Bio Exam 3

Which statement is correct? Evolutionary change is not always due to genetic differences. Natural selection chooses between populations, not individuals. Populations can evolve, but individuals cannot. Natural selection can change an individual's allele frequencies.

Populations can evolve, but individuals cannot.

After his journey on the HMS Beagle, Darwin made this now-famous sketch in his notebook. Which ideas does it represent?

All species are linked to one another by common ancestry. All species are connected to one another in a "family tree." Species descend from other species just as naturally as children come from parents.

Why is the continual use of the antibacterial triclosan in soaps a potential health risk?

Bacteria could evolve a resistance to commonly used antibiotics.

How did the drought lead to an increase in beak size in the medium ground finch population? The Grants reasoned that prior to the drought, the finch population fed primarily on small seeds that they could open easily. Although larger, tougher seeds were available, they were not typically eaten, not even by finches with larger beaks. during the drought, only a limited number of small seeds were produced, leaving mostly larger, tougher seeds available for food. Finches that were unable to eat the larger seeds died of starvation. Based on their observations and the data they collected, the Grants concluded that evolution by natural selection had occurred in the medium ground finch population. The increase in the average beak size of the offspring was a direct result of the change in the food supply during the drought. In order to have reached this conclusion, the Grants must have either assumed or proven that several other facts about the finch population were true. Which statements represent information that must be true in order for the Grants conclusion to be correct? Select the three statements that must be true.

Beak size varies among the birds in the finch population under study. Birds that could eat larger, tougher seeds survived and reproduced during the drought. Beak size is an inherited trait in the finch population under study.

Darwin and Wallace independently arrived at the same conclusion that species change over time. Which observations supported their conclusions?

Bird families clustered geographically: cockatoos in the Malay Archipelago and Australia, macaws and hummingbirds in the Americas. Tortoises from different Galapagos islands have distinct shells. The fossilized remains of giant sloths were similar to the smaller, living sloths Darwin encountered. Mockingbirds from different Galapagos islands had subtle, consistent differences. The bony shells of armadillos resembled fossilized shells from the extinct Glyptodon. Birdwing butterflies were found throughout the Malay archipelago, but species differed slightly from island to island.

Darwin and Wallace made independent observations in different parts of the world. Which statements are true?

Both observed slightly different species on nearby islands and concluded that species could change over time. Both collected huge numbers of specimens and realized that individuals vary within species. Both witnessed nature up close and realized it was a battlefield with massive casualties.

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?

Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

What did Wallace conclude from observing that the bones in manatee flippers look similar to the bones in a human arm and hand?

Manatees' arm and finger bones are evidence that manatees share a common ancestor with land mammals.

When Charles Darwin set sail on the HMS Beagle, what did he and most of his contemporary scientists think about the origin of species?

Most scientists, including Darwin, thought each species was specially created by God in its present form and did not change over time.

Which observations led Darwin to establish a relationship between extinct and living animals?

The bony shells of armadillos resembled the shells of ancient Glyptodon fossils. The fossilized remains of giant sloths were found in places where smaller sloths now live.

Although the Grants did not begin their study of the finch population until the early 1970s, there is enough information to assume that prior to the 1977 drought, rainfall was sufficient and the finch population thrived by eating abundant, smaller seeds. It is also assumed that during that period of time, no other environmental changes affected the finch population. After 1977, rainfall amounts returned to their normal pre-drought levels for the next 25 years. Smaller seeds were once again abundant on the island. Which graph shows your prediction of how the finch population's average beak size changed in the 25 years after the drought (shown in red)?

The graph that shows a decrease of the average beak size to around the average beak size before the drought

What does it mean to say that a trait is heritable?

The trait has a genetic basis and can be passed from parent to offspring

As Wallace traveled the Malay Archipelago, he noticed that western islands had placental mammals, like monkeys. Eastern islands had marsupial mammals, like kangaroos. How did Wallace explain this distribution?

The western islands were once connected to Asia and the eastern islands had been connected to Australia. The islands had never been connected to each other.

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?

Triazine-resistant weeds were more likely to survive and reproduce.

In biology, an adaptation is defined as _____.

a heritable trait that increases the fitness of an individual in a particular environment

Which of the following is the best modern definition of evolution?

descent with modification

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks, survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where Tribulus cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island.

evolution of yet larger, deeper beaks over time

In biology, fitness is defined as _____.

the ability of an individual to produce surviving offspring