Chapter 34 Concept

Which of the following statements are true of members of the phylum Nematoda? Choose all that apply.

- Also called round worms - Many species are parasitic - They undergo ecdysis

Which of the following are characteristics of lancelets (subphylum Cephalochordata)?

- Are filter feeders - All individuals have the four distinguishing chordate characteristics - Live mostly buried in the sand

Select all of the following that can be components of the skeleton of a sponge.

- Calcium carbonate spicules - Silica spicules - Spongin fibers

The main classes within the Mollusk phylum include:

- Cephalopoda - Bivalvia - Gastropoda - Polyplacophora

Indicate the correct arthropod subphylum containing each of the organisms listed below. Shrimp: _______ Butterflies: _________ Scorpions: _______ Centipedes: ________

- Crustacea - Hexapoda - Chelicerata - Myriapoda

What are the three clades of bilateral animals?

- Ecdysozoa - Deuterostomia - Lophotrochozoa

Which of the following are deuterostomes? Choose all that apply.

- Echinodermata - Chordata

Which of the following are characteristics of the phylum Ctenophora?

- Eight rows of cilia on their surface - Gastrovascular cavity - Two long tentacles that secrete a sticky substance for prey capture

What defense mechanisms are employed by cephalopods?

- Ejection of pigment into water to disorient predators - Color change for camouflage

Which of the following are the three major advantages of segmentation?

- Enhanced locomotion - Specialization - Redundancy of organs

What are the two major groups in the phylum Annelida?

- Errantia - Sedentaria

Select the characteristics of the subphylum Chelicerata.

- Fangs - Typically predatory or parasitic - Have bodies consisting of two tagmata

Which of the following are characteristics of both Nematoda and Arthropoda?

- Grow by molting their cuticle - In the clade Ecdysozoa

Indicate the correct arthropod subphyla indicated below: Body with head, thorax, and abdomen; highly modified mouthparts; often possess two pairs of wings and three pairs of legs:___________ Body of two to three parts; three or more pairs of legs; usually marine:__________ Body with head and highly segmented trunk; one or two pairs of walking legs per segment; terrestrial: ________Body comprised of cephalothorax and abdomen; six pairs of appendages; pedipalps; predatory or parasitic:___________

- Hexapoda - Crustacea - Myriapoda - Chelicerata

What are the four classes of the phylum Cnidaria?

- Hydrozoa - Scyphozoa - Cubozoa - Anthozoa

Which of the following statements are true regarding schistosomiasis?

- It causes damage to the liver, intestines, and lungs, and can ultimately lead to death. - Release of eggs causes inflammation and blockage of organs. - It is the most common trematode infection in humans.

Which of the following statements are true regarding the experiment conducted by Fiorito and Scotto in 1992 investigating the behavior of Octopus vulgaris?

- Learning by observing was achieved more quickly than the original training. - The experiment involved testing the behavior of octopuses that observed other octopuses that had been trained. - The results indicate that octopuses may learn from others in the wild.

Which of the following are characteristics of ctenophores?

- Many species are bioluminescent. - They move by coordinated beating of cilia. - They secrete a sticky substance for prey capture.

Which of the following are the three embryonic germ layers found in animals?

- Mesoderm - Ectoderm - Endoderm

Which of the following are true of leeches?

- Most feed on blood. - They have a fixed number of segments (often 34). - They may be used in medical applications. - Most species are external parasites of vertebrate animals.

What are the names of the five subphyla within the Arthropoda phylum?

- Myriapoda - Hexapoda - Crustacea - Chelicerata - Trilobita

Which of the following are major phyla in the group Ecdysozoa?

- Nematoda - Arthropoda

Which of the following are defining characteristics of the phylum Chordata?

- Pharyngeal slits - Hollow dorsal nerve cord - Muscular post-anal tail - Notochord

In humans, which of the following features are exhibited only during embryonic development?

- Pharyngeal slits - Postanal tail

What phyla are included in the Lophotrochozoa clade?

- Platyhelminthes - Rotifera - Brachiopoda - Bryozoa - Annelida - Mollusca

Which of the following are characteristics of members of the Cnidaria phylum?

- Possess a mesoglea - Found in marine or freshwater habitats

Which of the following are distinguishing characteristics of the Lophotrochozoa clade?

- Protostome development - A lophophore or a distinct trochophore larval stage

All members of the phylum Arthropoda have what characteristics?

- Segmentation - Jointed legs - An exoskeleton composed of chitin and protein

Which of the following are characteristics of tunicates (subphylum Urochordata)?

- Sessile adult that has only one of the chordate hallmarks - Adults are filter-feeders - They undergo metamorphosis from larvae to adult form

Which of the following statements are TRUE of complete metamorphosis?

- The body transformation from larva to adult occurs in the pupa stage - Has four types of stages

Which of the following are characteristics of centipedes?

- They are carnivores that actively pursue their prey. - The head has many sensory appendages, including antennae and appendages modified as mouthparts. - Their venom may be powerful enough to cause pain in humans.

Which of the following are characteristics of scorpions?

- They are generally found in tropical or subtropical regions - The young are carried on the back of the mother until their first molt

Members of the phylum Platyhelminthes have which of the following characteristics?

- They have mesoderm. - They are acoelomate. - They exhibit cephalization.

Characteristics of the millipedes (class Diplopoda) include:

- They may protect themselves by producing toxic secretions. - They are herbivores. - They may protect themselves using bright coloration to warn potential predators.

Which of the following are true of cephalochordates?

- They undergo deuterostome development. - They have all four chordate characters in the adult. - Gas exchange occurs across the body surface. - They live most of their lives buried in sand with the anterior end protruding into the water.

Which of the following statements accurately describe organisms in the mollusk class Gastropoda?

- They use a radula for feeding. - They are found in marine, freshwater, and terrestrial environments.

Which of the following are true of the phylum Chordata?

- This phylum includes invertebrate organisms. - This phylum includes all of the vertebrate organisms. - The endoskeleton is always internal, with muscles attached.

Which of the following are major characteristics of members of the arthropod subphylum Trilobita?

- Three tagmata: the head, thorax, and tail - A cuticle that is shed as the organism increases in size - Three lobes: an axial lobe and two pleural lobes

How do cnidarians use cnidocytes?

- To immobilize prey - For defense

Flatworms that are internally parasitic within humans or animals and thus of great medical or veterinary concern include:

- Trematodes - Cestodes

Which of the following are characteristics of echinoderms?

- Tube feet - Endoskeleton composed of calcareous plates - Presence of a water vascular system

Which of the following are subphyla of the phylum Chordata which consist of invertebrates?

- Urochordata - Cephalochordata

Features of the nematode body plan include:

- a mouth with stylets - a pseudocoelom that acts as a circulatory system and fluid-filled skeleton - longitudinal musculature

In Platyhelminthes, reproduction may occur:

- asexually by splitting into two, and each half regenerates the missing half. - sexually; hermaphroditic individuals fertilize the eggs of one another

Features of the arthropod body plan include:

- compound eyes composed of ommatidia - a cuticle composed of chitin and protein - segments fused into tagmata - jointed appendages

Select all of the arthropods that are often ectoparasitic and that have a cephalothorax and abdomen that are fused.

- mites - ticks

Components of the annelid body plan include:

- respiration that occurs through the skin surface - a double transport system consisting of a circulatory system and coelomic fluid - a ventral nerve cord containing giant axons

Place the following stages in the life cycle of a Chinese liver fluke (Clonorchis sinensis) in order. Begin at the top with the step that involves human consumption of fish infected with metacercarial cysts.

1. After being consumed by a human host, metacercarial cysts release juveniles that travel to the bile ducts 2. Eggs containing encapsulated miracidia are produced and pass out from the host via the feces 3. an intermediate host (a mollusk) eats the eggs, Sporocysts formed. 4. Asexual reproduction occurs to produce rediae that develop in the mollusk body 5. Asexual reproduction occurs to produce cercariae which break out of the mollusk body 6. Free-swimming cercariae infect fish through their gills and develop into metacercarial cysts and lodge in fish muscle.

Map the path of water through the water vascular system of echinoderms with the part of the body where water enters at the top.

1. Madreporite 2. Ring Canal 3. Five radial canals 4. Tube feet

What approximate fraction of all described species are arthropods?

3/4

Approximately what percentage of animal species are NOT invertebrates?

5

How many legs do insects have?

6

There are about ______ species of sponges.

8,000

The following diagram shows the body plan of a flatworm. Match the letter to its corresponding structure.

A - Cerebral ganglia B - Protonephridia C - Gastrovascular cavity D - Pharynx

Identify the major anatomical features of a larval tunicate by matching each term with the appropriate letter indicated on the figure.

A - Dorsal hollow nerve cord B - Excurrent siphon C - Incurrent siphon D - Pharyngeal slits E - Heart F - Stomach G - Notochord H - Postanal tail

Identify the anatomical features of an echinoderm by matching each term to the appropriate letter indicated on the diagram.

A - Endoskeleton B - Ring canal C - Stomach D - Gonads E - Tube feet F - Mouth

Match the terms to the correct letters indicating major features of the tunicate body plan.

A - Excurrent siphon B - Anus C - Intestine D - Stomach E - Heart F - Incurrent siphon

Match the major chordate characteristics with the appropriate letter indicated on the diagram of a generalized chordate body plan.

A - Notochord B - Dorsal hollow nerve cord C - Pharyngeal (gill) slits D - Brain E - Heart F - Stomach G - Muscular segments H - Postanal tail

Match the letters with the correct body part of mollusks.

A - Shell B - Visceral Mass C - Mantle D - Foot E - Radula

Which of the following statements is true about this diagram?

A = Polyp; B = Medusa

What is a lophophore?

A crown of ciliated tentacles

What is spongin?

A protein that lends skeletal support to sponges lacking spicules

How has the foot of some cephalopods been modified into?

A siphon to facilitate jet propulsion

Indicate the appropriate letter for each of the major chordate features indicated on the diagram of the generalized chordate body plan. Notochord = __ ; Pharyngeal (gill) slits = __ ; Postanal tail = __ ; Dorsal hollow nerve cord = __

A; C; H; B

In echinoderms, the base of each tube foot contains a muscular sac that holds water and regulates its contraction and expansion. What is this structure called?

Ampulla

Members of what phylum can be described as such: segmented organisms that have a complete digestive system, a ventral nerve cord, and a coelom that acts as a hydrostatic skeleton?

Annelida

The following is a diagram of an arthropod, as represented by a grasshopper. Match the letter to its appropriate structure.

Antennae - A Thorax - B Abdomen - C Wings - D

Organisms such as sea anemones and most corals that are always marine, may be colonial, and have a dominant polyp stage best describes members of what Cnidarian class?

Anthozoa

Hexapoda, Chelicerata, Trilobita, Myriapoda, and Crustacea are subphyla within the phylum _________

Arthropoda

The organisms shown here belong to the phylum

Arthropoda

Match each echinoderm class to its representative members.

Asteroidea - Sea stars Ophiuroidea - Brittle stars Echinoidea - Sea urchins and sand dollars Crinoidea - Sea lilies and feather stars Holothuroidea - sea cucumbers

In this photograph of a fossil trilobite, the axial lobe is represented by what letter?

B

To what mollusk class does this organism belong?

Bivalvia

Which of the following combinations are ALL classes in the phylum Mollusca?

Bivalvia, Cephalopoda, and Gastropoda

Which of the following statements is true regarding echinoderms and chordates?

Both have endoskeletons and undergo deuterostome development

The following is a diagram of an arthropod, as represented by a grasshopper. Match the letter to its appropriate structure.

Brain - A Crop - B Stomach - C Heart - D Rectum - E

Which of the following is a non-infectious nematode that has become a model genetic organism?

Caenorhabditis elegans

A(n) ______ is a hard, protective fold of the cuticle that covers the head and extends over most of the cephalothorax in some arthropods.

Carapace

Which of the following best describes the nervous system of echinoderms?

Central nerve ring with branches

The two most closely related subphyla to the vertebrates are the ______ and the _______.

Cephalochordata or lancelets; Urochordata or tunicates

Within Phylum Chordata, the subphyla

Cephalochordata or lancelets; Urochordata or tunicates

The most morphologically complex class of mollusks is ___________. Most members are fast-swimming marine predators with a series of arms and a beak-like jaw that allows them to capture and bite their prey.

Cephalopoda

What mollusks are identified as fast-swimming marine predators with a series of arms and a beak-like jaw for capturing and eating prey?

Cephalopods

What organisms are able to defend themselves using melanin, either by ejecting it into the water to confuse predators or by changing color for camouflage?

Cephalopods

The tapeworm shown here is a member of the class

Cestoda

Which of the following is the class to which tapeworms belong?

Cestoda

Match each major arthropod subphylum to its defining characteristics.

Chelicerata - Body comprised of a cephalothorax and abdomen; six pairs of appendages (four pairs walking legs, one pair of fangs, and one pair of pedipalps); terrestrial Myriapoda - Body comprised of a head and highly segmented trunk; one or two pairs of legs per segment; terrestrial Hexapoda - Body comprised of head, thorax, and abdomen; mouthparts modified for food type; usually two pairs of wings and three pairs of legs; usually terrestrial Crustacea - Body comprised of two or three parts; three or more pairs of legs; chewing mouthparts; usually marine

The mouthparts of various insects are shown here. Match the letter to the appropriate feeding method.

Chewing - A Piercing and blood sucking - B Nectar sucking - C Sponging liquid - D

Centipedes are members of the class _________

Chilopoda

Centipedes are members of what arthropod class?

Chilopoda

What substances make up the exoskeleton of an arthropod?

Chitin and protein

Which group of mollusks consists of marine organisms with shells composed of eight separate plates?

Chitons

Based on this phylogenetic tree, the taxonomic group of organisms that is most closely related to echinoderms is __________

Chordata

Rank the following taxonomic groups in order of evolutionary relatedness. Start with the group most closely related to echinoderms at the top.

Chordata Lophotrochozoa Cnidaria Porifera Ctenophora

What phyla are included in the Deuterostomia clade?

Chordata and Echinodermata

The segmented body plan of an earthworm (annelid) is shown here. Match each letter to its corresponding structure.

Clitellum - A Ventral nerve chord - B Setae - C Pulsating Vessels - D

Which of the following terms best describes a system in which blood flows throughout an animal entirely within a series of vessels?

Closed circulatory system

Which of the following best describes the circulatory system of annelid worms?

Closed, with dorsal and ventral vessels connected by pairs of pulsating vessels

The phylum ______ has four classes: Hydrozoa, Scyphozoa, Anthozoa, and Cubozoa.

Cnidaria

To what phylum does this organism in the picture belong?

Cnidaria

Fill in the names of the appropriate phyla for the distinguishing characteristics listed below. Phylum _______ : Diploblastic; gastrovascular cavity for extracellular digestion; radial symmetry; polyp and medusa forms; stinging cells Phylum:_______ Deuterostome development; notochord; pharyngeal slits; hollow dorsal nerve cord; muscular post-anal tail Phylum :______ Deuterostome development; water vascular system; endoskeleton composed of ossicles; tube feet Phylum: ___________ Bilateral symmetry; protostome development; body plan made up of mantle, visceral mass, and foot; some species have a shell

Cnidaria, Chordata, Echinodermata, Mollusca

How are coral reefs formed?

Cnidarian polyps build up limestone deposits using dissolved calcium and carbonate ions found in seawater.

What organisms are included in the phylum Ctenophora?

Comb jellies

The following diagram depicts the body plan of a common rotifer. Match each letter to its corresponding structure.

Corona - A Brain - B Protonephridium - C Stomach - D Toe - E

The organisms shown in the given photo are arthropods that belong to the subphylum ___________

Crustacea

To what phylum does this organism belong?

Ctenophora

What animal phylum includes members that are hermaphroditic, often bioluminescent, live in marine environments, and use cilia for movement?

Ctenophora

What phylum constitutes the earliest-diverging animal lineage?

Ctenophora

Which phylum contains members that are all hermaphrodites?

Ctenophora

Which phylum contains members that have only two germ layers, have eight rows of cilia for locomotion, and use two tentacles with sticky substances for capturing prey?

Ctenophora

The earliest-diverging animal phylum is __________

Ctenophora or Ctenophores

In this diagram of a sea star, what letter represents the madreporite?

D

Give the letter that indicates each of the following major anatomical features of an adult tunicate. Pharyngeal slits = __; Stolons = __; Stomach = __; Tunic = __.

D; G; F; C

Millipedes are members of the arthropod class ____________

Diplopoda

This diagram depicts the internal anatomy of an arthropod (grasshopper). The heart is represented by the letter ______.

E

What invertebrate organisms have a particularly important ecological role in enriching soil through their feeding and digestive processes?

Earthworms

Organisms that possess a cuticle undergo the process of ________ to allow for growth of the animal.

Ecdysis

This phylogenetic tree summarizes the evolutionary relationships among animal groups. According to it, the Lophotrochozoa are most closely related to the clade __________

Ecdysozoa

Which of the following undergo molting?

Ecdysozoans

What phylum of organisms have spiny skin, bilateral symmetry only as larvae, modified radial symmetry as adults, and possess a water vascular system?

Echinodermata

The clade Deuterostomia consists of two major phyla:

Echinodermata , Chordata

The phyla ________ and _________ are included in the Deuterostomia clade because their members undergo deuterostome embryonic development.

Echinodermatoa; Choradata

An internal skeleton is also known as a(n)

Endoskeleton

The protonephridia of flatworms are directly involved in which of the following processes?

Excretion

The metanephridia of mollusks function in which of the following?

Extraction of wastes

True or false: Members of the phylum Echinodermata exhibit radial symmetry throughout their life cycle.

False

True or false: Nematodes inhabit freshwater and terrestrial habitats, but are not found in marine environments.

False

What feeding mechanism is employed by lancelets?

Filter feeding; food particles are trapped in pharyngeal slits and moved to the digestive tract by ciliary action

In a flatworm, which of the following are ciliated cells that primarily function in maintaining osmotic balance between internal and external environments?

Flame cells

Which of the following does a mollusk use for movement?

Foot

What statement best describes symmetry in echinoderms?

Free-swimming larvae have bilateral symmetry, while the adult form is radially symmetrical

The largest mollusk class, which includes many species that have a a single coiled shell is:

Gastropoda

Fill in the name of the mollusk classes described below: Marine, freshwater, and terrestrial mollusks that may or may not possess a coiled shell; radula present __________. Predatory marine mollusks that may or may not possess a shell; closed circulatory system; mouth surrounded by tentacles with suckers __________. Marine mollusks that possess a shell composed of eight plates; feed on algae that grows on rock surfaces ___________. Mollusks that inhabit marine and freshwater habitats; enclosed within left and right shell halves; filter feeders ____________.

Gastropoda, Cephalopoda, Polyplacophora, Bivalvia

Different insects have evolved a variety of mouthparts whose components are modified for various functions. Match each insect group to its appropriate feeding style.

Grasshopper - Chewing Mosquitoes - Piercing and sucking Butterflies - Nectar drinking Houseflies - Liquid sponging

Identify the morphological features of a trilobite by matching each term to the appropriate letter indicated on the photo.

Head - A Thorax - B Tail - C

All ctenophores are ___________, possessing both ovaries and testes.

Hermaphodites or hermaphroditic

Insects are athropods that are members of the subphylum _________

Hexapoda

Sea cucumbers are members of the echinoderm class:

Holothuroidea

Match each Cnidaria class with its representative members and defining characteristics.

Hydrozoa - Ex: Hydra. Portuguese man-of-war. Can be freshwater; dominant polyp stage; polyps often colonial. Scyphozoa - Ex: jellyfish. Always marine; dominant medusa stage (can be very large) Anthozoa - Ex: sea anemones, most corals. Always marine; dominant polyp stage; can be colonial Cubozoa - Ex: box jellies, sea wasps. Always marine; dominant medusa stage; box-shaped

Which of the following statements best describes reproduction in the Platyhelminthes?

In all species, reproduction is either sexual or asexual

Insects are members of the arthropod class:

Insecta

The subphylum hexapoda includes:

Insects and relatives

This figure depicts the segmented body plan of an earthworm (annelid). Match each roman numeral to the appropriate structure.

Intestine - I Crop - II Pharynx - III Cerebral ganglia - IV

What was the major conclusion of the experiment conducted by Fiorito and Scotto in 1992 regarding the behavior of Octopus vulgaris?

Invertebrate animals, such as the octopus, are able to learn by watching the behavior of others.

Which of the following statements about the mesoglea layer in cnidarians is true?

It is thick in jellyfish and thin in hydra

What invertebrate organisms may be used in medical applications to remove excess blood that accumulates following surgery?

Leeches

Organisms that undergo protostome development and possess either a lophophore or a distinct trochophore larval stage are members of what major animal clade?

Lophotrochozoa

Based on this phylogenetic tree, which pair of clades are most closely related?

Lophotrochozoa and Ecdysozoa

What are chitons?

Marine mollusks with shells composed of eight separate plates

The arthropod class Diplopoda is comprised of what group of animals?

Millipedes

Some arthropods have long bodies, two pairs of walking legs per segment, and defend themselves through bright coloration, coiling, or ejecting toxic, repellent secretions. These arthropods are called ___________

Millipedes or Diplopoda

The organisms shown in this figure are members of what phylum?

Mollusca

This figure depicts organisms that belong to the phylum

Mollusca

Sponges are best described by what statement?

Multicellular but lack true tissues

Small, thin worms that usually range from 1 mm to 5 cm in length.

Nematoda

To what phylum does this animal belong?

Nematoda

While there are eight ecdysozoan phyla, the two most common are the ________ and the _________

Nematoda;

What organisms have longitudinal muscles, a pseudocoelom, and a cuticle composed primarily of collagen that they must molt as they grow?

Nematodes

This diagram shows the body plan of a lancelet. What chordate hallmark is indicated by the blue arrow?

Notochord

Match each chordate hallmark with its corresponding structure in an adult human. Instructions

Notochord - Spinal column Dorsal hollow nerve cord - Central nervous system Pharyngeal slits - Auditory (Eustachian) tubes Postanal tail - The tailbone (coccyx)

During incomplete metamorphosis, young insects look like miniature adults when they hatch from eggs. What are these young insects called?

Nymphs

A circulatory system that consists of a heart pumping hemolymph into sinuses that coalesce to form the hemocoel, allowing gases and nutrients to diffuse into tissues, is a(n) ____ circulatory system.

Open

What is the term for a circulatory system that involves open cavities called sinuses that allow organs to be continually bathed in hemolymph rather than blood being enclosed completely within a series of vessels?

Open circulatory system

Which of the following best describes the circulatory system of arthropods?

Open: Hemolymph is pumped from the tubelike heart to the hemocoel, where nutrients diffuse into tissues.

Chordates, like many animals, have a complete gut. However, in chordates, form close to the mouth. These are open to the outside and permit water to exit without having to go through the digestive tract.

Pharyngeal slits

In aquatic chordates, which structure provides an exit for water that entered through the mouth but will not enter the digestive tract?

Pharyngeal slits

Which of the following is the only chordate characteristic found in adult tunicates?

Pharyngeal slits

Acoelomate organisms that have a flattened body make up the phylum:

Platyhelminthes

Flatworms are members of the phylum

Platyhelminthes

The tapeworm shown here is a member of the phylum __________

Platyhelminthes

This organism contains a scolex and proglottids. To what phylum does this organism belong?

Platyhelminthes

To which phylum do flatworms belong?

Platyhelminthes

Match each mollusk class with its major characteristics.

Polyplacophora - Marine; eight-plated shell Gastropoda - Marine, freshwater, or terrestrial; radula present; shell coiled or absent Bivalvia - Marine or freshwater; mostly filter feeders; shell with two halves Cephalopoda - Marine; predatory; tentacles around mouth; shell usually absent or reduced; closed circulatory system

Sponges are members of the phylum __________

Porifera

To what phylum does the pictured organism belong?

Porifera

Match each phylum listed below with its distinguishing characteristics. Instructions

Porifera - Asymmetrical; no true tissues; choanocytes move water through the body wall and trap food particles Cnidaria - Radial symmetry; diploblastic; polyp and medusa forms; stinging cells Mollusca - Bilateral symmetry; triploblastic; body plan comprised of a foot, visceral mass, and mantle; some species have a shell for protection Arthropoda - Bilateral symmetry; triploblastic; segmented; a hard cuticle composed primarily of chitin; ecdysis Echinodermata - Larvae exhibit bilateral symmetry, adults radial; triploblastic; tube feet; deuterostome development; endoskeleton composed of ossicles

Match the animal phylum to its correct features.

Porifera - No organ systems; endoskeleton of spicules and collagen Platyhelminthes - Gastrovascular cavity, protonephridia with flame cells; cerebral ganglia with lateral nerve cords and nerve net; hydrostatic skeleton Mollusca - Complete gut; open circulatory system in most species; gills for respiration; metanephridia; ganglia with nerve cords; hydrostatic skeleton Echinodermata - Complete gut; tube feet; nerve ring and radial nerves; endoskeleton of plates beneath outer skin

The organism in the given photo is a member of the phylum _________

Porifera or sponges

At some point during embryo development, chordates possess a(n) ___________ that extends posterior to the anal opening. It is often used in locomotion in aquatic members of the phylum.

Postanal tail

What are nematocysts?

Powerful stinging capsules in cnidarians with an inverted coiled and barded thread

With one exception, the following are characteristics common to all mollusks. Which characteristic is NOT found in all mollusks?

Radula

Which of the following organisms have a pseudocoelom and a ciliated crown?

Rotifers

Blood flukes include what genus?

Schistosoma

Which of the following terms refers to the division of the body into compartments that are very similar to each other?

Segmentation

What is the name of the chitinous bristles found on each segment of most annelids?

Setae

What are parapodia?

Setae-bearing, footlike structures that can be pushed into substrate to provide traction during movement

In cestodes, the proglottids serve which of the following functions?

Sex organs

What are the roles of spongin protein and spicules in sponges?

Skeletal support

Which of the following best describes the function of the notochord?

Skeletal support

In a sponge, what are the skeletal structures composed of protein, silica, or calcium carbonate called?

Spicules

Match each group of arthropods to its associated subphylum.

Spiders, scorpions, ticks, mites - chelicerata Millipedes, centipedes - myriapoda Beetles, grasshoppers, flies, ants - hexapoda Crabs, lobsters, barnacles - crustacea

What organisms lack true tissue but use choanocytes to draw water through pores so that tiny food particles may be trapped and digested?

Sponges

What organisms make up the Porifera phylum?

Sponges

The tough protein that lends skeletal support to sponges that do not have spicules is called __________

Spongin

What are cnidocytes?

Stinging cells that can be used in defense or prey capture

The body plan of a lancelet is illustrated here. Match the letter to its appropriate structure.

Tentacles - A Pharyngeal slits - B Notochord - C Dorsal hollow nerve cord - D Anus - E

What is a spongocoel?

The central cavity of a sponge

In cnidarians, what is a medusa?

The free-swimming form that is umbrella-shaped with an opening on the concave underside that serves as a mouth and anus, surrounded by tentacles

What is a scolex?

The organ used by cestodes to attach to a host

Which of the following statements about the body forms of cnidarians is TRUE?

The polyp is sessile and the medusa is motile

What is ecdysis?

The process of molting or shedding a cuticle

Why is cephalization absent in most echinoderm classes?

Their symmetry prevents it.

How are giant axons useful to annelids?

They allow rapid responses to stimuli.

What statement is true of trematode and cestode worms?

They are internal parasites of animals, including humans.

How do annelid worms move?

They contract circular muscles against their coeleom which acts as hydrostatic skeleton to alternately elongate and contract segments.

What is meant by the statement: Nematodes are ubiquitous organisms?

They exist everywhere

How do ctenophores move?

They use the beating of their cilia.

What sentence best describes the feeding mechanism of a sponge?

Tiny food particles are trapped by flagellated cells as water is drawn through pores in the body of the sponge and exits via the osculum.

The class ______ includes the flukes.

Trematoda

In what arthropod subphylum does this organism belong?

Trilobita

True or false: Echinoderms and chordates are closely related, both have endoskeletons and deuterostome development.

True

True or false: Flatworms are aceolomate.

True

True or false: Only some chordates possess all four chordate characteristics in their adult life, but all chordates exhibit these features at some time during development.

True

Which of the following comprises the only free-living class of flatworms?

Turbellaria

Match

Turbellaria - Free-living; often found in lakes, ponds, and marine habitats. Monogenea - External parasites of fish Trematoda - Internal parasites; complex life cycle with multiple hosts; a mollusk is often the intermediate host and the definitive host is usually a vertebrate Cestoda - Internal parasites; often have two vertebrate host species; scolex; proglottids; absorb nutrients across the body surface

Cnidarians are able to defend themselves in what way?

Use of specialized stinging cells known as cnidocytes

An invertebrate animal is one that does not have:

a backbone

Some arthropods possess a carapace, which can be described as:

a hard, protective fold of the cuticle that covers that head and extends over the cephalothorax

In chordates, the nerve cord is:

a hollow tube that develops dorsal to the alimentary canal

In rotifers, the unique structure known as the mastax is:

a muscular pharynx that contains jaws for grasping and chewing

The nervous system of annelid worms may best be described as involving:

a pair of cerebral ganglia and a large ventral nerve cord containing giant axons

In nonchordate invertebrates, the nerve cord is:

a solid tube that develops ventral to the alimentary canal

Flatworms lack a fluid-filled cavity in which the gut is suspended, and so are termed ____________

acoelomate

Animals that lack a fluid-filled body cavity are called

acoelomates

According to an evolutionary study performed in 2011, the phylum _______ contains two major groups: the Errantia and the Sedentaria.

annelida

Organisms that have a complex nervous system involving a pair of cerebral ganglia and a ventral nerve cord with giant axons, a double transport system, respiration that occurs across the skin surface, a closed circulatory system, a complete digestive system, and reproduction that may be sexual or asexual are:

annelids

Members of the phylum ______ have a cuticle composed of chitin and protein, jointed appendages, and segments fused into functional units called tagmata.

anthropoda

Segmented organisms with jointed legs and a hard exoskeleton composed of chitin make up the phylum

anthropoda

The salivary secretion of leeches acts as a(n) ______.

anticoagulant

Cnidarians are found in ______ environments and possess ______ embryonic germ layers.

aquatic; two

The organisms depicted in the provided figure belong to the phylum ____________

arthropoda

Of all described living species present on Earth, about three-quarters are _________

arthropods

The phenomenon that results from chemical reactions that give off light instead of heat is _________

bioluminescence or chemiluminescence

Fast-moving, carnivorous arthropods with one pair of walking legs per segment are known as _______

centipedes or chilopods

The process that resulted in a head bearing sensory appendages in the phylum Platyhelminthes is called ___________

cephalization

The fused head and thorax of some arthropods such as chelicerates and crustaceans is the:

cephalothorax

Many chelicerates and crustaceans have a ________, which is a fused head and thorax.

cephalothorax or prosoma

The arthropod exoskeleton is composed of layers of ________ and _______

chitin; protein

Sponges have flagellated cells that line the spongocoel, help water flow through the pores, and trap food particles. These cells are known as _________

choanocytes

The flagellated cells that line the spongocoel of a sponge and help water flow through the pores are known as:

choanocytes

Ctenophores use ______ to propel themselves in the water column.

cilia

Members of the phylum Rotifera get their name from their:, which have a known as a corona that is used in locomotion and feeding?

ciliated crown

Platyhelminthes lack a specialized respiratory or __________ system to transport gases. They must obtain oxygen by ____________, which makes a flattened shape necessary so that all cells are close to the surface.

circulatory; diffusion

Annelids typically have a ______ circulatory system, with dorsal and ventral vessels connected by five pairs of pumping vessels that serve as muscular hearts.

closed

A ____________ system is one in which blood flows throughout an animal entirely within a series of vessels.

closed circulatory

The organism in this provided photo belongs to the phylum

cnidarian

The hairlike trigger on the surface of a cnidocyte is called the

cnidocil

In cnidarians, each cnidocyte has a hairlike trigger called a ______ on its surface. When it is stimulated, it can lead to the discharge of the ______, which is used in defense or capture of prey.

cnidocil; nematocyst

Cnidarians have stinging cells called ________ which contain powerful capsules called nematocysts. These are used in prey capture and defense.

cnidocytes

In cnidarians, ___________ are stinging cells used in defense and prey capture.

cnidocytes

Annelids have a fluid-filled _______ that acts as a hydrostatic skeleton.

coelom

Limestone deposits, known as ______________, form when small colonial cnidarians precipitate dissolved calcium and carbonate ions from seawater over many generations. Listen to the complete question

coral reefs

The organism shown here belongs to the phylum

ctenophore

Comb jellies make up the phylum

ctenophores

All ecdysozoans possess a(n) ___________, which is a nonliving cover that serves both to support and protect the animal.

cuticle

Ecdysozoans possess an external nonliving layer that functions in support and protection and must be shed periodically called the:

cuticle

Caenorhabditis elegans is used as a model organism to study what process?

development

The flattened body shape of flatworms facilitates:

diffusion of gases through the body wall

In chordates, the notochord lies between the ________ tract and the ________ cord.

digestive, nerve

The periodic shedding of the exoskeleton (cuticle) is known as molting or ________

ecdysis

Ecdysozoans are named as such because they all undergo __________

ecdysis or molting

The organisms shown here are members of the phylum

echinodermata

During development, the majority of insects undergo complete metamorphosis, which has four types of stages:

egg, larva, pupa, adult

During development, a minority of insects undergo incomplete metamorphosis, which has three types of stages:

egg, nymph, adult

The three embryonic germ layers found in animals are called

endoderm, ectoderm, mesoderm

Chordates and most echinoderms have a hard, internal skeleton, also known as a(n):

endoskeleton

Insects are the subject of the field of scientific study known as

entomology

True or False: Like insects, chelicerates have a body consisting of three tagmata: a head, thorax, and abdomen.

false

In the excretory systems of flatworms, specialized ciliated cells known as __________ move water through the protonephridia, helping maintain osmotic balance.

flame cells

Mollusks use a muscular _____ for movement.

foot

The body plan of a rotifer is shown here. The structure labeled A is the ______

foot

While there are some morphological variations between classes, mollusks have a basic body plan consisting of three parts: a muscular __________ (used for movement), a(n) ____________ mass (which contains the internal organs), and a(n) ___________ (which produces the shell in mollusks that have one).

foot; visceral; mantle

The mesoglea in cnidarians is a(n):

gelatinous layer that connects the endoderm and ectoderm

In aquatic organisms such as mollusks, filamentous organs that are specialized for gas exchange are known as _____

gills

Earthworms ingest soil and leaf tissue to extract nutrients. As this material passes through the earthworm's digestive system, it is finely ground into smaller fragments in the _________

gizzard; casting

A tissue is best defined as a

group of cells that have a similar structure and function.

Ecdysozoans undergo ecdysis primarily to allow for:

growth

In cnidarians, the cnidocil is the:

hairlike trigger found on the surface of stinging cells

In the circulatory system of arthropods, the __________ is pumped from the heart into the aorta or short arteries and then into open sinuses that coalesce to form the ________.

hemolymph; hemocoel

Nematode parasites of the human intestine that are able to infect a new host when larvae penetrate the skin of the host's foot are known as:

hookworms

The life cycle of a trematode worm is complex, with multiple hosts. For example, in the Chinese liver fluke, the adult fluke lives and reproduces in ______, eggs are eaten by ______, and cercariae infect the second intermediate host, a(n) ______, before beginning a new cycle.

humans; snails; fish

Cephalization is the process:

in platyhelminthes that produces a head that contains sensory appendages

There are more species of _______ than all other species of animals combined.

insects

Which of the following animals have more species than all the rest?

insects

Animals without backbones are known as ___________

invertebrates

In animals, about 95% of all species are ________

invertebrates

The mesoglea in ______ is enlarged and forms a transparent jelly.

jellyfish

Acoelomate animals:

lack a fluid-filled body cavity

Organisms that have a bladelike shape and size, and which burrow into the sand to filter feed are:

lancelets

Segmented worms that are often found in freshwater environments, acting as external parasites that feed on blood are _______

leeches

Bioluminescence is a phenomenon that causes an organism to produce:

light

Representative phyla of the ________ clade include Platyhelminthes, Rotifera, Bryozoa, Brachiopoda, Mollusca, and Annelida.

lochotrophozoa

A ___________ is a crown of ciliated tentacles that is one of the distinguishing characteristics of the Lophotrochozoa.

lophophore

Bilateral animals belong to three major clades: __________, Ecdysoza, and ___________.

lophotrochozoa, deuterstomia

The sievelike plate on the surface of an echinoderm that allows water to enter the water vascular system is known as the ______.

madreporite

Most sponges are found in ______ environments and have ______.

marine; no apparent symmetry

Rotifers have a unique structure called the ________, which consists of a muscular pharynx with jaws for grasping and chewing.

mastax

The development of the embryonic germ layer called ________ was a critical evolutionary innovation in animals, because it led to the development of muscles and more sophisticated organs.

mesoderm

Cnidarians possess a gelatinous substance called the ___________, which connects the endoderm and ectoderm.

mesoglea

In mollusks, organs called ________ extract nitrogenous and other wastes.

metanephridia

The phylogenetic grouping of nematodes and arthropods into Ecdysozoa suggests that ______ arose only once in evolution.

molting

The powerful capsules found in cnidocytes that have an inverted coiled and barbed thread are known as

nematocysts

The chordates are named after the ________, which is a single flexible rod composed of fibrous tissue encasing fluid-filled cells.

notochord

Chordates have four critical innovations that distinguish them from all other animal life. These are a(n) ________, __________ slits, a dorsal hollow cord _______, and a postanal ________

notochord pharyngeal nerve tail

In this body plan of a flatworm, the two blue arrows (at the top) are pointing to the:

ocelli

Mites and ticks may be best described as:

often parasitic; fused cephalothorax and abdomen

Lancelets and tunicates are:

our closest invertebrate relatives

Some annelid worms possess setae-bearing, fleshy, footlike structures called __________ that are pushed into the substrate to provide traction during movement.

parapodia

The cnidarian form that is characterized by a tubular body attached to the substrate at the aboral end with the tentacled oral end facing into the water column is the:

polyp

Most cnidarians exist as two different body forms: the ________ and the __________

polyp or sessile polyp; medusa or motile medusa

In cnidarians, the _________ stage is sessile whereas the __________ stage is motile.

polyp, medusa

In the diagram, A refers to the ________ body form in cnidarians and B refers to the __________ body form.

polyp; medusa

The chordate hallmark that is found posterior to the anal opening and is often used in locomotion in aquatic species is the:

postanal tail

Butterflies and moths have a coiled tongue, called the ___________, that can be uncoiled, enabling them to drink nectar from flowers.

proboscis

The coiled tongue of butterflies and moths is known as a(n):

proboscis

Cestodes possess a large number of repeating segments that serve as sex organs and are known as ___________. They produce thousands of eggs and are expelled from the body of the host through the feces.

proglottids

In the excretory system of flatworms, the two lateral canals capped by flame cells are termed __________

protonephridia

Blood flukes are the most common parasitic trematodes affecting humans; they are responsible for the disease ______.

schistosomiasis

Cestodes attach to their hosts by means of an organ at the head called the _______

scolex

Arthropods with pedipalps that are modified into large claws and an abdomen that tapers into a venom-injecting stinger are:

scorpions

The term __________ refers to the division of the body into compartments that are very similar to each other.

segmentation

Repetition of body parts, minimization of distortion during movement, and specialization of body regions are the three major advantages of __________ in annelids.

segmentation or metamerism

The phylum Annelida consists of the __________ worms.

segmented

Most annelids possess chitinous bristles, called ___________, on each segment.

setae or chaetae

Mollusks have a soft body, which may be covered by a tough external _____. Their basic body plan consists of three parts: a muscular ____ (used for movement), a(n) ________, Correct Unavailable mass (which contains the internal organs), and a(n) ______ (which produces the shell in mollusks that have one).

shell; foot; visceral; mantle

The foot of some cephalopods has become modified into a muscular ______, which allows movement that is similar to jet propulsion.

siphon

In sponges, some amoebocyte cells can form a tough skeletal fibers that support the body. This skeleton consists of sharp structures formed of protein, calcium carbonate, or silica, called ___________

spicules

In adult humans, the notochord becomes the _________ , and the dorsal hollow nerve cord becomes the __________ system.

spinal column; central nervous

The abdominal silk-producing glands of spiders are known as:

spinnerets

The silk-producing glands in the abdomen of spiders are known as _________

spinnerets

This diagram depicts the external anatomy of an arthropod (grasshopper). The structures labeled with the letter A are the ______.

spiracles

The central cavity of a sponge is known as the __________

spongocoel

The feeding mechanism of a sponge can be summarized as such: Water is drawn into the ______ by the beating action of ________. Small particulate matter and tiny plankton are trapped and eaten, while the water then flows out through the large opening at the top.

spongocoel; choanocytes

The development of mesoderm was an important step in animal evolution because it facilitated:

the development of complex organs

Most mollusk shells can be described as having

three layers with distinct seasonal growth lines

Most mollusk shells are complex _____-layered structures secreted by the __________ that continue to grow as the organism grows.

three; mantle

A group of cells that have a similar structure and function is known as a ________

tissue

The disease schistomiasis is caused by parasitic

trematode

Extinct bottom-feeding organisms with segmented bodies divided longitudinally into three lobes, that were approximately 3-10 cm in size, make up the arthropod subphylum __________

trilobita

Some members of the Lophotrochozoa clade undergo a larval stage called a _________ during their life cycle.

trochophore

What is the distinct larval form of some members of the clade Lophotrochozoa called?

trochophore

Urochordates are enclosed in nonliving structure made of a protein and cellulose-like material. This structure is called a(n):

tunic

Urochordates secrete a nonliving structure known as the ___________ that encloses the animal and is composed of a cellulose-like material and protein.

tunic

Which of the following accurately describes the number of body forms exhibited by most cnidarians?

two

To complete its development, a cestode needs

two separate vertebrate hosts.

The life cycle of tapeworms (class Cestoda) includes two separate ________ host species.

vertebrate

This figure shows the body plan of a mollusk. The roman numerals represent the following structures: I = ________ ____, II = __________, and III = _________.

visceral mass, mantle, foot