exploring life exercise 11: echinoderms and chordatesbio.wayne.edu/bio1500/ex11wkbk.pdf · exercise...

EXPLORING LIFE

EXERCISE 11: ECHINODERMS AND

CHORDATES

11-1

Exercise 11: Echinoderms and Chordates Workbook Contents Corresponding Section on CD Vocabulary Key Concepts Introduction 1. Introduction Deuterostomes 2. Deuterostomes The Deuterostome Body Plan 2A. The Deuterostome Body Plan Evolution of Deuterostomes 2B. Evolution of Deuterostomes Phylum Echinodermata 3. The Phylum Echinodermata General Characteristics and Structure 3A. General Characteristics and Structure Class Crinoidea (sea lilies and feather stars) 3B. Class Crinoidea - Sea Lilies and Feather Stars Class Stelleroidea (starfish and brittle stars) 3C. Class Stelleroidea - Sea Stars Class Echinoidea (sea urchins and sand dollars) 3D. Class Echinoidea - Sea Urchins Class Holothuroidea (sea cucumbers) 3E. Class Holothuroidea - Sea Cucumbers Phylum Chordata 4. Phylum Chordata The Three Subphyla of the Phylum Chordata 4A. The Three Subphyla of the Phylum Chordata Characteristics of the Chordates 4B. Characteristics of the Chordates Subphylum Vertebrata 5. Subphylum Vertebrata Classes of Vertebrates 5A. Classes of Vertebrates Evolution of the Vertebrates 5B. Evolution of the Vertebrates Summary & Review Vocabulary Amniotic Egg - An egg that is protected from the environment by a more or less impervious shell during its

development, requiring only oxygen from outside Ampullae - The 'bulbs' of the water vascular system that lie above each of the podia (or tube feet) of the

echinoderms. Water is forced from them to extend the feet and drawn in to exert suction. Archenteron - The cavity formed during the gastrula stage of embryonic development. It is lined with

endoderm and develops into the digestive tract. Blastopore - The opening formed by invagination during the gastrula phase of embryonic development. It

becomes the mouth in Protostomes and the anus in Deuterostomes. Cardiac Stomach - The first portion (nearest the mouth) of the sea star stomach. It can be everted through the

mouth and into the shells of bivalves through tiny slits between the valves, partially digesting the tissues of the bivalve within its own shell, but external to the sea star.

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Commensal - Describing an interaction between species that is a kind of symbiosis. Individuals of one species live close to and benefit from the presence and activities of the other, while that species is unaffected by the interaction.

Determinate Development - The developmental pathway followed by Protostomes. In it, the fate of each cell in the early embryo is completely determined; it will become a specific tissue or organ in the adult.

Deuterostome - An animal in which the blastopore (or a region very near it) develops to become the anus, and the opening for the mouth develops elsewhere. The deuterostomes include the Echinoderm and Chordate phyla.

Dioecious - Having the male and female sex organs on separate individuals Gastrula - The stage of animal embryonic development in which the hollow ball of cells invaginates, creating an

opening (the blastopore) into an interior chamber (the archenteron). Cells from around the lip of the blastopore migrate inward, and the three tissue layers - the ectoderm, mesoderm, and endoderm - are differentiated.

Indeterminate Development - The developmental pathway followed by Deuterostomes. In it, the fates of cells in the early embryo are not rigidly determined, and they may become many different parts of the adult organism.

Madreporite - The opening from the water vascular system to the outside environment in the sea stars and brittle stars. It is located on the dorsal surface of the animal.

Metamorphosis - A process in which there is a dramatic change in form and structure during post-embryonic development. In echinoderms, this is the change from bilateral symmetry in larval stages to radial symmetry in the adult organism.

Notocord - The dorsal rod of cartilage that forms the basic axial skeleton of all chordates. It persists in primitive groups, but is replaced by the growth of a vertebral column around it in the subphylum Vertebrata.

Ossicle - One piece of the internal, calcareous skeleton of the echinoderms. They may be articulated, as in the sea star, or rigidly sutured, as in the sand dollars.

Pharyngeal Slits - Lateral openings from the pharynx (the muscular tube connecting the mouth to the esophagus) from which the respiratory apparatus evolved. They are one characteristic of the chordates.

Placenta - The tissue surrounding the developing embryo in the uterus of mammals, formed in part from the inner lining of the uterus and in part from tissues from the embryo. Through it, the embryo is nourished and waste products are removed.

Podia - The tube feet of the sea stars and brittle stars. They are connected to the water vascular system, and may be extended or exert suction depending on whether fluid is forced into them or withdrawn into the bulbs (ampullae).

Protostome - An animal in which the blastopore opening becomes the mouth of the adult organism. Cleavage in their embryos occurs in a spiral pattern, and development is determinate. Among the protostome phyla are annelids, mollusks and arthropods.

Pyloric Caecum - The digestive gland of sea stars. It extends into each of the arms, normally taking up a large proportion of the volume of the arm, appearing like a fern or a feather when spread out in a dissection.

Radial Cleavage - A pattern of early embryonic development in which the planes of cleavage between cells in mitosis lie either parallel or perpendicular to the axis of the embryo. This pattern is characteristic of deuterostomes, and the fates of cells are indeterminate during early development.

Sessile - Animals that are attached to a substrate (ground or a host) are termed sessile. These animals are not mobile and do not move about, at least for extended periods.

Spiral Cleavage - The pattern of embryonic development in which the cleavage planes between dividing cells are at oblique angles (diagonal) to the axis of the embryo. This pattern of development is characteristic of protostomes, and the fates of cells are determined very early in embryonic growth

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KEY CONCEPTS This section of the workbook is set up to help you note important information relating to the key concepts of this exercise and then organize and summarize the information in order to develop a synthesis and prepare for a review. As you complete this exercise, you will focus on the structural and life cycle characteristics of the animals, particularly the simple ones, so that you will be able to distinguish: How these animals are classified 1. What structural and life cycle characteristics distinguish the echinoderms and chordates from every other group of animals? 2. What structural and life cycle characteristics distinguish each group within a phylum from every other group within that phylum? The evolutionary trends demonstrated in these animals 3. What are the evolutionary trends in development in the structural and life cycle characteristics of the echinoderms and chordates? The first several pages are questions that can be answered by following the progression of slides and paying careful attention to the information, both visual and audio. These questions should be read in advance of each section so that you can be better prepared to answer them by knowing what you are looking for. The underlined subheadings correspond to the sections of the exercise as outlined in the main menu. The subsequent pages are designed to help you summarize and synthesize the pertinent information to answer the questions posed above.

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KEY CONCEPTS Introduction 1. What sets deuterostomes apart from protostomes? 2. The objectives of this exercise are:

a.

b.

c.

Deuterostomes

The Deuterostome Body Plan

Coelom 3. A true coelom is formed within the embryonic ectoderm / endoderm / mesoderm and its interior

surface is lined with a layer called the . 4. Label the structures on this annelid cross section:

5. Label each statement as belonging to (D) deuterostomes or (P) protostomes: anus develops from blastopore coelom forms as an enlargement and evagination of mesoderm coelom forms from cell around the blastopore enterocoelous development

mesoderm forms from gut wall mesoderm split forms the coelom mouth develops from blastopore mouth develops from deuterostome schizocoelous development

Cleavage of Cells 6. Cells formed by division of early cells during radial / spiral cleavage in deuterostomes appear

at angles / parallel to / perpendicular to the axis. In radial / spiral cleavage of protostomes,

new cells appear at angles / parallel to / perpendicular to the axis. Development 7. Label each statement as belonging to (D) deuterostomes or (P) protostomes:

all cells in embryo are totipotent determinate development eventual function of cells is not determined by cell type

functions of cells are determined early and cannot be substituted indeterminate development mosaic development regulative development

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THE ECHINODERMS AND CHORDATES Evolution of Deuterostomes 8. While body structures of these animals may converge / diverge in adults, early in development they

generally exhibit bilateral / radial symmetry and have a gut that .

Members of Echinodermata acquire a flattened structure with bilateral / radial symmetry as adults. 9. Label each statement as belonging to animals with a (L) lophophore, (E) other echinoderms, (H) hemichordates, (C) chordates and/or (V) vertebrates.

includes bryozoans, brachiopods, phoronids and pterobranchs

ridge around mouth from which ciliated tentacles protrude

sessile filter feeders

tentacled structure used to gather plankton

tentacled structure functions in gas exchange

tube-like digestive system of three parts: prosome, mesosome and metasome

anus located close to mouth but outside tentacles

can evert stomach through mouth

digestion of prey begins externally

has proboscis, collar and trunk

breathe by pumping water in through mouth and out through pharyngeal slits

pharyngeal slits used for gas exchange

gills and lungs replace pharyngeal slits

closed circulatory system

Phylum Echinodermata

General Characteristics and Structure 10. Echinoderms are the only group of deuterostome / protostome invertebrates / vertebrates. 11. Circle the term(s) or phrase(s) on each line that best describe the structure and lifestyle of this phylum.

Habit a. benthic or pelagic

Habitats b. marine or freshwater or terrestrial

External Anatomy c. “skin”: spiny or scales or smooth or feathers or fur

Internal Anatomy d. support: calcareous ossicles or cartilage or bone

Symmetry e. as juveniles: radial/”5-sided” or bilateral

f. as adults: radial/”5-sided” or bilateral

g. head: none or distinct

Locomotion h. water vascular system or muscular system

Feeding i. food transport: water vascular system or digestive/circulatory systems

j. digestive tract: well-developed or not well-developed

k. digestion begins: internally or externally

Internal Anatomy l. excretion: no specialized organs or specialized organs

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KEY CONCEPTS EC: Describe the developmental process in echinoderms (both types). Be sure to include the terms: axocoel, hydrocoel, somatocoel, metamorphosis. Use another sheet of paper if you need more room.

Class Crinoidea (sea lilies and feather stars)

12. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

External Anatomy a. oral surface: upper surface (dorsal) or lower surface (ventral) or neither

b. mouth and anus at same end or mouth and anus at opposite ends

c. appendages: “arms” or pinnules or fins or legs or wings

Reproduction d. sexual or asexual/regeneration

Internal Anatomy e. gas exchange: surface of body or bursae or gills or lungs

f. calcareous ossicles: articulated or sutured or reduced

Feeding g. food to mouth by: grooves (ambulacral)/podia or tentacles or cilia

h. water vascular system: with podia or without podia

i. suspension or predatory or parasitic or scavenging or scraping or deposit

j. food: plankton or algae/plants or animals or bacteria or detritus

k. food transport: water vascular system or digestive/circulatory systems

Sea Lilies only

Locomotion l. walking or free-swimming or burrowing or none (sessile as adults)

Jointed appendages in whorls called ; function:

Feather Stars only

Locomotion m. walking or free-swimming or burrowing or none (sessile as adults)

Jointed appendages in whorls called ; function:

Both

Reproduction n. dioecious (separate sexes) or hermaphroditic

o. structures: gonads or no gonads

p. fertilization: internal or external; if external: structures rupture or do not

q. eggs: brooded internally or laid externally

r. care of young: none or minimal or extensive

s. development: direct (young have adult morphology) or metamorphosis

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THE ECHINODERMS AND CHORDATES 13. What does the developmental process shared by sea lilies and feather stars suggest about their evolutionary

relationship?

Class Stelleroidea (starfish and brittle stars) 14. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

External Anatomy a. oral surface: upper surface (dorsal) or lower surface (ventral) or neither

b. food to mouth by: grooves (ambulacral)/podia or tentacles or cilia

Internal Anatomy c. calcareous ossicles: articulated or sutured or reduced

Subclass Asteroidea (starfish) only

Locomotion d. walking or free-swimming or burrowing or none (sessile as adults)

e. makes use of water vascular system or does not

f. water vascular system: with podia or without podia

Subclass Ophiuroidea (brittle stars) only

Locomotion g. walking or free-swimming or burrowing or none (sessile as adults)

h. makes use of water vascular system or does not

i. water vascular system: with podia or without podia

Both

External Anatomy j. madreporite: opens to outside or inside

EC: Label the structures on this diagrams of a starfish:

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KEY CONCEPTS Question #14 continued:

EC: Describe the process of locomotion in sea stars:

Reproduction k. dioecious (separate sexes) or hermaphroditic

l. structures: gonads or no gonads

Sea Stars only

Reproduction m. gonads: single (1) or 1 pair or 5 pair

n. fertilization: internal or external; if external: structures rupture or do not

o. gametes shed through: gonopores or bursae

p. eggs: brooded internally or laid externally

q. care of young: none or minimal or extensive

r. development: direct (young have adult morphology) or metamorphosis Brittle Stars only

Internal Anatomy s. gas exchange: surface of body or bursae or gills or lungs

Reproduction t. fertilization: internal or external; if external: structures rupture or do not

u. gametes shed through: gonopores or bursae

v. eggs: brooded internally or laid externally

w. care of young: none or minimal or extensive

Both

Feeding x. suspension or predatory or scavenging or scraping or deposit

y. food: plankton or algae/plants or animals or bacteria or detritus

z. digestion: primarily external or primarily internal

aa. food transport: water vascular system or digestive/circulatory systems

bb. nutrient absorption: digestive glands or stomach or intestines

cc. appendages: “arms” or pinnules or fins or legs or wings

EC: Describe the feeding and digestion of starfish:

Reproduction dd. sexual or asexual/regeneration

11-9

THE ECHINODERMS AND CHORDATES Class Echinoidea (sea urchins and sand dollars)


Internal Anatomy a. calcareous ossicles: articulated or sutured/fused or reduced

Reproduction b. dioecious (separate sexes) or hermaphroditic

c. fertilization: internal or external if external: structures rupture or do not


External Anatomy e. oral surface: upper surface (dorsal) or lower surface (ventral) or neither

Feeding f. food to mouth by: tentacles or calcareous plates or cilia

g. suspension or predatory or scavenging or scraping or deposit

h. food: plankton or algae/plants or animals or bacteria or detritus

i. digestion: primarily external or primarily internal

j. nutrient absorption: digestive glands or stomach or intestines Class Holothuroidea (sea cucumbers) 16. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle features of this class.

External Anatomy a. appendages: “arms” or pinnules or fins or legs or wings or none

b. mouth and anus at same end or mouth and anus at opposite ends

c. oral surface: upper surface (dorsal) or lower surface (ventral) or neither

Internal Anatomy d. calcareous ossicles: articulated or sutured or reduced

Feeding e. food to mouth by: grooves (ambulacral)/podia or tentacles or cilia

Locomotion f. walking or free-swimming or burrowing or none (sessile as adults)

g. water vascular system: with podia or without podia

Feeding h. suspension or predatory or scavenging or scraping or deposit

i. food transport: water vascular system or digestive/circulatory systems

j. oxygen-carrying molecules: hemoglobin or no special molecule

k. circulation: respiratory trees or no special structure

EC: Label the structures on this diagram of a sea cucumber:

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KEY CONCEPTS Question #16 continued

External Anatomy l. madreporite: opens to outside or inside

Internal Anatomy m. gas exchange: surface of body or bursae or gills or lungs

EC: Describe some of the defense mechanisms of the sea cucumbers:

Reproduction n. dioecious (separate sexes) or hermaphroditic

o. structures: gonads or no gonads

p. gonads: single (1) or 1 pair or 5 pair

q. fertilization: internal or external if external: structures rupture or do not

r. gametes shed through: gonopore or bursae

s. eggs: brooded internally or laid externally

EC: What are the processes that involve rupturing sea cucumber anatomy? Describe the processes and the affected anatomy:

Phylum Chordata

The Three Subphyla of the Phylum Chordata Subphylum Urochordata (tunicates or sea squirts)

17. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle of this subphylum.

Symmetry a. as juveniles: radial/”5-sided” or bilateral

b. as adults: radial/”5-sided” or bilateral

c. head: none or distinct

Habitats d. marine or freshwater or terrestrial

Habit e. benthic or pelagic


Feeding g. suspension or predatory or scavenging or scraping or deposit

h. food: plankton or algae/plants or animals or bacteria or detritus

i. food to mouth by: tentacles or calcareous plates or cilia

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THE ECHINODERMS AND CHORDATES Subphylum Cephalochordata (lancelets) 18. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle of this subphylum.

Feeding a. suspension or predatory or scavenging or scraping or deposit

Habitats b. marine or freshwater or terrestrial

Symmetry c. as adults: radial/”5-sided” or bilateral

d. head: none or distinct

Internal Anatomy e. nervous system (adult): dorsal nerve cord or brain

f. internal support/protection: notocord or vertebral column or skull

Locomotion g. walking or free-swimming or burrowing or none (sessile as adults)

Subphylum Vertebrata 19. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle of this subphylum.

Symmetry a. as juveniles: radial/”5-sided” or bilateral

b. as adults: radial/”5-sided” or bilateral

c. head: none or distinct

Internal Anatomy d. nervous system (adult): dorsal nerve cord or brain

e. internal support/protection: notocord or vertebral column or skull

Characteristics of the Chordates 20. What are the two defining characteristics of this phylum? and .

In which subphyla are these characteristics apparent only in juveniles?

In which are retained throughout life?

Subphylum Vertebrata

Classes of Vertebrates

Class Agnatha (lampreys and hagfishes)

21. Circle the term(s) or phrase(s) on each line that best describe the structure or lifestyle of this phylum.

Feeding a. jaws: movable or lacking

b. predatory or parasitic or scavenging or scraping or deposit

c. food: plankton or algae/plants or animals or bacteria or detritus

Habitats d. marine or freshwater or terrestrial

Habit e. benthic or pelagic


EC: Research the internal anatomy of this class. What type of support structure do they have?

11-12

KEY CONCEPTS Class Chondrichthyes (sharks, rays and skates)


Internal Anatomy a. support: calcareous ossicles or cartilage or bone

Feeding b. jaws: movable or lacking

External Anatomy c. appendages: “arms” or pinnules or fins or legs or wings


e. water vascular system or muscular system

Internal Anatomy f. gas exchange: surface of body or bursae or gills or lungs

Habitats g. marine or freshwater or terrestrial Class Osteichthyes (bony fishes)


Internal Anatomy a. support: calcareous ossicles or cartilage or bone

b. gas exchange: surface of body or bursae or gills or lungs

Habitats c. marine or freshwater or terrestrial


e. water vascular system or muscular system

Feeding f. jaws: movable or lacking

Class Amphibia (frogs, toads, salamanders and newts)


Habitats a. marine or freshwater or terrestrial

Reproduction b. eggs: brooded internally or laid externally; if external: require water or not

c. development: direct (young have adult morphology) or metamorphosis

External Anatomy d. “skin”: spiny or scales or smooth or feathers or fur


In what ways are amphibians dependent on a wet or moist environment?

EC: Research the reason why amphibians are considered indicators of environmental quality:

11-13

THE ECHINODERMS AND CHORDATES Class Reptilia (crocodilians, turtles, snakes and lizards)


Habitats a. marine or freshwater or terrestrial

Reproduction b. eggs: brooded internally or laid externally; if external: require water or not

c. development: direct (young have adult morphology) or metamorphosis

External Anatomy d. “skin”: spiny or scales or smooth or feathers or fur


What adaptations do reptiles have that amphibians lack for a terrestrial lifestyle?

Class Aves (birds)


External Anatomy a. “skin”: spiny or scales or smooth or feathers or fur

What functions to feathers provide?

Locomotion b. walking or free-swimming or burrowing or flying

c. appendages: “arms” or pinnules or fins or legs or wings

Internal Anatomy d. “bloodedness”: cold or warm

Reproduction e. fertilization: internal or external

f. eggs: brooded internally or laid externally

g. care of young: none or minimal or extensive Class Mammalia (mammals)


External Anatomy a. “skin”: spiny or scales or smooth or feathers or fur

Reproduction b. care of young: none or minimal or extensive

What do mammals nourish their young with?

11-14

KEY CONCEPTS Evolution of the Vertebrates 28. Fill in the vertebrate phylogenetic tree with the classes and the theoretical ancestor:

29. Number, then label the following as advances found in the class(es): (C) Chondrichthyes, (O) Osteichthyes, (A) Amphibia, (R) Reptilia, (Av) Aves, and/or (M) Mammalia

Skeletal System

first jaw, pectoral and pelvic appendages

cartilagenous skeleton

bony skeleton

limbs to side of body

limbs beneath body

Respiratory System

gills

primitive lungs

gas absorption also through skin

advanced lungs

Circulatory System

single ventricle; blood is mixed

partially divided ventricle

two separate ventricles

Reproductive System

external fertilization

eggs lack protection; must be in water

internal fertilization

amniotic egg

eggs develop internally; placental

11-15

SUMMARY & REVIEW 1. True or False: Echninoderms and chordates are protostomes.

True or False: Deuterostomes have a true coelom formed within the embryonic mesoderm.

True or False: A true coelom is lined with a layer called the pericardium.

2. Fill in the following chart with the appropriate word or phrase in each box provided:

3. What two characteristics unite the Echinodermata and the Chordata?

a. b. Fill out the charts on the next two pages. Then, using these charts, answer the following questions.

4. What characteristics are unique to each class within the Echinodermata?

a. Crinoidea:

b. Stellaroidea:

c. Echinoidea:

d. Holothuroidea: 5. What characteristics are unique to each phylum/subphylum?

a. Echinodermata:

b. Chordata:

a. Urochordata:

b. Cephalochordata:

c. Vertebrata:

6. What characteristics are unique to each class within the Vertebrata?

e. Agnatha:

f. Chondrichthyes:

g. Osteichthyes:

h. Amphibia:

i. Reptilia:

i. Aves:

j. Mammalia:

Protostome DeuterostomeStructure that develops from blastoporeCoelom formationCleavageregulative or mosaic developmentschizocoelus or enterocoelus developmentdeterminate or indeterminate development

11-16

THE ECHINODERMS AND CHORDATES Mark an "X" next to each characteristic that is found in all or some of the members of each of these groups.

Ech

inod

erm

ata

Crin

oide

a

Ste

llaro

idea

Ech

inoi

dea

Hol

othu

roid

ea

Cho

rdat

a

Uro

chor

data

Cep

halo

chor

data

Ver

tebr

ata

Ag

nath

a

Ch

ondr

icht

hyes

O

stei

chth

yes

Am

phib

ia

Re

ptili

a

Av

es

M

amm

alia

Habitats marine freshwater terrestrial - moist terrestrial - dry

Symmetry radial/5-sided juvenile bilateral juvenile radial/5-sided adult bilateral adult no distinct head distinct head

Internal Anatomy calcareous ossicles

ossicles articulated ossicles fused ossicles reduced

cartilage bone

no jaws jaws

no specialized excretory structures specialized excretory structures dorsal nerve cord brain notochord in adult vertebral column and skull in adult cold-blooded warm-blooded

Gas Exchange surface of body bursae gills lungs

Food Transport/Digestion water vascular system digestive system/tract

not well developed well developed

initial external digestion initial internal digestion nutrient absorption - digestive glands nutrient absorption - stomach nutrient absorption - intestines

11-17

SUMMARY & REVIEW

Ech

inod

erm

ata

Crin

oide

a

Ste

llaro

idea

Ech

inoi

dea

Hol

othu

roid

ea

Cho

rdat

a

Uro

chor

data

Cep

halo

chor

data

Ver

tebr

ata

Ag

nath

a

Ch

ondr

icht

hyes

O

stei

chth

yes

Am

phib

ia

Re

ptili

a

Av

es

M

amm

alia

External Anatomy spiny "skin" scales smooth feathers fur oral surface dorsal oral surface ventral oral surface neither madreporite opens to outside madreporite inside mouth and anus at same end mouth and anus at opposite ends

Locomotion water vascular

without podia with podia

muscular system Appendages

"arms" (not pectoral or pelvic) pinnules tentacles fins legs (pectoral and/or pelvic) wings other special appendages no appendages

Reproduction asexual/regeneration sexual dioecious hermaphroditic gonads no gonads external fertilization

gametes through gonopores gametes through bursae

internal fertilization eggs laid externally - in water eggs laid externally - not in water eggs brooded internally no care of young some care of young metamorphosis direct development

11-18

THE ECHINODERMS AND CHORDATES Evolutionary Trends 7. Without looking at your Key Concepts, fill in the following vertebrate phylogenetic tree.

8. Using the charts on the previous pages, list the characteristics of the deuterostomes in order from most primitive to most derived. The first one has been done for you as an example:

a. habitats: restricted; usually marine to somewhat restricted; need moisture to not restricted; found in many habitats

b. adult symmetry: to

c. head: to

d. internal support: to to

e. excretion: to

f. gas exchange: to to

g. initial digestion: to

h. mouth and anus placement: to

i. locomotion: to

j. reproduction: to

k. fertilization: to

l. eggs laid: to to

m. ventricles: to to 9. What characteristics were necessary for successful colonization of terrestrial habitats?

a.

b.

c.

d.

e.

11-19

SUMMARY & REVIEW 10. Write the letter of the group next to the appropriate common name and organism:

A. Stelleroidea bony fishes

B. Echinoidea “both life”

C. Holothuroidea cartilagenous fishes

D. Crinoidea feathered vertebrates

E. Urochordata furred vertebrates

F. Cephalochordata jawless fishes

G. Agnatha lancelet

H. Chondrichthyes scaled terrestrial vertebrates

I. Osteichthyes sea cucumber

J. Amphibia sea lily

K. Reptilia sea squirt

L. Aves sea urchin

M. Mammalia starfish

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