ch 14

Select all of the characteristics of sea daisies.

two concentric ring canals Presence of a hydropore

Select all of the characteristics of members of class Holothuroidea.

An elongated, cylindrical body A leathery body wall

Brittle stars and basket stars are members of what echinoderm class?

Ophiuroidea

Scientists believe that the ancestral animals that gave rise to all extinct and extant groups of echinoderms were bilateral and tripartite. What is current consensus regarding the ancestral echinoderms?

They were sessile, radial animals, which then evolved into free-moving groups.

In a sea cucumber, the ______ serves as a hydrostatic skeleton.

coelom

Echinoderms have a unique kind of connective tissue called catch that can change quickly from a looser, more liquid form to a solid form. This gives echinoderms the ability to hold different positions without muscular effort.

collagen

In brittle stars, invaginations called bursae function in ______.

gas exchange

Members of the Hemichordata are characterized by the presence of slits and an evagination of the mouth cavity that resembles, but is not homologous to, the chordate .

gill ; notochord

In echinoderms, the calcareous sieve-like structure that leads to the water-vascular system is known as the .

madreporite

Irregular echinoids exhibit ______.

short spines

While they typically have five arms, brittle stars have a distinct morphology that is very different from that of sea stars (Asteroidea). Select all of the following that are characteristic of brittle stars.

- Tube feet without suckers - Lack of papulae and pedicellaria - Ambulacral grooves closed and covered by ossicles

The members of what taxon have a flattened body composed of a central disc connected to tapering rays and is covered by a ciliated, often brightly colored epidermis?

Asteroidea

Match each echinoderm class to its representative organisms.

Asteroidea- Sea stars Ophiuroidea- Brittle stars, basket stars Holothuroidea- Sea cucumbers Echinoidea- Sea urchins, sand dollars, heart urchins Crinoidea Feather stars, sea lilies

Select common characteristics of members belonging to the clade Ambulacraria.

Axial complex Tripartite coelom Similar larval forms

Sea stars, brittle stars, sea urchins, sea cucumbers, and sea lilies are all members of what phylum?

Echinodermata

Select all structures that are found within or bordering the ambulacral groove of sea stars.

Spines Radial nerve Tube feet

Select all of the feeding modes present in acorn worms.

Suspension feeders Deposit feeders

A typical echinoid test is made of ______.

Ten sets of plates, which have many moveable, stiff spines

Choose all characteristics of phylum Hemichordata.

They have gill slits. Most are sessile. Most are wormlike bottom dwellers.

In addition to gas exchange, the respiratory tree of a sea cucumber also functions in _______.

excretion

Choose all characteristics of the pterobranch Cephalodiscus.

1. U-shaped digestive tract 2. lives in a tube 3. stalked animals

Select all of the external features of the echinoderm class Asteroidea.

A. A flattened body with five or more tapered rays emanating from a central disc B. Open ambulacral grooves, each lined by tube feet C. Papulae for respiration

Based on the most current record, select all that are thought to be characteristics of ancestral echinoderms (which gave rise to all extant and extinct groups of echinoderms).

Bilateral Three pairs of coelomic spaces

In sea stars, the mouth leads to a stomach comprised of two parts; the stomach is the larger, lower part that can be everted to consume prey, and the stomach is the smaller, upper part that is connected to the digestive glands.

Cardiac; Pyloric

What is the ecological role of sea stars in ocean communities?

Carnivores

Excretion and respiration in sea stars are facilitated by their spacious body , which is filled with fluid.

Cavity

Echinoderms can be found living under what conditions?

Intertidal zones Great ocean depths

Match each echinoderm class to important characteristics that help to define it.

OphiuroideaChoice, Ambulacral grooves closed and covered by ossicles; tube feet without suckers and not used for locomotion Holothuroidea Cylindrical shape; ossicles reduced; spines absent Echinoidea No arms; compact skeleton with closely fitting plates; movable spines; closed ambulacral grooves Asteroidea Tube feet with suckers; many are star-shaped; open ambulacral grooves Crinoidea Spines absent; five arms branching at base and ciliated ambulacral grooves on oral surface

Match each structure of an adult echinoderm to its corresponding area in an anterior-posterior axis.

Oral surface -Anterior end Aboral surface -Posterior end Arm - Lateral growth zone

Select the answer that best describes sexual reproduction in sea stars?

Separate sexes; external fertilization

Select all of the following that describe members of class Echinoidea.

The body is enclosed within a test comprised of closely fitting ossicles. Some species are secondarily bilateral with short spines. They are found in a wide diversity of marine habitats, from intertidal areas to deep oceans.

Select the two structures that an acorn worm uses to exchange gases.

Vascular branchial epithelium Body surface

Fill in the blanks to complete the sentence. Echinoderms have a unique set of hydraulic canals, tube feet, and dermal ossicles that collectively form the - system.

Water Vascular

In sea stars, what system has primary functions in locomotion and food gathering, and additional functions in respiration and excretion?

Water-vascular system

Triploblastic metazoans that undergo embryonic development, characterized by radial regulative cleavage and enterocoely, are .

deuterostomes

The endoskeleton of sea stars and other echinoderms is comprised predominantly of ______.

ossicles

On the aboral surface, the pincerlike structures that occur around the bases of echinoderm spines and that function in keeping the body clean, protecting papulae, and capturing food are called ______.

pedicellariae

What structure in echinoids bears venom glands?

pedicellariae

The free-swimming larva of holothurians is called a(n) ______.

auricularia

Select all that are true of a bipinnaria.

1. cilia arranged in bands 2. free-swimming 3. eventually transforms into a brachiolaria

Select all of the structures that are absent in crinoids.

1. spines 2. pedicellariae 3. madreporite

Select all of the following that describe the nervous system of sea stars.

1. the nervous system consists of three subsystems 2. a nerve net connects the subunits 3. a single eyespot occurs at the tip of each arm. 4. Nerve rings and radial nerves are places at different levels. which of the following

Select all of the following that are true of the digestive system of sea stars.

1. the stomach is comprised of two parts 2. the stomach can be everted through the mouth to during feeding

Choose all features of Enteropneusta.

1. their body is divided into three regions 2. the are worm-like animals

In sea stars, what is the ambulacrum?

A band found on the oral side that runs from the mouth to the tip of each arm

Select all of the characteristics of crinoids.

A calyx covered by leathery skin A doliolaria larval stage Attachment to the substrate via a stalk for at least some portion of the life cycle

In this diagram of the echinoid test, match each letter to its correct structure.

A- Primary tubercule B- Spine C- Pedicellaria D- Pore for tube feet

Select all of the following that are true of the madreporite of sea stars.

A. It is found on the body's exterior .C. It leads to the water vascular system. E. It is circular in shape.

Because they share a number of characteristics including deuterostome development, a tripartite coelom, similar larval forms, and a highly specialized metanephridium, the phyla and are classified within the superphylum Ambulacraria.

Blank 1: Echinodermata or Echinoderm Blank 2: Hemichordata or Hemichordate

As it develops, a bipinnaria will grow three adhesive arms and a sucker at its anterior end. At this point, the sea star larva is called a , and it attaches to a substratum, where it undergoes metamorphosis.

Blank 1: brachiolaria

Brittle stars exchange gases in their , five pairs of sacs that open by slits near the base of the arms.

Blank 1: bursae

In an acorn worm, blood from the dorsal vessel enters the , which is located above the buccal diverticulum. From there, the blood enters a network of blood sinuses called the , which has an excretory function.

Blank 1: heart Blank 2: glomerulus

Consider the anterior-posterior axis of echinoderms. Studies of gene expression in developing echinoderms have shown that the aboral surface is the end of the animal, while the oral surface is its end.

Blank 1: posterior Blank 2: anterior

In members of class Echinoidea, species that are hemispherical in shape with radial symmetry and relatively long spines are called "", whereas those that have bilateral symmetry and short spines are called "irregular".

Blank 1: regular

In brittle stars, food is processed in the saclike , and indigestible material is removed through the .

Blank 1: stomach Blank 2: mouth

How do sea stars exchange gases with the outside and excrete their wastes?

Both gases and wastes can leave the body by diffusion through papulae and tube feet.

Select all of the echinoderms included in class Ophiuroidea.

Brittle stars and basket stars

Choose all structures that are found on a crinoid.

Cirri Stalk Arms Pinnules Calyx

Sea stars can use their tube feet for locomotion by applying pressure to the liquid in the tube feet using various sets of muscles. Which of the following statements accurately describe those processes? Select all that apply.

Contraction of longitudinal muscles in the tube foot retracts the podium. Contraction of muscles in the ampulla forces liquid into the podium of the tube foot, extending it. Contraction of muscles on one side of the tube foot causes the tube foot to bend toward that side.

Echinoderms that are attached to the substrate via a stalk for a substantial portion of their lives and have numerous branching arms are members of what class?

Crinoidea

Tiny pentaradial animals that have tube feet around their periphery but no arms are called sea .

Daisies

Members of what echinoderm class have a body that lacks arms, is often hemispherical or disc-shaped, and is enclosed within a hard test composed of closely fitted ossicles?

Echinoidea

Select all of the functions of the water-vascular system in sea stars.

Gathering food Excretion Respiration Locomotion

Select all of the internal structures present in acorn worms.

Glomerulus Dorsal blood vessel Heart

Select all of the internal structures present in acorn worms

Heart Glomerulus Dorsal blood vessel

An auricularia is the larval stage of which echinoderm class?

Holothuroidea

Echinoderms that have an elongated, cylindrical body with reduced ossicles and a leathery body wall are members of what class?

Holothuroidea

Select all of the following that are true of catch collagen.

It allows an animal to hold a particular position without the use of its muscles. It is able to quickly change from a more liquid to a more solid form. It binds together ossicles of the mesodermal endoskeleton.

Select all of the following that describe the water-vascular system.

It includes the tube feet. It opens to the outside through pores in the madreporite. It is only found in echinoderms. It often plays an important role in locomotion.

What accurately describes locomotion in brittle stars?

Locomotion is by arm movement.

Choose all features of the digestive system in brittle stars.

Mouth surrounded by movable plates that act as jaws Lack of anus Saclike stomach

The endoskeleton of sea stars is comprised of calcareous plates called , which are connected to one another by a specialized connective tissue made of an unusual mutable collagen called collagen.

Ossicles; Catch

What body region of acorn worms is muscular and collects food in mucous?

Proboscis

What part of an acorn worm functions to collect food in mucous strands on its surface?

Proboscis

The following is a list of ways in which sea stars can develop. What is the most common?

Production of free-swimming larvae

Select all of the components of the echinoderm nervous system.

Radial nerves Epidermal nerve plexus Nerve rings

Select all of the following that are developmental characteristics of deuterostomes.

Radial regulative cleavage Formation of the mouth from a second opening (not the blastopore) Coelom formation by enterocoely

Select all of the following that are members of phylum Echinodermata.

Sea cucumbers, Sea lilies, Sea urchins, Brittle stars

What echinoderms act as significant predators of molluscs?

Sea stars

Select all of the features that are present in brittle stars.

Slender arms madreporite tube feet

Sea stars can easily move up vertical surfaces. How do they generate the necessary suction force in their tube feet?

Small muscles lift the middle of the foot's disk-like end, which produces a suction force when the foot is applied to a hard surface.

From the following list, choose all that occur during the metamorphosis of a brachiolaria into a young sea star.

The left side of the larva becomes its oral surface. The right side of the larva becomes its aboral surface. The larval mouth and anus disappear, and a new mouth and anus form.

Choose all features of the pterobranchs.

Their anus is located near the mouth. They are colonial. Their tentacles are extensions of the mesosome.

Select all of the following that are true of reproduction in sea stars.

They are capable of both sexual and asexual reproduction. Most species have separate sexes. Gonads occur in pairs in each interradial space.

True or false: Echinoderms rarely inhabit brackish waters.

True

From the list below, choose the three distinct regions that make up the body of an acorn worm (Enteropneusta).

Trunk Collar Proboscis

The larval stage of echinoderms in Class Asteroidea is called a ______.

bipinnaria

What type of feeding is characteristic of Enteropneusta?

ciliary-mucus feeding

Functions of pedicellariae include ______.

cleaning the body protecting the papulae

While development is quite varied in different species, most sea stars produce free-swimming, bilateral .

larvae

The jointed arm of a brittle star is a column of articulated vertebrae or , which are connected by muscles and covered by plates.

ossicles.

In acorn worms, on each side of the trunk behind the collar, external openings called gill lead to densely ciliated gill , which in turn connect to gill slits in the sides of the pharynx.

pores chambers

The most common type of pedicellaria found in echinoids are ______.

three-jawed forms mounted on long stalks