Microevolution Quiz – Flashcards

A population of pond snails has two genetically determined types: one with a black stripe on its shell and one with a plain brown shell. Evidence indicates that there is absolutely no difference between the two snail types in terms of their fitness: each type survives, grows, and mates with the same average level of success. Over time, black-striped snails become more or less common in a population due to chance events. At one point, for example, the pond nearly dries up and the few surviving snails happen to be mostly black-striped. This evolutionary change is the result of... A) mutation B) genetic drift C) gene flow D) natural selection E) sexual selection

A storm uproots 60% of the trees in a population. This is an example of: A) Gene flow B) Natural selection C) Genetic drift D) Gene pool

The sickle cell allele is more likely to have higher prevalence in populations where: A) Antibiotics are available B) Antibiotics are not available C) Malaria is present D) Malaria is not present

Modern HIV therapy controls HIV infection through what strategy? A) A single drug that stops viral replication is paired with another drug that prevents the virus from mutating so that it cannot evolve resistance. B) A single very effective drug stops viral replication by targeting a key viral enzyme that is indispensable to the virus. C) Several different drugs are used that target different viral enzymes; if the virus evolves resistance to one drug, a different set of drugs is used.

Which gene pool has changed through some process of microevolution? A) A moth population increases from 3,000 individuals to 33,000 individuals over a period of favorable weather. B) A mouse population (about 10,000 mice total) starts with 99% of the mice tan and 1% white; after 20 years 70% are tan and 30% are white. C) Your cells express different genes today than they did when you were born.

Humans are the only primate species in which mammary glands (breasts) remain large and prominent throughout adulthood. Other primates' mammary glands swell only when they are nursing offspring; scientists are not sure why human females have noticeable breasts on a permanent basis. One hypothesis is that they increase a female's ability to attract mates. If so, this would be an example of a trait favored by... A) genetic drift B) natural selection C) sexual selection D) gene flow E) artificial selection

Each year a gardener saves seeds from those tomato plants that produce the juiciest fruits. She uses these seeds to plant the next year's crop of 20 plants. Over time, the gardener develops her own special variety of very juicy tomatoes. This is best described as an example of... A) mutation B) sexual selection C) genetic drift D) natural selection E) artificial selection

What sorts of effects do new mutations have on the individuals that inherit them? A) Mutations do not affect proteins or alter phenotypes; they only affect gene sequences (DNA). B) Mutations disrupt the normal development of an organism. They produce phenotypes that are bizarre and have a poor chance of survival. C) Mutations can have a wide range of effects on proteins and therefore phenotypes. They may have no effect, a negative effect, or a positive effect on survival, growth, mating success, etc.

______________ can occur only if there are two or more separate gene pools that are exchanging individuals (through migration) or genes. A) natural selection B) mutation C) genetic drift D) gene flow