Chapter 34: The Invertebrates

development

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

aquatic; two

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

Ctenophora or ctenophores

Comb jellies make up the phylum

ecdysis or molting

Ecdysozoans are named as such because they all undergo

often parasitic; fused cephalothorax and abdomen

Mites and ticks may be best described as:

Holothuroidea

Sea cucumbers are members of the echinoderm class:

Ctenphora

The earliest-diverging animal phylum is

anticoagulant

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

Blank 1: Cephalochordata or lancelets Blank 2: Urochordata or tunicates

The two most closely related subphyla to the vertebrates are the _____ and the ____

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

What are parapodia?

In the clade Ecdysozoa Grow by molting their cuticle

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

Possess a mesoglea Found in marine or freshwater habitats

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

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

Which of the following are characteristics of the phylum Ctenophora?

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

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

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

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

A lophophore or a distinct trochophore larval stage Protostome development

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

Bivalvia, Cephalopoda, and Gastropoda

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

They undergo ecdysis Many species are parasitic Also called round worms

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

three layers with distinct seasonal growth lines

three layers with distinct seasonal growth lines

Group of cells that have similar structure and function

A tissue is best defined as a

group of cells that have a similar structure and function.

A tissue is best defined as a

lack a fluid-filled body cavity

Acoelomate animals:

Segmentation An exoskeleton composed of chitin and protein Jointed legs

All members of the phylum Arthropoda have what characteristics?

closed

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

Lophotrochozoa and Ecdysozoa

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

Lophotrochozoa Deuterostomia

Bilateral animals belong to three major clades: _______, Ecdysoza, and _____

proglottids

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.

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

Characteristics of the millipedes (class Diplopoda) include:

Blank 1: notochord Blank 2: pharyngeal Blank 3: nerve Blank 4: tail

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 ______

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

Components of the annelid body plan include:

Cilia

Ctenophores use _____ to propel themselves in the water column.

Blank 1: gizzard Blank 2: castings

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 _____ Once excreted, this material, called _____, eriches the soil

cuticle

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

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

Features of the arthropod body plan include:

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

Features of the nematode body plan include:

Blank 1: Gastropoda or gastropods Blank 2: Cephalopoda Blank 3: Polyplacophora or Chitons Blank 4: Bivalvia or bivalves

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 ______.

acoelomate or acoelomates

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

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

How are coral reefs formed?

They allow rapid responses to stimuli.

How are giant axons useful to annelids?

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

How do annelid worms move?

They use the beating of their cilia.

How do ctenophores move?

A siphon to facilitate jet propulsion

How has the foot of some cephalopods been modified into?

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

In Platyhelminthes, reproduction may occur:

Spicules

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

Pharyngeal slits

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

a hollow tube that develops dorsal to the alimentary canal

In chordates, the nerve cord is:

cnidocytes or cnidocyte

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

cnidocil; nematocyst

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.

polyp medusa

In cnidarians, the _____ stage is sessile whereas the _____ stage is motile

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

In cnidarians, what is a medusa?

metanephridia

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

a solid tube that develops ventral to the alimentary canal

In nonchordate invertebrates, the nerve cord is:

Blank 1: Crustacea Blank 2: Hexapoda Blank 3: Chelicerata Blank 4: Myriapoda

Indicate the correct arthropod subphylum containing each of the organisms listed below. Shrimp: ______ Butterflies _____ scorpions ______ centipedes____

cephalothorax or prosoma

Many chelicerates and crustaceans have a ______which is a fused head and thorax

madreporite ring canal five radial canals tube feet

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

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

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

Annelida

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?

shell foot visceral mantle

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) _______ mass (which contains the internal organs), and a(n)______(which produces the shell in mollusks that have one).

hookworms

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:

annelids

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:

Blank 1: Cnidaria Blank 2: Chordata Blank 3: Echinodermata Blank 4: Mollusca

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

1. Chordata 2. Lophotrochozoa 3. Cnidaria 4. Porifera 5. Ctenophora

Rank the following taxonomic groups in order of evolutionary relatedness. Start with the group most closely related to echinoderms at the top. Position 1 of 5 Ctenophora incorrect toggle button unavailable Ctenophora

mastax

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

leeches

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

ticks mites

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

They lack true tissue. They have free-swimming larvae. They are multicellular.

Select all of the following that are characteristics of sponges

Calcium carbonate spicules Spongin fibers Silica spicules

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

Fangs Typically predatory or parasitic Have bodies consisting of two tagmata

Select the characteristics of the subphylum Chelicerata.

Have bodies consisting of two tagmata Typically predatory or parasitic Fangs

Select the characteristics of the subphylum Chelicerata.

millipedes, Diplopoda, millipede, or Diplopod

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

Multicellular but lack true tissues

Sponges are best described by what statement?

chitin protein

The arthropod exoskeleton is composed of layers of ______ and ______.

postanal tail

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

polyp

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:

spongocoel; choanocytes

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.

choanocytes

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

diffusion of gases through the body wall

The flattened body shape of flatworms facilitates:

siphon

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

cephalothorax

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

humans; snails; fish

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.

gelatinous layer that connects the endoderm and ectoderm

The mesoglea in cnidarians is a(n):

Extraction of wastes

The metanephridia of mollusks function in which of the following?

Cephalopods or Cephalopoda

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.

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

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

Elephantiasis

The person in the picture exhibits the disease:

two separate vertebrate hosts.

To complete its development, a cestode needs

Platyhelminthes

To which phylum do flatworms belong?

Myriapoda Hexapoda Chelicerata Trilobita Crustacea

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

Errantia Sedentaria

What are the two major groups in the phylum Annelida?

The organ used by cestodes to attach to a host

What is a scolex?

The process of molting or shedding a cuticle

What is ecdysis?

They exist everywhere

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

Exchange of gases

What is the function of gills?

Cephalopods

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

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.

What sentence best describes the feeding mechanism of a sponge?

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

What statement best describes symmetry in echinoderms?

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

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

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

Which of the following are characteristics of centipedes?

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

Which of the following are characteristics of ctenophores?

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

Which of the following are characteristics of echinoderms?

Found in marine or freshwater habitats Possess a mesoglea

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

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

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

Visceral mass Foot Mantle

Which of the following are the three main parts of a mollusk's body plan?

Enhanced locomotion Specialization Redundancy of organs

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

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

Which of the following are true of cephalochordates?

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

Which of the following are true of leeches?

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

Which of the following are true of the phylum Chordata?

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

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

The polyp is sessile and the medusa is motile

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

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

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

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

Which of the following statements are true regarding schistosomiasis?

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

Both have endoskeletons and undergo deuterostome development

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

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?

foot visceral mantle

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).

Radula

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

a muscular pharynx that contains jaws for grasping and chewing

a muscular pharynx that contains jaws for grasping and chewing

hemolymph hemocoel

n 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 _____