CH 26

molecular systematics

-discipline that uses data from DNA and other molecules to determine evolutionary relationships p542 online

genus

-first part of a binomial -(plural) genera -before species

maximum liklihood

-given certain probability rules about how DNA sequences change over time

monophyletic group (clade)

-group of species and their common ancestor -"single tribe"

clade

-includes an ancestral species and all of its descendants

homologies

-similarity in characteristics resulting from a shared ancestry

polyphyletic

-some members have different ancestors -"many tribes"

outgroup

-species or group of species from an evolutionary lineage that is known to have diverged

analogy

-think analogous -critical in reconstructing phylogenies -no common ancestry

specific epithet

-unique for each species within the genus -second part of a binomial

cladogram

.

homologous genes

.

d

. A researcher wants to determine the genetic relatedness of several breeds of dog (Canis familiaris). The researcher should compare homologous sequences of __________ that are known to be __________. (a) carbohydrates; poorly conserved (b) fatty acids; highly conserved (c) lipids; poorly conserved (d) proteins or nucleic acids; poorly conserved (e) amino acids; highly conserved

3

. Which of the following numbers represents a polyphyletic taxon? (a) 2 (b) 3 (c) 4 (d) 5 (e) more than one of these

(d) 4

20. A common ancestor for both species C and E could be at position number __________. (a) 1 (b) 2 (c) 3 (d) 4 (e) 5

Answer: A

24) Which extinct species should be the best candidate to serve as the outgroup for the clade whose commonancestor occurs at position A) A B) B C) C D) D E) E

Concerning growth in genome size over evolutionary time, which of these does not belong with the others? A) orthologous genes 13 B) gene duplications C) paralogous genes D) gene families

A

For a proponent of PhyloCode classification, what is true of the reptile clade if birds are not included in it? A) It becomes paraphyletic and, thus, an invalid reflection of evolutionary history. B) It becomes a subclass, instead of a class. C) It becomes a superclass, whereas the birds remain a class. D) PhyloCode does not concern itself with what is, or is not, a clade.

A

If birds are excluded from the class Reptilia, the term that consequently describes the class Reptilia is A) paraphyletic. B) polyphyletic. C) monophyletic.

A

In a comparison of birds with mammals, having four appendages is A) a shared ancestral character. B) a shared derived character. C) a character useful for distinguishing birds from mammals. D) an example of analogy rather than homology. E) a character useful for sorting bird species.

A

The scientific discipline concerned with naming organisms is called A) taxonomy. B) cladistics. C) binomial nomenclature. D) systematics. E) phylocode

A

The term "homoplasy" is most applicable to which of these features? A) the legless condition found in various types of extant lizards B) the 5-digit condition of human hands and bat wings C) the beta-hemoglobin genes of mice and of humans D) the fur that covers Australian moles and North American moles E) the basic skeletal features of dog forelimbs and cat forelimbs

A

Theoretically, molecular clocks are to molecular phylogenies as radiometric dating is to phylogenies that are based on the A) fossil record. B) geographic distribution of extant species. C) morphological similarities among extant species. D) amino acid sequences of homologous polypeptides.

A

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom? A) molecular B) behavioral C) nutritional D) anatomical E) ecological

A

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom? A) molecular B) behavioral C) nutritional D) anatomical E) ecological

A

Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient proteobacterium and an ancient cyanobacterium? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

A

Which kind of DNA should provide the best molecular clock for gauging the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago? A) that coding for ribosomal RNA B) intronic DNA belonging to a gene whose product performs a crucial function C) paralogous DNA that has lost its function (i.e., no longer codes for functional gene product) D) mitochondrial DNA E) exonic DNA that codes for a non-crucial part of a polypeptide

A

Which of the following is not true of all horizontally oriented phylogenetic trees, where time advances to the right? A) Each branch point represents a point in absolute time. B) Organisms represented at the base of such trees are ancestral to those represented at higher levels. C) The more branch points that occur between two taxa, the more divergent their DNA sequences should be. 9 D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left. E) The more branch points there are, the more taxa are likely to be represented.

A

Which of the following pairs are the best examples of homologous structures? A) bat wing and human hand B) owl wing and hornet wing C) porcupine quill and cactus spine D) bat forelimb and bird wing E) Australian mole and North American mole

A

Which of these processes can be included among those responsible for the horizontal components of this phylogeny? A) endosymbiosis B) mitosis C) binary fission D) point mutations E) S phase of the cell cycle

A

Which of these are homologous structures? A) Plant root and plant leaf B) There are no homologous plant structures. C) Ivy leaf and pine needle

Ivy leaf and pine needle (The leaves of all living plants evolved from leaves of early plants. There are many homologous plant structures. For instance, all plant leaves and modified leaves (such as thorns and tendrils) are homologous structures derived from the leaves of early plants. Read about homology.)

Which of these are homologous structures?

Ivy leaf and pine needle The leaves of all living plants evolved from leaves of early plants. There are many homologous plant structures. For instance, all plant leaves and modified leaves (such as thorns and tendrils) are homologous structures derived from the leaves of early plants. Read about homology.

Linnaean classification mnemonic device

King Philip Cut Open Five Green Snakes. Kingdom, Phylum, Class, Order, Family, Genus, Species.

false

Linnaean system may tells us about groups evolutionary relationships to one another

To infer phylogeny, systematists must gather as much information as possible about the morphology, genes, and biochemistry of the relevant organisms.

To infer phylogeny, systematists must do what?

Systematists have used a wide variety of traits to reconstruct the phylogenies of particular groups of organisms. Which one of the following traits produces a good estimate of phylogeny?

biochemical traits behavioral traits molecular traits gross morphological traits Most researchers today appreciate that both morphology and molecular biology are essential sources of data for phylogenetic study.

yes

can scientist use molecular divergence to tell when a species diverge

The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma. These species have apparently undergone speciation from ancestral stock since the last glacial retreat about ten thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

mitochondrial DNA

By definition a clade is _____.

monophyletic A clade is defined as a group that includes an ancestral species and all of its descendants.

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____.

mutations to homologous genes

Which of the following would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock?

natural selection

Molecular clocks are based on the idea that _____.

on average neutral mutations arise at a constant rate The idea of a molecular clock rests on the assumption that neutral mutations can arise and become fixed in populations. The rate of occurrence of these mutations is not affected by natural selection, so it is assumed that the rate is relatively constant over time.

Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with _____.

phylogenies

false placement of species into orders, classes, and so on, does not necessarily reflect evolutionary history

placement of species into orders, classes, and so on, reflect evolutionary history

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up

a paraphyletic group.

In a comparison of birds and mammals, having four limbs is

a shared ancestral character.

Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character? (Concept 26.3) A) Cladistic character B) Polyphyletic character C) Analogous character D) Shared ancestral character. E) Shared derived character

D) Shared ancestral character.

homoplasies

- a similar (analogous) structure or molecular sequence that has evolved independently in two species

kingdom

- taxonomic category, second broadest after domain

taxon

-(plural) taxa -a named taxonomic unit at any given level of classification

domain

-Bacteria, Eukarya, Archaea

binomial

-Linnaeus instituted a two-part format for Latin scientific names -italicized -consists of the genus name and the specific epithet

shared ancestral

-a character, shared by members of a particular clade, that originated in an ancestor that is not a member of that clade -originated in the ancestor of the taxon -example: a mammal's backbone

homoplasy

-a similar (analogous) structure or molecular sequence that has evolved independently in two species

ingroup

-a species or group of species whose evolutionary relationships we seek to determine

family

-above genus

shared derived

-an evolutionary novelty that is unique to a particular clade -example: a mammal's hair which is not found in ancestors

cladistics

-approach to systematics -common ancestry is the primary criterion used to classify organisms -place species into groups called clades

class

-between order and phylum

character

-can be ancestral or derived -shared characteristics between organisms

paraphyletic group

-consists if ancestral species and some of its descendants, but not all of them -"beside the tribe" -p543 online

What process has clearly been involved in producing the tree/bush/ring of life? (Concept 26.6) A) Horizontal gene transfer B) mitosis C) phylogenetics D) artificial selection E) taxonomy

A) Horizontal gene transfer

Select the correct statement about phylogenetic trees. A) Phylogenetic trees may expand quickly to maximum width and then narrow over time. B) Phylogenetic trees always show increased branching, representing increased diversity over time. C) All phylogenetic trees are similarly shaped.

A) Phylogenetic trees may expand quickly to maximum width and then narrow over time. (There is considerable variation in the form of phylogenetic trees. Some expand quickly to maximum width. Some become tapered through time as most branches become extinct and only a few diversify. Some show rapid and early diversification, and maintain this width by balance of extinction and speciation. Read about phylogenetic trees.)

In the two-kingdom system, why were fungi classified in the kingdom Plantae? A) They are sedentary. B) They are heterotrophs. C) They lack cell walls. D) They are unicellular. E) They are autotrophs.

A) They are sedentary.

In a comparison of birds with mammals, having four appendages is A) a shared ancestral character. B) a character useful for sorting bird species. C) an example of analogy rather than homology. D) a shared derived character. E) a character useful for distinguishing birds from mammals.

A) a shared ancestral character

There is(are) _____ eukaryotic domain(s). A) one B) two C) three D) four E) five

A) one

The domains of life are _____. (Concept 26.6)

Archaea, Bacteria, Eukarya

Prokaryotic cells are found in the domain(s) _____. A) Bacteria and Archaea B) Bacteria and Eukarya C) Bacteria and Protista D) Bacteria E) Protista and Archaea

Bacteria and Archaea

A phylogenetic tree that is "rooted" is one A) that extends back to the origin of life on Earth. B) at whose base is located the common ancestor of all taxa depicted on that tree. C) that illustrates the rampant gene swapping that occurred early in life's history. D) that indicates our uncertainty about the evolutionary relationships of the taxa depicted on the tree. E) with very few branch points.

B

Darwin analogized the effects of evolution as the above-ground portion of a many-branched tree, with extant species being the tips of the twigs. The common ancestor of two species is most analogous to which anatomical tree part? A) a single twig that gets longer with time B) a node where two twigs diverge C) a twig that branches with time D) the trunk E) neighboring twigs attached to the same stem

B

If the eukaryotic condition arose, independently, several different times during evolutionary history, and if ancestors of these different lineages are extant and are classified in the domain Eukarya, then the domain Eukarya would be A) paraphyletic. B) polyphyletic. C) monophyletic.

B

If, someday, an archaean cell is discovered whose SSU-rRNA sequence is more similar to that of humans than the sequence of mouse SSU-rRNA is to that of humans, the best explanation for this apparent discrepancy would be A) homology. B) homoplasy. C) common ancestry. D) retro-evolution by humans. E) co-evolution of humans and that archaean.

B

In Figure 26.4 from your textbook, which similarly inclusive taxon descended from the same common ancestor as Canidae? A) Felidae B) Mustelidae C) Carnivora D) Canis E) Lutra

B

Members of which kingdom have cell walls and are all heterotrophic? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

B

The correct sequence, from the most to the least comprehensive, of the taxonomic levels listed here is A) family, phylum, class, kingdom, order, species, and genus. B) kingdom, phylum, class, order, family, genus, and species. C) kingdom, phylum, order, class, family, genus, and species. D) phylum, kingdom, order, class, species, family, and genus. E) phylum, family, class, order, kingdom, genus, and species.

B

The human nuclear genome includes hundreds of genes that are orthologs of bacterial genes, and hundreds of other genes that are orthologs of archaean genes. This finding can be explained by proposing that A) neither archaea nor bacteria contain paralogous genes. B) the eukaryotic lineage leading to humans involved at least one fusion of an ancient bacterium with an ancient archaean. C) the infection of humans by bacteriophage introduced prokaryotic genes into the human genome. D) horizontal gene transfer did not occur to any significant extent among the prokaryotic ancestors of humans.

B

The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma that have apparently undergone speciation from ancestral stock since the last glacial retreat about 10,000 years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species? A) nuclear DNA B) mitochondrial DNA C) small nuclear RNA D) ribosomal RNA E) amino acids in proteins

B

When it acts upon a gene, which of these processes consequently makes that gene an accurate molecular clock? A) transcription B) directional natural selection C) mutation D) proofreading E) reverse transcription

B

Which individual would make the worst systematist? One who is uncomfortable with the A) Linnaean system of classification. B) notion of hypothetical phylogenies. C) PhyloCode method of classification. D) notion of permanent polytomies

B

Which mutation should least require realignment of homologous regions of a gene that is common to several related species? A) 3-base insertion B) 1-base substitution C) 4-base insertion D) 1-base deletion E) 3-base deletion

B

Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago? (Concept 26.4) A) rRNA is traditionally the nucleic acid chosen for recent comparisons. B) DNA coding for rRNA changes relatively slowly. C) rRNA mutates rapidly. D) rRNA cannot mutate. E) rRNA is never the nucleic acid chosen for comparisons.

B) DNA coding for rRNA changes relatively slowly.

By definition a clade is _____. (Concept 26.3) A) analogous B) Monophyletic C) paraphyletic D) polyphyletic E) parsimonious

B) Monophyletic

Which observation supports the position of eukaryotes at the convergence of the "ring of life"? A) Only eukaryotes perform mitosis. B) The nuclear genome of eukaryotes contains genes from archaeans and from bacteria. C) Eukaryotes and archaeans both lack peptidoglycan in their cell walls. D) Circular chromosomes are present in both bacteria and archaeans. E) Introns are rare in both bacteria and archaeans.

B) The nuclear genome of eukaryotes contains genes from archaeans and from bacteria. (A leading hypothesis proposes that eukaryotes are the result of fusion involving a bacterium and an archaean, thereby explaining the presence of both kinds of genes.)

Phylogeny is the evolutionary history of related groups of organisms. Organisms are grouped into taxa based on homologous characteristics, shared traits that result from common ancestry. Which statement is true? A) Homologous structures look the same and serve the same function, but they differ in evolutionary origin and structure. B) The term "monophyletic" refers to a taxon that includes an ancestral species and all of its descendants. C) Ancestral traits are always simpler than derived traits.

B) The term "monophyletic" refers to a taxon that includes an ancestral species and all of its descendants.

false Besides corroborative similarities and fossil evidence, another clue to distinguishing between homology and analogy is the complexity of the characters being compared. The more elements that are similar in two complex structures, the more likely it is that they evolved from a common ancestor.

Besides corroborative similarities and fossil evidence, another clue to distinguishing between homology and analogy is the complexity of the characters being compared. The more elements that are similar in two complex structures, the more likely it is that they did not evolved from a common ancestor.

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of A) archaeans and bacteria. B) fungi and animals. C) Hawaiian silverswords. D) sharks and dolphins E) mosses and ferns.

C

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of A) archaeans and bacteria. B) fungi and animals. C) chimpanzees and humans. D) sharks and dolphins. E) mosses and ferns. A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of A) archaeans and bacteria. B) fungi and animals. C) chimpanzees and humans. D) sharks and dolphins. E) mosses and ferns.

C

A taxon, all of whose members have the same common ancestor, is A) paraphyletic. B) polyphyletic. C) monophyletic.

C

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? A) lion B) domestic cat C) wolf D) leopard E) tiger

C

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with A) classifying organisms using the morphospecies concept. B) the scientific discipline known as taxonomy. C) phylogenies. D) nested, ever-more inclusive categories of organisms. E) a hierarchical classification scheme.

C

Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids A) are found in the most crucial portions of proteins. B) include all mitochondrial DNA. C) are abundant in ribosomes. D) are proportionately more common in eukaryotic introns than in eukaryotic exons. E) comprise a larger proportion of pre-mRNA (immature mRNA) than of mature mRNA.

C

Phylogenetic hypotheses (such as those represented by phylogenetic trees) are strongest when 11 A) they are based on amino acid sequences from homologous proteins, as long as the genes that code for such proteins contain no introns. B) each clade is defined by a single derived character. C) they are supported by more than one kind of evidence, such as when fossil evidence corroborates molecular evidence. D) they are accepted by the foremost authorities in the field, especially if they have won Nobel Prizes. E) they are based on a single DNA sequence that seems to be a shared derived sequence.

C

Shared derived characters are most likely to be found in taxa that are A) paraphyletic. B) polyphyletic. C) monophyletic.

C

The best classification system is that which most closely A) unites organisms that possess similar morphologies. B) conforms to traditional, Linnaean taxonomic practices. C) reflects evolutionary history. D) corroborates the classification scheme in use at the time of Charles Darwin. E) reflects the basic separation of prokaryotes from eukaryotes.

C

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however, are alike in having 4-chambered hearts (2 atria, 2 ventricles). The 4-chambered hearts of birds and mammals are best described as A) structural homologies. B) vestiges. C) homoplasies. D) the result of shared ancestry. E) molecular homologies.

C

The common housefly belongs to all of the following taxa. Assuming you had access to textbooks or other scientific literature, knowing which of the following should provide you with the most specific information about the common housefly? A) order Diptera B) family Muscidae C) genus Musca D) class Hexapoda E) phylum Arthropoda

C

The legless condition that is observed in several groups of extant reptiles is the result of A) their common ancestor having been legless. B) a shared adaptation to an arboreal (living in trees) lifestyle. C) several instances of the legless condition arising independently of each other. D) individual lizards adapting to a fossorial (living in burrows) lifestyle during their lifetimes.

C

The most important feature that permits a gene to act as a molecular clock is A) having a large number of base pairs. B) having a larger proportion of exonic DNA than of intronic DNA. C) having a reliable average rate of mutation. D) its recent origin by a gene-duplication event. E) its being acted upon by natural selection

C

The term that is most appropriately associated with clade is A) paraphyletic. B) polyphyletic. C) monophyletic.

C

The various taxonomic levels (viz, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of A) how widely the organisms assigned to each are distributed throughout the environment. B) the body sizes of the organisms assigned to each. C) their inclusiveness. D) the relative genome sizes of the organisms assigned to each. E) morphological characters that are applicable to all organisms.

C

Ultimately, which of these serves as the basis for both the principle of maximum parsimony and the principle that shared complexity indicates homology rather than analogy? A) the laws of thermodynamics B) Boyle's law C) the laws of probability D) chaos theory E) Hutchinson's law

C

What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system? A) the number of cells present in individual organisms B) the geological stratum in which fossils first appear C) the nutritional modes they employ D) the biogeographic province where each first appears E) the features of their embryos

C

What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system? A) the number of cells present in individual organisms B) the geological stratum in which fossils first appear C) the nutritional modes they employ D) the biogeographic province where each first appears E) the features of their embryos

C

When using a cladistic approach to systematics, which of the following is considered most important for classification? A) shared primitive characters B) analogous primitive characters C) shared derived characters D) the number of homoplasies E) overall phenotypic similarity

C

Which of the following is the best explanation for the high degree of sequence homology observed in Exon I among these five species? A) It is the most-upstream exon of this gene. B) Due to alternative gene splicing, this exon is often treated as an intron. C) It codes for a polypeptide domain that has a crucial function. D) These five species must actually constitute a single species. E) This exon is rich in G-C base pairs; thus, it is more stable.

C

Which of these four gene parts should allow the construction of the most accurate phylogenetic tree, assuming that this is the only part of the gene that has acted as a reliable molecular clock? A) Intron I B) Exon I C) Intron VI D) Exon V

C

A rose bush is classified in domain _____ and kingdom _____. A) Eukarya ... Fungi B) Eukarya ... Protista C) Eukarya ... Plantae D) Eukarya ... Animalia E) Bacteria ... Archaea

C) Eukarya ... Plantae

What process actually increases the number of genes in an organism's genome? (Concept 26.4) A) Mutation B) Parsimony C) Gene duplication D) Cladistics E) All of the above.

C) gene duplication

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? A) domestic cat B) lion C) wolf D) tiger E) leopard

C) wolf

e

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in __________. (a) morphology (b) the pattern of embryological development (c) biochemical pathways (d) habitat and lifestyle choices (e) mutations to homologous genes

Which of the following taxonomic categories contains all the others listed here?

Class Class includes all categories except phylum, kingdom, and domain.

a

Concerning growth in genome size over evolutionary time, which of these does not belong with the others? (a) orthologous genes (b) gene duplications (c) paralogous genes (d) gene families

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis familiaris). The researcher should compare homologous sequences of __________ that are known to be __________. A) carbohydrates; poorly conserved B) fatty acids; highly conserved C) lipids; poorly conserved D) proteins or nucleic acids; poorly conserved E) amino acids; highly conserved

D

Generally, within a lineage, the largest number of shared derived characters should be found among two organisms that are members of the same A) kingdom. B) class. C) domain. D) family. E) order.

D

In angiosperm plants, flower morphology can be very intricate. If a tree, such as a New Mexico locust, has flowers that share many morphological intricacies with flowers of the sweet pea vine, then the most likely explanation for these floral similarities is the same general explanation for the similarities between the A) dorsal fins of sharks and of dolphins. B) reduced eyes of Australian moles and North American moles. C) scales on moth wings and the scales of fish skin. D) cranial bones of humans and those of chimpanzees. E) adaptations for flight in birds and adaptations for flight in bats.

D

Regarding these sequence homology data, the principle of maximum parsimony would be applicable in A) distinguishing introns from exons. B) determining degree of sequence homology. C) selecting appropriate genes for comparison among species. D) inferring evolutionary relatedness from the number of sequence differences.

D

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to A) inheritance of acquired characteristics. B) sexual selection. C) inheritance of shared derived characters. D) possession of analogous structures. E) possession of shared primitive characters.

D

The HIV genome's reliably high rate of change permits it t o serve as a molecular clock. Which of these features is most responsible for this genome's high rate of change? A) the relatively low number of nucleotides in the genome B) the relatively small number of genes in the genome C) the genome's ability to insert itself into the genome of the host D) the lack of proofreading by the enzyme that converts HIV's RNA genome into a DNA genome

D

The four-chambered hearts of birds and the four-chambered hearts of mammals evolved independently of each other. If one were unaware of this independence, then one might logically conclude that A) the birds were the first to evolve a 4-chambered heart. B) birds and mammals are more distantly related than is actually the case. C) early mammals possessed feathers. D) the common ancestor of birds and mammals had a four-chambered heart. E) birds and mammals should be placed in the same family.

D

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that includes species T, X, Y, and Z makes up A) a polyphyletic grouping. B) an ingroup, with species U as the outgroup. C) a monophyletic clade. D) a paraphyletic grouping. E) a valid taxon.

D) a paraphyletic grouping.

The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that A) having multiple copies of genes is essential for the occurrence of sympatric speciation in the wild. B) paralogous genes can occur only in diploid species; thus, they are absent from most prokaryotes. C) polyploidy is a necessary precondition for the occurrence of sympatric speciation in the wild. D) having an extra copy of a gene permits modifications to the copy without loss of the original gene product.

D

The relative lengths of the amphibian and mouse branches in the phylogeny in Figure 26.12 in your textbook indicate that A) amphibians evolved before mice. B) mice evolved before amphibians. C) the genes of amphibians and mice have only coincidental homoplasies. D) the homologous gene has evolved more slowly in mice. E) the homologous gene has evolved more rapidly in mice.

D

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair? A) It is a shared derived character of mammals, even if cynodonts continue to be classified as reptiles. B) It is a shared derived character of the amniote clade, and not of the mammal clade. C) It is a shared ancestral character of the amniote clade, but only if cynodonts are reclassified as mammals. D) It is a shared derived character of the mammals, but only if cynodonts are reclassified as mammals

D

Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that includes species T, X, Y, and Z makes up A) a valid taxon. B) a monophyletic clade. C) an ingroup, with species U as the outgroup. 26 D) a paraphyletic grouping. E) a polyphyletic grouping.

D

To apply parsimony to constructing a phylogenetic tree, A) choose the tree that assumes all evolutionary changes are equally probable. B) choose the tree in which the branch points are based on as many shared derived characters as possible. C) base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution. D) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology. E) choose the tree with the fewest branch points.

D

Traditional zoologists have long agreed that birds evolved from dinosaurs. What keeps such zoologists from agreeing that birds, like dinosaurs, should be considered reptiles? A) There is not yet enough evidence to be sure. B) Stubbornness, insofar as they are unwilling to change their thinking when new data warrants it. C) They deny the validity of genetic molecular data. D) They differ in what they consider to be important traits for assigning organisms to the class Reptilia.

D

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. 62) Taxonomically, what should be done with the birds? A) The traditional stance is correct. Such dramatic morphological change as undergone by birds merits that the birds be placed in their own order, separate from the reptiles. B) The birds should be reclassified, and their new taxon should be the subclass Aves. Genetic similarity trumps morphological dissimilarity. C) The rest of the reptiles should be reclassified as a subclass within the class Aves. D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

D

Which eukaryotic kingdom is polyphyletic and therefore not acceptable, based on cladistics? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

D

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history? A) polyphyletic taxa B) paraphyletic taxa C) monophyletic taxa D) Two of the responses are correct.

D

Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right? A) Each branch point represents a point in absolute time. B) Organisms represented at the base of such trees are descendants of those represented at higher levels. C) The fewer branch points that occur between two taxa, the more divergent their DNA sequences should be. D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left. E) The more branch points there are, the fewer taxa are likely to be represented.

D

Which of these would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock? A) neutral mutations B) genetic drift C) mutations within introns D) natural selection E) most substitution mutations involving an exonic codon's 3rd position

D

Which portion of this tree may ultimately be better depicted as a "ring"? A) the bacterial lineage B) the archaean lineage C) the eukaryotic lineage D) the weblike part near the base of the tree E) the part corresponding to the first living cell on Earth

D

Which process hinders clarification of the deepest branchings in a phylogenetic tree that depicts the origins of the three domains? A) binary fission B) mitosis C) meiosis D) horizontal gene transfer E) gene duplication

D

Which process is observed in prokaryotes and is responsible for the vertical components of the various bacterial and archaean lineages? A) mitosis B) meiosis C) sexual reproduction D) binary fission

D

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of homology? A) Dogs and wolves have very similar morphologies. B) Dogs and wolves belong to the same order. C) Dogs and wolves are both members of the order Carnivora. D) Dogs and wolves shared a common ancestor very recently. E) Convergent evolution has occurred.

D

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? A) Dogs and wolves have very similar morphologies. B) Dogs and wolves belong to the same order. C) Dogs and wolves are both members of the order Carnivora. D) Dogs and wolves shared a common ancestor very recently.

D

To apply parsimony to constructing a phylogenetic tree, A) choose the tree in which the branch points are based on as many shared derived characters as possible. B) choose the tree with the fewest branch points. C) choose the tree that assumes all evolutionary changes are equally probable. D) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology. E) base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution.

D) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology.

Animals that possess homologous structures probably _____. (Concept 26.2) A) are not related B) have increased genetic diversity C) by chance had similar mutations in the past D) evolved from the same ancestor E) are headed for extinction

D) evolved from the same ancestor

Which process occurred frequently in the early history of the three domains on Earth, and makes determining phylogenetic relationships of that time difficult? A) mitosis B) meiosis C) binary fission D) horizontal gene transfer E) alternative RNA splicing

D) horizontal gene transfer (Horizontal gene transfer permits gene flow from one organism's genome to another organism's genome, It occurs commonly between prokaryotes of different species, and even between prokaryotes and eukaryotes.)

Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?

DNA coding for rRNA changes relatively slowly.

Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in A) morphology. B) the pattern of embryological development. C) biochemical pathways. D) habitat and lifestyle choices. E) mutations to homologous genes.

E

Dozens of potato varieties exist, differing from each other in potato-tuber size, skin color, flesh color, and shape. One might construct a classification of potatoes based on these morphological traits. Which of these criticisms of such a classification scheme is most likely to come from an adherent of the phylocode method of classification? A) Flesh color, rather than skin color, is a valid trait to use for classification because it is less susceptible to change with the age of the tuber. B) Flower color is a better classification criterion, because below-ground tubers can be influenced by minerals in the soil as much as by their genes. C) A more useful classification would codify potatoes based on the texture and flavor of their flesh, because this is what humans are concerned with. D) The most accurate phylogenetic code is that of Linnaeus. Classify potatoes based on Linnaean principles; not according to their color. E) The only biologically valid classification of potato varieties is one that accurately reflects their genetic and evolutionary relatedness.

E

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology? A) A and B B) A and C C) B and D D) C and F 3 E) D and F

E

If the genes of yeast are 50% orthologous to those of humans, and if the genes of mice are 99% orthologous to those of humans, then what percentage of the genes of fish might one validly predict to be orthologous to the genes of humans? A) 10% B) 30% C) 40% D) 50% E) 80%

E

Neutral theory proposes that A) molecular clocks are more reliable when the surrounding pH is close to 7.0. B) most mutations of highly conserved DNA sequences should have no functional effect. 18 C) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral pH. D) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral electrical charge. E) a significant proportion of mutations is not acted upon by natural selection.

E

Paralogous genes that have lost the function of coding for a functional gene product are known as "pseudogenes." Which of these is a valid prediction regarding the fate of pseudogenes over evolutionary time? A) They will be preserved by natural selection. B) They will be highly conserved. C) They will ultimately regain their original function. D) They will be transformed into orthologous genes. E) They will have relatively high mutation rates.

E

Species that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their A) plasmids. B) chloroplast genomes. C) mitochondrial genomes. D) homologous genes that are poorly conserved. E) homologous genes that are highly conserved.

E

The importance of computers and of computer software to modern cladistics is most closely linked to advances in A) light microscopy. B) radiometric dating. C) fossil discovery techniques. D) Linnaean classification. E) molecular genetics.

E

What is true of gene duplication (NOTE: gene duplication is a process that is distinct from DNA replication)? 17 A) It is a type of point mutation. B) Its occurrence is limited to diploid species. C) Its occurrence is limited to organisms without functional DNA-repair enzymes. D) It is most similar in its effects to a deletion mutation. E) It can increase the size of a genome over evolutionary time.

E

Which is an obsolete kingdom that includes prokaryotic organisms? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

E

Which kingdom has been replaced with two domains? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

E

Which of these illustrates the correct representation of the binomial scientific name for the African lion? A) Panthera leo B) panthera leo C) Panthera leo(leo italizied) D) Panthera Leo E) Panthera leo(all of it italized)

E

In the five-kingdom system, which kingdom consists primarily of unicellular eukaryotes? A) Fungi B) Protista C) Plantae D) Animalia E) Monera

E) Monera

Molecular clocks are based on the idea that _____. (Concept 26.5) A) Molecules resonate at a certain frequency that can be measured. B) Advantageous mutations arise at a constant rate. C) Directional selection occurs at a constant rate. D) Mutations occur once every generation. E) On average neutral mutations arise at a constant rate.

E) On average neutral mutations arise at a constant rate (The idea of a molecular clock rests on the assumption that neutral mutations can arise and become fixed in populations. The rate of occurrence of these mutations is not affected by natural selection, so it is assumed that the rate is relatively constant over time.)

Systematists have used a wide variety of traits to reconstruct the phylogenies of particular groups of organisms. Which one of the following traits produces the best estimate of the true phylogeny? (Concept 26.2) A) gross morphological traits B) molecular traits C) behavioral traits D) biochemical traits E) all of the above traits combined

E) all of the above traits combined

Which of the following taxonomic categories contains all the others listed here? (Concept 26.1) A) genus B) species C) order D) family E) class

E) class

The relative lengths of the amphibian and mouse branches in the phylogeny in the figure above indicate that A) amphibians evolved before mice. B) mice evolved before amphibians. C) the genes of amphibians and mice have only coincidental homoplasies. D) the homologous gene has evolved more rapidly in mice. E) the homologous gene has evolved more slowly in mice.

E) the homologous gene has evolved more slowly in mice.

Refer to the figure above. Which of the following forms a monophyletic group?

E, F, and G

A human is classified in domain _____ and kingdom _____. Eukarya ... Fungi Eukarya ... Protista Eukarya ... Plantae Eukarya ... Animalia Bacteria ... Archaea

Eukarya ... Animalia

maximum parsimony

For phylogenies based on DNA, the most parsimonious tree requires the fewest base changes which principal is this

Which of the following would be useful in creating a phylogenetic tree of a taxon? I) morphological data from fossil species II) genetic sequences from living species III) behavioral data from living species

I, II, and III

B section 26.4

If the sequence of Species A differs from that of the other four species due to simple misalignment, then what should the computer software find when it compares the sequence of Species A to those of the other four species? (a) The nucleotide at position 1 should be different in Species A, but the same in species B-E. (b) The nucleotide sequence of Species A should have long sequences that are nearly identical to those of the other species, but offset in terms of position number. (c) The sequences of species B-E, though different from that of Species A, should be identical to each other, without exception. (d) If the software compares, not nucleotide sequence, but rather the amino acid sequence of the actual protein product, then the amino acid sequences of species B-E should be similar to each other, but very different from that of Species A. (e) Computer software is useless in determining sequences of introns; it can only be used with exons.

In the five-kingdom system, prokaryotes are placed in the kingdom _____. Protista Animalia Fungi Plantae Monera

Monera

In Figure 26.4 in your textbook, which similarly inclusive taxon descended from the same common ancestor as Canidae?

Mustelidae

One reason for misclassification might be that over the course of evolution, a species has lost a key feature shared by its close relatives.

Sometimes, however, taxonomists have placed a species within a genus (or other group) to which it is not most closely related. what is this cause of thiis?

A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans.

false...they are intended to show patterns of descent

Phylogenetic Trees shows phenotypic relations ships

Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium?

Plantae

Answer: Lizards are more closely related to salamanders than to humans.

Question:

Which observation supports the position of eukaryotes at the convergence of the "ring of life"?

The nuclear genome of eukaryotes contains genes from archaeans and from bacteria.

Given that phylogenies are based on shared derived characteristics, which of the following traits is useful in generating a phylogeny of species W, X, Y, and Z? Species W Species X Species Y Species Z Trait 1 A A A A Trait 2 A A B B Trait 3 A B C D

Trait 2

the first letter

Which word in a binomial naming is capatilized

It is ambiguious because there are more than one type of monkeys

Why does using the word monkey cause confusion?

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?

Wolf

no

do closely related species always share common ancestors

The best classification system is that which most closely _____.

eflects evolutionary history

Eukaryotes that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their _____.

homologous genes that are highly conserved

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as _____.

homoplasies

classifying species incorrectly

in organisms that do not appear to be closely related, the bases that their otherwise very different sequences happen to share may simply be coincidental matches, called molecular homoplasies what problem can this cause

2

refers to a lineage that diverges early in the history of a group and hence

true

scientist use characteristic feature to relate species by using phylogeny trees

Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character?

shared ancestral character A shared ancestral character is one that originated in an ancestor of the taxon. In this case it appears that feathers originated in some dinosaur lineages and were passed down to birds.

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

to serve as an outgroup

gene deletion and insertion.

what kind of mutation causes a small difference among genes over the years.