Title: Invertebrates
Course: Question Banks

Q: ________ are epithelial-like cells forming the outermost layer of sponges.
- Amoebocytes (Incorrect. These motile cells have a variety of functions in sponges, including delivering nutrients and giving rise to eggs for sexual reproduction.)
- Choanocytes (Incorrect. Collar cells form the linings of some spaces through which water flows in sponges.)
- Pinacocytes (Correct. These cells enclose the jelly-like mesohyl that contains suspended cells with various functions in the sponge.)
A: Pinacocytes

Q: ________ differentiate into more specific cell types, including collencytes and lophocytes.
- Choanocytes (Incorrect. Collar cells always line the inner portions of some space through which water flows in sponges.)
- Pinacocyte (Incorrect. These cells enclose the jelly-like mesohyl that contains suspended cells with various functions in the sponge.)
- Amoebocytes (Correct. These motile cells have a variety of functions in sponges, including delivering nutrients and giving rise to eggs for sexual reproduction; they will also differentiate into further specialized cells.)
A: Amoebocytes

Q: ________, composed of either calcium carbonate or silica, provide additional stiffness to the body of some sponges.
- Ostia (Incorrect. Ostia are pores which allow water to enter the body of a sponge.)
- Sclerocyte (Incorrect. Sclerocyte cells secrete these structures.)
- Spicules (Correct. When present in the mesohyl, they provide stiffness. When spicules are present externally, they may ward off predators.)
A: Spicules

Q: In sponges, food particles are digested by ________.
- a digestive system (Incorrect. Sponges do not have tissues, so they cannot have a digestive system.)
- external enzymes (Incorrect. Sponges do not digest food outside their own cells.)
- individual cells (Correct. Sponges use choanocytes primarily to digest bacteria captured from the water; nutrients are then transported by amoebocytes usually.)
A: individual cells

Q: Some freshwater sponges use ________ during an atypical form of reproduction.
- budding (Incorrect. Some sponges do use budding for asexual reproduction but it is not really “atypical.”)
- sperm (Incorrect. All sexual reproduction in sponges involves sperm.)
- gemmules (Correct. Only freshwater sponges form gemmules, environmentally resistant structures used during an atypical type of asexual reproduction.)
A: gemmules

Q: Generally the ________ form of sponges are sessile.
- larval (Incorrect. The larval form of sponges swims freely to find new substratum.)
- adult and larval (Incorrect. The larval form of sponges swims freely to find new substratum.)
- adult (Correct. Adult sponges are attached to a fixed substratum.)
A: adult

Q: Cnidarians are named for their ________, specialized stinging cells.
- nematocysts (Incorrect. These are the actual stingers in the cells, not the cells.)
- barbed threads (Incorrect. Not all Cnidarians have barbed threads as part of their stingers.)
- cnidocytes (Correct. Cnidarians are so named because they contain cnidocytes, specialized stinging cells.)
A: cnidocytes

Q: Cnidarians that have a ________ adult form are sessile as adults.
- medusa (Incorrect. Medusa Cnidarians are the bell like motile forms we think of as jellyfish.)
- dioecious (Incorrect. Dioecious simply means there are two different sexes; it occurs in both body plans of Cnidarians.)
- polyp (Correct. Cnidarians whose adult form is the polyp body plan are sessile as adults.)
A: polyp

Q: Cnidarians have a non-living, jelly-like ________ connective layer between their two main membrane layers.
- epidermis (Incorrect. This is the outer membrane layer of a Cnidarian that arises from the ectoderm.)
- gastrodermis (Incorrect. This is the inner membrane layer of a Cnidarian that arises from the endoderm.)
- mesoglea (Correct. The mesoglea resides between the two membrane layers of the Cnidarian body.)
A: mesoglea

Q: In the Anthozoa class there are no ________ forms.
- polyp (Incorrect. All anthozoans are polyps.)
- sessile (Incorrect. Anthozoans are often non-motile adult polyps.)
- medusa (Correct. Anthozoans never have a medusa body plan.)
A: medusa

Q: The ________ are the sea anemones, sea pens, and corals.
- scyphozoans (Incorrect. Class Scyphozoa is the medusa-shaped jellyfish class.)
- cubozoans (Incorrect. Class Cubozoa are the box jellies.)
- anthozoans (Correct. These are the major types of class Anthozoa.)
A: anthozoans

Q: Sea anemones use their stingers to ________.
- protect their hosts (Incorrect. Sea anemones do not have a “host,” though a limited number do ride on hermit crabs.)
- filter food particles (Incorrect. Sea anemones are not filter feeders.)
- immobilize prey (Correct. Sea anemones capture small fish and shrimp as prey after stunning them with their cnidocytes and nematocysts.)
A: immobilize prey

Q: The ________ are the “traditional” jellies.
- anthozoans (Incorrect. Class Anthozoa are the sea anemones, sea pens, and corals.)
- cubozoans (Incorrect. Class Cubozoa are the box jellies.)
- scyphozoans (Correct. Class Scyphozoa is the medusa-shaped jellyfish class.)
A: scyphozoans

Q: Scyphozoans spend most of their life cycle as ________.
- sessile filter-feeders (Incorrect. Scyphozoans are not filter-feeders or generally sessile.)
- scyphistoma (Incorrect. This is the polyp larval form of some scyphozoans but is not the majority of the life cycle.)
- motile carnivores (Correct. Jellyfish are usually free-swimming predators.)
A: motile carnivores

Q: In scyphozoans, nerve cells are ________.
- only found in rhopalia (Incorrect. Some jellyfish have neurons present in clusters called rhopalia, but not all.)
- localized to the tentacles (Incorrect. Jellyfish tentacles do have nerve cells, but this is not the only location on the body.)
- scattered over the body (Correct. Nerve cells are scattered all over the body of a jellyfish.)
A: scattered over the body

Q: The most venomous group of all the cnidarians are the ________.
- anthozoans (Incorrect. Class Anthozoa are the sea anemones, sea pens, and corals.)
- scyphozoans (Incorrect. Class Scyphozoa is the medusa-shaped jellyfish class.)
- cubozoans (Correct. Class Cubozoa are the box jellies, the most venomous type of cnidarians.)
A: cubozoans

Q: A cubozoan develops into a ________ from a planula larva.
- medusa (Incorrect. The box jellies do not develop directly into medusa form from planula larva.)
- pedalia (Incorrect. This is the name of the muscular pads at the corners of the square bell canopy.)
- polyp (Correct. Planula larva develop into polyps with limited mobility before then transforming into medusa.)
A: polyp

Q: The cubozoans reach sizes of up to ________.
- 2 m (Incorrect. Only the largest scyphozoan species reach this size.)
- 10 cm (Incorrect. The much smaller anthozoans are generally less than 10cm in size.)
- 15–25 cm (Correct. Overall the cubozoans are not very large animals; some are tiny yet still deadly.)
A: 15–25 cm

Q: Class ________ has gonads derived from epidermal tissue.
- Cubozoa (Incorrect. Cubozoans derive their gonads from gastrodermal tissue.)
- Scyphozoa (Incorrect. Scyphozoans derive their gonads from gastrodermal tissue.)
- Hydrozoa (Correct. All other cnidarians have gonads that develop from gastrodermal tissue.)
A: Hydrozoa

Q: The ________ is a hydrozoan with both polypoid and medusoid individuals living as a free-floating colony.
- Hydra (Incorrect. This is a solitary polyp hydrozoan.)
- Obelia (Incorrect. This is a colonial hydroid that only has polyp members.)
- Physalia (Correct. The Portuguese Man O’War has both polypoid and medusoid members in its colonies.)
A: Physalia

Q: The hydrozoans are ________ animals.
- exclusively marine (Incorrect. The scyphozoans are exclusively marine.)
- predominantly freshwater (Incorrect. The hydrozoans are predominantly marine but there are some freshwater species.)
- mostly marine (Correct. The hydrozoans are predominantly marine but there are some freshwater species.)
A: mostly marine

Q: In protostomy, the ________ becomes the mouth opening.
- lophophore (Incorrect. The lophophore is a set of ciliated tentacles surrounding the mouth.)
- trochophore (Incorrect. Trochophore are a form of larvae that has two bands of cilia around the body.)
- blastopore (Correct. The blastopore, or the point at which the ectoderm involutes, becomes the mouth opening to the alimentary canal in all protostomes.)
A: blastopore

Q: The lophotrochozoans have a ________.
- pseudocoelom (Incorrect. Most of these animals have a true coelom.)
- enterocoelom (Incorrect. The coelom of the deuterostomes forms by pinching off the mesodermal layer of cells.)
- schizocoelom (Correct. The protostomic coelom of this superphylum is formed by the splitting of a mesodermal layer of cells.)
A: schizocoelom

Q: The lophotrochozoans display the first signs of ________ of the animal phyla.
- tissues (Incorrect. Cnidarians have tissues as well.)
- separate sexes (Incorrect. Even the simple sponges have species with different sexes.)
- cephalization (Correct. Cephalization begins with the lophotrochozoans when nervous tissue and sensory organs are concentrated in the head of the organism.)
A: cephalization

Q: Most flatworms have a ________ in which the “mouth” also expels waste.
- complete digestive system (Incorrect. A complete digestive system has two openings, not just one.)
- feeding tube (Incorrect. The flatworm digestive system is not described as a feeding tube.)
- gastrovascular cavity (Correct. Flatworms have an incomplete digestive system based on a gastrovascular cavity.)
A: gastrovascular cavity

Q: ________ cells contain cilia whose beating creates the currents that drive waste fluids out of the flatworm body.
- Kidney (Incorrect. Flatworms do not have kidney cells.)
- Chain (Incorrect. Flatworms do not have chain cells.)
- Flame (Correct. The flatworm excretory system uses flame cells to direct waste fluids from tubules and out of the body.)
A: Flame

Q: The ________ are ectoparasites that begin life as free-swimming larva before attaching to a host.
- turbellarians (Incorrect. Turbellarians are mainly free-living marine species.)
- cestodes (Incorrect. The cestodes, and the trematodes, are internal parasites.)
- monogeneans (Correct. The monogeneans are ectoparasites, mainly of fish.)
A: monogeneans

Q: Rotifers are named for the ________ at the anterior end of their bodies.
- spiny crown (Incorrect. Rotifers do not have a spiny crown at the anterior end of their bodies.)
- iridescent ring of scales (Incorrect. Rotifers do not have an iridescent ring of scales at their heads.)
- rotating, wheel-like structure (Correct. This corona is characteristic of all rotifers.)
A: rotating, wheel-like structure

Q: Most species of rotifers determine the gender of offspring by ________.
- ambient temperatures (Incorrect. This is how quite a few reptiles, including alligators, determine sex.)
- genotype (Incorrect. This is how most mammals determine sex: males have one combination of chromosomes (such as XY) and females a different combination (XX).)
- haplodiploidy (Correct. Unfertilized eggs (haploid) develop into male rotifers and fertilized eggs (diploid) develop into females. Bees use the same approach.)
A: haplodiploidy

Q: Food leaves the mouth of a rotifer and enters the ________, a structure unique to this group.
- corona (Incorrect. The corona is also unique to rotifers but this is the rotating, wheel-like structure on the head of the rotifers.)
- pseudocoel (Incorrect. Many different groups of animals have a pseudocoel.)
- mastax (Correct. This pharynx with jaw-like structures is unique to the rotifers and occurs between the mouth and digestive gland.)
A: mastax

Q: Most ________ are marine carnivores.
- mollusks (Incorrect. While most mollusks are marine species, they have a variety of “eating habits.”)
- annelids (Incorrect. Annelids are found in marine, terrestrial, and freshwater habitats.)
- nemerteans (Correct. The majority of the ribbon worms are marine carnivorous species, though not all.)
A: nemerteans

Q: The ________ have a unique proboscis in a rhynchocoel.
- mollusks (Incorrect. The mollusks are characterized by a muscular foot, a visceral mass of organs and a mantle.)
- segmented worms (Incorrect. The segmented worms are characterized by true segmentation (metamerism) and have setae/chaetae on every segment.)
- ribbon worms (Correct. This is a unique feature of the phylum Nemertea.)
A: ribbon worms

Q: Nemertini have brains composed of ________.
- two parallel nerve cords (Incorrect. The flatworm “brain” is composed of a pair of connected nerve cords and a large ganglion at the anterior end.)
- a ring of fused ganglia (Incorrect. Annelids have a ring of fused ganglia around the pharynx.)
- a ring of four ganglia (Correct. A ring of four nerve masses makes up the brain of the ribbon worms.)
A: a ring of four ganglia

Q: The ________ share a variety of characteristics, including a muscular foot and a mantle that may or may not secrete a shell.
- ribbon worms (Incorrect. All members of phylum Nemertea have a proboscis surrounded by rhynchocoel.)
- segmented worms (Incorrect. The segmented worms are characterized by true segmentation (metamerism).)
- mollusks (Correct. Phylum Mollusca is characterized by a muscular foot, a visceral mass of organs and a mantle.)
A: mollusks

Q: Grazing mollusks may use a ________ to scrape or shred food.
- mantle (Incorrect. The mantle is the dorsal epidermis in mollusks.)
- veliger (Incorrect. This is a larval stage of mollusks.)
- radula (Correct. The radula has chitinous tooth-like ornamentation and serves to shred or scrape food.)
A: radula

Q: All ________ are carnivorous predators with beak-like jaws.
- bivalves (Incorrect. The bivalves (clams, oysters, mussels, scallops, and geoducks) are suspension feeders.)
- chitons (Incorrect. The chitons (eight-plated shelled mollusks) use their radula to scrape food off the substratum.)
- cephalopods (Correct. The “heat foot” animals (octopi, squids, cuttlefish, and nautilus) are carnivorous predators.)
A: cephalopods

Q: All ________ are characteristized by of metamerism.
- ribbon worms (Incorrect. All members of phylum Nemertea have a proboscis surrounded by rhynchocoel.)
- mollusks (Incorrect. Phylum Mollusca is characterized by a muscular foot, a visceral mass of organs and a mantle.)
- segmented worms (Correct. Annelida is characterized by true segmentation (metamerism).)
A: segmented worms

Q: Annelids have ________ present in every segment.
- clitellum (Incorrect. This structure, which plays a role in reproduction, is found in the anterior third of an annelid body.)
- parapodia (Incorrect. These fleshy, paired appendages are only present in the polychaetes.)
- chaetae (Correct. These chitinous hairlike extensions are anchored in the epidermis and project from the cuticle of segmented worms.)
A: chaetae

Q: ________ contain a sucker at the anterior end and lack chaetae.
- Earthworms (Incorrect. Earthworms do not have an anterior sucker but they do have reduced chaetae.)
- Featherdusters (Incorrect. The featherdusters are marine annelids that are filter feeders. They do not have suckers and do have chaetae.)
- Leeches (Correct. Leeches (Hirudinea) have suckers at both ends of the animal and lack chaetae.)
A: Leeches

Q: ________ have a tubular morphology and circular cross-section.
- Flatworms (Incorrect. The flatworms have a more flattened cross-section with tapered edges.)
- Cnidarians (Incorrect. Cnidarians are neither tubular, nor do they have a circular cross section.)
- Nematodes (Correct. The roundworms are tubular with circular cross-sections.)
A: Nematodes

Q: Most nematodes possess ________ nerve cords.
- two parallel (Incorrect. The flatworms have two nerve cords running along the length of the body.)
- three conjoined (Incorrect. No invertebrate animals have three conjoined nerve cords.)
- four longitudinal (Correct. Most nematodes have four nerve cords running the length of the body; the ventral nerve cord is better developed.)
A: four longitudinal

Q: Nematodes have ________ digestive system.
- no (Incorrect. Nematodes do have a digestive system.)
- an incomplete (Incorrect. Nematodes do not have an incomplete digestive system.)
- a complete (Correct. Nematodes have a complete digestive system with a mouth and anus.)
A: a complete

Q: The complete mapping of all cells in ________ make it useful for studying cell differentiation.
- D. medinensis (Incorrect. There is no complete cell map for D. medinensis.)
- W. bancrofti (Incorrect. There is no complete cell map for W. bancrofti.)
- C. elegans (Correct. Knowing which cells give rise to which make C. elegans particularly useful for studying cell-fate determinations, cell differentiation, cell-cell communication, and apoptosis.)
A: C. elegans

Q: ________ cycling is useful for studying insulin signaling in C. elegans.
- Glucose (Incorrect. Glucose cycling is not a feature used to study insulin signaling in C. elegans.)
- Estrogen (Incorrect. Estrogen cycling is not used to study insulin signaling in C. elegans.)
- Hexosamine (Correct. Hexosamine cycling modulates insulin signaling in C. elegans, making it a useful model for diabetes studies.)
A: Hexosamine

Q: Elephantiasis is caused by the parasitic ________.
- Dracunculus medinensis (Incorrect. Guinea worms cause dracunculiasis.)
- Trichinella (Incorrect. Trichinella worms cause trichinosis.)
- Wuchereria bancrofti (Correct. This is the causative agent of elephantiasis in humans.)
A: Wuchereria bancrofti

Q: Approximately ________ percent of animals are arthropods.
- 55 (Incorrect. This percentage is too low.)
- 70 (Incorrect. This is not the correct percentage of animals made up of arthropod species.)
- 85 (Correct. Nearly 85 percent of all animals are arthropods.)
A: 85

Q: Body regions in arthropods are known as ________.
- segments (Incorrect. Arthropods do have segmented bodies but this is not the name of the functional body regions.)
- hemocoel (Incorrect. This is the central cavity, or blood cavity, in arthropods.)
- tagma (Correct. Functional body regions in arthropods are called tagma.)
A: tagma

Q: The lungs of arachnids are known as ________.
- filamentous gills (Incorrect. Crustaceans have filamentous structures making up their gills.)
- spiracles (Incorrect. Spiracles are the outside openings of the tracheae in insects and myriapods.)
- book lungs (Correct. Arachnid lungs contain a vertical stack of hemocoel wall tissue that resembles the pages of a book.)
A: book lungs

Q: ________ have three tagma and one pair of legs on each.
- Myriapoda (Incorrect. The myriapods have between 10 and 750 legs, including millipedes and centipedes.)
- Crustacea (Incorrect. Crustacea have two tagma and variable numbers of legs.)
- Hexapoda (Correct. These include the “common” insects we see every day, with six legs.)
A: Hexapoda

Q: The ________ are named for the first pair of appendages which are specialized mouthparts.
- Myriapoda (Incorrect. Myriapods are named for their many feet.)
- Crustacea (Incorrect. Crustaceans are named for their chitinous exoskeleton.)
- Chelicerata (Correct. Chelicerates have chelicerae, specialized claw-like or fang-like mouthparts.)
A: Chelicerata

Q: In deuterostomes, the ________ develops first.
- mouth (Incorrect. The mouth develops first in protostomes.)
- coelomic cavity (Incorrect. The timing of this development is not used to identify this superphylum.)
- anus (Correct. Deuterostome means “mouth second,” so the anal opening develops first.)
A: anus

Q: The chordates are distinguished by the presence of ________.
- an anal opening before a mouth (Incorrect. This is a characteristic of all deuterostomes.)
- spiny skin (Incorrect. This is the characteristic of the echinoderms.)
- notochord and dorsal hollow nerve cord (Correct. Chordates also have pharyngeals slits and a post-anal tail.)
A: notochord and dorsal hollow nerve cord

Q: Deuterostomes have a(n) ________.
- pseudocoelom (Incorrect. Deuterostomes have a true coelom.)
- schizocoelom (Incorrect. The deuterostome coelom does not form from mesodermal splitting.)
- enterocoelom (Correct. The coelom of deuterostomes forms from coelomic pouches that fuse to form the coelomic cavity.)
A: enterocoelom

Q: All chordates share four features ________.
- throughout their life cycle (Incorrect. Not all chordates have the four distinguishing characteristics throughout their life cycles.)
- as adults (Incorrect. Not all chordates have the four distinguishing characteristics as adults; actually few have all four as adults.)
- at some stage of development (Correct. All chordates share four features that appear at some stage in embryonic development.)
A: at some stage of development

Q: The ________ include two clades of invertebrates.
- echinoderms (Incorrect. Echinoderms are all invertebrates.)
- deuterostomes (Incorrect. There are more than two clades of invertebrate deuterostomes.)
- chordates (Correct. There are two clades of invertebrate chordates, the Urochordata and Cephalochordata.)
A: chordates

Q: One of the key features found in all chordates is the ________.
- spinal cord (Incorrect. Not all chordates have a spinal cord.)
- vertebral column (Incorrect. The invertebrate chordates do not have a vertebral column.)
- notochord (Correct. This characteristic actually provides the group with its name.)
A: notochord

Q: Adult echinoderms have ________ symmetry.
- bilateral (Incorrect. Echinoderms are not bilaterally symmetrical.)
- ambulacral (Incorrect. Echinoderms do not have ambulacral symmetry.)
- pentaradial (Correct. Echinoderms all have five arms arranged symmetrically around a central point.)
A: pentaradial

Q: ________ have a water vascular system that serves as their circulatory system.
- Cnidarians (Incorrect. Cnidarians do not have a water vascular circulatory system.)
- Deuterostomes (Incorrect. Some, but not all, deuterostomes have a water vascular circulatory system.)
- Echinoderms (Correct. The coelom of echinoderms is modified into a unique circulatory system called a water vascular system.)
A: Echinoderms

Q: Echinoderms are able to ________.
- reproduce by budding (Incorrect. Some echinoderms can reproduce asexually but they do so by fragmentation.)
- undergo parthenogenesis (Incorrect. Echinoderms do not reproduce from unfertilized eggs.)
- regenerate following fragmentation (Correct. Echinoderms can regenerate even when 75 percent of their body mass is lost.)
A: regenerate following fragmentation

Q: The ________ have thick ambulacra extending from their central disk.
- brittle stars (Incorrect. Brittle stars have long, thin arms sharply demarcated from their central disk.)
- sea urchins (Incorrect. Sea urchins do not have arms, but are hemispherical with five rows of tube feet.)
- sea stars (Correct. Sea stars have thick arms extending from the central disk where organs penetrate into the arms.)
A: sea stars

Q: The Ophiuroidea have ________.
- no arms, but they are hemispherical with five rows of tube feet (Incorrect. Sea urchins do not have arms, but are hemispherical with five rows of tube feet.)
- thick ambulacra extending from their central disk (Incorrect. Sea stars have thick arms extending from the central disk where organs penetrate into the arms.)
- long, thin arms sharply demarcated from their central disk (Correct. Brittle stars have long, thin arms sharply demarcated from their central disk; they lash them or wrap them around objects to move.)
A: long, thin arms sharply demarcated from their central disk

Q: The ________ are functionally bilateral as adults.
- Echinoidea (Incorrect. Sea urchins do not have arms, but are hemispherical with five rows of tube feet; therefore they are pentaradially symmetrical.)
- Crinoidea (Incorrect. Sea lilies and feather stars have pentaradial symmetry as adults.)
- Holothuroidea (Correct. The sea cucumbers are functionally bilateral because their oral-aboral axis forces them to lie horizontally.)
A: Holothuroidea