Evolution Chapter 11,12,14,15 Study Guide

In 1977, Sidney Fox tried a different approach to testing the prebiotic synthesis of biological molecules. He mixed a number of different amino acids together at a high temperature (120°C) in an environment lacking water. When he subsequently placed the mixture into water to investigate what the amino acids would form, what happened next? a. He found ribose in very low supply. b. He found that a mechanism for joining the amino acids together to make proteins was completely absent. c. He added CO and had success with creating polypeptides. d. He found some peptide-like structures, but the bonds between the amino acids were weak and unstable.

He found some peptide-like structures, but the bonds between the amino acids were weak and unstable.

The apicoplast is an organelle found only in species in a phylum called Apicoplasta. This phylum includes a deadly human parasite, Plasmodium falciparum, which is responsible for malaria. Which of the following is FALSE regarding the apicoplast organelle? a. Apicoplasts are unique organelles with a quadruple membrane. b. There was only one endosymbiosis event, which probably involved a large cyanobacterium engulfed by a protozoan cell, and they both developed second membranes for protection. c. The primary endosymbiosis occurred when one prokaryotic host engulfed a cyanobacterium, giving rise to the initial eukaryote, which was subsequently engulfed in a secondary endosymbiosis. d. Apicoplasts in Plasmodium falciparum and related species are involved in the production of at least 500 different gene products.

There was only one endosymbiosis event, which probably involved a large cyanobacterium engulfed by a protozoan cell, and they both developed second membranes for protection.

Which of the following describes the phenetic species concept? a. This concept looks at populations that share a past evolutionary history and a common evolutionary fate. b. This concept looks at organisms that are clustered together in a phenotype space and is often used by numerical taxonomists. c. This concept draws species boundaries using shared derived characters that are unique to one monophyletic group and absent from all other populations in the phylogeny. d. This concept describes species as groups of actually or potentially interbreeding populations, with no gene flow between them.

This concept looks at organisms that are clustered together in a phenotype space and is often used by numerical taxonomists.

The famous Cretaceous-Paleogene (K-Pg) extinction occurred about 65 million years ago, close to the boundary between the Cretaceous and Paleogene periods, with profound effects on many different taxa, including the dinosaurs. Which of the following is widely accepted as the cause of this extinction? a. The K-Pg mass extinction was the result of multiple volcanic eruptions in Siberia. b. This mass extinction occurred gradually over the course of millions of years, likely as a result of gradual changes in temperature, humidity, sea level, and other environmental properties. c. This mass extinction occurred as a result of an impact with an extraterrestrial body, such as an asteroid, as evidenced by the layer of clay demarcating the K-Pg boundary that contains iridium. d. The K-Pg mass extinction was the result of a large supernova that had exploded near Earth, producing radiation and triggering climate changes.

This mass extinction occurred as a result of an impact with an extraterrestrial body, such as an asteroid, as evidenced by the layer of clay demarcating the K-Pg boundary that contains iridium.

The painted turtle (Chrysemys picta) has an amazing physiology that tolerates wide swings in temperature and oxygen levels and has a wide geographic distribution in North America. In the winter, it goes into hibernation under the ice of the ponds in which it lives and has been observed to tolerate anoxic conditions for up to 170 days at 3oC. What would you predict about this species' ability to survive environmental perturbations that can lead to an extinction event? a. This species has a low probability of surviving. b. This species has an even probability of surviving. c. This species has a high probability of surviving. d. This species has a high probability of extinction.

This species has a high probability of surviving.

Which of the following is FALSE regarding studies on volvocine algae to explore the evolution of individuality? a. The division of labor between germ and soma lines has evolved on at least three separate occasions in this group. b. Volvox carteri individuals are made up of many small somatic cells and few large reproductive cells. c. Volvox carteri individuals are made up of thousands of flagella-bearing germ cells and only a handful of somatic cells. d. There is exceptional variation found within this group. Some species are unicellular; some species are made of cells that live in groups but do not have specialized germ and soma lines; and some species show well-differentiated germ cell and somatic cell lines.

Volvox carteri individuals are made up of thousands of flagella-bearing germ cells and only a handful of somatic cells.

Fossils are the remains of past-living organisms that can form in several different ways. Which of the following describes fossilization by dissolution? a. Organisms are fossilized as layers of thin carbon spread on sandstone and shale. b. Organisms are fossilized within a gooey tree resin called amber. c. Minerals such as calcium and phosphorus, once part of a living organism, are slowly replaced through chemical processes by such minerals as iron and silica. d. Water seeps into a fossil and breaks it down, but the shape of the fossil is preserved in the sediment around it, providing a rough outline of the organism.

Water seeps into a fossil and breaks it down, but the shape of the fossil is preserved in the sediment around it, providing a rough outline of the organism.

In order to understand the origin of life on Earth, evolutionary biologists collaborate with__________. a. atmospheric scientists b. chemists c. geologists d. all of the answer options are correct

all of the answer options are correct

The famous radiation of Galápagos finches from the common ancestor species on the western coast of South America is probably a result of __________. a. allopatric speciation b. peripheral isolate speciation c. parapatric speciation d. sympatric speciation

allopatric speciation

In a study of red spruce trees and black spruce trees, scientists found that the red spruce was living in a smaller geographic area and had much less genetic variation than the black spruce. They proposed that the red spruce might have arisen from a southern population of black spruce, which became geographically isolated from other black spruce populations at some point during the Pleistocene glaciations. What is this an example of? a. allopatric speciation with the peripheral isolate model b. sympatric speciation with the ring species model c. sympatric speciation d. allopatric speciation with the vicariance model

allopatric speciation with the peripheral isolate model

During the 1990s, Nancy Knowlton and her colleagues studied pairs of sister species of the genus Alpheus (snapping shrimp) (Knowlton 1993). In each of these sister species, one species in the pair lived on the Caribbean side of the Isthmus of Panama, while the other species lived on the Pacific side. What type of speciation might be responsible for this speciation? a. sympatric speciation with the ring species model b. allopatric speciation with the vicariance model c. allopatric speciation with the peripheral isolate model d. sympatric speciation

allopatric speciation with the vicariance model

Stanley Miller and Harold Urey developed and conducted experimental tests for a "prebiotic soup" model of the origin of life, which had been proposed a few decades earlier by Aleksandr Oparin and J.B.S. Haldane. What did Miller and Urey show could be synthesized abiotically? a. complex proteins b. ribosomes c. single-stranded RNA molecules d. amino acids

amino acids

In all of the extinctions that have ever occurred on Earth, the majority of species loss was due to __________. a. global warming extinctions b. mass extinctions c. background extinctions d. punctuated equilibrium

background extinctions

In a hypothetical scenario, imagine that you have discovered a rare species of bird on a remote Pacific island. You spend some time studying their ecology and habitation and discover that although these birds look alike, they are indeed two distinct populations with very different mating calls. You propose that these two populations must be two species since they are no longer able to mate with one another. Which of the following species concepts would you use to defend your statement? a. biological species concept b. ecological species concept c. phenetic species concept d. phylogenetic species concept

biological species concept

One of the main features of a eukaryotic cell is the nucleus. Recent evidence suggests that the cell nucleus may have evolved from archaeal ancestors and that the organelles may have evolved from bacterial ancestors, but there is another important factor that has shaped the evolution of nuclear genomes. Which of the following is a source of some eukaryotic nuclear genes? a. only chloroplast genes b. both mitochondrial and chloroplast genes c. "promiscuous" genes from unrelated species of eukaryotes d. only mitochondrial genes

both mitochondrial and chloroplast genes

What type of infectious disease is devastating populations of frogs in North America, Alaska, and Australia today? a. various bacterial infections that cause sterility in frogs b. chytridiomycosis, which interferes with the ability of amphibians to transport chemicals across the epidermis c. an incurable water mold that infects amphibian larvae d. highly contagious viral infections, which are spread by human contamination of the waters

chytridiomycosis, which interferes with the ability of amphibians to transport chemicals across the epidermis

In the slime mold species Dictyostelium discoideum, single-celled individuals gather in the migratory slug stage of development, in response to environmental cues. Which molecule is associated with this signaling? a. small RNAs b. steroid hormones c. lactose d. cyclic adenosine monophosphate (cAMP)

cyclic adenosine monophosphate (cAMP)

"A species is a lineage of populations which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate." This definition best represents the __________. a. ecological species concept b. phenetic species concept c. biological species concept d. evolutionary species concept

evolutionary species concept

Which of the following molecules involved in membrane structure was likely favored by natural selection in the evolution of early cells? a. nucleic acids b. polypeptides c. fatty acids d. steroid hormones

fatty acids

Which one of the following is NOT a major transition in the evolution of life, according to biologists John Maynard Smith and Eörs Szathmary? a. formation of the solar system including Earth b. origin of self-replicating molecules capable of heredity c. evolution of sexual reproduction d. evolution of multicellular organisms from single-celled ancestors

formation of the solar system including Earth

Which of the following best represents the definition of an individual, as proposed by evolutionary biologist Rick Michod? a. groups of organisms of the same species that live in a closed system of mutual dependency b. integrated and indivisible wholes that can reproduce and pass heritable variations on to their offspring c. any level of organization that is subject to natural selection d. single cells and cells in multicellular organisms, because each has a complete set of genes

integrated and indivisible wholes that can reproduce and pass heritable variations on to their offspring

A researcher is trying to determine if populations of a butterfly seen on the eastern slope of the Rocky Mountains in Colorado are actually separate species. The researcher and her graduate students spent a summer capturing the butterflies at several locations, carefully documenting traits such as color, wing span, antennae length, proboscis length, etc. Which species concept could be applied using these data? a. evolutionary species concept b. biological species concept c. ecological species concept d. phenetic species concept

phenetic species concept

David Jablonski and his coworkers found that for gastropods (slugs and snails) of the late Cretaceous period, the key to a broad geographic range at the species level—and thus increased chances of surviving the mass extinction near the K-Pg boundary—was the nature of their larval stage. Which of the following best describes a stage that contributes to the increased geographic ranges of the gastropod taxa? a. nonplankotrophic larvae that feed in closed water pools and develop into adults at a relatively slow rate b. any type of larvae that feed in closed water pools and develop into adults at a faster rate c. planktotrophic larvae that feed in the open water on very small prey and develop into adults at a relatively slow rate d. planktotrophic larvae that feed in and near reefs and develop into adults at a faster rate

planktotrophic larvae that feed in the open water on very small prey and develop into adults at a relatively slow rate

Different races of the apple maggot fly have different breeding seasons depending on the host species they prefer (downy hawthorn or apple trees). Because of this temporal difference in breeding, which type of reproductive isolating mechanism is occurring? a. postzygotic b. prezygotic c. hybrid sterility d. gametic incompatibility

prezygotic

In a hypothetical flowering plant species, one population evolves a different response to environmental stimuli and begins to bloom significantly later in the season than nearby populations. What type of reproductive isolating mechanism would this be? a. hybrid sterility b. postzygotic c. prezygotic d. gametic incompatibility

prezygotic

In 1970, Lynn Margulis proposed that the origin of two eukaryotic organelles, mitochondria and chloroplasts, occurred through endosymbiosis. According to more recent phylogenetic analyses based on molecular genetic data, which of these prokaryotic lineages is a candidate for the ancestral source of mitochondria? a. proteobacteria b. cyanobacteria c. archaea d. ancient protozoa

proteobacteria

Paleontological studies on a lineage of bryozoans (whose fossils preserve many of their morphological characteristics) show a pattern of evolution with little or no change for long stretches of time. Occasionally, however, speciation occurred in a burst of change and diversification. This is an example of __________. a. anagenesis b. cladogenesis c. punctuated equilibrium d. phyletic gradualism

punctuated equilibrium

In paleobiology, one of the main concepts is that fossils found lower down in the sediment at a particular locality are older than those found closer to the surface. This often is called __________. a. Lagerstatten b. radiometric dating c. the Signor-Lipps effect d. the law of superposition

the law of superposition

All of the following are true regarding Sol Spiegelman's experiment on the origins of life, except that __________. a. the most common size of the RNA strand in the final test tubes was a little over 200 nucleotides long b. variation in the length of the RNA strands occurred at each round of replication c. there was no selection for any of the variations in length d. shorter RNA sequences were favored by selection because they took less time to replicate

there was no selection for any of the variations in length

Which gas was most likely the LEAST abundant in early Earth's atmosphere? a. NH3 b. O2 c. CH4 d. H2

O2

Based on the figure shown, which of the following statements is correct? a. The Excavate clade is the only eukaryotic group where all clade members are unicellular . b. The Amoebozoa clade is the only eukaryotic group with clades including members that are both unicellular and multicellular. c. Animals are the only group within the Opisthokont clade whose members are all multicellular. d. All plants and algae are multicellular.

Animals are the only group within the Opisthokont clade whose members are all multicellular.

Which of the following statements regarding the Midas and Arrow cichlids in Lake Apoyo does NOT suggest that the speciation event responsible for forming these two species occurred in sympatry rather than allopatry? a. The Midas and Arrow cichlids are a monophyletic clade. b. Lake Apoyo is large, creating geographic isolation between the two species. c. Lake Apoyo is small, shallow, and homogeneous. d. Not even one mitochondrial haplotype was found in any other Nicaraguan lake that was the same as those found in the two Lake Apoyo species.

Lake Apoyo is large, creating geographic isolation between the two species.

Many species of mammals and birds are known to live in close communities, while other species live solitary lives. What do we know about the benefits of sociality, such as that observed in cliff swallows? a. In birds that live in large colonies, there is often a significant positive relationship between colony size and the percentage of nests with unhatched eggs. b. There is often a significant negative correlation between group size and survival rate of the population. c. There is often a significant positive correlation between group size (such as colony size in cliff swallows) and survival rate of the population. d. The phylogeny of social groups indicates that sociality is often a shared derived trait, which evolves only once or twice in a given lineage.

There is often a significant positive correlation between group size (such as colony size in cliff swallows) and survival rate of the population.

Two common species of frogs from the genus Bombina (B. bombina and B. variegata) live in similar latitudes and ecological conditions, but in two different regions, Central and Eastern Europe. In a narrow strip between these regions, scientists have observed a third species, which might be a hybrid between the former diverging populations of the ancestral species. What evolutionary process might be responsible for the speciation in Bombina? a. parapatric speciation b. allopatric speciation c. sympatric speciation d. sympatric speciation with the ring species model

parapatric speciation

By 10,000 years ago, two-thirds of 150 genera of the Pleistocene megafauna that were present just 40,000 years earlier had gone extinct. What seems to be the reason for this relatively recent extinction of so many large mammal species? a. Hunting by humans, habitat fragmentation, and the ice age played a large role in this extinction. b. This extinction was probably due to new pathogens. c. Global warming seems to be a contributing factor in the loss of these large mammal species. d. This extinction was the result of a period of extreme volcanic activity.

Hunting by humans, habitat fragmentation, and the ice age played a large role in this extinction.

Slime molds are unusual eukaryotes. They spend most of their life cycle as single-celled organisms, and yet under certain conditions, they form a slug-like multicellular stage and then a fruiting body composed of both somatic cells and reproductive spores. The best known species of slime mold is a soil dweller, Dictyostelium discoideum. Why is it important to study this and related species of slime molds? a. Slime molds first appeared about 1 billion years ago. b. Dictyostelium discoideum is an important human pathogen. c. Slime molds provide clues as to how multicellularity may have evolved. d. Dictyostelium discoideum is one of the most abundant organisms on Earth.

Slime molds provide clues as to how multicellularity may have evolved.

Which of the following is FALSE regarding the evolution of chloroplasts? a. Chloroplasts are derived from ancient free-living photosynthetic cyanobacteria. b. Cyanobacteria are related to algal plastids. c. RNA shows that the chloroplasts of plants are closely related to cyanobacteria. d. Chloroplasts are derived from ancient free-living photosynthetic archaebacteria.

Chloroplasts are derived from ancient free-living photosynthetic archaebacteria.

The following graphs show three different types of evolutionary change in a hypothetical clade. The y axis represents time, while the x axis represents a character (body size, in this example). Which of the following graphs represents an active evolutionary trend? a. Graph C b. Graph A c. Graphs B and C only d. Graph B

Graph C

Which of the following statements about the Lincoln and Joyce experiment on self-replicating ribozymes is most likely correct? a. In the self-replicating ribozymes, variation in the rate of replication was not heritable. b. Ribozymes produced true protein-based enzymes. c. Truly self-replicating enzymes had not evolved in Earth's early environment. d. The self-replicating ribozymes that had more efficient catalytic activities would soon began to dominate their populations.

The self-replicating ribozymes that had more efficient catalytic activities would soon began to dominate their populations.

Among the oldest fossils yet discovered on Earth are microfossils from 600 meters below the Agnes gold mine of South Africa, which are __________ years old. a. 4.5 billion b. 3.5 million c. 3.2 billion d. 3.2 million

3.2 billion

Radiocarbon dating (14C) is a useful tool for measuring absolute age for about __________ years into the past. a. 5,000,000 b. 150,000,000 c. 50,000 d. 500,000

50,000

Why is the higher fidelity of DNA proofreading and repair (compared to RNA) evolutionarily important? a. A lower mutation rate allows for longer genes and less storage of information in the genome. b. A lower mutation rate allows for longer genes and more storage of information in the genome. c. A lower mutation rate allows DNA to specialize in only functioning as a genetic storage system. d. A lower mutation rate results in shorter, more efficient genomes.

A lower mutation rate allows for longer genes and more storage of information in the genome.

Itay Budin and Jack Szostak sought to understand how cell membranes composed of single-chain lipid molecules could possibly evolve to the more complex phospholipids seen in modern cell membranes (Budin and Szostak 2009). Which statement best summarizes their results? a. Adding a small fraction of phospholipid molecules resulted in vesicles with lower phospholipid content; these cells tended to be reduced in size, conferring a selective advantage. b. Adding a small fraction of phospholipid molecules resulted in vesicles with higher phospholipid content; these cells tended to grow in size conferring a selective advantage. c. Adding a large fraction of phospholipid molecules resulted in vesicles with lower phospholipid content; these cells tended to be reduced in size, conferring a selective advantage. d. Adding a large fraction of phospholipid molecules resulted in vesicles with higher phospholipid content; these cells tended to grow in size conferring a selective advantage.

Adding a small fraction of phospholipid molecules resulted in vesicles with higher phospholipid content; these cells tended to grow in size conferring a selective advantage.

After confirming that Amphilophus citrinellus and Amphilophus zaliosus were indeed two species that originated from a single colonization of Lake Apoyo by their common ancestor, what evidence explained this was a sympatric speciation event rather than an allopatric speciation event? a. Although Lake Apoyo is a very heterogeneous habitat, body morphology in the two species supported speciation via competition, rather than geographic separation. b. Although Lake Apoyo is a very homogeneous habitat, body morphology in the two species supported speciation based on geographic separation, rather than habitat and ecological specialization. c. Although Lake Apoyo is a very homogeneous habitat, body morphology in the two species supported speciation based on habitat and ecological specialization, rather than geographic separation. d. Although Lake Apoyo is a very heterogeneous habitat, body morphology in the two species supported speciation based on geographic separation, rather than speciation via competition.

Although Lake Apoyo is a very homogeneous habitat, body morphology in the two species supported speciation based on habitat and ecological specialization, rather than geographic separation.

Why did the role of horizontal gene transfer ultimately become diminished over evolutionary time? a. The evolution of multicellularity made it impossible for horizontal gene transfer to occur in modern organisms. b. As cells became more simplified, they became more streamlined and efficient in functioning, so there was no selective advantage to the uptake of additional genetic material via horizontal gene transfer. c. As cells became more complicated, they also became more integrated, less modular and less likely to take up new genes by horizontal gene transfer. d. The evolution from an RNA-based world to a DNA-based world made it impossible for horizontal gene transfer to occur in modern organisms.

As cells became more complicated, they also became more integrated, less modular and less likely to take up new genes by horizontal gene transfer.

In the cliff swallows studied by Charles and Mary Brown, it is common to find a blood-sucking parasite, an insect known as the swallow bug. This bug often clings to the feet of birds, can move from swallow to swallow within colonies, and is responsible for most of the nest failures and juvenile mortality in these birds (Brown and Brown 1996). The graph shows a correlation between the colony size and the number of bugs per nest. What conclusion(s) can we make based on this study? a. As colony size increases, the number of swallow bugs per nest decreases. b. As group size increases, the fitness cost of parasitism increases. c. Group living for swallows is practically cost free and provides many benefits. d. Group living for swallows has more evolutionary costs than benefits.

As group size increases, the fitness cost of parasitism increases.

The human parasite Mycoplasma genitalium, with one of the smallest genomes of any organism that can be grown in a laboratory, as well as Chlamydia trachomatis, an obligate intracellular parasite, are examples of the types of organisms that functional genomics researchers have focused on. What is the main purpose of the study of such genomes? a. These and other endosymbionts do not have their own genomes. b. By studying such genomes, researchers try to discover the basic and essential cellular functions of early life. c. These parasites are very ancient prokaryotes with small genomes. d. They are prokaryotes with large and complex genomes.

By studying such genomes, researchers try to discover the basic and essential cellular functions of early life.

In light of recent achievements in the field of genomics, would it be reasonable to expect that the use of comparative genomics might shed light on the extinct genomes of early life? a. Simple prokaryotes today have very different genomes than early life, so we could not learn very much from the comparative genomics of the extant species. b. Despite efforts in molecular prokaryotic genetics, we could not predict what kinds of genes may have been present in pre-LUCA genomes. c. Comparative genomics and studies of bacteria with very small genomes shed light on a common ancestor, and researchers can estimate the minimal characteristics that a cell would need to operate as a living organism. d. Because today's living organisms, including bacteria, are so different, it would not be useful to look at genomics as there is no trace of early life currently in existence.

Comparative genomics and studies of bacteria with very small genomes shed light on a common ancestor, and researchers can estimate the minimal characteristics that a cell would need to operate as a living organism.

Evolutionary biologists are very interested in understanding the patterns and processes that guide the tempo and mode of evolution. In specific clades, they sometimes point to trends (patterns of directional change over time). One such trend is also known as Cope's rule. Which of the following statements is TRUE? a. Cope's rule is universal. b. Cope's rule states that species in mammalian clades tend to either increase or decrease in body size, dependent on predation pressure. c. Cope's rule states that species in mammalian clades tend to increase in body size over evolutionary time. d. Cope's rule states that species in mammalian clades tend to decrease in body size over evolutionary time.

Cope's rule states that species in mammalian clades tend to increase in body size over evolutionary time.

Which of the following statements regarding the benefit of making the switch from an RNA- to a DNA-based genetic system during the evolution of life is correct? a. DNA is a more stable molecule because deoxyribose is less reactive than is ribose. b. Replication of RNA is too fast to be favored by natural selection. c. The double stranded structure of DNA has a much greater potential for interaction with outside molecules. d. DNA replication systems do not have the proofreading capabilities that are usually present in RNA replication.

DNA is a more stable molecule because deoxyribose is less reactive than is ribose.

The Dobzhansky-Muller model explains hybrid infertility in crosses between two close species (such as the fruit flies D. simulans and D. melanogaster). Which of the following is the best explanation of this model? a. Two species develop strong prezygotic mechanisms of reproductive isolation and mating is less likely to proceed. b. Changes in the numbers of chromosomes cause hybrid zygotes to have lower fitness and often make them infertile. c. Hybridization between the two sister species is impossible because of the imminent hybrid sterility. d. Epistatic interactions between the alleles of two or more loci, undergoing different evolutionary paths in the two speciating groups, lead to the fitness costs of hybridization.

Epistatic interactions between the alleles of two or more loci, undergoing different evolutionary paths in the two speciating groups, lead to the fitness costs of hybridization.

A number of evolutionary studies show a strong phylogenetic link between prokaryotic and eukaryotic cells. Which of the following is the best statement about the evolutionary origins of eukaryotic cells? a. Eukaryotes shared a common ancestor with species in the domain Bacteria. b. Eukaryotes probably evolved from a lost prokaryotic lineage, which could not be placed in either the Archaea or Bacteria domains. c. Eukaryotes shared a common ancestor with species in the domain Archaea. d. Eukaryotic "informational" genes are most closely related to archaeal genes, while their "operational" genes are most closely related to bacterial genes.

Eukaryotic "informational" genes are most closely related to archaeal genes, while their "operational" genes are most closely related to bacterial genes.

An analysis by Maria Rivera and James Lake suggests that ancient eukaryotic cells emerged from the fusion of an archaeal cell (most likely from the phylum Eocyta) and a bacterium (Rivera and Lake 2004). Which of the following is correct regarding this working hypothesis? a. Eukaryotic cells probably evolved through endosymbiosis, in which either the archaeal or bacterial cell was engulfed within the other. b. Eukaryotic cells probably evolved when a parasitic species of bacteria residing in another prokaryotic cell became less harmful. c. The eukaryotic lineage probably began when an archaeal cell became integrated into a bacterial cell. d. The eukaryotic lineage probably began when a bacterial cell became integrated into an archaeal cell.

Eukaryotic cells probably evolved through endosymbiosis, in which either the archaeal or bacterial cell was engulfed within the other.

This figure illustrates the concept of a ring species formation in Ensatina eschscholtzii salamanders in California. The species originated in northern California and southern Oregon and then expanded south along the Sierra Nevada range. Which statement accurately describes gene flow and gene patterns in these populations? a. Gene flow decreases as you move south, resulting in the southern populations being more genetically distinct from one another than other populations. b. Gene flow decreases through the middle part of the range but increases as the species comes back in contact at the southern end of the range. c. Gene flow increases as you move south, resulting in little genetic differentiation between the southern species when compared to other species in the range. d. Gene flow decreases as you move south, resulting in the southern populations being more genetically similar to one another than other populations.

Gene flow decreases as you move south, resulting in the southern populations being more genetically distinct from one another than other populations.

Which of the following is FALSE regarding the evolution of group living? a. Group living provides many benefits, but it does not improve foraging success (finding food). b. Group living includes benefits associated with safety from predators. c. Group living requires new levels of coordination and communication between individuals. d. A group is defined as a set of conspecific individuals that affect each other's fitness.

Group living provides many benefits, but it does not improve foraging success (finding food).

What do we know about horizontal gene transfer (HGT) in the evolution of early life? a. HGT was probably a powerful force during early cell evolution, leading to complex cellular organisms. b. HGT played a significant role in the evolution of contemporary prokaryotes, but not in the early stages of the evolution of life. c. HGT never played an important role in the evolution of either prokaryotes or eukaryotes. d. HGT played a small, insignificant role in the origin of complex cellular organisms.

HGT was probably a powerful force during early cell evolution, leading to complex cellular organisms.

The Hawaiian Islands have gone through at least two waves of human colonization (in prehistoric times and again starting in the seventeenth and eighteenth centuries). Of the approximately 125 to 145 bird species that once inhabited the Hawaiian Islands before human colonization, 90 to 110 are now extinct. Which of the following is most likely TRUE when it comes to the first wave of extinctions? a. Human colonization devastated the natural habitats and food sources of the native species, such as flower nectar and fruit. b. Human colonization introduced a fungal disease that killed the birds via lung infection, leading to their extinction. c. Human colonization devastated the larger species of birds through hunting. d. Human colonization introduced nonnative species, which killed the larger birds first.

Human colonization introduced nonnative species, which killed the larger birds first.

Two parapatric subspecies of sagebrush (mountain big sagebrush and basin big sagebrush) produce hybrid sagebrush, which often is found in the intermediate elevation. In the following graph, you can see a relative composite fitness for each of them, raised in three different environments (below 1800 meters in the basin zone, above 1900 meters in the mountain zone, and in the hybrid zone between 1800 and 1900 meters). Which of the following best explains the findings in this experiment? a. There was no significant difference in fitness between the three subspecies in the hybrid zone, providing support for the ecologically neutral dynamic equilibrium model. b. There was no significant difference in fitness between the three subspecies in the hybrid zone, so the bounded superiority model was not supported. c. Hybrids had significantly better fitness than the other subspecies in the hybrid zone, supporting the ecologically neutral dynamic equilibrium model. d. Hybrids had significantly better fitness than the other subspecies in the hybrid zone, supporting the bounded hybrid superiority model.

Hybrids had significantly better fitness than the other subspecies in the hybrid zone, supporting the bounded hybrid superiority model.

How does the dominance theory explain why the heterogametic sex is at a disadvantage in Haldane's rule? a. If a dominant allele has a negative effect on the fitness of hybrids, it will always be expressed in the heterogametic hybrids that possess that allele because they only need one copy of the respective sex chromosome. b. If a recessive allele linked to a sex chromosome has a positive effect on the fitness of hybrids, that allele will never be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele. c. If a recessive allele linked to a sex chromosome has a negative effect on the fitness of hybrids, that allele will always be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele. d. Beneficial dominant alleles will never be fully expressed in hybrids as they only carry one copy of the sex chromosome that carries the allele.

If a recessive allele linked to a sex chromosome has a negative effect on the fitness of hybrids, that allele will always be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

Which of the following defines Haldane's rule and its predictions? a. If among hybrid offspring one sex is absent, rare, or sterile, that sex is heterogametic (has two different sex chromosomes). b. If among hybrid offspring one sex is absent, rare, or sterile, that sex is homogametic (has two of the same sex chromosomes). c. If among hybrid offspring one sex is absent, rare, or sterile, that sex is always female. d. If among hybrid offspring one sex is absent, rare, or sterile, that sex is always male.

If among hybrid offspring one sex is absent, rare, or sterile, that sex is heterogametic (has two different sex chromosomes).

Which of the following statements best explains secondary reinforcement? a. If the reproductive isolating mechanisms that developed during the geographic isolation are somewhat weak but the hybrids between two populations have lower fitness, then the speciation process may continue. b. When geographic isolation comes to an end, two populations always complete the divergence process and become separate species. c. If the reproductive isolating mechanisms that developed during the geographic isolation are strong but the hybrids have higher fitness than the parent species, then the speciation process will cease. d. If the reproductive isolating mechanisms that developed during the geographic isolation are sufficiently weak as to allow free interbreeding across reunited populations, then the speciation process will halt and a single species will remain.

If the reproductive isolating mechanisms that developed during the geographic isolation are somewhat weak but the hybrids between two populations have lower fitness, then the speciation process may continue.

Why did the human introduction of feral pigs on Santa Cruz Island accelerate the extinction of the native island fox and increase the population of skunks? a. Increased pig numbers led to a decline in the fox population due to pig attacks on fox kits; the decrease in the number of foxes then led to an increase in the number of skunks, as foxes are predators of skunks. b. Pigs destroyed fox dens, thereby reducing fox reproduction, and also attracted the golden eagle, which scared away skunk predators and therefore led to an increase in the number of skunks. c. Increased pig numbers attracted the golden eagle, which is a fierce predator of foxes, but pig activity also improved skunk habitat. d. Increased pig numbers attracted the golden eagle, which is a fierce predator of foxes, and skunks (the main prey of island foxes) therefore increased in population size.

Increased pig numbers attracted the golden eagle, which is a fierce predator of foxes, and skunks (the main prey of island foxes) therefore increased in population size.

Which of the following is correct regarding the endemic species as they relate to the study of background extinction? a. There is no difference between global and endemic species when it comes to the study of extinction. b. Extinctions are not very common in endemic species. c. It is much easier to study extinction in endemic species because such local extinction becomes synonymous with global extinction for that species. d. It is much better to focus on species that live throughout the world and prevent their extinction.

It is much easier to study extinction in endemic species because such local extinction becomes synonymous with global extinction for that species.

Which of the following statements about LUCA is NOT correct? a. It represents a phylogenetic event horizon. b. It represents a base to the tree of life. c. The acronym stands for "last universal common ancestor." d. It refers to a single, ancestral organism.

It refers to a single, ancestral organism.

Biologists have documented asexual reproduction in some animal lineages. Even in certain vertebrates, such as reptiles, a few species reproduce only with parthenogenesis (development from unfertilized eggs). However, parthenogenesis has never been documented in mammals. What is the current genetic explanation for this difference between mammals and other vertebrates? a. The number of offspring produced sexually is equal to the number of offspring in asexual reproduction. b. The number of offspring produced sexually exceeds the number of offspring in asexual reproduction. c. Mammals evolved a process of genetic imprinting and therefore some genes from the father's genomes need to be expressed. d. Mammals are the only class of vertebrates with evolutionary benefits of recombination.

Mammals evolved a process of genetic imprinting and therefore some genes from the father's genomes need to be expressed.

What is the meaning of the phrase "dead clade walking," which was coined by David Jablonski in 2002? a. Following mass extinctions, such as in the Permian, there is nothing to be found in many rock strata. b. New clades that emerge following mass extinction quickly die out due to a lack of nutrients and other resources. c. Many of the clades that survive a period of mass extinction go extinct during the following geological time period. d. More susceptible clades die off very early and quickly at the beginning of mass extinction events.

Many of the clades that survive a period of mass extinction go extinct during the following geological time period.

This figure illustrates the results of selection for yeast strains that are well adapted to either high-salt or low-glucose environments. Over the course of selection, many mutations have occurred in populations in both environments. If the Dobzhansky-Muller model applies to this experiment, what do you predict will happen if the two strains produce a hybrid? a. Matings between individuals from the two strains will have greater reproductive success compared to the controls. b. Matings between individuals from the two strains will have reduced reproductive success compared to the controls. c. Matings between individuals from the two strains will be completely unsuccessful. d. Matings between individuals from the two strains will have no difference in reproductive success compared to the controls.

Matings between individuals from the two strains will have reduced reproductive success compared to the controls.

Which of the following statements regarding the complexity of living organisms is FALSE? a. The body size of the largest living organisms has increased over evolutionary time. b. The complexity of multicellular organisms, as measured by the number of cell types, has increased over evolutionary time. c. Natural selection always results in an increase of complexity over evolutionary time. d. Modern bacteria and archaea are not always more complex than their ancestors that lived before the origin of multicellular life.

Natural selection always results in an increase of complexity over evolutionary time.

The origin of cell structures might be hypothesized to have involved a hypercycle, based on mutualism at the molecular level. Which of the following is correct regarding the hypercycle model? a. Natural selection will favor a hypercycle that is not enclosed in a membrane. b. Natural selection will favor a hypercycle that is enclosed in a membrane. c. Molecular mutualisms may have been important among the cells in the DNA world, but not for the replicators in the RNA world. d. Molecular mutualisms always favor replicators that increase their own replication rates but not those of others.

Natural selection will favor a hypercycle that is enclosed in a membrane.

Which two scientists elaborated on Darwin's idea of the "warm little pond" and formulated the "prebiotic soup hypothesis" as the first hypothesis for the abiotic origin of life on Earth? a. Cech and Altman b. Oparin and Haldane c. Wallace and Lyell d. Miller and Urey

Oparin and Haldane

It is very difficult to find the fossil remains of an entire organism. Which of the following is NOT a factor that paleontologists use when choosing sites to search for the best fossils? a. Paleontologists typically select novel, unexplored areas to search for fossils as this is the best method to fill gaps in information that we see in the fossil record. b. Paleontologists often use predictions derived from phylogenetic reconstruction, biogeography, or molecular genetics to explore a particular area. c. Paleontologists are unlikely to be the first researchers to be searching for fossils from their organism of interest. Instead, they often choose sites where others have already uncovered related fossils. d. Paleontologists typically focus on the sites that best match the geological and abiotic conditions in which fossilization may have occurred.

Paleontologists typically select novel, unexplored areas to search for fossils as this is the best method to fill gaps in information that we see in the fossil record.

As opposed to background extinction, a mass extinction typically refers to the loss of many groups of organisms over a broad geographic range. Which of the following mass extinctions in Earth's geological history was the most devastating for the marine families? a. Devonian b. Cretaceous-Paleogene boundary c. Permian d. Triassic

Permian

The first genetic material on Earth was most likely __________. a. a large lipid b. DNA c. RNA d. a small protein

RNA

Based on the phylogeny of Lepidosauria, if two sister species from the _____ clade were lost to extinction, this would prune the tree only slightly and would cause only a minimal loss of phylogenetic history. But if the two species of _____ were to go extinct, this loss would prune away a piece of phylogenetic history dating back to well before the divergence of snakes and lizards. a. Gekkota, Serpentes b. Tuataras, Serpentes c. Serpentes, Gekkota d. Serpentes, Tuataras

Serpentes, Tuataras

Identify which of the given examples is the best match for the following statement. "Individuals give up the ability to reproduce independently, and they join together to form a larger grouping that shares reproduction." a. Within a single multicellular body, different cells may specialize in generating movement, digesting food, processing information, or other tasks. b. Single-stranded RNA with low replication fidelity is replaced as an informational molecule by double-stranded DNA with high replication fidelity. c. Economy of scale arises when a group can perform a task more efficiently than a single individual can. d. Solitary individuals start living together in colonial groups, sometimes even giving up the possibility of independent replication, as we see in many species of social insects.

Solitary individuals start living together in colonial groups, sometimes even giving up the possibility of independent replication, as we see in many species of social insects.

In the common bluegill sunfish, foraging in small groups increases success in finding food. They feed on small, aquatic insects that live in underwater vegetation, and when bluegills forage together, they are able to flush out many more insects. Which of the following is correct in this case of group foraging? a. The bluegill example illustrates an "active" benefit of group living and communication. b. Bluegill foraging is a product of complex patterns of social rules. c. The bluegill example illustrates a "passive" benefit of group foraging. d. The bluegill example illustrates one of the costs of group foraging.

The bluegill example illustrates a "passive" benefit of group foraging.

Over the last few decades, there has been a major decline in amphibian populations worldwide, including the extinction of many amphibian species. Which of the following is FALSE regarding the amphibian decline? a. Extinction of an endemic amphibian species results in global extinction of that species. b. One of the major factors driving these extinctions may be infectious disease. c. The current rate of extinction in amphibians is much higher than typical background extinction rates. d. The extinctions seem to be due to the increased predation of amphibians around the world.

The extinctions seem to be due to the increased predation of amphibians around the world.

Eugene Koonin and his colleagues used the distributions of genes in the minimal gene sets of Haemophilus influenza and Mycoplasma genitalium to predict the distribution of a minimal gene set for Bacillus subtilis (Koonin 2003). What did they conclude from their comparison? a. The predicted distribution of genes in B. subtilis was a close fit to the minimal gene sets observed. b. The minimal gene set of B. subtilis was significantly different from the comparison sets, having a smaller number of genes required for minimal function. c. The minimal gene set of B. subtilis was significantly different from the comparison sets, having a larger number of genes required for minimal function. d. The researchers were unable to use the minimal gene sets observed in H. influenza and M. genitalium to predict the minimal gene set of B. subtilis.

The predicted distribution of genes in B. subtilis was a close fit to the minimal gene sets observed.

Which of the following suggests that sympatric speciation is occurring in Rhagoletis pomonella (the apple maggot fly)? a. Although there are no genetic differences between isolated populations found in apple trees and downy hawthorn trees, there are significant behavioral differences between the groups. b. The sympatric races of the apple maggot fly are diverging, and potentially on the path to becoming separate species as evidenced by fruit preference documented in the maggots. c. Although the apple tree was introduced into North America about 400 years ago, the different races of the apple maggot fly have not evolved any adaptations that correspond to the different fruiting times of their hosts. d. The forms of the apple maggot fly are already true species that will not interbreed if placed in the same host environment.

The sympatric races of the apple maggot fly are diverging, and potentially on the path to becoming separate species as evidenced by fruit preference documented in the maggots.

Which of the following is FALSE regarding the evolution of multicellularity? a. The evolution of multicellularity represents one of the major transitions in the history of life on Earth. b. The transition has occurred independently many times, in many taxa, over evolutionary history. c. In the early steps toward an obligate multicellularity, cells may have often joined together temporarily and then disbanded. d. The transition from unicellular to multicellular life occurred only once in evolutionary history, giving rise to all multicellular organisms today.

The transition from unicellular to multicellular life occurred only once in evolutionary history, giving rise to all multicellular organisms today.