Echinodermata and Echinodermata and Invertebrate ChordatesInvertebrate Chordates

Chapter 40Chapter 40

Phylum EchinodermataPhylum EchinodermataCharacteristicsCharacteristics• Age of echinoderms is estimated as more than Age of echinoderms is estimated as more than

500 mil years500 mil years• All marineAll marine • Known as spiny-skinned animalsKnown as spiny-skinned animals • Endoskeleton known as the test is made of Endoskeleton known as the test is made of

calcium plates or ossicles with protruding calcium plates or ossicles with protruding spinesspines

• Includes sea stars, brittle stars, sand dollars, Includes sea stars, brittle stars, sand dollars, sea urchins, & sea cucumberssea urchins, & sea cucumbers

• Undergo metamorphosis from bilateral, free-Undergo metamorphosis from bilateral, free-swimming larva to sessile or sedentary adultswimming larva to sessile or sedentary adult

• Larval stage known as dipleurula or bipinnariaLarval stage known as dipleurula or bipinnaria • Adults have pentaradial ( 5 part) symmetryAdults have pentaradial ( 5 part) symmetry • Lack segmentation or metamerismLack segmentation or metamerism • CoelomateCoelomate • Breathe through skin gills as adultsBreathe through skin gills as adults • Capable of extensive regenerationCapable of extensive regeneration

Characteristics cont…Characteristics cont…• Ventral (lower) surface called the oral surface Ventral (lower) surface called the oral surface

& where mouth is located& where mouth is located • Dorsal (upper) surface known as aboral Dorsal (upper) surface known as aboral

surface & where anus is locatedsurface & where anus is located • Have a nervous system but no head or brain in Have a nervous system but no head or brain in

adultsadults • No circulatory, respiratory, or excretory No circulatory, respiratory, or excretory

systemssystems • Have a network of water-filled canals called Have a network of water-filled canals called

the water vascular system to help move & the water vascular system to help move & feedfeed

• Tube feet on the underside of arms help in Tube feet on the underside of arms help in moving & feedingmoving & feeding

• One-way digestive system consists of mouth One-way digestive system consists of mouth with oral spines, gut, & anuswith oral spines, gut, & anus

• Deuterostomes (blastopore becomes the anus)Deuterostomes (blastopore becomes the anus) • Separate sexesSeparate sexes • Reproduce sexually & asexuallyReproduce sexually & asexually

Phylum EchinodermataPhylum Echinodermata• Includes 5 classes:Includes 5 classes:

          * Crinoidea - sea lilies &           * Crinoidea - sea lilies & feather starsfeather stars          * Asteriodea - starfish          * Asteriodea - starfish          * Ophiuroidea - basket stars &           * Ophiuroidea - basket stars &

brittle starsbrittle stars          * Echinoidea - sea urchins &           * Echinoidea - sea urchins & sand dollarssand dollars          * Holothuroidea - sea           * Holothuroidea - sea

cucumberscucumbers

Class CrinoideaClass CrinoideaCharacteristicsCharacteristics• SessileSessile • Sea lilies & feather starsSea lilies & feather stars • Have a long stalk with branching arms Have a long stalk with branching arms

that attach them to rocks & the ocean that attach them to rocks & the ocean bottombottom

• Can detach & move aroundCan detach & move around • Mouth & anus on upper surfaceMouth & anus on upper surface • May have 5 to 200 arms with sticky tube May have 5 to 200 arms with sticky tube

feet to help capture food (filter feeders) & feet to help capture food (filter feeders) & take in oxygentake in oxygen

• Common in areas with strong currents & Common in areas with strong currents & usually nocturnal feedersusually nocturnal feeders

Class CrinoideaClass Crinoidea

                                                             

FEATHER STAR

                                                             

SEA LILY

Class AsteroideaClass AsteroideaCharacteristicsCharacteristics

• Usually sedentary along shorelinesUsually sedentary along shorelines

• Starfish or sea starsStarfish or sea stars

• Come in a variety of colorsCome in a variety of colors

• Prey on bivalve mollusks such as Prey on bivalve mollusks such as clams & oystersclams & oysters

• Have 5 arms that can be regeneratedHave 5 arms that can be regenerated

• Arms project from the central diskArms project from the central disk

• Mouth on oral surface (underside)Mouth on oral surface (underside)

Class AsteroideaClass Asteroidea

                                     

Starfish Feeding on Clam

Class OphiuroideaClass OphiuroideaCharacteristicsCharacteristics

• Largest class of echinodermsLargest class of echinoderms • Includes basket stars & brittle starsIncludes basket stars & brittle stars• Live on the ocean bottom beneath Live on the ocean bottom beneath

stones, in crevices, or in holesstones, in crevices, or in holes • Have long, narrow arms resembling a Have long, narrow arms resembling a

tangle of snakestangle of snakes • Arms readily break off & regenerateArms readily break off & regenerate • Move quicker than starfishMove quicker than starfish • Feed by raking in food with arms or Feed by raking in food with arms or

trapping it with its tube feettrapping it with its tube feet

Class OphiuroideaClass Ophiuroidea

                                              

                                                                                                  BASKET STARBASKET STAR

                                                                        

BRITTLE STAR

Class EchinoideaClass EchinoideaCharacteristicsCharacteristics

• Includes sea urchins & sand dollarsIncludes sea urchins & sand dollars • Internal organs enclosed by endoskeleton Internal organs enclosed by endoskeleton

or test made of fused skeletal platesor test made of fused skeletal plates • Body shaped like a sphere (sea urchin) or Body shaped like a sphere (sea urchin) or

a flattened disk (sand dollar)a flattened disk (sand dollar) • Lack armsLack arms • Bodies covered with movable spinesBodies covered with movable spines • Have a jawlike, crushing structure called Have a jawlike, crushing structure called

Aristotle's lantern to grind foodAristotle's lantern to grind food • Use tube feet to moveUse tube feet to move

Class EchinoideaClass EchinoideaCharacteristics cont…Characteristics cont…

• Sea Urchins:Sea Urchins:        * Spherical shape        * Spherical shape        * Live on ocean bottom        * Live on ocean bottom        * Scrape algae to feed        * Scrape algae to feed        * Long, barbed spines make         * Long, barbed spines make venom for venom for protection protection

• Sand Dollars:Sand Dollars:        * Flattened body        * Flattened body        * Live in sand along coastlines        * Live in sand along coastlines        * Shallow burrowers        * Shallow burrowers        * Have short spines        * Have short spines

Class EchinoideaClass Echinoidea

                                  

                                 SEA URCHIN

                                                              

SAND DOLLAR

Class HolothuroideaClass HolothuroideaCharacteristicsCharacteristics • Includes sea cucumberIncludes sea cucumber• Lack armsLack arms • Shaped like a pickle or cucumberShaped like a pickle or cucumber • Live on ocean bottoms hiding in caves during Live on ocean bottoms hiding in caves during

the day the day  • Have a soft body with a tough, leathery outer Have a soft body with a tough, leathery outer

skinskin • Five rows of tube feet run lengthwise on the Five rows of tube feet run lengthwise on the

aboral (top) surface of the bodyaboral (top) surface of the body • Have a fringe of tentacles (modified tube feet) Have a fringe of tentacles (modified tube feet)

surrounding the mouth to sweep in food & surrounding the mouth to sweep in food & waterwater

• Tentacles have sticky ends to collect planktonTentacles have sticky ends to collect plankton • Show bilateral symmetryShow bilateral symmetry • Can eject parts of their internal organs Can eject parts of their internal organs

(evisceration) to scare predators; regenerate (evisceration) to scare predators; regenerate these structures in daysthese structures in days

Class HolothuroideaClass Holothuroidea

                                                                   

SEA CUCUMBER

Structure & Function of Structure & Function of StarfishStarfishBody PlanBody Plan• Range in size from 1 centimeter to 1 Range in size from 1 centimeter to 1

metermeter • Mouth located on oral surface (underside)Mouth located on oral surface (underside) • Have an endoskeleton made of calcium Have an endoskeleton made of calcium

platesplates • Sharp, protective spines made of calcium Sharp, protective spines made of calcium

plates called ossicles found under the plates called ossicles found under the skin on the aboral (top) surfaceskin on the aboral (top) surface

• Have pedicellariae or tiny, forcep-like Have pedicellariae or tiny, forcep-like structures surrounding their spines to structures surrounding their spines to help clean the body surfacehelp clean the body surface

Structure & Function of Structure & Function of StarfishStarfishBody PlanBody Plan

                                      

ABORAL SURFACE

Structure & Function of Structure & Function of StarfishStarfish Water Vascular SystemWater Vascular System • Network of canals creating hydrostatic Network of canals creating hydrostatic

pressure to help the starfish movepressure to help the starfish move • Water enters through sieve plate or Water enters through sieve plate or

madreporite on aboral surface into a short, madreporite on aboral surface into a short, straight stone canalstraight stone canal

• Stone canal connects to a circular canal Stone canal connects to a circular canal around the mouth called the ring canalaround the mouth called the ring canal

• Five radial canals extend down each arm & Five radial canals extend down each arm & are connected to the ring canalare connected to the ring canal

• Radial canals carry water to hundreds of Radial canals carry water to hundreds of paired tube feetpaired tube feet

                                                 

WATER VASCULAR SYSTEM

Structure & Function of Structure & Function of StarfishStarfish Water Vascular SystemWater Vascular System• Bulb-like sacs or ampulla on the Bulb-like sacs or ampulla on the

upper end of each tube foot upper end of each tube foot contract & create suction to help contract & create suction to help move, attach, or open bivalvesmove, attach, or open bivalves

• Rows of tube feet on oral surface Rows of tube feet on oral surface (underside) are found in (underside) are found in ambulcaral grooves under each ambulcaral grooves under each armarm

Structure & Function of Structure & Function of StarfishStarfish Water Vascular SystemWater Vascular System

                                                                    

      TUBE FEET

                                   

Tube Feet in Ambulcaral Grooves

Feeding & DigestionFeeding & Digestion

• Tube feet attach to bivalve mollusk Tube feet attach to bivalve mollusk shells & create suction to pull valves shells & create suction to pull valves apart slightlyapart slightly

• Starfish everts (turns inside out) its Starfish everts (turns inside out) its stomach through its mouth & inserts it stomach through its mouth & inserts it into preyinto prey

• Stomach secretes enzymes to partially Stomach secretes enzymes to partially digest bivalve then stomach withdrawn digest bivalve then stomach withdrawn & digestion completed inside starfish& digestion completed inside starfish

Other Body SystemsOther Body Systems

• No circulatory, excretory, or respiratory No circulatory, excretory, or respiratory systemssystems

• Coelomic fluid bathes organs & distributes Coelomic fluid bathes organs & distributes food & oxygenfood & oxygen

• Gas exchange occurs through skin gills & Gas exchange occurs through skin gills & diffusion into the tube feetdiffusion into the tube feet

• No head or brainNo head or brain • Have a nerve ring surrounding the mouth Have a nerve ring surrounding the mouth

that branch into nerve cords down each armthat branch into nerve cords down each arm • Eyespots on the tips of each arm detect lightEyespots on the tips of each arm detect light • Tube feet respond to touchTube feet respond to touch

ReproductionReproduction

• Separate sexesSeparate sexes • Two gonads (ovaries or testes) in each Two gonads (ovaries or testes) in each

arm produce eggs or spermarm produce eggs or sperm • Have external fertilizationHave external fertilization • Females produce up to 200,000,000 eggs Females produce up to 200,000,000 eggs

per seasonper season • Fertilized eggs hatch into bipinnaria larva Fertilized eggs hatch into bipinnaria larva

which settles to the bottom after 2 years which settles to the bottom after 2 years & changes into adult& changes into adult

• Asexually reproduce by regenerating armsAsexually reproduce by regenerating arms

Characteristics of Characteristics of ChordatesChordates • All chordates have a notochord, dorsal nerve All chordates have a notochord, dorsal nerve

cord, pharyngeal pouches, & postanal tail at cord, pharyngeal pouches, & postanal tail at some time in their lifesome time in their life

• Notochord is a firm, flexible rod of tissue Notochord is a firm, flexible rod of tissue located on the dorsal side of the body that located on the dorsal side of the body that becomes part of the endoskeleton in becomes part of the endoskeleton in vertebratesvertebrates

• Dorsal nerve cord is a hollow tube lying dorsal Dorsal nerve cord is a hollow tube lying dorsal to the notochord that becomes the brain & to the notochord that becomes the brain & spinal cord in vertebratesspinal cord in vertebrates

• Pharyngeal pouches are small outpockets of the Pharyngeal pouches are small outpockets of the anterior part of the digestive tract that become anterior part of the digestive tract that become gills in aquatic chordates & jaws, inner ear, & gills in aquatic chordates & jaws, inner ear, & tonsils in terrestrial chordatestonsils in terrestrial chordates

• Postanal tail consists of muscle tissue & lies Postanal tail consists of muscle tissue & lies behind the posterior opening of the digestive behind the posterior opening of the digestive tracttract

Characteristics of Characteristics of ChordatesChordates

Subphyla of ChordatesSubphyla of Chordates

• The Phylum Chordata  includes all of the The Phylum Chordata  includes all of the vertebrates, as well as two groups of vertebrates, as well as two groups of marine animals that lack backbones and are marine animals that lack backbones and are called invertebrate chordatescalled invertebrate chordates

• The phylum is divided into three subphyla, The phylum is divided into three subphyla, determined by the development of the determined by the development of the notochordnotochord

• Subphylum Cephalochordata contains about Subphylum Cephalochordata contains about 24 species of blade-shaped animals known 24 species of blade-shaped animals known as lancelates that retain the notochord, as lancelates that retain the notochord, dorsal nerve chord, pharyngeal pouches, dorsal nerve chord, pharyngeal pouches, and postanal tail throughout their lifeand postanal tail throughout their life

Subphyla of Chordates Subphyla of Chordates cont…cont…• Subphylum Urochordata  contains 2,000 Subphylum Urochordata  contains 2,000

species commonly called tunicates species commonly called tunicates because their bodies are covered by a because their bodies are covered by a tough covering, or tunictough covering, or tunic     * Called sea squirts because they      * Called sea squirts because they shoot shoot out a stream of water when out a stream of water when touchedtouched     *Sessile, barrel-shaped, filter feeding      *Sessile, barrel-shaped, filter feeding

animals that live on the sea bottom animals that live on the sea bottom      *Adults have a pouch-like pharynx      *Adults have a pouch-like pharynx with with slitsslits     *Adults do not have a notochord,      *Adults do not have a notochord, dorsal dorsal nerve cord, or postanal tail nerve cord, or postanal tail

Subphyla of Chordates Subphyla of Chordates cont…cont…• Subphylum Vertebrata is the largest Subphylum Vertebrata is the largest

subphylum in which the notochord subphylum in which the notochord is replaced with vertebraeis replaced with vertebrae*  Skeletons consist of bone &/or *  Skeletons consist of bone &/or cartilagecartilage* Brain is protected by a cranium* Brain is protected by a cranium* Well developed 4 chambered heart * Well developed 4 chambered heart

with a closed circulatory systemwith a closed circulatory system* Includes fish, amphibians, reptiles, * Includes fish, amphibians, reptiles,

birds, & mammalsbirds, & mammals

Chordate CharacteristicsChordate CharacteristicsFeatureFeature VertebrataVertebrata Cephalo-Cephalo-

chordatachordataUro-Uro-chordatachordata

NotochorNotochordd

Dorsal Dorsal Nerve Nerve cordcordPharyngeaPharyngeal pouchl pouch

Postanal Postanal tailtail