This Document Contains Chapters 27 to 28 Chapter 27: The Rise of Animal Diversity 27.1 Multiple-Choice Questions 1) Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition by A) preying on animals. B) ingesting it. C) consuming living, rather than dead, prey. D) using enzymes to digest their food. Answer: B 2) Which of the following is (are) unique to animals? A) cells that have mitochondria B) the structural carbohydrate, chitin C) nervous conduction and muscular movement D) heterotrophy E) flagellated gametes Answer: C 3) A sponge's structural materials (spicules, spongin) are manufactured by the A) pore cells. B) epidermal cells. C) choanocytes. D) amoebocytes. Answer: D 4) In terms of food capture, which sponge cell is most similar to the cnidocyte of a cnidarian? A) amoebocyte B) choanocyte C) epidermal cell D) pore cell Answer: B 5) Sponges are most accurately described as A) marine predators. B) chemoautrophs. C) freshwater scavengers. D) filter feeders. E) aquatic predators. Answer: D 6) Which of the following characterize at least some members of the phylum Cnidaria? 1. a gastrovascular cavity 2. a polyp stage 3. a medusa stage 4. cnidocytes 5. a pseudocoelom A) 1 B) 2 and 3 C) 3, 4, and 5 D) 1, 2, 3, and 4 E) All of the above are correct Answer: D 7) Which of the following is true of members of the phylum Cnidaria? A) They are not capable of locomotion because they lack true muscle tissue. B) They are primarily filter feeders. C) They have either, or both, of two body forms: mobile polyps and sessile medusae. D) They may use a gastrovascular cavity as a hydrostatic skeleton. E) They are the simplest organisms with a complete alimentary canal (two openings). Answer: D 8) The members of which clade in the phylum Cnidaria occur only as polyps? A) Hydrozoa B) Scyphozoa C) Anthozoa D) Cubozoa Answer: C 9) Which clade in the phylum Cnidaria includes "jellies" with rounded (as opposed to boxlike) medusae? A) Hydrozoa B) Scyphozoa C) Anthozoa D) Cubozoa Answer: B 10) Which of the following is a diploblastic phylum of aquatic predators? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata Answer: A 11) Corals are most closely related to which group? A) jellies B) freshwater hydras C) sea anemones D) sponges E) barnacles Answer: C 12) The last common ancestor of all animals was probably a A) unicellular chytrid. B) unicellular yeast. C) multicellular algae. D) multicellular fungus. E) flagellated protist. Answer: E 13) Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna? A) true tissues B) hard parts C) bilateral symmetry D) cephalization E) embryos Answer: B 14) The most ancient branch point in animal phylogeny is that between having A) radial or bilateral symmetry. B) a well-defined head or no head. C) diploblastic or triploblastic embryos. D) true tissues or no tissues. E) a body cavity or no body cavity. Answer: D 15) According to the evidence collected so far, the animal kingdom is A) monophyletic. B) paraphyletic. C) polyphyletic. D) euphyletic. E) multiphyletic. Answer: A 16) If a multicellular animal lacks true tissues, then it can properly be included among the A) eumetazoans. B) metazoans. C) choanoflagellates. D) lophotrochozoans. E) bilateria. Answer: B 17) 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. A) 5 only B) 1 and 3 C) 3 and 5 D) 3, 4, and 5 Answer: C 18) 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? A) The contrary fossil evidence will be seen as a hoax. B) The fossil evidence will be understood to have been interpreted incorrectly because it is incomplete. C) The fossil record will henceforth be ignored. D) Phylogenies involving even the smallest bit of fossil evidence will need to be discarded. E) Only phylogenies based solely on fossil evidence will need to be discarded. Answer: B 19) Which characteristic(s) is (are) shared by both cnidarians and flatworms? A) dorsoventrally flattened bodies B) true muscle C) radial symmetry D) a digestive system with a single opening E) two of these Answer: D 20) Some researchers claim that sponge genomes have homeotic genes, but no Hox genes. If true, this finding would A) strengthen sponges' evolutionary ties to the Eumetazoa. B) mean that sponges must no longer be classified as animals. C) confirm the identity of sponges as "basal animals." D) mean that extinct sponges must have been the last common ancestor of animals and fungi. E) require sponges to be reclassified as choanoflagellates. Answer: C 21) The last common ancestor of all bilaterians is thought to have had four Hox genes. Most extant cnidarians have two Hox genes, except Nematostella (of β-catenin fame), which has three Hox genes. On the basis of these observations, some have proposed that the ancestral cnidarians were originally bilateral and, in stages, lost Hox genes from their genomes. If true, this would mean that A) Radiata should be a true clade. B) the radial symmetry of extant cnidarians is secondarily derived, rather than being an ancestral trait. C) Hox genes play little actual role in coding for an animal's "body plan." D) Cnidaria may someday replace porifera as the basal bilaterians. E) cnidarians are the basal metazoans. Answer: B 22) What do animals as diverse as corals and monkeys have in common? A) body cavity between body wall and digestive system B) number of embryonic tissue layers C) type of body symmetry D) presence of Hox genes E) degree of cephalization Answer: D 23) Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator—prey relationships? A) increased incidence of worm burrows in the fossil record B) increased incidence of larger animals in the fossil record C) increased incidence of organic material in the fossil record D) increased incidence of fern galls in the fossil record E) increased incidence of hard parts in the fossil record Answer: E 24) Whatever its ultimate cause(s), the Cambrian explosion is a prime example of A) mass extinction. B) evolutionary stasis. C) adaptive radiation. D) a large meteor impact. Answer: C 25) An adult animal that possesses bilateral symmetry is most certainly also A) triploblastic. B) a deuterostome. C) eucoelomate. D) highly cephalized. Answer: A 26) At least one of these has been found in all species of eumetazoan animals studied thus far. A) Hox B) Dlx C) Otx D) FOXP2 E) more than one of these Answer: A 27) 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 A) 5 → 3 → 2 → 4 → 1 B) 5 → 3 → 2 → 1 → 4 C) 5 → 3 → 4 → 2 → 1 D) 3 → 5 → 4 → 2 → 1 E) 3 → 5 → 2 → 1 → 4 Answer: B 28) 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. A) 2 → 4 → 3 → 1 B) 2 → 1 → 4 → 3 C) 2 → 4 → 1 → 3 D) 2 → 3 → 1 → 4 E) 2 → 1 → 3 → 4 Answer: C 29) Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion? A) binary fission B) mitosis C) random segregation D) gene duplication E) chromosomal condensation Answer: D 30) If nudibranch rhinophores are located at the anteriors of these sea slugs, then they contribute to the sea slugs' A) segmentation. B) lack of torsion. C) cephalization. D) identity as lophotrochozoans. E) ability to successfully carry out a sessile lifestyle. Answer: C 31) Which of these, if true, would support the claim that the ancestral cnidarians had bilateral symmetry? 1. Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects. 2. Cnidarians have fewer Hox genes than bilaterians. 3. All extant cnidarians, including Nematostella, are diploblastic. 4. β-catenin turns out to be essential for gastrulation in all animals in which it occurs. 5. All cnidarians are acoelomate. A) 1 only B) 1 and 4 C) 2 and 3 D) 2 and 4 E) 4 and 5 Answer: B 32) 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. anterior-posterior orientation of segments in protostome embryos 3. positioning of tentacles in cnidarians 4. anterior-posterior orientation in vertebrate embryos A) 4 → 1 → 3 → 2 B) 4 → 2 → 3 → 1 C) 4 → 2 → 1 → 3 D) 3 → 2 → 1 → 4 E) 3 → 4 → 1 → 2 Answer: D 33) A brachiopod can be distinguished from a bivalve by the presence of A) two hinged shells. B) a digestive system with separate mouth and anus. C) a lophophore. D) suspension feeding. E) a distinct head. Answer: C 34) Which of the following animal groups is entirely aquatic? A) Mollusca B) Crustacea C) Echinodermata D) Nematoda E) Platyhelminthes Answer: C 35) Chordate pharyngeal slits appear to have functioned first as A) the digestive system's opening. B) suspension-feeding devices. C) components of the jaw. D) gill slits for respiration. E) portions of the inner ear. Answer: B 36) Which of the following statements would be least acceptable to most zoologists? A) The extant lancelets are contemporaries, not ancestors, of vertebrates. B) The first fossils resembling lancelets appeared in the fossil record around 530 million years ago. C) Recent work in molecular systematics supports the hypothesis that lancelets are the basal clade of chordates. D) The extant lancelets are the immediate ancestors of the fishes. E) Lancelets display the same method of swimming as do fishes. Answer: D 37) Which extant chordates are postulated to be most like the earliest chordates in appearance? A) lancelets B) adult tunicates C) amphibians D) reptiles E) chondrichthyans Answer: A 38) A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics? A) legs B) no jaws C) an amniotic egg D) endothermy Answer: B 39) How many of the following statements about craniates is (are) correct? 1. Craniates are more highly cephalized than are no craniate chordates. 2. Craniates' genomic evolution includes duplication of clusters of genes that code for transcription factors. 3. The craniate clade is synonymous with the vertebrate clade. 4. Pharyngeal slits that play a major role in gas exchange originated in craniates. 5. The two-chambered heart originated with the early craniates. A) only 1 is correct B) 1 and 5 are correct C) 2, 3, and 5 are correct D) 1, 2, 4, and 5 are correct E) all 5 options are correct Answer: D 40) What do all craniates have that earlier chordates did not have? A) brain B) vertebrae C) cartilaginous pipe surrounding notochord D) partial or complete skull E) bone Answer: D 41) Lampreys differ from hagfishes in A) lacking jaws. B) having a cranium. C) having pharyngeal clefts that develop into pharyngeal slits. D) having a notochord throughout life. E) having a notochord that is surrounded by a tube of cartilage. Answer: E 42) The feeding mode of the extinct conodonts was A) herbivory. B) suspension feeding. C) predation. D) filter feeding. E) absorptive feeding. Answer: C 43) The earliest known mineralized structures in vertebrates are associated with which function? A) reproduction B) feeding C) locomotion D) defense E) respiration Answer: B 44) A team of researchers has developed a poison that has proven effective against lamprey larvae in freshwater cultures. The poison is ingested and causes paralysis by detaching segmental muscles from the skeletal elements. The team wants to test the poison's effectiveness in streams feeding Lake Michigan, but one critic worries about potential effects on lancelets, which are similar to lampreys in many ways. Why is this concern misplaced? A) A chemical poisonous to lampreys could not also be toxic to organisms as ancestral as lancelets. B) Lamprey larvae and lancelets have very different feeding mechanisms. C) Lancelets do not have segmental muscles. D) Lancelets live only in saltwater environments. E) Lancelets and lamprey larvae eat different kinds of food. Answer: D 45) Jaws first occurred in which extant group of fishes? A) lampreys B) chondrichthyans C) ray-finned fishes D) lungfishes E) placoderms Answer: B 46) Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans? A) a mineralized, bony skeleton B) opercula C) bony fin rays D) a spiral valve intestine E) a swim bladder Answer: A 47) To which of the following are the scales of chondrichthyans most closely related in a structural sense? A) osteichthyan scales B) reptilian scales C) mammalian scales D) bird scales E) chondrichthyan teeth Answer: E 48) Which group's members have had both lungs and gills during their adult lives? A) sharks, skates, and rays B) lungfishes C) lancelets D) amphibians E) ichthyosaurs and plesiosaurs Answer: B 49) There is evidence that ray-finned fishes evolved A) in response to a crisis that wiped out the chondrichthyans. B) directly from lampreys and hagfish. C) early in the Cambrian period. D) directly from lancelets. E) the swim bladder from a lung. Answer: E 50) The swim bladder of ray-finned fishes A) was probably modified from simple lungs of chondrichthyans. B) developed into lungs in saltwater fishes. C) first appeared in sharks. D) provides for regulation of buoyancy. E) Two of the options listed are correct. Answer: D 51) Which of the following belong to the lobe-fin clade? A) chondrichthyans B) ray-finned fishes C) lampreys D) hagfishes E) tetrapods Answer: E 52) Arrange these taxonomic terms from most inclusive (most general) to least inclusive (most specific). 1. lobe-fins 2. amphibians 3. gnathostomes 4. osteichthyans 5. tetrapods A) 4, 3, 1, 5, 2 B) 4, 3, 2, 5, 1 C) 4, 2, 3, 5, 1 D) 3, 4, 1, 5, 2 E) 3, 4, 5, 1, 2 Answer: D 53) During chordate evolution, what is the sequence (from earliest to most recent) in which the following structures arose? 1. amniotic egg 2. paired fins 3. jaws 4. swim bladder 5. four-chambered heart A) 2, 3, 4, 1, 5 B) 3, 2, 4, 1, 5 C) 3, 2, 1, 4, 5 D) 2, 1, 4, 3, 5 E) 2, 4, 3, 1, 5 Answer: A 54) Which of the following are the most abundant and diverse of the extant vertebrates? A) ray-finned fishes B) birds C) amphibians D) nonbird reptiles E) mammals Answer: A 55) What should be true of fossils of the earliest tetrapods? A) They should show evidence of internal fertilization. B) They should show evidence of having produced shelled eggs. C) They should indicate limited adaptation to life on land. D) They should be transitional forms with the fossils of chondrichthyans that lived at the same time. E) They should feature the earliest indications of the appearance of jaws. Answer: C 56) Which of these are amniotes? A) amphibians B) fishes C) mammals D) placental mammals only E) egg-laying mammals only Answer: C 57) Why is the amniotic egg considered an important evolutionary breakthrough? A) It has a shell that increases gas exchange. B) It allows deposition of eggs in a terrestrial environment. C) It prolongs embryonic development. D) It provides insulation to conserve heat. E) It permits internal fertilization to be replaced by external fertilization. Answer: B 58) Which of these characteristics added most to vertebrate success in relatively dry environments? A) the shelled, amniotic egg B) the ability to maintain a constant body temperature C) two pairs of appendages D) bony scales E) a four-chambered heart Answer: A 59) Which of the following are the only extant animals that descended directly from dinosaurs? A) lizards B) crocodiles C) snakes D) birds E) tuataras Answer: D 60) A trend first observed in the evolution of the earliest tetrapods was A) the appearance of jaws. B) the appearance of bony vertebrae. C) feet with digits. D) the mineralization of the endoskeleton. E) the amniotic egg. Answer: C 61) Among the invertebrate phyla, phylum Arthropoda is unique in possessing members that have A) a cuticle. B) a ventral nerve cord. C) open circulation. D) wings. E) segmented bodies. Answer: D 62) Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that A) arthropods evolved before vertebrates did. B) extant terrestrial arthropods are better adapted to terrestrial life than are extant terrestrial vertebrates. C) ancestral arthropods must have been poorly adapted to aquatic life, and thus experienced a selective pressure to invade land. D) vertebrates evolved from arthropods. E) arthropods have had more time to coevolve with land plants than have vertebrates. Answer: E 63) Which of these would a paleontologist be most likely to do in order to determine whether a fossil represents a reptile or a mammal? A) Look for the presence of milk-producing glands. B) Look for the mammalian characteristics of a four-chambered heart and a diaphragm. C) Because mammals are eutherians, look for evidence of a placenta. D) Use molecular analysis to look for the protein keratin. E) Examine the teeth. Answer: E 64) In which vertebrates is fertilization exclusively internal? A) chondrichthyans, osteichthyans, and mammals B) amphibians, mammals, and reptiles C) chondrichthyans, osteichthyans, and reptiles D) reptiles and mammals E) reptiles and amphibians Answer: D 65) Match the extant vertebrate group with the description. Internal fertilization, leathery amniotic egg, and skin that resists drying are characteristics of A) amphibians. B) nonbird reptiles. C) chondrichthyans. D) mammals. E) birds. Answer: B 66) Organisms at which of the following trophic levels increased the most because of the movement of animals onto land? A) herbivores and carnivores B) decomposers and producers C) producers D) decomposers Answer: A 67) The decline of cyanobacteria in the early Cambrian oceans was most likely related to A) the movement of animals onto land. B) the evolution of land plants. C) an increase in the number of predatory fish. D) an increase in filter-feeding organisms. E) a decline in the number of marine decomposers. Answer: D 68) If all of the animals died in a large region of an ocean, we would expect an increase in the A) number of filter feeders. B) number of cyanobacteria. C) number of decomposers. D) clarity of the ocean waters. E) temperature of the ocean waters. Answer: B 69) Evidence indicates that an ancestral finch species from South America arrived on the Galapágos Islands and formed many new species, adapting to the diverse environments on the islands. With the evolution of these new bird species on the Galapágos Islands, we expect to find a corresponding A) increase in the number of bird parasites on the Galapágos Islands. B) decrease in the number of bird parasites on the Galapágos Islands. C) increase in the number of bird parasites in South America. D) decrease in the number of bird parasites in South America. E) elimination of bird parasites on the Galapágos Islands. Answer: A 70) A new, sixth global mass-extinction event appears to be occurring on Earth today. The most likely explanation for the dramatic loss of species is A) global warming. B) natural fluctuations in global temperatures and precipitation. C) the evolution of new types of viruses. D) human activity that alters natural environments. E) decreases in atmospheric levels of oxygen. Answer: D 71) As a result of harvesting a higher proportion of older and larger cod and other fish species for food A) the number of fish in these populations has increased dramatically. B) the age and size of fish reaching sexual maturity have decreased. C) many new species of predators have evolved in these regions. D) the affected fish species have stopped reproducing. E) many of the fish in these populations have started to reproduce asexually. Answer: B 27.2 Art Questions Figure 27.1 1) Which of the following factors, when used to label the horizontal axis of the graph in Figure 27.1, would account most directly for the shape of the plot? A) spongin concentration (gm/unit volume) B) rate of cribrostatin synthesis (molecules/unit time) C) number of pores per sponge D) number of spicules per sponge E) number of choanocytes per sponge Answer: E Placozoan evolutionary relationships to other animals are currently unclear, and different phylogenies can be created, depending on the character used to infer relatedness. Sponges have no tissues, but about 20 cell types. Tp (Trichoplax adhaerens) produces a neuropeptide almost identical to one found in cnidarians. The genome of Tp, although the smallest of any known animal, shares many features of complex eumetazoan (even human!) genomes. The next three questions refer to the phylogenetic trees that follow. I. II. III. 2) Which phylogeny has been created by emphasizing genomic features of placozoans? A) I B) II C) III Answer: C 3) Which phylogeny has been created by emphasizing the structural simplicity of placozoans? A) I B) II C) III Answer: A 4) Which phylogeny has been created by emphasizing a protein found in placozoans? A) I B) II C) III Answer: B A: Morphological phylogeny. B: Molecular phylogeny. 5) Which of the following is a point of conflict between the phylogenetic analyses presented in these two figures? A) the relationship of taxa of segmented animals to taxa of nonsegmented animals B) that sponges are basal animals C) that chordates are deuterostomes D) the monophyly of the bilaterians E) the monophyly of the animal kingdom Answer: A 6) What is true of the deuterostomes in the molecular phylogeny (B) that is not true in the traditional phylogeny (A)? A) Deuterostomia is paraphyletic. B) To maintain Deuterostomia as a clade, some phyla had to be removed from it. C) Deuterostomia now includes the Acoela. D) It is actually a grade, rather than a clade. E) It diverged from the rest of the Bilateria earlier than did the Acoela. Answer: B 7) In the traditional phylogeny (A), the phylum Platyhelminthes is depicted as a sister taxon to the rest of the protostome phyla, and as having diverged earlier from the lineage that led to the rest of the protostomes. In the molecular phylogeny (B), Platyhelminthes is depicted as a lophotrochozoan phylum. What probably led to this change? A) Platyhelminthes ceased to be recognized as true protostomes. B) The removal of the acoel flatworms (Acoela) from the Platyhelminthes allowed the remaining flatworms to be clearly tied to the Lophotrochozoa. C) All Platyhelminthes must have a well-developed lophophore as their feeding apparatus. D) Platyhelminthes' close genetic ties to the arthropods became clear as their Hox gene sequences were studied. Answer: B Figure 27.2 Fishes that have swim bladders can regulate their density and thus their buoyancy. There are two types of swim bladder: physostomus and physoclistus. The ancestral version is the physostomus version, in which the swim bladder is connected to the esophagus via a short tube (Figure 27.2). The fish fills this version by swimming to the surface, taking gulps of air, and directing them into the swim bladder. Air is removed from this version by "belching." The physoclistus version is more derived, and has lost its connection to the esophagus. Instead, gas enters and leaves the swim bladder via special circulatory mechanisms within the wall of the swim bladder. 8) The presence of a swim bladder allows the typical ray-finned fish to stop swimming and still A) effectively circulate its blood. B) be highly maneuverable. C) use its lateral line system. D) use its swim bladder as a respiratory organ. E) not sink. Answer: E 9) Rank the following fish, from most to least, in terms of the amount of energy each must use to maintain its position (depth) in the water column over the long term. 1. physoclistus fish 2. physostomus fish 3. chondrichthyan fish A) 1, 2, 3 B) 2, 3, 1 C) 2, 1, 3 D) 3, 1, 2 E) 3, 2, 1 Answer: E 10) If a physoclistus fish removes gas from its swim bladder, this fish's density cannot actually change until that gas arrives at the A) mouth. B) gills. C) skin. D) heart. E) anus. Answer: B 11) Which shark structure is most analogous to a swim bladder full of gas? A) its lateral line system B) its spiral valve C) its liver D) its dead-end nostrils E) its gills Answer: C 12) When a shark stops swimming, it does which of the following? 1. sinks 2. quickly dies 3. oxygenates its blood less effectively A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 1, 2, and 3 Answer: D 13) We should expect the inner wall of the swim bladder to be lined with tissue that is derived from A) ectoderm. B) endoderm. C) mesoderm. D) mesoglea. E) neurectoderm. Answer: B 14) Regarding its position in the water column, the same thing that happens to a shark when it stops swimming also happens to a A) physostomus fish when it gulps air. B) physoclistus fish when it moves gas from the blood into the water. C) physoclistus fish when it moves gas from the swim bladder into the blood. D) physoclistus fish when it moves gas from the blood into the swim bladder. Answer: B 15) In coelacanths, a swim bladder is present, but the swim bladder is full of adipose tissue (fat), which is there on a fairly permanent basis. If such a swim bladder is used by coelacanths to affect buoyancy, then it does so in much the same way as does the A) liver of a shark. B) physoclistus swim bladder. C) physostomus swim bladder. D) lung of a lungfish. Answer: A 16) Which graph properly depicts the relationship between the amount of gas in the swim bladder and the density of the fish? A) B) C) D) E) Answer: C Table 27.1. Proposed Number of Hox Genes in Various Extant and Extinct Animals 17) What conclusion is apparent from the data in Table 27.1? A) Land animals have more Hox genes than do those that live in water. B) All bilaterian phyla have had the same degree of expansion in their numbers of Hox genes. C) Acoel flatworms should be expected to contain seven Hox genes. D) The expansion in number of Hox genes throughout vertebrate evolution cannot be explained merely by three duplications of the ancestral vertebrate Hox cluster. E) Extant insects all have seven Hox genes. Answer: D 18) All things being equal, which of these is the most parsimonious explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in Table 27.1? A) The occurrence of seven independent duplications of individual Hox genes. B) The occurrence of two distinct duplications of the entire seven-gene cluster, followed by the loss of one cluster. C) The occurrence of a single duplication of the entire seven-gene cluster. Answer: C 27.3 Scenario Questions Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which is a nerve or muscle cell, and none of which has a cell wall. They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. 1) In how many of the following ways is Tp unlike the typical animal? 1. Tp is multicellular. 2. Tp lacks muscle and nerve cells. 3. Tp has cilia. 4. Tp has a different place where digestion of food occurs. 5. Tp lacks cell walls. A) only one way B) two ways C) three ways D) four ways E) all five ways Answer: B 2) On the basis of the information in the previous paragraph, which of these should be able to be observed in Tp? A) the act of fertilization B) the process of gastrulation C) eggs D) All three of the responses above are correct. E) Two of the responses above are correct. Answer: C 3) Tp's body symmetry seems to be most like that of A) most sponges. B) cnidarians. C) worms. D) tetrapods. E) Two of the responses above are correct. Answer: A An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Last, she added some vertebrates–a parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish. 4) One day, little Tommy (a student in an under supervised class of 40 fifth graders) got the urge to pet Nemo (the clownfish), who was swimming among the waving petals of a pretty underwater "flower" that had a big hole in the midst of the petals. Tommy giggled upon finding that these petals felt sticky. A few hours later, Tommy was in the nurse's office with nausea and cramps. Microscopic examination of his fingers would probably have revealed the presence of A) teeth marks. B) spines. C) spicules. D) nematocysts. E) a radula. Answer: D 5) Had the teacher wanted to point out organisms that belong to the most successful animal phylum, the teacher should have chosen the A) bivalves and gastropods. B) sea anemones and hydra. C) shrimp and copepods. D) polychaete. Answer: C Terry catches a ray-finned fish from the ocean and notices that attached to its flank is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker, and two small eyes. Terry thinks it might be a marine leech, a hagfish, or a lamprey. 6) Which feature excludes the organism from possibly being a leech? A) elongated shape B) lack of scales C) lack of external segmentation D) round mouth E) anterior sucker Answer: C The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not molt (though their host does), and their embryos undergo spiral cleavage. 7) Which of these features is least useful in assigning the phylum Cycliophora to a clade of animals? A) having a true coelom as a body cavity B) having a body symmetry that permits a U-shaped intestine C) having embryos with spiral cleavage D) lacking ecdysis (molting) Answer: A 8) Basing your inferences on information in the previous paragraph, to which clade(s) should cycliophorans belong? 1. Eumetazoa 2. Deuterostomia 3. Bilateria 4. Ecdysozoa 5. Lophotrochozoa A) 1 only B) 1 and 3 C) 1, 3, and 5 D) 2, 3, and 4 E) 2, 3, and 5 Answer: C 9) Using similarities in embryonic development, body symmetry, and other anatomical features to assign an organism to a clade involves 1. cladistics based on body plan. 2. molecular-based phylogeny. 3. morphology-based phylogeny. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1 and 3 Answer: E 10) Which of these, if discovered among cycliophorans, would cause the most confusion concerning our current understanding of cycliophoran taxonomy? A) if the ciliated feeding ring is a lophophore B) if embryos are diploblastic C) if the body cavity is actually a pseudocoelom D) if the organisms show little apparent cephalization Answer: B 11) What is true of the feeding stage of cycliophorans? 1. It is chemoheterotrophic. 2. It is sessile. 3. It captures food in a manner similar to that of animals with lophophores. 4. It has radial symmetry. A) 1 and 2 B) 1 and 3 C) 2 and 4 D) 1, 2, and 3 E) 2, 3, and 4 Answer: D 12) Cycliophorans have two types of larvae. One type of larva is produced when the digestive system of a female is impregnated by a male. The digestive system then collapses and develops into a larva, which swims away in search of a new host after the surrounding female dies. Which is the embryonic tissue that is apparently most important in forming this type of larva? A) mesohyl B) mesoderm C) ectoderm D) endoderm E) mesoglea Answer: D 27.4 End-of-Chapter Questions 1) Which of the following clades contains the greatest number of animal species? A) the vertebrates B) the bilaterians C) the sponges D) the deuterostomes E) the insects Answer: B 2) Fossil steroid and molecular clock evidence suggests that animals originated A) between 770 and 710 million years ago. B) more than 100 million years before the oldest known fossils of large animals. C) during the Cambrian explosion. D) after sponges diverged from other metazoans. E) both A and B Answer: E 3) Which of the following was probably the least important factor in bringing about the Cambrian explosion? A) the emergence of predator-prey relationships among animals B) the accumulation of diverse adaptations, such as shells and different modes of locomotion C) the origin of Hox genes and other genetic changes affecting the regulation of developmental genes D) the movement of animals onto land E) the accumulation of sufficient atmospheric oxygen to support the more active metabolism of mobile animals Answer: D 4) Which of the following could be considered the most recent common ancestor of living tetrapods? A) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates B) an armored gnathostome with two pairs of appendages C) an early ray-finned fish that developed bony skeletal supports in its paired fins D) a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes E) an early terrestrial caecilian whose legless condition had evolved secondarily Answer: A 5) Which clade does not include humans? A) synapsids B) lobe-fins C) lophotrochozoans D) tetrapods E) osteichthyans Answer: C 6) In the figure given below, the Deuterostomia clade is most closely related to which two main clades? A) Ctenophora and Cnidaria B) Lophotrochozoa and Ecdysozoa C) Cnidaria and Bilateria D) Platyhelminthes and Rotifera E) Echinodermata and Hemichordata Answer: B Chapter 28: Plant Structure and Growth 28.1 Multiple-Choice Questions 1) Choose the option that best describes the relationship between the cell wall thickness of parenchyma cells versus sclerenchyma cells. A) The cell walls of parenchyma cells are thinner than those of sclerenchyma cells. B) The cell walls of parenchyma cells are thicker than those of sclerenchyma cells. C) The cell walls of both types of cells are roughly equal. D) The thickness of the cell walls for both types of cells is too variable for a comparison to be made. E) The cell walls of collenchyma cells are thicker than sclerenchyma or parenchyma cells. Answer: A 2) Which structure is incorrectly paired with its tissue system? A) root hair—dermal tissue B) palisade parenchyma—ground tissue C) guard cell—dermal tissue D) companion cell—ground tissue E) tracheid—vascular tissue Answer: D 3) Which of the following is derived from the ground tissue system? A) root hair B) cuticle C) periderm D) pith E) phloem Answer: D 4) Which part of a plant absorbs most of the water and minerals taken up from the soil? A) root cap B) root hairs C) the thick parts of the roots near the base of the stem D) storage roots E) sections of the root that have secondary xylem Answer: B 5) Land plants are composed of all of the following tissue types except A) mesodermal. B) epidermal. C) meristematic. D) vascular. E) ground tissue. Answer: A 6) Vascular plant tissue includes all of the following cell types except A) vessel elements. B) sieve cells. C) tracheids. D) companion cells. E) cambium cells. Answer: E 7) Which cells are no longer capable of carrying out the process of DNA transcription? A) tracheids B) mature mesophyll cells C) companion cells D) meristematic cells E) glandular cells Answer: A 8) ________ is to xylem as ________ is to phloem. A) Sclerenchyma cell; collenchyma cell B) Apical meristem; vascular cambium C) Vessel element; sieve-tube member D) Cortex; pith E) Vascular cambium; cork cambium Answer: C 9) Which of the following cells transport sugars over long distances? A) parenchyma cells B) collenchyma cells C) sclerenchyma cells D) tracheids and vessel elements E) sieve-tube elements Answer: E 10) Which of the following have unevenly thickened primary walls that support young, growing parts of the plant? A) parenchyma cells B) collenchyma cells C) sclerenchyma cells D) tracheids and vessel elements E) sieve-tube elements Answer: B 11) Which of the following are most responsible for supporting mature, nongrowing parts of the plant? A) parenchyma cells B) collenchyma cells C) trichomes D) tracheids and vessel elements E) sieve-tube elements Answer: D 12) The vascular bundle in the shape of a single central cylinder in a root is called the A) cortex. B) stele. C) endodermis. D) periderm. E) pith. Answer: B 13) One important difference between the anatomy of roots and the anatomy of leaves is that A) only leaves have phloem and only roots have xylem. B) root cells have cell walls and leaf cells do not. C) a waxy cuticle covers leaves but is absent from roots. D) vascular tissue is found in roots but is absent from leaves. E) leaves have epidermal tissue but roots do not. Answer: C 14) A student examining leaf cross sections under a microscope finds many loosely packed cells with relatively thin cell walls. The cells have numerous chloroplasts. What type of cells are they? A) parenchyma B) xylem C) endodermis D) collenchyma E) sclerenchyma Answer: A 15) A vessel element would likely lose its protoplast in which section of a root? A) zone of cell division B) zone of elongation C) zone of differentiation D) root cap E) apical meristem Answer: C 16) Which of the following cell types retains the ability to undergo cell division? A) a sclereid B) a parenchyma cell 2 mm from the tip of a root C) a functional sieve-tube element D) a tracheid E) a stem fiber Answer: B 17) Axillary buds A) are initiated by the cork cambium. B) have dormant meristematic cells. C) are composed of a series of internodes lacking nodes. D) grow immediately into shoot branches. E) do not form a vascular connection with the primary shoot. Answer: B 18) Which of the following is incorrectly paired with its structure and function? A) sclerenchyma—supporting cells with thick secondary walls B) periderm—protective coat of woody stems and roots C) pericycle—waterproof ring of cells surrounding the central stele in roots D) mesophyll—parenchyma cells functioning in photosynthesis in leaves E) ground meristem—primary meristem that produces the ground tissue system Answer: C 19) A plant has the following characteristics: a taproot system, several growth rings evident in a cross section of the stem, and a layer of bark around the outside. Which of the following best describes the plant? A) herbaceous eudicot B) woody eudicot C) woody monocot D) herbaceous monocot E) woody annual Answer: B 20) Which of the following statements is false? A) A preprophase band determines where a cell plate will form in a dividing cell. B) The way in which a plant cell differentiates is determined by the cell's position in the developing plant body. C) Homeotic genes often control morphogenesis. D) Plant cells differentiate because the cytoskeleton determines which genes will be turned "on" and "off." E) Arabidopsis was the first plant to have its genome sequenced. Answer: D 21) Compared to most animals, the growth of most plants is best described as A) perennial. B) weedy. C) indeterminate. D) derivative. E) primary. Answer: C 22) Cells produced by lateral meristems are known as A) dermal and ground tissue. B) lateral tissues. C) pith. D) secondary tissues. E) shoots and roots. Answer: D 23) Plants contain meristems whose major function is to A) attract pollinators. B) absorb ions. C) photosynthesize. D) produce more cells. E) produce flowers. Answer: D 24) Which of the following is a true statement about growth in plants? A) Primary growth is localized at meristems, whereas secondary growth is localized at buds. B) Some plants lack secondary growth. C) Secondary growth occurs only in stems. D) Reproductive structures are produced by secondary growth. E) Monocots have only primary growth, and eudicots have only secondary growth. Answer: B 25) Additional vascular tissue produced as secondary growth in a root originates from which cells? A) vascular cambium B) apical meristem C) endodermis D) phloem E) xylem Answer: A 26) Which of the following cells or tissues arise from lateral meristem activity? A) secondary xylem B) leaves C) trichomes D) tubers E) cortex Answer: A 27) Which of the following is a true statement? A) Flowers may have secondary growth. B) Secondary growth is a common feature of eudicot leaves. C) Secondary growth is produced by both the vascular cambium and the cork cambium. D) Primary growth and secondary growth alternate in the life cycle of a plant. E) Plants with secondary growth are typically the smallest ones in an ecosystem. Answer: C 28) Gas exchange, which is necessary for photosynthesis, can occur most easily in which leaf tissue? A) epidermis B) palisade mesophyll C) spongy mesophyll D) vascular tissue E) bundle sheath Answer: C 29) Water is most likely to enter a mesophyll cell A) as a gas. B) as a liquid. C) covalently bound to sugars. D) coupled to ion transport. E) via endocytosis. Answer: B 30) CO2 enters the inner spaces of the leaf through the A) cuticle. B) epidermal trichomes. C) stoma. D) phloem. E) walls of guard cells. Answer: C 31) The driving force that pushes the root tip through the soil is primarily A) continuous cell division in the root cap at the tip of the root. B) continuous cell division just behind the root cap in the center of the apical meristem. C) elongation of cells behind the root apical meristem. D) the elongation of root hairs. E) continuous cell division of root cap cells. Answer: C 32) Shoot elongation in a growing bud is due primarily to A) cell division at the shoot apical meristem. B) cell elongation directly below the shoot apical meristem. C) cell division localized in each internode. D) cell elongation localized in each internode. E) cell division at the shoot apical meristem and cell elongation directly below the shoot apical meristem. Answer: D The following question is based on parts of a growing primary root. I. root cap II. zone of elongation III. zone of cell division IV. zone of cell differentiation V. apical meristem 33) Which of the following is the correct sequence from the growing tips of the root upward? A) I, II, V, III, IV B) III, V, I, II, IV C) II, IV, I, V, III D) IV, II, III, I, V E) I, V, III, II, IV Answer: E 34) Which of the following root tissues gives rise to lateral roots? A) endodermis B) phloem C) cortex D) epidermis E) pericycle Answer: E 35) Pores on the leaf surface that function in gas exchange are called A) hairs. B) xylem cells. C) phloem cells. D) stomata. E) sclereids. Answer: D 36) A person working with plants may reduce the inhibition of apical dominance by auxin via which of the following? A) pruning shoot tips B) deep watering of the roots C) fertilizing D) treating the plants with auxins E) feeding the plants nutrients Answer: A 37) What effect does "pinching back" have on a houseplant? A) increases apical dominance B) inhibits the growth of lateral buds C) produces a plant that will grow taller D) stimulates lateral buds to grow E) increases the flow of auxin down the shoot Answer: D 38) What tissue makes up most of the wood of a tree? A) primary xylem B) secondary xylem C) secondary phloem D) mesophyll cells E) vascular cambium Answer: B 39) If you were able to walk into an opening cut into the center of a large redwood tree, when you exit from the middle of the trunk (stem) outward, you would cross, in order, A) the annual rings, new xylem, vascular cambium, phloem, and bark. B) the secondary xylem, cork cambium, phloem, and periderm. C) the vascular cambium, oldest xylem, and newest xylem. D) the secondary xylem, secondary phloem, and vascular cambium. E) the summer wood, bark, and phloem. Answer: A 28.2 Art Questions Figure 28.1 1) Which of the following are true statements about the cells shown in the photograph in Figure 28.1? A) They are parenchyma cells. B) They are photosynthetic. C) They are usually found in roots. D) They are phloem cells. E) They are parenchyma cells and photosynthetic. Answer: E The following questions are based on the drawing of root or stem cross sections shown in Figure 28.2. Figure 28.2 2) A monocot stem is represented by A) I only. B) II only. C) III only. D) IV only. E) both I and III. Answer: B 3) A plant that is at least 3 years old is represented by A) I only. B) II only. C) III only. D) IV only. E) both I and III. Answer: D 4) A woody eudicot is represented by A) I only. B) II only. C) III only. D) IV only. E) both I and III. Answer: D 28.3 Scenario Questions 1) Suppose George Washington completely removed the bark from around the base of a cherry tree but was stopped by his father before cutting the tree down. The leaves retained their normal appearance for several weeks, but the tree eventually died. The tissue(s) that George left functional was/were the A) phloem. B) xylem. C) cork cambium. D) cortex. E) companion and sieve-tube members. Answer: B 2) As a youngster, you drive a nail in the trunk of a young tree that is 3 meters tall. The nail is about 1.5 meters from the ground. Fifteen years later, you return and discover that the tree has grown to a height of 30 meters. About how many meters above the ground is the nail? A) 0.5 B) 1.5 C) 3.0 D) 15.0 E) 28.5 Answer: B 28.4 End-of-Chapter Questions 1) The innermost layer of the root cortex is the A) core. B) pericycle. C) endodermis. D) pith. E) vascular cambium. Answer: C 2) Heartwood and sapwood consist of A) bark. B) periderm. C) secondary xylem. D) secondary phloem. E) cork. Answer: C 3) Lateral roots arise from the A) periderm. B) vascular cambium. C) pericycle. D) root apical meristem. E) root cap. Answer: C 4) Which of the following arise, directly or indirectly, from meristematic activity? A) secondary xylem B) leaves C) dermal tissue D) tubers E) all of the above Answer: E 5) Which of the following would not be seen in a cross section through the woody part of a root? A) sclerenchyma cells B) parenchyma cells C) sieve-tube elements D) root hairs E) vessel elements Answer: D Test Bank for Campbell Biology in Focus Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson, Jane B. Reece 9780321813664, 9780321962751, 9780134710679
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