Ch 10

What is the best definition of a population?

• a group of species that share the same habitat

• a group of individuals of the same species that have the potential to interbreed

• a group of individuals of the same species that live in the same general location and have the potential to interbreed

• a group of individuals of related species that live in the same general location and have the potential to interbreed

• a group of individuals of the same species that live in the same general location and have the same genotypes

Which statement about Charles Darwin is false?

• He dropped out of medical school.

• He and Alfred Russell Wallace independently developed the theory of evolution by natural selection.

• He was enthusiastic about unleashing his theory of natural selection on the world as soon as he thought of it.

• He was under constant pressure from his father to make something of himself.

• He spent five years traveling the world, observing living organisms and collecting fossils.

Darwin made which of the following observations during his journey aboard the HMS Beagle?

• Although Galápagos finches had different physical attributes, they resembled mainland finches in Ecuador.

• The largest and most fit organisms tended to have a higher rate of survival.

• Galápagos finch populations were growing faster than the available food supply.

• In Argentina, extant glyptodonts closely resembled extinct armadillos, only the armadillos were much larger.

• He discovered the fossil remains of large animals, such as giant ground sloths and mastodons, deep in coal and slate mines.

Which statement represents a change in people’s worldview after Darwin published The Origin of Species?

• Earth is mostly unchanging.

• Earth is approximately 6,000 years old.

• Organisms are fixed, with no additions or extinctions.

• Every extant organism was put on earth by a creator at the same time.

• Organisms change and adapt over time.

Evolution is defined as:

• survival of the fittest.

• a change in the frequency of a physical trait in a population over time.

• a progressive “ladder” of changes from the most primitive organisms to the most advanced organisms.

• a change in a physical trait of an individual during its lifetime.

• a change in the frequency of alleles in a population over time.

Evolution occurs:

• only through natural selection.

• only when the environment is changing.

• only via natural selection, genetic drift, migration, or mutation.

• almost entirely because of directional selection.

• by altering physical traits but not behavioral traits.

The origin of all genetic variation is:

• mutation.

• natural selection.

• gene flow.

• genetic drift.

• non-random mating.

In a particular population, over the course of several dozen generations, an adenine was replaced by a guanine at a particular noncoding locus in the DNA base sequence. The evolutionary mechanism responsible for this change was:

• genetic drift.

• migration.

• mutation.

• directional selection.

• disruptive selection.

When a sudden change in the environment, such as a flood or fire, reduces the size of a population, the survivors’ collective gene pool will be only a limited representation of what was present before the disaster. This phenomenon is called the:

• Hardy-Weinberg effect.

• the founder effect.

• bottleneck effect.

• culling effect.

• genetic load.

Genetic drift leads to fixation when an allele’s frequency reaches _____ in a population.

• 1%

• 10%

• 50%

• 51%

• 100%