetah ancestors dropped to low numbers and were obliged to inbreed, mating with close relatives to survive. Now, cheetahs are all genetically very similar. What pattern is this?

• Genetic bottleneck

• Founder effect

• Sexual selection

• Artificial selection

The equation for allele frequencies in a population:

• p + 2pq = 1

• p² + 2pq + q² = 1

• p - q = 1

• p + q = 1

• 2p² + pq + 2q² = 1

The frequency of homozygous recessive individuals in a population:

• p

• q

• 2pq

• p²

• q²

The frequency for alleles coding for favorable traits __________________ in a population over time

• increases

• decreases

• stays the same

• fluctuates randomly

True or false: new mutations occur randomly.

• True

• False

Aside from damage to the DNA, what is the main source of new mutations in a gene pool?

• Malfunctioning mitochondria

• DNA replication errors

• Damage to RNA

• Migration to a new environment

Does natural selection act directly on genotype, phenotype, both, or neither of the two?

• Genotype

• Phenotype

• Both

• Neither