CHP33 Invertebrates

tapeworm(cestoda)antomy:

- anterior head: scolex -segments of body: proglottids - gravid proglottid

diseases caused by nematodes

- ascarias -pinworm -guinea worm -trichonosis -elephantasis

characteristics of chelicerates

- claw like feeding appendages: chelicerae -only horse shoe crab is a marine animal - most are in the arachnids class (spiders, scorpions, ticks, horse shoe crab) -has a cephalothorax & abdomen

characterisics of antrhopods

- coelamte,segmented, outer chitin skeleton, protosome development - they molt(shed) its exoskeleton in a process called ecdysis -open circulatory system

Characteristics of sea Urchins and sand dollars:

- have tube feet -sea urchins use spine & tube feet -sanddollars use spine only -omnivores

scyphozoans(Cnidaria)

- jellyfish, medusa dominant -medusa posseses velum -make up majority of jellyfish in the sea

phylum: porifera ex:sponges

- marine, hemaphrodites -don't have true tissues/ organs - have one germ layer -filterfeeders( sessiles supenders) -porous body -made up of choanocyte and amoeboid cells -don't belong in the clade eumetazoa

Phylum Mollusca

- mollusks have soft body, have hard exoskleleton

characteristics of Crustaceans:

- mostly aquatic animals -biramous appendages -head, thorax, abdomen -two pair of attennas and 5 legs(swimmeretts) -cephalothorax has a thick plate: carapace -Malacostra(decapod) class: 5 pairs of appendages(crabs, lobster,shrimp) -Maxiillopoda class: lack appendages, short abdomen(copepods and barnacles) barnacles kicks food in its mouth w/ its cirri feet, hermaphrodites, penis fencing

anthozoans (cnidaria)

- only occur as polyps -polyp possess actinopharynx(digestive tract) and mesenteries(tissue extends from the body wall) -ex: sea anemone, corals, sea pen, sea fan

Hydrozoans (Cnidaria)

- polyp stage is dominant - solitary & colonial - sexual reproduction in medusa stage and asexual in polyp stage

Phylum: Anthropods

- tribolites(early extinct antrhopods)

6 classes of Echinoderm phylum:

-Asteroida: sea stars -Ophiuroidea: brittle stars -Echinoidea: sea urchins n sand dollars -Holothuroidea: sea cucumbers

Cnidarians 4 classes:

-Hydrozoa -scyphozoa -cubozoa -anthozoa

Flatworms characteristics

-No coelom due to flat body -marine parasites -bilateral & unsegmented -acoelemate hermaphrodites -triploblastic -single opening for mouth and anus -respiration occurs thru skin - in wet damp areas

corals ( anthozoans)(cnidaria)

-calcium carbonate skeleton -obtain nutritents by prey capturing or the xo algae -when stressed the expel xo algae (coral bleaching)leads to death of corals, also leads to global warming -provide food & shelter for marine life -coral polyps reduce acidity

Characteristics of Asteroidea:

-central disk -tube feet -organs & digestive tract found in the arms - eyespot on each arm to detect light -pedicellarie -have a cardiac and pyloric stomach -madreporite

5 Subphylums of Phylum Arthropoda:

-chelicerates: horseshoe crab, scorpions,ticks, mites -myriapods: centipedes and millipedes -hexapods: insects -Crustaceans: crabs, lobsters, shrimps, barnacles -Trilobitomorpha: extinct trilobites

Echinoderm Phylum:

-closely related to chordates - coelomate and deuterosome development -have internal skeleton: ossicle -sessile(slow) moving -water vascular system: locomotion, feeding, and gas exchange -can regenerate

Phylum Cnidaria ex: jellyfish and Corals

-cnidarians are the oldest group of Eumetazoa - all animals are in the clade Eumetazoa except sponges -corals and sea anemone have mutualistic relationship w/ xooanthelle algae

mollusks characteristics:

-complete digestive tract -posess true coelem that has hemolymph(blood, fluid, lymph) -gonorchoristic/ hemaphrodite -radula teeth except class bivalve -open circulatory system

Characteristics of hexapods (insects):

-complete metamorphosis: the larval stage looks entirely different from the adult stage - incomplete metamorphosis: the larval stage looks similar to the adult -recycle nutrients -pollinators( bbes, flies, butterfly, beetles) -food for larger animals

choanocyte (collar cells)

-draws water into pores of the sponge -traps food and gives it to amoeboid cells to help with digestion

flatworm reproduction

-hermaphrodite, don't self fertilize -penis fencing asexual occurs thru transverse fisssion

Characteristics of Holothuroidea:

-lack spine -scavengers -expel sticky thread

Characteristics of Ophiurodea:

-long arms -central disk -tube feet have chemo-sensors

Cubozoans (cnidaria)

-medusa is box shaped with 4 tentacles -contains velarium that allows it to swim faster than any other jellyfish -well developed light sensors - ex: sea wasp

sponge anatomy:

-osculum: opening where water exits -mesenchyme: a substance that binds sponge cells together -spicules: skeletal support structure and antipredatory(silica, calcium or collagen)

4 classes of Mollusks:

-polyplacophora: chitons have 8 dorsal plates, oval shape -gastropoda: snails/slugs breathe w gills, some have lungs, its systems are well developed -bivalvia: clams/oysters -cephalopoda: squid/octupus

what are cnidarians characteristics?

-radial symmetry -hydrostatic skeleton( water gives their body shape) -alternate b/w polyp(nonmotile) and medusa(motile) life cycle -diploblastic animal w/ no organs -has nerve net (nervous system) -only animals w/ nermatocyst (cells that contain coiled venom thread) on tentacles

amoeboid cells

-secrete spicules(skeletal support) and spongin fiber( flexible protein) that forms skeleton of sponges -can turn into other cells

how do sponges reproduce

-sexual under favorable conditions -asexual under unfavorable conditions by fragmentation or gemmules

cnidarian anatomy:

-single opening functions as mouth and anus(leads to gastrovascular activity -umbrella shaped body(bell)

Platyhelminthes (flatworms) divided into 4 classes:

-turbellaria ex. planaria nonparasitic, has eyespots, ganglia(N.S) more complex than cnidarians -monogenea ex. (flukes) ectoparasites of fishes no intermediate host (grows& matures sexually) -trematoda ex. flukes parasites of verterbrates (fishes and humans) life cycle 2 hosts intermediate host & defintitive host( sexually mates in) -cestoda ex. tapeworms endoparasites of vertebrates(humans) absorb nutrients thru skin no mouth or digestive tract hermaphrodites

Characterisitcs of Nematoda (roundworms)

-unsegmented, triploblastic animals w protostome development -pseudocoelmate -complete digestive tract -tough outer skin:cuticle -longitude muscles only -sexual

1) Which cells in a sponge are primarily responsible for trapping and removing food particles from circulating water? A) choanocytes B) mesoglea cells C) pore cells (porocytes) D) epidermal cells

A

A shared derived characteristic for members of the arthropod subgroup that includes spiders would be the presence of A) chelicerae. B) an open circulatory system. C) an exoskeleton. D) a cuticle. E) a cephalothorax.

A

An organism is able to extend its feeding structure(s) through a hole in its body wall. If the organism were a sea star, it would extend its A) stomach. B) lophophore. C) pharynx. D) mandibles. E) tentacles.

A

From this description, one can conclude that the organisms that have caught Sarahʹs attention are A) insects. B) crustaceans. C) aquatic spiders. D) myriapods. E) eurypterids.

A

Generally, members of which flatworm class(es) are nonparasitic? A) Turbellaria B) Trematoda C) Cestoda D) Monogenea E) A, C, and D

A

If a lung were to be found in a mollusc, where would it be located? A) mantle cavity B) coelom C) foot D) visceral mass E) excurrent siphon

A

In a tide pool, a student encounters an organism with a hard outer covering that contains much calcium carbonate, an open circulatory system, and gills. The organism could potentially be a crab, a shrimp, a barnacle, or a bivalve. Which structure below would allow for the most certain identification? A) a mantle B) a heart C) a body cavity D) a lophophore E) eyes

A

Infection with which parasite might cause excessive elasticity in human skeletal muscles? A) trichinella worms B) tapeworms C) copepods D) blood flukes E) rotifers

A

Nematode worms and annelid worms share which of the following features? A) use of fluid in the body cavity as a hydrostatic skeleton B) ecdysis C) presence of a circulatory system D) presence of segmentation E) absence of species with parasitic lifestyles

A

Of the annelid classes below, which make castings that are agriculturally important? A) Oligochaeta B) Polychaeta C) Hirudinea (leeches) D) all three of these E) two of these

A

Sarah observed that the mystery pond organisms never come up to the pondʹs surface. If she catches one of these organisms and observes closely, perhaps dissecting the organism, she should find 1. gills. 2. spiracles. 3. tracheae. A) 1 only B) 3 only C) 1and3 D) 2 and 3 E) 1, 2, and 3

A

Which molluscan class includes marine organisms whose shell consists of eight plates? A) chitons B) bivalves C) gastropods D) cephalopods

A

Which of the following have a mouth that is directed upward? A) class Crinoidea (sea lilies and feather stars) B) class Asteroidea (sea stars) C) class Ophiuroidea (brittle stars) D) class Echinoidea (sea urchins and sand dollars) E) class Holothuroidea (sea cucumbers)

A

Which of the following is a characteristic of adult echinoderms? A) secondary radial symmetry B) spiral cleavage C) gastrovascular cavity D) exoskeleton E) lophophore

A

Which of the following is a diploblastic phylum of aquatic predators? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata

A

Which of the following is correctly associated with sponges? A) osculum B) body cavity C) cnidocytes D) spicules made of chitin E) muscle cells and nerve cells

A

While working in your garden, you discover a worm-like, segmented animal with two pairs of jointed legs per segment. The animal is probably a A) millipede. B) caterpillar. C) centipede. D) polychaete worm. E) sow bug.

A

A radially symmetrical animal that has two embryonic tissue layers probably belongs to which phylum? A) Porifera B) Cnidaria C) Platyhelminthes D) Nematoda E) Echinodermata

B

Humans most frequently acquire trichinosis by A) having sexual contact with an infected partner. B) eating undercooked pork. C) inhaling the eggs of worms. D) eating undercooked beef. E) being bitten by tsetse flies.

B

In terms of food capture, which sponge cell is most similar to the cnidocyte of a Cnidarian? A) zygote B) choanocyte C) gamete D) epidermal cell E) pore cell

B

Of the annelid classes below, which have parapodia? A) Oligochaeta B) Polychaeta C) Hirudinea (leeches) D) all three of these E) two of these

B

Parrotfish have mouths adapted to scrape algae off of coral, and can even munch on coral. The aquariumʹs corals rapidly dwindled; in their place were shards of A) chitin. B) calcium carbonate. C) silica. D) bone. E) chitin impregnated with calcium carbonate.

B

Protostomes that have a closed circulatory system and obvious segmentation are part of which phylum? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata

B

The bivalves started to die one by one; only the undamaged shells remained. To keep the remaining bilvalves alive, the teacher would have had to remove the A) sea anemones. B) sea star. C) gastropods. D) ectoprocts. E) parrotfish.

B

The larvae of many common tapeworm species that infect humans are usually found A) encysted in freshwater snails. B) encysted in the muscles of an animal, such as a cow or pig. C) crawling in the abdominal blood vessels of cows and pigs. D) encysted in the human brain. E) crawling in the intestines of cows and pigs.

B

The teacher was unaware of the difference between suspension feeding and predation. The teacher thought that by providing live copepods (2 mm long) and feeder fish (2 cm long) the dietary needs of all of the organisms would be satisfied. Consequently, which two organisms would have been among the first to starve to death (assuming they lack photosynthetic endosymbionts)? 1. sponges 2. coral animals 3. bivalves 4. sea stars 5. shrimp A) 1 and 2 B) 1 and 3 C) 2and5 D) 3 and 4 E) 4 and 5

B

What would be the most effective method of reducing the incidence of blood flukes in a human population? A) Reduce the mosquito population. B) Reduce the freshwater snail population. C) Purify all drinking water. D) Avoid contact with rodent droppings. E) Carefully wash all raw fruits and vegetables.

B

Which class of the phylum Cnidaria includes ʺjelliesʺ with rounded (as opposed to boxlike) medusae? A) Hydrozoa B) Scyphozoa C) Anthozoa D) Cubozoa E) Both A and C are referred to as ʺjellies.ʺ

B

Which molluscan class includes organisms that are primarily suspension feeders? A) chitons B) bivalves C) gastropods D) cephalopods

B

Which of the following are entirely, or partly, composed of calcium carbonate? A) spicules of siliceous sponges B) coral animalsʹ exoskeletons C) molluscsʹ mantles D) insectsʹ cuticles E) nematodesʹ cuticles

B

Which of the following can extend the stomach through their mouth to feed? A) class Crinoidea (sea lilies and feather stars) B) class Asteroidea (sea stars) C) class Ophiuroidea (brittle stars) D) class Echinoidea (sea urchins and sand dollars) E) class Holothuroidea (sea cucumbers)

B

Which of the following characteristics most likely explains why insects are so successful at dispersing to distant environments? A) hemocoel B) wings C) jointed appendages D) chewing mandibles E) internal fertilization

B

Which of the following is a characteristic of nematodes? A) All species can be characterized either as scavengers or as decomposers. B) They have only longitudinal muscles. C) They have a true coelom. D) They have a gastrovascular cavity. E) Many species are diploblastic.

B

While snorkeling, a student observes an active marine animal that has a series of muscular tentacles bearing suckers associated with its head. Segmentation is not observed, but a pair of large, well-developed eyes is evident. The student is observing an animal belonging to which class? A) chitons B) bivalves C) gastropods D) cephalopods

B

A radula is present in members of which class(es)? A) chitons B) bivalves C) gastropods D) cephalopods

C

A terrestrial mollusc without a shell belongs to which class? A) chitons B) bivalves C) gastropods D) cephalopods

C

Corals are most closely related to which group? A) jellies B) freshwater hydras C) sea anemones D) sponges E) barnacles

C

Had the teacher wanted to point out organisms that belong to the most successful animal phylum, the teacher should have chosen the 1. bivalves. 2. sea anemones. 3. shrimp. 4. polychaete. 5. copepods. A) 1 only B) 4 only C) 3and5 D) 4 and 5 E) 1, 2, and 3

C

If the teacher had used a dissecting microscope to examine the outer surfaces of the empty bivalve shells, the teacher would probably have seen marks that had been left by A) jaws. B) nematocysts. C) tube feet. D) a lophophore. E) a madreporite.

C

If the worms discovered during the autopsies have all features characteristic of their phylum, dissection of the worms should reveal the presence of 1. nephridia. 2. chaetae. 3. segmentation. 4. a gastrovascular cavity. 5. the acoelomate condition. A) 5 only B) 1 and 2 C) 4and5 D) 1, 2, and 3 E) 3, 4, and 5

C

In a small stream, you pick up a rock and observe many small, flattened worms crawling on its undersurface. You decide that they belong to the phylum Platyhelminthes. To which class do they probably belong? A) Cestoda B) Monogenea C) Turbellaria D) Trematoda

C

Many of which of the following annelid classes are parasites? A) Oligochaeta B) Polychaeta C) Hirudinea (leeches) D) all three of these E) two of these

C

Protostomes with a unique drape of tissue that may secrete a shell are part of which phylum? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata

C

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong? A) Platyhelminthes B) Arthropoda C) Nematoda D) Acoela E) Annelida

C

The members of which class of the phylum Cnidaria occur only as polyps? A) Hydrozoa B) Scyphozoa C) Anthozoa D) Cubozoa E) both B and D

C

The species in the aquarium that possess true bilateral symmetry include the 1. sponges. 2. molluscs. 3. echinoderm. 4. sea anemones. 5. ectoprocts. A) 2 only B) 1 and 4 C) 2and5 D) 2, 3, and 5 E) 2, 3, 4, and 5

C

What distinguishes complete metamorphosis from incomplete metamorphosis in insects? A) presence of wings in the adult, but not in earlier life stages B) presence of sex organs in the adult, but not in earlier life stages C) radically different appearance between adults and earlier life stages D) only A and B E) A, B, and C

C

Which of the following animal groups is entirely aquatic? A) Mollusca B) Crustacea C) Echinodermata D) Arthropoda E) Annelida

C

Which of the following are characteristics of arthropods? 1. protostome development 2. bilateral symmetry 3. a pseudocoelom 4. three embryonic germ layers 5. a closed circulatory system A) 1 and 2 B) 2 and 3 C) 1,2,and4 D) 2, 3, and 5 E) 3, 4, and 5

C

Which of the following can be used to distinguish a nematode worm from an annelid worm? 1. type of body cavity 2. number of muscle layers in the body wall 3. presence of segmentation 4. number of embryonic tissue layers 5. shape of worm in cross-sectional view A) 2 only B) 2 and 3 C) 1,2,and3 D) 1, 2, 3, and 5 E) all five of these

C

Which of the following correctly characterizes the phylum Rotifera? A) a single-opening digestive tract B) a pair of mandibles made of chitin C) parthenogenic reproduction D) inability to persist in environments where they might undergo desiccation E) a relatively large size

C

Which of the following have distinct central disks and long, flexible arms? A) class Crinoidea (sea lilies and feather stars) B) class Asteroidea (sea stars) C) class Ophiuroidea (brittle stars) D) class Echinoidea (sea urchins and sand dollars) E) class Holothuroidea (sea cucumbers)

C

Which of the following is found only among annelids? A) a hydrostatic skeleton B) segmentation C) a clitellum D) a closed circulatory system E) a cuticle made of chitin

C

While sampling marine plankton in a lab, a student encounters large numbers of fertilized eggs. The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has a true coelom. These eggs probably belonged to a(n) A) chordate. B) echinoderm. C) mollusc. D) nematode. E) arthropod.

C

A stalked, sessile marine organism has several feathery feeding structures surrounding an opening through which food enters. The organism could potentially be a cnidarian, a lophophorate, a tube-dwelling worm, a crustacean, or an echinoderm. Finding which of the following in this organism would allow the greatest certainty of identification? A) the presence of what seems to be radial symmetry B) a hard covering made partly of calcium carbonate C) a digestive system with mouth and anus separate from each other D) a water vascular system

D

A student observes a worm-like organism crawling about on dead organic matter. Later, the organism sheds its outer covering. One possibility is that the organism is a larval insect (like a maggot). On the other hand, it might be a member of which phylum, and one way to distinguish between the two possibilities is by looking for the presence of A) Platyhelminthes; a cuticle of chitin. B) Nematoda; an alimentary canal. C) Annelida; a body cavity. D) Nematoda; a circulatory system. E) Annelida; muscle in the body wall.

D

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange, and modified segmentation. A knowledgeable zoologist should predict that its adults would also feature A) eight legs. B) two pairs of antennae. C) a sessile lifestyle. D) an open circulatory system. E) parapodia.

D

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.

D

If the teacher had wanted to demonstrate that some invertebrates possess a closed circulatory system, the teacher should have removed and dissected a A) mollusc. B) sea star. C) shrimp. D) polychaete. E) parrotfish.

D

Of the annelid classes below, which have externally segmented bodies? A) Oligochaeta B) Polychaeta C) Hirudinea (leeches) D) all three of these E) two of these

D

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 ʺflowerʺ that had a big hole in the midst of the petals. Tommy giggled upon finding that these petals were sticky feeling. A few hours later, Tommy was in the nurseʹs 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.

D

Protostomes that have an open circulatory system and an exoskeleton of chitin are part of which phylum? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata

D

The clownfish and parrotfish died on the same day. Autopsies revealed the presence of many small, flat worms using tiny suckers to attach to the fish gills. Most likely, these worms were members of which phylum, and which class? A) Annelida, Hirudinea B) Annelida, Polychaetae C) Platyhelminthes, Cestoda D) Platyhelminthes, Monogenea E) Platyhelminthes, Turbellaria

D

Which characteristic is shared by both cnidarians and flatworms? A) dorsoventrally flattened bodies B) flame bulbs C) radial symmetry D) a digestive system with a single opening E) both A and D

D

Which molluscan class includes members that undergo embryonic torsion? A) chitons B) bivalves C) gastropods D) cephalopods

D

Which of the following are characteristics of the phylum Cnidaria? 1. a gastrovascular cavity 2. a polyp stage 3. a medusa stage 4. cnidocytes 5. a pseudocoelom A) 1 and 4 B) 2 and 3 C) 2,3,and4 D) 1, 2, 3, and 4 E) all five of these

D

Which of the following can have long, movable spines? A) class Crinoidea (sea lilies and feather stars) B) class Asteroidea (sea stars) C) class Ophiuroidea (brittle stars) D) class Echinoidea (sea urchins and sand dollars) E) class Holothuroidea (sea cucumbers)

D

Which of the following describe(s) echinoderms? A) They have an endoskeleton of hard calcareous plates. B) Tube feet provide motility in most species. C) They have a pseudocoelom. D) Only A and B are true. E) A, B, and C are true. Answer: D

D

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).

D

Which of these can be observed in the mesohyl of various undisturbed sponges at one time or another? 1. amoebocytes 2. spicules 3. spongin 4. zygotes 5. choanocytes A) 1 only B) 1 and 2 C) 1,2,and3 D) 1, 2, 3, and 4 E) all five of these

D

Which phylum is characterized by animals that have a segmented body? A) Cnidaria B) Platyhelminthes C) Silicea D) Arthropoda E) Mollusca

D

While vacationing in a country that lacks adequate meat inspection, a student ate undercooked ground beef. Sometime later the student became easily fatigued, and lost body weight. At about the same time, whitish, flattened, rectangular objects full of small white spheres started appearing in his feces. Administration of niclosamide cured the problem. The student had probably been infected by a A) pinworm. B) hookworm. C) nematode. D) tapeworm. E) proboscis worm.

D

Characteristics of Myriapods:

Diplopoda class: millipedes, have 2 pairs of legs per segment, scavengers Chilopoda class: centipedes, have 1 pair of legs per each segment, predators

A spongeʹs structural materials (spicules, spongin) are manufactured by the A) pore cells. B) epidermal cells. C) choanocytes. D) zygotes. E) amoebocytes.

E

Deuterostomes that have an endoskeleton are part of which phylum? A) Cnidaria B) Annelida C) Mollusca D) Arthropoda E) Echinodermata

E

If the pond organisms are larvae, rather than adults, Sarah should expect them to have all of the following structures, except A) antennae. B) an open circulatory system. C) an exoskeleton of chitin. D) complex eyes. E) sex organs.

E

If the teacher wanted to show the students what a lophophore is, and how it works, the teacher would point out a feeding A) hydra. B) sponge. C) bivalve. D) gastropod. E) ectoproct.

E

The name of which of the following annelid classes indicates the relative number of bristles (chaetae) its members have? A) Oligochaeta B) Polychaeta C) Hirudinea (leeches) D) all three of these E) two of these

E

The possession of two pairs of antennae is a characteristic of A) spiders. B) insects. C) centipedes. D) millipedes. E) crustaceans.

E

The teacher and class were especially saddened when the colonial hydrozoan died. They had watched it carefully, and the unfortunate creature never even got to produce offspring by budding. Yet, everyone was elated when Tommy (now recovered) noticed a small colonial hydrozoan growing in a part of the tank far from the location of the original colony. The teacher, who proclaimed a miracle, was apparently unaware that these hydrozoans exhibit A) spontaneous generation. B) abiogenesis. C) alternation of generations. D) ecdysis. E) a medusa stage.

E

Which chemical is synthesized by some sponges and acts as an antibiotic? A) streptomycin B) spongin C) calcium carbonate D) silica E) cribrostatin

E

Which of the following are elongated in the oral-aboral axis? A) class Crinoidea (sea lilies and feather stars) B) class Asteroidea (sea stars) C) class Ophiuroidea (brittle stars) D) class Echinoidea (sea urchins and sand dollars) E) class Holothuroidea (sea cucumbers)

E

Which of the following characteristics is probably most responsible for the great diversification of insects on land? A) segmentation B) antennae C) eyes D) bilateral symmetry E) exoskeleton

E

Which of the following combinations of phylum and description is incorrect? A) Echinodermatabilateral symmetry as a larva, coelom present B) Nematodaroundworms, pseudocoelomate C) Cnidariaradial symmetry, polyp and medusa body forms D) Platyhelminthesflatworms, gastrovascular cavity, acoelomate E) Calcareagastrovascular cavity, coelom present

E

Which of the following statements about tapeworm feeding methods is correct? A) They have complete digestive tracts. B) They use degenerate mouths to ingest some of their food. C) As adults, they live and feed in the hostʹs bloodstream. D) They are autotrophic. E) They absorb nutrients across their body walls.

E

ou find a small animal with eight legs crawling up your bedroom wall. Closer examination will probably reveal that this animal has A) antennae. B) no antennae. C) chelicerae. D) A and C E) B and C

E