According to Darwin, the driving force behind evolution is

In the phrase "Survival of the Fittest" the term "Fittest" refers to the organism's

Natural selection acts upon

From an evolutionary standpoint, the two male elk depicted above are engaged in

The birds shown above all have very different beak structure. These differences are known in evolutionary biology as

A gene mutation in a certain flower allows the flower to produce more seeds. The seeds each have the same chance of producing a new plant as do seeds from flowers that do not possess this mutation. It can be expected that

Delicious fruit is an adaptation in some flowering plants that assists in

Individual organisms within an existing population cannot

For centuries, dog breeders have chosen to breed particular dogs to pass on, or even enhance, desirable traits. This is an example of

The theory of evolution predicts that

The image above shows different body shapes within a population of giraffes (play along, OK?) The difference in body shape are an example of

The differences in antibiotic resistance among these bacteria is an example of

It is estimated that most people carry about 50 potentially lethal alleles. This is possible because

A population of people are isolated on an island, with no new immigrants over many generations. For this group, any new genetic variations are most likely to come from

An individual has his appendix removed, dyes his hair black, and intentionally gorges on food until he is morbidly obese. Which of these traits is likely to be passed on to any offspring?

A particular breed of hare has a coat that turns white in the winter to blend with the snow in its environment. One winter, no snow falls and the white coats make the hares easy for predators to see against the brown dirt. The most immediate expected result of this environmental change is that

Fireflies are able to distinguish between their own species and other species by the rate and brightness of their flashing patterns. This is an example of:

The best explanation for the very few species of mammals on the Galapagos Islands is:

Rapid changes in the gene pool of a population are LEAST likely to occur when there is:

Polydactyly (having six fingers per hand) is a hereditary condition caused by a dominant gene. The rarity with which this condition is seen in human populations is probably because

The picture above is of a male blue-footed booby, engaged in a mating "dance." This is an example of:

Domesticated rats, the variety you can purchase at a pet store, come in a wide range of color and coat patterns. Many of these coat variations are rarely, if ever, seen in nature. Their presence in the pet store is the result of

Two populations of similar organisms will be considered separate species when they

Great Danes and Chihuahuas are both descended from wild breeds of dogs, but can no longer interbreed. This is due to:

The numbers in the picture above show the postions of 3 fossils found deposited in the sedimentary rock. Which statement IS NOT true?

The evolutionary model known as punctuated equilibrium explains why

In biological terms, the organism that is most successful within its population is the one that

Edible fruit is an adaptation in some flowering plants that provides an advantage in

In a population of white and brown rats, 16% of the rats have a white coat. Assuming that white coat color is a recessive trait, what percentage of the rats are heterozygous for the color allele?

In a population of white and brown rats, 16% of the rats have a white coat. Assuming that white coat color is a recessive trait, what percentage of the total color alleles code for brown coats?

Which of the following are considered a disturbing influence on a population that is at Hardy-Weinberg equilibrium?

An experiment was conducted by Diane Dodd in which a single population of fruit flies was divided into two, with one of the populations fed with starch-based food and the other with maltose-based food. After the populations had diverged over many generations, the groups were again mixed; it was observed that the flies continued to prefer mating with others from the same original population. This process could eventually result in

In a population of white and brown rats, 16% of the rats have a white coat. Assuming that white coat color is a recessive trait, is the frequency of the white color allele in the population?

Above you see the lovable castaways of Gilligan's Island. Imagine that Ginger, the red head, is struck on the head by a falling coconut and killed. Her demise eliminates the red-hair allele from the small population of the island. The elimination of the allele is an example of

Information courtesy Wikipedia

The House Sparrow is native to Europe, Asia, and parts of North Africa. It was introduced to North America when a group of one hundred birds from England was released in Brooklyn, New York, and today its range is spread from northern British Columbia to Labrador in and down through most of the United States through Central America. It is most commonly found in agricultural, urban, or suburban areas, and avoids unmodified areas such as woodlands, forests, grasslands, and deserts. The process by which the house sparrow has spread through North America is known as

The use of antibiotics over the last sixty-five years has resulted in a drastic increase in populations of bacteria that are resistant to many antibiotics. The most probable cause of this change in bacterial populations is that