CH22HW PT.3

Natural selection is based on all of the following except

individuals adapt to their environments and, thereby, evolve.

Part C - Natural selection in monkey flowers Some monkey flowers (Mimulus guttatus) living near the sites of copper mines can grow in soil containing high concentrations of copper, which is toxic to most plants. Copper tolerance is a heritable trait. The map below shows the area near an old copper mine, which contaminated the nearby soil with copper. A stream flows past the mine toward the lake at the bottom right of the map. Use the map to determine which of the statements below are true. Select the three statements that are true.

Select the three statements that are true. Nearly 100% of monkey flowers growing in copper-contaminated soil are copper tolerant. If you were to test monkey flowers growing on the shore of the lake, you would expect nearly 100% of them to be copper tolerant. The population that existed before mining must have included both copper-tolerant and copper-intolerant plants. Correct Copper tolerance in monkey flowers is an example of a direct observation of evolution. Natural selection favors the survival and reproduction of copper-tolerant plants in copper-contaminated soils. Therefore, the allele for copper tolerance must have been present in some plants when the soil became contaminated. Because copper tolerance provides no benefit to plants in uncontaminated soils, the trait is not as common in plant populations growing outside the contaminated area.

From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.

organisms had adapted to new environments, giving rise to new species Darwin reasoned that natural selection had increased the match between the organisms and their environment.

Which of the following must exist in a population before natural selection can act upon that population?

sexual reproduction genetic variation among individuals

Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of

the fossil record.

The following question refers to the figure, which shows an outcrop of sedimentary rock whose strata are labeled A-D. If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?

two strata

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

uniformitarianism

Part B Scientists studying evolution on the Solomon Islands described which animal as the 'poster child' for the biological species concept?

white-eye bird

How many finch species did Darwin send to the British Museum?

13 Thirteen distinct species of finch were identified

Part A Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes.

Part B - Phylogenetic trees and geographic relationships The island fox, Urocyon littoralis, is endemic to the Channel Islands, which are located off the coast of southern California. Six of the eight Channel Islands support fox populations, and each of these islands is home to a distinct subspecies, as shown in the table below. Island Subspecies Northern Channel Islands Santa Cruz U. l. santacruzae Santa Rosa U. l. santarosae San Miguel U. l. littoralis Southern Channel Islands San Nicolas U. l. dickeyi San Clemente U. l. clementae Santa Catalina U. l. catalinae The island fox shares a common ancestor with the gray fox, Urocyon cinereoargenteus, which is found on the mainland. Both species have similar coloration and a diploid chromosome number of 66. One structural difference between the two species is the reduced size of the island fox, a feature known as dwarfism. The various island subspecies also differ from each other in size, number of tail vertebrae, and other characteristics. The phylogenetic tree below shows the evolutionary relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate locations on the tree. First, drag the blue labels onto the blue targets to identify the common ancestors at the branch points. Next, drag one white label onto the white target to identify the homologous characteristic. Then, drag one pink label onto the pink target to identify the relationship between the two species.

Correct One notable difference between gray foxes and island foxes is the small size of island foxes. This character (dwarfism) was exhibited by the common ancestor of all six island fox subspecies. Note that the northern Channel Island fox subspecies are more closely related to each other than to any of the southern subspecies, and that the southern subspecies are more closely related to each other than to the northern subspecies.

Evidence for Evolution Charles Darwin described evolution as "descent with modification," meaning that species change through time. A great deal of evidence indicates that life has evolved over time and continues to evolve. Natural selection is the primary mechanism by which evolution takes place. Part A - Scientific evidence supporting evolution Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories. Drag each phrase to the appropriate bin.

Correct Scientists have directly observed evolution occurring in many instances, including the development of drug resistance in bacteria and other pathogens. The fossil record has provided evidence for extinct species and for transitional forms of organisms, such as the ancestors of present-day horses. Homologies include similarities in structure, development, and DNA sequences in different organisms. Vestigial structures are homologous structures that have a reduced function or no function at all. Examples include the pelvic bones of whales. The geographic distribution of species, such as the high concentration of marsupial mammals in Australia, can provide evidence about common ancestors. In addition, the endemic species found on many island chains yield information about evolution on those islands.

Of the following anatomical structures, which is homologous to the wing of a bird?

Flipper of a cetacean

Part A The Galápagos Islands are cooled by the _____

Humboldt Current The Humboldt carries cool water northward from Antarctica.

Natural selection is based on all of the following except

Individuals adapt to their environments and, thereby, evolve.

Part D Why did the biologists consider a frog that they found to be a new species?

Its call was unique.

Which of the following observations led to Darwin's major inferences?

Members of a population vary in their heritable traits. Although organisms can produce huge numbers of offspring, many of these offspring do not survive. The first and fourth answers are correct. Both are important observations that led to Darwin's major inferences.

Part C Based on the video, what can you infer about speciation--the process by which one species splits into two or more species?

Physical separation of populations is often part of the speciation process.

A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?

The proportion of mottled fish will increase over time. The mottled fish will tend to escape predation because they are camouflaged against the mottled lake bottom. The mottled fish will most likely produce more offspring.

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

An adaptation is _____.

a trait that gives an organism a reproductive advantage in the current environment Evolutionary adaptations are inherited characteristics that enhance an organism's ability to survive and reproduce in a particular environment.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

by identifying the bones as being homologous structures by proposing that humans, bats, and dolphins share a common ancestor

Part E When Darwin wrote On the Origin of Species, he knew very little about the subject of _____, an essential component of evolutionary theory today.

genetics

Part A Where are the Solomon Islands located?

in the South Pacific

The theory of evolution through natural selection is considered a scientific theory because _____.

it is broad enough in scope to explain many observations it is supported by a massive body of evidence from many disciplines it is general enough to provide many testable hypotheses All of these answers relate to the definition of a scientific theory.