AL's quiz 9

Which of the following describes the most likely order of events in allopatric speciation?

genetic isolation, genetic drift, divergence

The possible collision of a large meteorite with Earth 65 million years ago may explain

the mass extinction that killed off the dinosaurs

Which of the following organisms would be most likely to form a fossil?

a common squirrel

The largest unit within which gene flow can readily occur is ________.

A species

The first person to put forth the idea that Earth's continents are in continual but slow motion was

Alfred Wegener

Which of the following is not considered a plausible hypothesis for the causes of mass extinctions?

Competition among organisms

Which of the following geological periods is the most recent (closest to the present)?

Cretaceous

How was early Earth from more than three billion years ago different from today's Earth? Unlike Earth today, early Earth ________.

Had an atmosphere rich in gasses released from volcanic eruptions

Supporting the claim that a meteorite caused the mass extinction at the end of the Cretaceous period, abnormally high concentrations of _______ have been found in rocks dating from that time.

Iridium

Which statement describes unity within a species?

Members have the potential to interbreed in nature and produce viable, fertile offspring.

Why would gene duplication events, such as those seen in the Hox gene complex, set the stage for adaptive radiation?

One copy of a gene can perform the original function, while other copies are available to take on new functions.

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of ________.

Sympatric speciation and habitat isolation

Why are fossils considered to be an incomplete record of evolution?

The fossil record is biased for organisms that had hard shells and skeletons.

How are two different species most likely to evolve from one ancestral species?

allopatrically, after the ancestral species has split into two populations

A hybrid zone is properly defined as ________.

an area where mating occurs between members of two closely related species, producing viable offspring

Which of the following would be least likely to appear in the fossil record?

desert-dwelling species

Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy: Hyla chrysoscelis is diploid, and Hyla versicolor is tetraploid. The frogs are identical in appearance, but their mating calls, which females use to find mates, differ. Which difference most likely evolved first?

polyploidy

Two species of frogs belonging to the same genus occasionally mate, but the embryos stop developing after a day and then die. These two frog species separate by ________.

reduced hybrid viability

Among known plant species, which of these have been the two most commonly occurring phenomena that have led to the origin of new species?

sympatric speciation and polyploidy

A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island, and their beaks begin to change. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________.

tend to slow the adaptation to the new food plants