Chap. 32 – Flashcards
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Most animals exhibit the following structures or functions except
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autotrophic nutrition
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The young of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following most directly favors the evolution of the latter more radical kind of metamorphosis?
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changes in the homeobox genes governing early development
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The number of legs an insect has, or the number of vertebrae in a vertebral column, or the number of joints in a digit (such as a finger) are all strongly influenced by ________ genes.
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hox
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Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?
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increased incidence of hard parts in the fossil record
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Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent? 1.Protostomes invade terrestrial environments. 2.Cambrian explosion occurs. 3.Deuterostomes invade terrestrial environments. 4.Vertebrates become top predators in the seas.
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2, 4, 1, 3
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During which era did the greatest radiation of mammals occur?
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Cenozoic
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During metamorphosis, echinoderms undergo a transformation from motile larvae to a sedentary (and sometimes sessile) existence as adults. What is true of adults, but not of larvae? Adults should
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have radial symmetry
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Which of the following is an incorrect association of an animal germ layer with the tissues or organs to which it gives rise?
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mesoderm-nervous system
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What distinguishes a coelomate animal from a pseudocoelomate animal is that coelomates
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have a body cavity completely lined by mesodermal tissue, whereas pseudocoelomates do not
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An animal that swims rapidly in search of prey that it captures using visual senses concentrated at its anterior end is likely to be all of the following except
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diploblastic
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Which of the following is descriptive of protostomes?
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spiral and determinate cleavage, blastopore becomes mouth, schizocoelous development
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The most ancient branch point in animal phylogeny is that between having
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true tissues or no tissues.
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What is characteristic of all ecdysozoans?
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some kind of exoskeleton, or hard outer covering
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According to the evidence collected so far, the animal kingdom is
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monophyletic
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According to both the molecular- and morphology-based animal phylogenies, the following are all protostomes except
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echinoderms
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If the current molecular evidence regarding animal origins is well substantiated in the future, then what will be true of any contrary evidence regarding the origin of animals derived from the fossil record?
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The fossil evidence will be understood to have been incorrect because it is incomplete.
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Protostomes exhibit ________ cleavage; deuterostomes exhibit ________ cleavage.
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spiral and determinate; radial and indeterminate
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Among the characteristics unique to animals is
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gastrulation
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Acoelomates are characterized by
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a solid body without a cavity surrounding internal organs.
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Which of the following subdivisions of the animal kingdom encompasses all the others in the list?
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Eumetazoa
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Which of the following terms or structures is not associated with animals?
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cell wall
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What is the correct sequence of the following four events during an animal's development? 1. gastrulation 2. metamorphosis 3. fertilization 4. cleavage
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3, 4, 1, 2
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Which of these genetic processes may be most helpful in accounting for the Cambrian explosion?
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gene duplication
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If one encounters the deepest stratum in which aquatic and flying reptiles can be found, then one has likely found a stratum that was laid during which era?
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Mesozoic
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The major branches of Eumetazoa are the Radiata and the Bilateria. These names refer to what characteristic of these animals?
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body symmetry
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Cephalization is primarily associated with
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bilateral symmetry
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You are trying to identify an organism. It is an animal, but it does not have nerve or muscle tissue. It is neither diploblastic nor triploblastic. It is probably a
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sponge
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Which of the following functions is an advantage of a fluid-filled body cavity?
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A, B, and C
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The blastopore is a structure that is evident in the
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gastrula
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Which of the following characteristics generally applies to protostome development?
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determinate cleavage
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With the current molecular-based phylogeny in mind, rank the following from most inclusive to least inclusive. 1.ecdysozoan 2.protostome 3.eumetazoan 4.triploblastic
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3, 4, 2, 1
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What kind of data should probably have the greatest impact on animal taxonomy in the coming decades?
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nucleotide sequences of homologous genes
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The common ancestor of all animals was probably a
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protist
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Which of the following organisms are deuterostomes?
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both C and D
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As a group, how do poriferans, cnidarians, and platyhelminthes differ from other animal phyla?
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They do not have a body cavity
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Why are annelids, arthropods, and molluscs placed in the same clade?
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They are protostomes
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Which of the following was the least likely factor causing the Cambrian explosion?
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the movement of animals onto land
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A direct consequence of indeterminate cleavage is
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the ability of cells isolated from the early embryo to develop into viable individuals
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Which of the following combinations of phylum and description is incorrect?
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Porifera-coelomates, mouth from blastopore
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What should animals as diverse as corals and monkeys have in common?
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presence of Hox genes
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A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny?
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collagen genes
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Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition
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by ingesting it
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At which stage would one be able to first distinguish a diploblastic embryo from a triploblastic embryo?
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gastrulation
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Which of the following is not unique to animals?
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sexual reproduction
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What may have occurred to prevent species that are of the same grade from also belonging to the same clade?
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adaptation by different lineages to the same selective pressures
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The Hox genes came to regulate each of the following in what sequence, from earliest to most recent?
1. identity and position of paired appendages in protostome embryos
2. formation of channels in sponges
3. anterior-posterior orientation of segments in protostome embryos
4. positioning of tentacles in cnidarians
5. anterior-posterior orientation of somites in vertebrate embryos
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2, 4, 3, 1, 5
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Almost all of the major animal body plans seen today appeared in the fossil record over 500 million years ago at the beginning of the
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Cambrian period
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Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?
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mineralized hard parts
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Whatever its ultimate cause(s), the Cambrian explosion is a prime example of
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adaptive radiation
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What is the probable sequence in which the following clades of animals originated, from earliest to most recent?
1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians
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5, 3, 2, 1, 4
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Organisms showing radial symmetry would likely
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move from place to place relatively slowly, if at all
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ephalization is generally associated with all of the following except
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a sessile existence
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What is the main basis for placing the arthropods and nematodes in the Ecdysozoa in one hypothesis of animal phylogeny?
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Analysis of genes shows that their sequences are quite similar, and these sequences differ from those of the lophotrochozoans and deuterostomes.
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Bilateral symmetry in the animal kingdom is best correlated with
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motility and active predation and escape
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The distinction between the sponges and other animal phyla is based mainly on the absence versus the presence of
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true tissues
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Organisms that are neither coelomate nor pseudocoelomate should, apart from their digestive systems, have bodies that
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are solid with tissue
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You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is an acoelomate?
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Muscular activity of its digestive system distorts the body wall
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The blastopore denotes the presence of an endoderm-lined cavity in the developing embryo, a cavity that is known as the
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archenteron
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Protostome characteristics include all of the following except
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indeterminate cleavage
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At the phylum level, you are most closely related to a(n)
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sea star
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What does recent evidence from molecular systematics reveal about the r elationship between grades and clades?
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Some, but not all, grades reflect evolutionary relatedness.
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Echinoderms are
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deuterstomes
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Phylogenetic trees are best described as
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hypothetical portrayals of evolutionary relationships.
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If a multicellular animal lacks true tissues, then it can be classified among the
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metazoans
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Which of the following statements concerning animal taxonomy is (are) true? 1. Animals are more closely related to plants than to fungi.
2. All animal clades based on body plan have been found to be incorrect.
3. Kingdom Animalia is monophyletic.
4. Only animals reproduce by sexual means.
5. Animals are thought to have evolved from flagellated protists similar to modern choanoflagellates.
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3, 5