Homework #6 Descent with Modification
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Activity: The Voyage of the Beagle: Darwin’s Trip Around the World
Click here to complete this activity.
Then answer the questions.
Darwin’s thinking while on the Beagle was greatly influenced by his reading of a book written by _____.
Darwin was greatly influenced by Lyell’s Principles of Geology.
According to this climatograph, London experiences more precipitation during _____ than during any other month.
Precipitation is greatest in October.
Which of these is a consequence of uniformitarianism?
Earth is very old.
Populations reproduce faster than their food supply.
A Creator made Earth.
Earth is round, not flat.
Uniformitarianism holds that geologic processes occur today in much the same way as they did in the past.
The Argentinean pampas are a type of _____.
temperate deciduous forest
The pampas are treeless plains.
At the fossil site at Punta Alta, Darwin found evidence _____.
that Brazilian flatworms were a type of slug
of divine creation
that extinction does not happen
that the pampas could support large mammals
At Punta Alta, Darwin found the bones of types of mammals that no longer lived.
Patagonia is a _____.
Patagonia is a desert.
His experiences with Fuegians and slavery convinced Darwin that differences among all peoples are primarily _____ differences.
cultural and genetic
due to height
genetic and height-related
Darwin observed that there is no inborn superiority or inferiority separating different peoples.
Species in hot climates tend to _____ compared to species in cold climates.
experience less interspecific competition
be less colorful
have larger surface-to-volume ratios
have smaller surface-to-volume ratios
have less fear of humans
This makes it easier for these species to cool off.
In the Andes, at elevations of 12,000 feet, Darwin collected fossilized marine shells. The existence of marine shells at this altitude provided evidence that _____.
Earth’s surface does not change
marine organisms can survive at great elevation
the deposit had been gradually uplifted to its present location
someone carried them from the oceans and left them on the mountains
geologic processes occur at a rapid rate
The location where the marine shells were found was once at the bottom of an ocean.
The Galápagos Islands are located _____.
off the coast of California
Off the coast of Ecuador
in the Antarctic
off the coast of Brazil
in the Arctic
The Galápagos Islands are located on the equator off the coast of Ecuador.
Why were the Galápagos Islands so important to Darwin’s formulation of natural selection?
The species found on the Galápagos Islands are also found in Australia.
Each island in the Galápagos possessed unique species.
They provided evidence in support of uniformitarianism.
They are where Darwin did most of his writing.
The Galápagos Islands are the only place in the world where finches are found.
The origin of so many unique species in a small geographical area intrigued Darwin, and played a role in his formulation of natural selection.
Activity: Darwin and the Galapagos Islands
Click here to complete this activity.
Then answer the questions.
The Galápagos Islands are cooled by the _____.
The Humboldt carries cool water northward from Antarctica.
How many finch species did Darwin send to the British Museum?
Thirteen distinct species of finch were identified.
Activity: Artificial Selection
Click here to view this animation.
Then answer the questions.
Which of the following statements about natural selection is true?
What conditions must be met for natural selection to occur?
Natural selection favors individuals that reproduce more than others.
Natural selection can be used by farmers to generate organisms with desirable traits.
Natural selection is a process whereby genes are selected randomly for preservation in the next generation.
Natural selection occurs in opposition to evolution.
Individuals who are better able to survive and reproduce are more likely to be selected for than individuals who don’t survive or cannot reproduce.
Which term describes a trait that increases an individual’s ability to survive in a particular environment?
How do individuals change to accommodate their environment?
An adaptation is a trait that increases an individual’s ability to survive in a particular environment.
Which term describes the ability of a trait to be passed on to offspring?
How do offspring obtain traits from their parents?
Heritability is the ability of a trait to be passed on to offspring.
Which of the following organisms could be produced by artificial selection?
Remember that artificial selection only works for heritable traits.
A cow that produces a large quantity of milk.
A dog that serves as the “eyes” for a blind individual.
A rabbit that is housebroken.
A chimpanzee that communicates through sign language.
A cow’s ability to produce milk is a heritable trait that can be manipulated by artificial selection.
Which pair of chickens should a farmer breed to produce larger chickens?
Consider which parental animals have the traits desired in the offspring.
Small hen, small rooster
Small hen, large rooster
Large hen, large rooster
Large hen, small rooster
Large parents should be bred to produce larger offspring.
A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year’s crop:
Individual A—Yield: 179 bushels/acre; drought resistance: high
Individual B—Yield: 220 bushels/acre; drought resistance: low
Individual C—Yield: 185 bushels/acre; drought resistance: medium
Individual D—Yield: 140 bushels/acre; drought resistance: high
Individual E—Yield: 200 bushels/acre; drought resistance: medium
Which of the following crosses would produce the highest corn yield with the highest resistance to drought?
Determine the average yield and drought resistance expected from each cross.
A and B
C and E
B and B
A and E
This cross would result in an average corn yield of 189.5 bushels/acre and have a medium-high drought resistance, which is the best you can get for both traits.
Chapter 22 Question 2
Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier’s attempt to explain the existence of
the fossil record.
the origin of new species.
Chapter 22 Question 5
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?
Disuse of an organ may lead to its eventual disappearance.
Only favorable adaptations have survival value.
Spontaneous mutations can result in the appearance of new traits.
If the giraffes did not have to compete with each other, longer necks would not have been passed on to the next generation.
Characteristics acquired during an organism’s life are generally not passed on through genes.
Chapter 22 Question 7
In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko’s attempts in this regard were most in agreement with the ideas of
Chapter 22 Question 9
Which of these conditions should completely prevent the occurrence of evolution in a population over time?
The environment is changing at a relatively slow rate.
The population lives in a habitat where there are no competing species present.
All phenotypic variation between individuals is due only to environmental factors.
The population size is large.
Chapter 22 Question 8
Charles Darwin was the first person to propose
that population growth can outpace the growth of food resources.
a mechanism for how evolution occurs.
that evolution occurs.
that Earth is older than a few thousand years.
a mechanism for evolution that was supported by evidence.
Chapter 22 Question 11
Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?
Earth changed over the years through a series of catastrophic upheavals.
The environment is responsible for natural selection.
Earth is more than 10,000 years old.
Populations tend to increase at a faster rate than their food supply normally allows.
Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future.
Chapter 22 Question 19
The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an example of artificial selection because
humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin.
humans are becoming resistant to bacteria by taking methicillin.
humans purposefully raise MRSA in large fermenters in an attempt to make the bacteria ever-more resistant.
S. aureus is cultivated by humans to replenish the soil with nutrients.
Activity: Reconstructing Forelimbs
Click here to complete this activity.
Then answer the questions.
Which of the following is(are) homologous to the bones in this image?
The digits of a cat are homologous to those of these whale bones.
The wing of a bat is homologous to the _____ of a whale.
The bones of a bat wing and a whale flipper are homologous.
Chapter 22 Question 24
If two modern organisms are distantly related in an evolutionary sense, then one should expect that
they shared a common ancestor relatively recently.
their chromosomes should be very similar.
they should share fewer homologous structures than two more closely related organisms.
they live in very different habitats.
they should be members of the same genus.
Chapter 22 Question 32
Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?
Chapter 22 Question 35
It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that
island forms and mainland forms have identical gene pools.
common environments are inhabited by the same organisms.
the islands were originally part of the continent.
island forms and mainland forms descended from common ancestors.
the island forms and mainland forms are converging.
Chapter 22 Question 48
About 13 different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that
arrived a few million years ago. Genetically, there are four distinct lineages, but the 13 species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza).
If the six ground finch species have evolved most recently, then which of these is the most logical prediction?
They should share fewer anatomical homologies with each other than they share with the tree finches.
They should be limited to the six islands that most recently emerged from the sea.
Their genomes should be more similar to each other than are the genomes of the five tree finch species.
The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species.
ABC News Video: Exploring Evolution in the Solomon Islands
Watch the ABC News video (2:18 minutes). Then answer the questions to the right.
Where are the Solomon Islands located?
off the southern tip of Florida
off the coast of California
in the South Pacific
in the Mediterranean Sea
Scientists studying evolution on the Solomon Islands described which animal as the ‘poster child’ for the biological species concept?
Based on the video, what can you infer about speciation–the process by which one species splits into two or more species?
New species typically form as a consequence of new parasites or predators in the environment.
It is rare for new species to form on islands.
Different species are typically very different in appearance, even if they are closely related.
Physical separation of populations is often part of the speciation process.
Why did the biologists consider a frog that they found to be a new species?
It was larger than any known frog.
Its call was unique.
It jumped higher than other known frogs.
Its coloration was different from other known frogs.
When Darwin wrote On the Origin of Species, he knew very little about the subject of _____, an essential component of evolutionary theory today.
ABC News Video: Protecting the Galapagos Islands
Watch the ABC News video (2:07 minutes). Then answer the questions below.
Where are the Galapagos Islands located?
northeast of Australia along the Great Barrier Reef
near the tip of South Africa
600 miles west of Ecuador, near the equator
in the Mediterranean Sea, as part of the Greek Islands
Which of the following sets of animals are likely to be found on the Galapagos Islands?
tortoises, finches, blue-footed boobies
beaver, snakes, armadillos
frogs, lungfish, mountain goats
ostriches, cougars, porcupines
Which species is threatening the natural wildlife on the Galapagos Islands?
The Galapagos Islands were the first place on Earth to _____.
suffer the complete extinction of all native species
be declared off-limits to all humans
be declared a world heritage site
be invaded by human-introduced species
Tourism on the Galapagos Islands is being restricted by requiring tourists to _____.
be escorted by trained guides at all times
view the islands only from the water
visit each island in groups of only ten individuals at a time
stay at least 100 feet away from all animals on the islands
Current Events: A Colorful Way to Watch Evolution in Nebraska’s Sand Dunes (New York Times, 8/8/2011)
Read this New York Times article and then answer the questions.
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What is unique about deer mice?
They are the only mice found in one distinct color.
They are the most populous mouse found in North America.
They are the only mice that hibernate.
They are the only mice that reproduce three times per year.
For this project, which of the following are scientists studying?
lab and wild mice
You wish to research how genetics determine color of deer mice. How many genes should you focus on?
The three-spine stickleback typically lacks armor in fresh water. Why?
To allow for faster growth.
The armor hinders its hunting.
It doesn’t need the protection.
Due to delayed development.
Which of the following is true?
Genotype and phenotype are the same thing.
Genotype determines phenotype.
Phenotype determines genotype.
Genotype and phenotype are not related.
Misconception Question 108
Soapberry bugs use needlelike “beaks” to feed on seeds within the fruits of various plants. Bugs feed most successfully when their beak length matches the size of the fruit on which they are feeding. For 25 years, populations of soapberry bugs in central Florida have been feeding on small goldenrain tree fruits that were introduced to the area, rather than on the larger native balloon vine fruits that serve as food for other soapberry bug populations. Beak lengths of soapberry bugs are variable, but the average beak length is shorter in soapberry bug populations that feed on goldenrain tree fruits than in populations that feed on balloon vine fruits, as shown in the graph. How does natural selection act on beak length in soapberry bug populations?
Natural selection increases beak length in soapberry bug populations.
The action of natural selection on beak length in soapberry bug populations varies with the environment.
Natural selection decreases beak length in soapberry bug populations.
Traits favored by natural selection may change as the environment in which a population lives changes. Selection and adaptation must always be discussed in the context of a particular environment. Soapberry bugs feed most effectively when their beak length closely matches the size of the seed-containing fruit. In central Florida, where soapberry bugs feed on small goldenrain tree fruits, natural selection has reduced average beak length in the population of bugs. However, in Louisiana, where soapberry bugs feed on larger fruits, natural selection has increased average beak length in the population of bugs.
Misconception Question 109
What happened in the soapberry bug population in central Florida when the bugs began to feed on smaller goldenrain tree fruits?
Bugs developed short beaks, because they needed them to feed on the small fruits.
Bugs with shorter beaks had more access to food, allowing them to produce more offspring.
The length of each bug’s beak gradually became shorter over time.
Bugs that happened to have short beaks were better able to feed on the small fruits. Their increased access to food allowed them to produce more offspring, which also had small beaks. However, bugs with small beaks did not arise in order to feed on the small fruits. Evolutionary change comes about as the proportion of individuals in the population displaying a particular trait increases from generation to generation. The trait does not change gradually in all members of the population.
Chapter 22 Question 5
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that
humans and chimpanzees share a relatively recent common ancestor.
humans and chimpanzees are not closely related.
chimpanzees evolved from humans.
convergent evolution led to the DNA similarities.
humans evolved from chimpanzees.
Chapter 22 Pre-Test Question 1
Which of the following is an example of the pattern of evolution? (Overview)
The pattern of evolutionary change is revealed by data.
the fossil record of the evolution of modern cetaceans
the inheritance of acquired characteristics
descent with modification
The fossil record contains observable data regarding both the morphological development and biogeographical distribution of early cetaceans.
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.
Hint 1. What are the meanings of the terms relating to evidence for evolution?
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.
Hint 2. Skeletal structure of mammalian forelimbs
The forelimbs of mammals, regardless of shape or function, have the same arrangement of bones. The most parsimonious explanation (the one that is least complex and requires the fewest evolutionary changes) is that the different forelimbs represent variations of a structure present in a common ancestor. The image below shows the forelimbs of four mammals: human, cat, whale, and bat.
Similar characteristics in different species that result from having a common ancestor are called homologies.
Hint 3. Transitional forms and extinct species
The fossil record shows that present-day organisms differ from past organisms and that many species have become extinct. In addition, fossils can
document evolutionary changes that have occurred in particular groups of organisms through time. For example, the following diagram shows part of the fossil record of horses. Notice that the large present-day horse (Equus), which has a single toe on each foot and teeth adapted for grazing, evolved from a small, many-toed ancestor (Hyracotherium) with teeth adapted for browsing. With the exception of Equus, all of the organisms shown in the diagram are extinct.
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.
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.
|Santa Cruz||U. l.|
|San Miguel||U. l. littoralis|
|San Nicolas||U. l. dickeyi|
|Southern Channel||San||U. l.|
|Santa||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.
Hint 1. How to read a phylogenetic tree
A phylogenetic tree is a diagram that reflects evolutionary relationships among groups of organisms. Each branch point in the tree represents the common ancestor of the lineages beginning at that point or to the right of it. In the tree below, branch point 1 represents the common ancestor of species A, B, and C, whereas branch point 2 represents the common ancestor of species B and C.
A hatch mark in a phylogenetic tree represents a homologous characteristic shared by all the groups to the right of the mark. In this example, the hatch mark indicates a homologous characteristic shared by species B and C; that characteristic is not found in species A.
In the tree below, species B and C are more closely related than species A and B because they share the more recent common ancestor.
Hint 2. How can you determine the relatedness of species on a phylogenetic tree?
Based on the information in the tree below, rank the given pairs of species from most closely related to least closely related.
Rank the pairs from most closely related to least closely related.
Hint 3. Can you place homologous characteristics on a phylogenetic tree?
The following table lists characters of five imaginary animal species. A check-mark (√) indicates the presence of a character, and a dash ( ) indicates the absence of a character.
|eyes tail||legs||hair posture|
Add the characters to the appropriate places on the phylogenetic tree shown below. Drag the labels onto the phylogenetic tree. ANSWER:
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.
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.
Hint 1. Process of natural selection
Natural selection includes the following main ideas:
Individuals within a population vary.
Much of the variation is due to heritable traits.
In any given environment, some heritable traits give individuals a higher probability of surviving and reproducing.
Individuals that have such traits tend to leave more offspring than other individuals.
Therefore, the frequency of favorable traits increases in the population over generations.
Hint 2. Can you outline the steps in natural selection in another example?
The increased frequency of copper tolerance in monkey flowers can be compared to the increased frequency of drug resistance in bacteria. What are the steps leading to drug resistance in a population of bacteria?
Drag the labels to their appropriate labels on the flowchart.
Natural selection favors copper tolerance in all soils near the old mine, not only in the contaminated soils.
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.
Copper-tolerant plants are found only in contaminated soils.
Copper contamination in the soil created copper-tolerant plants.
Nearly 100% of monkey flowers growing in copper-contaminated soil are copper tolerant.
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.
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