Ch 26 Flashcards

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5) 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



6) The various taxonomic levels (for example, phyla, genera, classes) 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) their inclusiveness

C) the relative genome sizes of the organisms assigned to each

D) morphological characters that are applicable to all organisms



7) If organisms A, B, and C belong to the same class but to different orders and if organisms C, D, and E 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 D

B) B and D
C) B and C
D) D and E



8) Carolus Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with ________.
A) a hierarchical classification scheme
B) taxonomy

C) phylogenies
D) nested, increasingly inclusive categories of organisms



9) 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) reflects the basic separation of prokaryotes from eukaryotes



12) Some beetles and flies have antler-like structures on their heads, much like male deer. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of ________.
A) convergent evolution

B) similarity due to shared ancestry

C) homology
D) parsimony



13) The term convergent evolution is most applicable to which of the following features?

A) the legless condition found in various lineages of extant lizards
B) the five-digit condition of human hands and bat wings
C) the fur that covers Australian moles and North American moles

D) the bones of bat forelimbs and the bones of bird forelimbs



14) If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be ________.
A) homology

B) convergent evolution
C) common ancestry
D) retro-evolution by humans



15) Which of the following pairs are the best examples of homologous structures? A) eyelessness in the Australian mole and eyelessness in the North American mole B) owl wing and hornet wing
C) bat wing and bird wing

D) bones in the bat wing and bones in the human forelimb



16) Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). If the molecular data best reflect the evolutionary history of these two groups, then the morphological similarities of these two species is most likely due to ________.

A) the inheritance of acquired characteristics B) sexual selection
C) possession of analogous (convergent) traits D) possession of shared primitive characters



17) The importance of computers and of computer software to modern systematics s is most closely linked to advances in ________.
A) light microscopy
B) radiometric dating

C) fossil discovery techniques
D) molecular genetics



18) 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 ________.

A) structural homologies
B) vestiges
C) structural analogies
D) the result of shared ancestry



19) Imagine that a phylogeny was developed for a group of mammals based on bone structure. Which of the following statements would be a reasonable prediction about a phylogeny for the same group of species based on similarities and differences in the structure of a particular enzyme?

A) The same phylogeny would be unlikely.
B) The same phylogeny would be predicted.
C) No prediction could be made.
D) The amino acid sequence would be identical in all species.



25) Which of the following would be most useful in creating a phylogenetic tree of a taxon?

A) morphological data from fossil and living species
B) a knowledge of color patterns in fossil and living species
C) a knowledge of mutation rates in modern species

D) morphological data from fossil species



26) 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?

A) to serve as an outgroup
B) to see if the lily is a cryptic orchid species

C) to see if the lily and the orchids show all the same shared derived characters D) to demonstrate likely homoplasies



27) Which of the following statements best describes the rationale for applying the principle of maximum parsimony in constructing phylogenetic trees?
A) Parsimony allows the researcher to "root" the tree.
B) Similarity due to common ancestry should be more common than similarity due to convergent evolution.

C) The molecular clock validates the principle of parsimony.
D) The outgroup roots the tree, allowing the principle of parsimony to be applied.



29) Which of the following statements is accurate with regard to a phylogeny, as represented by a phylogenetic tree?
A) Descendant groups (branches) from the same node likely share many derived characters.
B) A monophyletic group can be properly based on convergent features.

C) The ancestral group often has all the derived characters of the descendant species. D) Shared ancestral characters are excellent traits to use in developing a phylogeny.



31) 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) polyphyletic taxa and paraphyletic taxa



33) There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared ________.
A) derived character of mammals, even if cynodonts continue to be classified as reptiles

B) derived character of all vertebrates and not of the mammal clade

C) ancestral character of the all vertebrates, but only if cynodonts are reclassified as mammals

D) derived character of mammals, but only if cynodonts are reclassified as mammals



40) In a comparison of birds and mammals, having four limbs 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



41) To apply the principle of maximum parsimony to construction of 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) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology
D) choose the tree with the fewest branch points



42) 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



44) Concerning growth in genome size over evolutionary time, which of these is least associated with the others?
A) orthologous genes
B) gene duplications

C) paralogous genes
D) gene families



45) 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 ________.
A) plasmids
B) mitochondrial genomes

C) homologous genes that are poorly conserved

D) homologous genes that are highly conserved



46) 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



47) 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 10 thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

A) conserved regions of nuclear DNA

B) mitochondrial DNA
C) amino acids in proteins
D) ribosomal RNA



48) 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? Dogs and wolves ________.
A) have very similar morphologies

B) belong to the same order
C) are both members of the order Carnivora
D) share a very recent common ancestor



49) 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



51) The most important feature that permits a gene to act as a molecular clock is ________.

A) a large number of base pairs
B) being acted upon by natural selection
C) a reliable average rate of mutation

D) a recent origin by a gene-duplication event



52) Molecular clocks are more reliable when ________.
A) the surrounding pH is close to 7.0
B) most mutations of highly conserved DNA sequences should have no functional effect
C) the DNA codes for amino acid sequences whose side groups (or R groups) have a neutral pH

D) a significant proportion of mutations are not acted upon by natural selection



53) Which of the following 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



55) Based on cladistics, which eukaryotic kingdom is polyphyletic and, therefore, unacceptable?

A) Plantae
B) Fungi
C) Animalia

D) Protista



56) Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium?
A) Plantae
B) Fungi

C) Animalia
D) Protista



57) 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 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?

A) Among themselves, they should share relatively few ancestral traits, especially those that enabled ancestral forms to adapt to extreme conditions.
B) 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.

C) They should contain genes that originated in eukaryotes that are the hosts for numerous species of bacteria.
D) They should currently be undergoing a high level of horizontal gene transfer with non- extremophilic archaeans.



58) Use the following information to answer the question.

Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.

A crucial photosynthetic gene of the cyanobacterium that gave rise to the chromatophore is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the chromatophore. This is evidence of ________.
A) reciprocal mutations in the chromatophore and nuclear genomes

B) horizontal gene transfer from bacterium to eukaryotes
C) genetic recombination involving a protist and an archaean
D) transduction by a phage that infects both prokaryotes and eukaryotes



59) 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) mtDNA
B) rRNA genes

C) morphological
D) ecological



63) Which of the following statements is accurate, at least according to our present knowledge?

A) Eukaryotes acquired nuclear genes only in the distant past; these genes can allow survival in anaerobic environments.
B) Genes from prokaryotes have been acquired by some eukaryotes; these genes can allow survival in extreme environments.

C) Prokaryotes acquired genes from eukaryotes many times; these genes can allow survival in extreme environments.
D) Prokaryotes acquired genes from fungi; these genes can allow the digestion of cellulose.



65) If additional DNA sequence evidence shows that yeast genes for synthesizing proteins are more similar to protein-synthesizing genes in bacteria than those in archaea, a modern systematist would ________.
A) redraw the phylogeny to show eukaryotes sharing a more recent common ancestor with bacteria than archaea

B) redraw the phylogeny to show more recent common ancestry between archaea and yeast than between eukaryotes and archaea
C) retain the phylogeny that shows a more recent common ancestor between eukaryotes and archaea

D) retain the phylogeny that shows a more recent common ancestor between bacteria and archaea



66) Which of the following statements about horizontal gene transfer is accurate?
A) Horizontal gene transfer was quite common in the early stages of evolution of life on Earth.

B) Horizontal gene transfer among organisms does not occur today.
C) Horizontal gene transfer moves only genes that play a role in metabolism.
D) Horizontal gene transfer occurs only among closely related organisms.



67) The kingdom Monera was dismantled because of which of the following reasons? A) Some Monera contained nuclei in their cells.
B) The Monera, as originally constituted, contained both plants and animals.
C) The Monera, as originally constituted, was monophyletic.

D) Some, but not all, of the organisms in Monera contained DNA sequences that were similar to those of eukaryotes.



68) Imagine that you discovered the following information:

RNA polymerase

Antibiotic sensitivity

Membrane Lipids

small, simple
C chains unbranched

present insensitive
C chains branched

Eukaryotes complex
present insensitive
C chains branched

These data would support which of the following conclusions?
A) Eukaryotes share a more recent common ancestor with bacteria than with archaea. B) Bacteria are the only one of the three groups that lacks a nucleus.
C) Archaea are more similar to bacteria than to eukaryotes.
D) Eukaryotes are more similar to archaea than to bacteria.