BIO II Chapter 32-Animals Diversity and the Evolution of Body Plans

How are colonies formed in cnidarians? -A polyp produces medusae asexually, but instead of dispersing, they settle next to each other, forming a colony. -A polyp produces new polyps asexually and they all remain attached to one another, forming a colony. -Several planula larvae settle together and remain attached to each other, forming a colony.

-A polyp produces new polyps asexually and they all remain attached to one another, forming a colony.

Which of the following describes asexual reproduction in sponges? -A sponge can produce a free-swimming larva which settles on a surface and metamorphoses into an adult. -A sponge can break into fragments and each fragment can become an individual. -A sponge can produce a sessile larva, which remains attached to the parent and eventually metamorphoses into an adult.

-A sponge can break into fragments and each fragment can become an individual.

Match each sponge cell type to its description. -Choanocytes -Epithelial cells -Amoeboid cells -Egg and sperm cells =Flattened cells that surround the body of the sponge, sometimes contracting to close the ostia to protect the inner cells of the sponge =Flagellated, collar cells that circulate water and trap food particles =Cells found within the mesohyl of the sponge that often secrete spicules or spongin =Cells that are involved in sexual reproduction, joining and developing into a ciliated larva

-Choanocytes =Flagellated, collar cells that circulate water and trap food particles -Epithelial =Flattened cells that surround the body of the sponge, sometimes contracting to close the ostia to protect the inner cells of the sponge -Amoeboid cells=Cells found within the mesohyl of the sponge that often secrete spicules or spongin -Egg and sperm cells=Cells that are involved in sexual reproduction, joining the developing into a ciliated larva

Which of the following statements about extracellular digestion is NOT true? -It requires a gastrovascular cavity. -It allows ingestion of larger food particles than intracellular digestion. -It is employed by cnidarians. -It is the main method of digestion used by sponges.

-It is the main method of digestion used by sponges.

What are the functions of a hydrostatic skeleton in animals lacking a skeleton of shell or bone? -It provides a rigid structure against which muscles can operate. -It gives shape to the animal. -It contains joints which allows specific movements of different body parts. -It provides a rigid, hard case that protects the body.

-It provides a rigid structure against which muscles can operate. -It gives shape to the animal.

Which of the following are common animal characteristics? -Locomotion -Cell walls -Heterotrophic -Paraphyletic -Sexual reproduction -Multicellular

-Locomotion -Heterotrophic -Sexual reproduction -Multicellular

Which of the following accurately describes mesenteries in anthozoan polyps? -Symbiotic dinoflagellates that contribute to energy acquisition through photosynthesis -A certain type of solid tentacle that surrounds the mouth -Needles of calcium carbonate used in defense and structural support -Longitudinal sheets of tissue that compartmentalize the gastrovascular cavity

-Longitudinal sheets of tissue that compartmentalize the gastrovascular cavity

Protostomes can be divided into two clades. What is the two groups?

-Lophotrochozoa -Ecdysozoa

Consider a cnidarian, which forms both a polyp and a medusa stage. Which of the following statements about the life cycle of such a cnidarian are TRUE? -Polyps reproduce sexually -Medusae reproduce asexually -Medusae are free-swimming -Polyps are sessile

-Medusae are free-swimming -Polyps are sessile

Which of the following are characteristics of hard corals? -No gastrovascular cavity -Polyp form is dominant -Symbiotic photosynthetic zooxanthellae -An exoskeleton of calcium carbonate

-Polyp form is dominant -Symbiotic photosynthetic zooxanthellae -An exoskeleton of calcium carbonate

In what capacities do nematocysts function (choose all that apply)? -Reproduction -Prey capture -Excretion -Defense

-Prey capture -Defense

Which of the following types of symmetry is characteristic of animals that are organized such that any longitudinal plane that cuts through their central axis will result in two equal halves. -Asymmetry -Bilateral symmetry -Radial symmetry

-Radial symmetry

Which of the following are members of class Anthozoa? -Sea fans -Hydra -Portuguese man-of-war -Stony corals -Sea anemones -Sea pansies

-Sea fans -Stony corals -Sea anemones -Sea pansies

Which of the following refers to a type of body plan where an animal's body is divided into nearly identical units. -Segmented body plan -Radial body plan -Determinate body plan -Schizocoelous body plan -Indeterminate body plan

-Segmented body plan

Choose the statement that most accurately describes the presence of tissues in animals. -Specialized tissues are found in all animals except sponges. -Specialized tissues are found in all animals except vertebrates. -Specialized tissues are found in all heterotrophs. -Specialized tissues are found in all animals.

-Specialized tissues are found in all animals except sponges.

Which of the following differentiates sponges from colonial protists? -Sponges eat bacteria. -Sponges can reproduce sexually and asexually. -Sponges have a free-swimming stage. -Sponges are made of several functionally differentiated cell types.

-Sponges are made of several functionally differentiated cell types.

Which of the following statement best describes sponges? -Like colonial protists, sponges are made of cells that are functionally identical. -Sponges have several types of cells that perform different functions. -Like most animals, sponges are multicellular and have specialized tissues.

-Sponges have several types of cells that perform different functions.

Which of the following is true of Deuterostomes? -The blastopore develops from mesoderm. -The blastopore develops into the anus. -The blastopore develops into mouth, anus, and intestines. -The blastopore develops into the mouth.

-The blastopore develops into the anus.

Which of the following best describes how animals obtain the organic molecules necessary to sustain life? -They obtain organic molecules by feeding on other organisms or their products. -They are autotrophs and therefore perform photosynthesis. -They synthesize their own organic molecules from inorganic sources.

-They obtain organic molecules by feeding on other organisms or their products.

Which of the following is true of the two body forms found in cnidarians (polyp and medusa)? -They share only some parts of their morphology, namely, the tentacles. -They share the same basic morphology - mouth, gastrovascular cavity, and tentacles. -They do not share any parts of their morphology.

-They share the same basic morphology - mouth, gastrovascular cavity, and tentacles.

Which of the following is most true regarding molecular and traditional analysis of phylogenies? -Most deep evolutionary relationships have been misunderstood until now. -Molecular data are only useful to determine deep phylogenetic relationships. -Though there are differences between the two phylogenies, there is much agreement in the deep parts of the evolutionary tree. -Molecular data is making morphological data obsolete; morphological analyses are being replaced.

-Though there are differences between the two phylogenies, there is much agreement in the deep parts of the evolutionary tree.

Which of the following are carried out in the gastrovascular space of cnidarians? -Gamete production (in all species) -Waste discharge -Gravity sensing -Digestion -Gas exchange -Gamete production (in most species)

-Waste discharge -Digestion -Gas exchange -Gamete production (in most species)

Animals that lack a coelom do not form a monophyletic clade; therefore, -animal classification should be based on whether or not an animal has a coelom. -animal classification cannot be based on whether or not an animal has a coelom. -animals that have a coelom are closely related, but not much be said about animals that do not have a coelom.

-animal classification cannot be based on whether or not an animal has a coelom.

Most sponges are -radial -asymmetrical -pentaradial -bilateral

-asymmetrical

Order the major events in a generalized life cycle of a cnidarian as they occur starting with gamete formation at the top. -gamete formation by the medusa form -polyp formation -Aseuxual production of Medusae -Fertilization -development of the planula larva

-gamete formation by the medusa form -Fertilization -development of the planula larva -polyp formation -Aseuxual production of Medusae

Protostomes are animals in which the embryonic blastopore becomes the -mouth -mesoderm -ectoderm -anus

-mouth

All animals exhibit some form of body symmetry except -vertebrates -annelids -brachiopods -sponges -cnidarians

-sponges

What is a peritoneum?

A layer of mesoderm-derived epithelial cells that surrounds the coelom

Stony corals, sea anemones, sea fans, sea whips, sea pansies, and sea pens are all members of what class in phylum Cnidaria?

Anthozoa

Why can't we base animal classification on whether or not an animal has a coelom?

Because the acoelomate and pseudocoelomate conditions have evolved multiple times

The outer layer of the sponge is covered by flattened _____ cells that sometimes contract in response to potentially harmful stimuli to protect the inner cells of the sponge. One type of inner cells are _____ , flagellated and collared cells that help circulate water through the sponge and collect food particles. Various types of _____ cells are found in the mesohyl and may secrete structural components such as spicules or spongin fibers.

Blank 1: epithelial or epithelium Blank 2: choanocytes Blank 3: amoeboid

The flagellated cells that line the internal cavity of a sponge and help water flow through the ostia are known as ____.

Choanocytes

What organisms are included in the phylum Ctenophora?

Comb jellies

Comb jellies make up the phylum ________.

Ctenophora

The body of a sponge is bounded by flattened ____ cells.

Epithelial

What type of cells surround the body of a sponge?

Epithelial cells

True or false: As molecular data has become widely available most of what was previously known about the deep relationships of animal phyla to each other has been proven wrong.

False Recall: Many basal relationships on the evolutionary tree are corroborated both by morphological and molecular data.

What cnidarian class contains members that exhibit both the polyp and medusa stages of the life cycle, may be solitary or colonial, and may live in freshwater?

Hydrozoa or hydroids

What is the main body form found in class Cubozoa?

Medusa

Animals that undergo embryonic development where the embryonic blastopore develops to become the animal's mouth are ____.

Protosomes

Members of what cnidarian class have a relatively conspicuous and complex medusa stage, propel themselves through water using rhythmic contraction of muscles, and are very unlikely to kill a human through stinging by nematocysts?

Scyphozoa

crimson anemone is a member of a small group of highly muscular, soft-bodied anthozoans called ____.

Sea anemone

How many clades does the Bilateria comprise?

Two (2)

Sponges can reproduce _____ simply by breaking into fragments, each of which continues to grow as a new individual.

asexually

The largest class of _____ is Anthozoa.

cnidaria

A body cavity derived entirely from mesoderm is called a ____.

coelom

As their name implies, flatworms in the phylum Acoela lack ____.

coeloms

In many cnidarian species, the polyp produces other polyps asexually; if they remain attached to one another, they form a group that is referred to as a(n) ____.

colony

In ____ development, the type of tissue each embryonic cell will form in the adult is determined very early in embryonic development when developmental signals are located in different regions of the egg.

determinate

Animals that undergo embryonic development where the blastopore develops into the animals' anus are called

deuterostomes

Based on ample evidence, the echinoderms and chordates form a monophyletic clade called the ____.

deuterostomes or Deuterostomia

In those animals that have a body cavity, the cavity is filled with

fluid or liquid

The ____ cavity of cnidarians is the site of digestion, gas exchange, waste discharge, and, in many species, gamete formation.

gastrovascular

Deuterostomes exhibit ____ development.

indeterminate

The ____ is a gelatinous, protein-rich matrix found between the inner and outer cell layers in a sponge. Amoebocytes and eggs are found within this matrix.

mesohyl

All animals descend from a common ancestor and are therefore

monophyletic

Cnidarians use _____ in prey capture and defense.

nematocysts

The unique stinging intracellular structures that assist a typical cnidarian in defense and prey capture are known as ____.

nematocysts

The pores in the body of a sponge, through which water is drawn in, are known as _____.

ostia

Despite their simplicity, the appearance of noncoelomate invertebrates was very important - these organisms possessed the basic animal body ____, from which that of all other animals evolved.

plan, organization, design, or structure

In cnidarians, a zygote develops into a planktonic ciliated _____ larva that metamorphoses into a polyp.

planula

In cnidarians, the planktonic ciliated larva that metamorphoses into a polyp is known as a(n) ______. -cercaria -miracidium -planula -instar

planula

A body cavity called ____ the develops in an animal embryo between the mesoderm and endoderm.

pseudocoelom

The parts of an animal which exhibits ____ symmetry are arranged in such a way that a longitudinal plane cut at any angle through the central axis results in two halves that are identical.

radial

Soft-bodied, muscular anthozoans that can live in waters of all depths throughout the world and range from a few millimeters to over a meter in diameter are ______.

sea anemones

The only animals that lack any form of body symmetry are ____.

sponges, Parazoa, or Porifera

Most sponges do not have a definite ____ and do not posses tissues.

symmetry

Cnidarians have several distinct ____ types, but do not have organs or organ systems.

tissue

In order to get adequate movement of gases, nutrients, and other chemicals in the body, most larger animals must have which of the following? -A digestive tract -A coelom -A mesoderm -A pseudocoelom -A circulatory system

-A circulatory system

Animals lacking a true body cavity are called ____, animals with a true body cavity are called ____, while animals with a body cavity only partially lined with mesodermal tissue are called ____.

Blank 1: acoelomates Blank 2: coelomates Blank 3: pseudocoelomates

The five key innovations in animal evolution include tissues, a body____, various patterns of embryonic development, segmentation, and ____.

Blank 1: cavity Blank 2: symmetry

Coral reefs have great economic importance, because they serve as refuges for the young of many _____ and ____ that are eaten by humans; in addition they protect the coasts of many tropical islands.

Blank 1: crustaceans Blank 2: fishes or fish

Hard corals secrete an _____ of calcium carbonate around themselves. These animals can form coral reefs in shallow waters in the tropics, because they contain symbiotic photosynthetic ____.

Blank 1: exoskeleton Blank 2: dinoflagellates or zooxanthellae

In _____ digestion, food particles must be small enough to be engulfed and digested by cells whereas in _____ digestion, larger food items are first broken down with digestive enzymes before the particles are engulfed by cells.

Blank 1: intracellular Blank 2: extracellular

The body cavity of most animals is filled with ____. By contrast, the body cavity of vertebrates is filled with ____.

Blank 1: liquid or fluid Blank 2: gas

The ____ form of cnidarians is free-swimming and umbrella-shaped, with a mouth on the concave underside that is surrounded by ____.

Blank 1: medusa Blank 2: tentacles

The polyp form of cnidarians has a tubular body with a ____ hat is surrounded by ______.

Blank 1: mouth Blank 2: tentacles

A hydrostatic skeleton serves two main functions: it provides a rigid structure against which can _____ operate and it gives the animal _____.

Blank 1: muscles Blank 2: shape or form

Most cnidarians exist as two different body forms: the _____ and the ______.

Blank 1: polyp or sessile polyp Blank 2: medusa or motile medusa

In all animals except ____, cells differentiate into specialized ____ which are groups of cells that take on particular functions in the animal's body.

Blank 1: sponges, Porifera, or Parazoa Blank 2: tissues

One way in which climate change affects corals is that water that is ____ than usual can cause the symbiosis of corals with zooxanthellae to break down; this leads to coral ____.

Blank 1: warmer or hotter Blank 2: bleaching

Small animals can distribute gases and nutrients through the fluid in the body cavity, however, larger animals need a specialized ____ system to perform this task.

Circulatory

In contrast to Parazoa, the ____ includes all animals that have true tissues and body symmetry.

Eumetazoa or eumetazoans

True or false: The two different body forms of cnidarians are different in almost all aspects of their shape and function.

False Recall: These two seemingly different forms share the same fundamental morphology and function.

Members of what phylum are unique among animals because they lack true tissues or symmetry and have cells that can disassociate, reassemble, differentiate from one type to another, and dedifferentiate from a specialized to an unspecialized state?

Porifera

Which of the following best explains why animals are considered monophyletic? -They have similar body plans -They are multicellular -They are actively mobile -They have a common ancestor -They reproduce sexually

They have a common ancestor

Although nematocysts typically occur in the tentacles of cnidarians, they may also be found in the _____ cavity where they aid in digestion.

gastrovascular

In contrast to unicellular organisms like Protozoa, animals (metazoans) are all ____ organisms because they are made up of many cells.

multicellular

In certain cnidarian life cycles where both body forms exist, how are medusae produced? -From eggs and sperm, through fertilization -Asexually, from polyps -From larvae, through metamorphosis -Asexually, from other medusae

-Asexually, from polyps

What are the flagellated cells that line the internal cavity of a sponge and help water flow through the ostia called?

-Choanocytes

Members of what phylum are characterized by a diploblastic, radially symmetrical body plan and, while not having organs and organ systems, possess distinct tissues? -Cnidaria -Porifera -Rotifera -Bryozoa

-Cnidaria

Animals can be classified based on the development of a body cavity. Match each type of animal with the correct definition. -Coelomate -Acoelomate -Pseudocoelomate matches =Animal with a fluid-filled body cavity lined with tissue from the mesoderm =Animal with a body cavity not completely lined with tissue from the mesoderm =Animal that lacks a body cavity

-Coelomate =Animal with a fluid-filled body cavity lined with tissue from the mesoderm -Acoelomate =Animal that lacks a body cavity -Pseudocoelomate matches =Animal with a body cavity not completely lined with tissue from the mesoderm

Cnidarians known as box jellies are part of what class? -Cubozoa -Anthrozoa -Hydrozoa -Scyphozoa -Staurozoa

-Cubozoa

Which of the following phyla belong to the Deuterostomes? -Echinoderms -Brachopodia -Chordates -Bryozoa -Lophophorates

-Echinoderms -Chordates

What clade includes all animals that have true tissues and body symmetry? -Deuterostomia -Protostomia -Eumetazoa -Bilateria -Parazoa

-Eumetazoa

Select characteristics of the mesoglea of cnidarians. -Found between the epidermis and the gastrodermis -Can contain many cells -Can be acellular -Lines up the internal surfaces of a cnidarian -Found on the external side of the epidermis

-Found between the epidermis and the gastrodermis -Can contain many cells -Can be acellular

Select the terms that accurately describe an organism that obtains energy and organic molecules by ingesting other organisms. -Heterotroph -Omnivore -Detritivore -Carnivore -Autotroph

-Heterotroph -Omnivore -Detritivore -Carnivore

Which of the following are negative effects of climate change on corals? -Higher CO2 in the atmosphere leads to higher CO2 in the ocean water, which means leads to suffocation in many animals, including corals. -Higher CO2 in the atmosphere leads to lower pH in the ocean water which makes calcium-carbonate less available for corals. -Lower ozone levels in the atmosphere lead to increased UV radiation which is directly killing many coral species. -Coral bleaching (loss of zooxanthellae) can occur if water is warmer than usual.

-Higher CO2 in the atmosphere leads to lower pH in the ocean water which makes calcium-carbonate less available for corals. -Coral bleaching (loss of zooxanthellae) can occur if water is warmer than usual.

Where do the gametes of an anthozoan polyp form? -In the mesenteries -In the nematocytes -In their hollow tentacles -In the epithelial cells

-In the mesenteries

Which of the following correctly describes how a heterotrophic organism obtains energy and organic molecules? -Photosynthesis -Constructing organic molecules from inorganic substances -Ingesting other organisms

-Ingesting other organisms

Which of the following accurately describes the pseudocoelom? -It is a body cavity that develops embryologically between the endoderm and ectoderm. -It is a body cavity that develops embryologically between the mesoderm and ectoderm. -It is a body cavity that develops embryologically between the mesoderm and endoderm.

-It is a body cavity that develops embryologically between the mesoderm and endoderm.

Which of the following lies between the epidermis and the gastrodermis of cnidarians? -Digestive space -Gastrovascular cavity -Mesoglea -Nematocyst

-Mesoglea

Which term refers to the unique stinging intracellular structures of cnidarians? -Nematocysts -Proglottids -Choanocytes -Colloblasts -Spicules

-Nematocysts

What cnidarian form is characterized by a cylindrical body with a mouth surrounded by tentacles at the end of the cylinder opposite where it is attached to substrate or colonial tissue? -Medusa -Planula -Polyp

-Polyp

What cnidarian form is characterized by a cylindrical body with a mouth surrounded by tentacles at the end of the cylinder opposite where it is attached to substrate or colonial tissue? -Polyp -Medusa -Planula

-Polyp

Which of the following are characteristics unique to sponges when compared to other animals? -They lack true tissues. -Their cells are able to differentiate from one type to another. -When cells are disassociated, they can seek each other out and reassemble. -They lack true symmetry. -They are the only animals capable of asexual reproduction.

-They lack true tissues. -Their cells are able to differentiate from one type to another. -When cells are disassociated, they can seek each other out and reassemble. -They lack true symmetry.

Which of the following are true of members of class Hydrozoa? -Some members live in freshwater -They do not form colonies -Some are bioluminescent -They exhibit biradial symmetry -The medusa stage is usually not present in the life cycle

-Some members live in freshwater -Some are bioluminescent

Which of the following cannot build their own organic molecules from inorganic chemicals? -Sponges -Mosses -Sunflowers -Kelp

-Sponges

Which of the following are characteristics of members of class Anthozoa? -Tentacles are hollow -They do not form colonies -Medusa is the dominant form and no polyps are formed. -Compartmentalization of the gastrovascular cavity by mesenteries

-Tentacles are hollow -Compartmentalization of the gastrovascular cavity by mesenteries

Which of the following accurately describes animals with a segmented body plan? -The animal's body can be divided into two equal parts through a number of planes passing through the central axis. -The animal's heart and lungs are found in the upper segment of the body and the remaining organs in the lower segment. -The animal's body is split into only two parts; a head and a tail. -The animal's body is divided into nearly identical units.

-The animal's body is divided into nearly identical units.

Which of the following best explains determinate development? -The cells differentiate into tissues late in embryonic development. -If one cell is removed from the embryo, the cell that is removed can develop into a complete embryo. -If one cell is removed from the embryo, development of the remaining cells will continue to form a complete embryo. -The cells differentiate into tissues early in development.

-The cells differentiate into tissues early in development.

In cnidarians, what is a medusa? -A stinging cell that has a trigger and a nematocyst capsule with an inverted and barbed thread -A body form in which adjoined polyps create a colony that resembles a jellyfish (as in the Portuguese man-of-war) -The free-swimming form that is umbrella-shaped with a mouth on the concave underside, surrounded by tentacles -The tubular sessile form that has a mouth at the top that is surrounded by tentacles -A single polyp in coral

-The free-swimming form that is umbrella-shaped with a mouth on the concave underside, surrounded by tentacles

Which of the following are characteristics of members of class Scyphozoa? -The medusa is the major body form, with the polyp being greatly reduced or even absent in some species. -The gastrovascular cavity is compartmentalized by mesenteries. -They move by jetting water from the gastrovascular cavity or space beneath it, using the rhythmic contraction of muscles. -Most species possess deadly toxins that are capable of killing humans. -Their main form resembles a medusa, but is actually a polyp attached to the substrate by a short stalk.

-The medusa is the major body form, with the polyp being greatly reduced or even absent in some species. -They move by jetting water from the gastrovascular cavity or space beneath it, using the rhythmic contraction of muscles.

Choose all characteristics of acoel flatworms. -Their mouth leads to a solid digestive syncytium. -They do not have a nervous system. -They have bilateral symmetry. -They have a well developed stomach. -They do not have a coelom.

-Their mouth leads to a solid digestive syncytium. -They have bilateral symmetry. -They do not have a coelom.

In sponges, what is the function of the tiny pores in the body known as ostia? -Water loaded with wastes can exit the sponge through the ostia. -They allow water to enter the channels of the body. -The main function of ostia is to allow sperm cells to enter the body of a sponge -Sponges are filter-feeders and ostia act as their food-collecting filters.

-They allow water to enter the channels of the body.

Which of the following statements is true of all colonial protist cells with the exception of reproductive cells, but is not true of sponge cells? -They are morphologically different. -They are functionally similar. -They are functionally different.

-They are functionally similar.

Which of the following is true of all animals? -They are multicellular -They have similar body plans -They are unicellular -They have complex body plans

-They are multicellular

Which of the following statements about sponges is true? -They are colonial and have true tissues. -They are multicellular but do not have true tissues. -They are multicellular and have true tissues. -They are colonial but do not have true tissues.

-They are multicellular but do not have true tissues.

Which of the following is true of Cnidarians? -They have distinct tissues. -They have three cell layers. -They have organs.

-They have distinct tissues.

Which of the following are characteristics of cnidarians? -They have radial symmetry. -They are triploblastic. -They are diploblastic. -They have no true tissues or body symmetry. -They are made of distinct tissues.

-They have radial symmetry. -They are diploblastic. -They are made of distinct tissues.

Noncoelomate invertebrates, such as sponges and jellyfish, and noncoelomate worms, are evolutionarily important because of which of the following statements? -They were some of the first eukaryotic organisms on Earth. -They were the earliest organisms on Earth. -A third of animal phyla are based on a body plan similar to that of noncoelomate worms. -They possessed the basic animal body plan from which the body plan of all other animals evolved.

-They possessed the basic animal body plan from which the body plan of all other animals evolved.

Which of the following are reasons why corals are economically very important to humans? -Many island nations rely on coral reefs to build their houses. -They serve as refuge sites for the young of many crustaceans and fishes eaten by humans. -They protect the coastal regions of many tropical islands. -The coral reefs are a major source of calcium carbonate used in agriculture worldwide.

-They serve as refuge sites for the young of many crustaceans and fishes eaten by humans. -They protect the coastal regions of many tropical islands.

How many nematocytes are typically found in the tentacle of a cnidarian? -Thousands -One -A few hundred -Tens

-Thousands

Select the key innovations in animal evolution. -Tissues -Body cavity -Sexual reproduction -Symmetry -Segmentation -Alternation of generations -Various patterns of embryonic development

-Tissues -Body cavity -Symmetry -Segmentation -Various patterns of embryonic development

Which of the following accurately describes the number of body forms exhibited by most cnidarians? -Three -Two -Four -Five

-Two

When is indeterminate development observed (choose all that apply)? -When the cells formed during cleavage lose their totipotency very early. -When a cell formed during cleavage is removed from an embryo; all development ends. -When the cells formed during cleavage have not yet lost their totipotency. -When each cell formed during cleavage retains the ability to develop into a complete embryo.

-When the cells formed during cleavage have not yet lost their totipotency. -When each cell formed during cleavage retains the ability to develop into a complete embryo.

Common characteristics of animals include: -unicellular, autotrophs, cell walls, sexual reproduction -multicellularity, heterotrophic, sexual reproduction, missing cell walls -heterotrophs, unicellular, cells walls, extracellular matrix -autotrophs, asexual reproduction, lack of cell junctions, sessile

-multicellularity, heterotrophic, sexual reproduction, missing cell walls

What cnidarian class contains solitary or colonial polyps with hollow tentacles and mesenteries that compartmentalize the gastrovascular cavity?

Anthozoa

Within phylum Cnidaria, the class that includes the most species is _____.

Anthozoa

This group of animals is characterized by a transition to bilateral symmetry.

Bilateria

What is the name of the gelatinous, protein-rich matrix found between the inner and outer cell layers in a sponge (amoebocytes and eggs are found within this matrix)?

Mesohyl

The ____ are small openings (pores) which allow water to enter a sponge.

Ostia

The pores in the body of a sponge, through which water is drawn in, are known as which of the following?

Ostia

In cnidarians, asexual reproduction in polyps can produce what phases of the life cycle?

Polyps and medusae