I.I. Keystone SpeciesKeystone Species

I.I. EchinodermataEchinodermata

A.A. Echinoidea (Sea urchins, Sand dollars)Echinoidea (Sea urchins, Sand dollars)• Approximately 1000 speciesApproximately 1000 species

• Includes heart urchins, sea biscuitsIncludes heart urchins, sea biscuits• Round, rigid test with movable spines and Round, rigid test with movable spines and

pedicellariaepedicellariae• Spines and tube feet used for locomotionSpines and tube feet used for locomotion

• Tube feet in shallow ambulacral grooves along Tube feet in shallow ambulacral grooves along outside of testoutside of test

• Complete digestive systemComplete digestive system• Mouth on bottom, anus on topMouth on bottom, anus on top

• HerbivoresHerbivores• Feed on seaweeds and seagrasses (especially Feed on seaweeds and seagrasses (especially

drifting) plus attached encrusting organismsdrifting) plus attached encrusting organisms• Mouth includes Mouth includes Aristotle’s lanternAristotle’s lantern

I.I. EchinodermataEchinodermata

B.B. Holothuroidea (Sea cucumbers)Holothuroidea (Sea cucumbers)• Lack spinesLack spines

• Five rows of tube feet run from mouth to anusFive rows of tube feet run from mouth to anus• Endoskeleton reduced to small calcareous spicules Endoskeleton reduced to small calcareous spicules

in skinin skin• Complete digestive systemComplete digestive system• Respiration through Respiration through respiratory treesrespiratory trees

• Deposit and suspension feedersDeposit and suspension feeders• Most tube feet used for locomotionMost tube feet used for locomotion• Tube feet around mouth modified as branched Tube feet around mouth modified as branched

tentacles that pick up food from substrate or filter tentacles that pick up food from substrate or filter particles from waterparticles from water

• ““Earthworms of the sea”Earthworms of the sea”• Deposit feeders have long, coiled intestines (Deposit feeders have long, coiled intestines (why?why?))

• Evisceration as defense mechanismEvisceration as defense mechanism• Can eject toxic filaments or viscera (internal organs) Can eject toxic filaments or viscera (internal organs)

through anus to deter predatorsthrough anus to deter predators

Enypniastes eximia

I.I. EchinodermataEchinodermata

C.C. Crinoidea (Feather stars, Sea lilies)Crinoidea (Feather stars, Sea lilies)• Suspension feedersSuspension feeders

• Mouth oriented upwardMouth oriented upward• Capture particles with tube feet/mucusCapture particles with tube feet/mucus• Ciliated ambulacral grooves transport food to Ciliated ambulacral grooves transport food to

mouthmouth• Cling to substrate with Cling to substrate with cirricirri

• Capable of swimming Capable of swimming Video ClipVideo Clip• Feather stars – UnstalkedFeather stars – Unstalked

• Cosmopolitan, but especially abundant in warm Cosmopolitan, but especially abundant in warm waterwater

• Capable of swimmingCapable of swimming• Sea lilies – StalkedSea lilies – Stalked

• Uncommon, restricted to deep waterUncommon, restricted to deep water

II.II. LophophoratesLophophorates

• Three phyla – all animals possess Three phyla – all animals possess lophophorelophophore• Ciliated hollow tentacles arranged in a horseshoeCiliated hollow tentacles arranged in a horseshoe

• Suspension feedersSuspension feeders• Bilateral symmetry, Bilateral symmetry, coelomcoelom (body cavity), U-shaped gut (body cavity), U-shaped gut

A.A. Bryozoa/Ectoprocta – BryozoansBryozoa/Ectoprocta – Bryozoans• Colonies consist of interconnected individual Colonies consist of interconnected individual zooidszooids

• Encrusting and lacy forms (CaCOEncrusting and lacy forms (CaCO33 tests) tests)• Retractable lophophoreRetractable lophophore

B.B. Phoronida – Phoronids, Horseshoe WormsPhoronida – Phoronids, Horseshoe Worms• Worm-shapedWorm-shaped• Agglutinated sediment tubes attached to hard substrate Agglutinated sediment tubes attached to hard substrate

in shallow waterin shallow waterC.C. Brachiopoda – Lamp ShellsBrachiopoda – Lamp Shells

• Abundant in fossil recordAbundant in fossil record• Superficially resemble clams, but shells are dorsal-Superficially resemble clams, but shells are dorsal-

ventral, not left-right as in mollusksventral, not left-right as in mollusks• Many attached to substrate with Many attached to substrate with pediclepedicle (short stalk) (short stalk)

Bryozoa

II.II. LophophoratesLophophorates

• Three phyla – all animals possess Three phyla – all animals possess lophophorelophophore• Ciliated hollow tentacles arranged in a horseshoeCiliated hollow tentacles arranged in a horseshoe

• Suspension feedersSuspension feeders• Bilateral symmetry, Bilateral symmetry, coelomcoelom (body cavity), U-shaped gut (body cavity), U-shaped gut

A.A. Bryozoa/Ectoprocta – BryozoansBryozoa/Ectoprocta – Bryozoans• Colonies consist of interconnected individual Colonies consist of interconnected individual zooidszooids

• Encrusting and lacy forms (CaCOEncrusting and lacy forms (CaCO33 tests) tests)• Retractable lophophoreRetractable lophophore

B.B. Phoronida – Phoronids, Horseshoe WormsPhoronida – Phoronids, Horseshoe Worms• Worm-shapedWorm-shaped• Agglutinated sediment tubes attached to hard substrate Agglutinated sediment tubes attached to hard substrate

in shallow waterin shallow waterC.C. Brachiopoda – Lamp ShellsBrachiopoda – Lamp Shells

• Abundant in fossil recordAbundant in fossil record• Superficially resemble clams, but shells are dorsal-Superficially resemble clams, but shells are dorsal-

ventral, not left-right as in mollusksventral, not left-right as in mollusks• Many attached to substrate with Many attached to substrate with pediclepedicle (short stalk) (short stalk)

II.II. LophophoratesLophophorates

• Three phyla – all animals possess Three phyla – all animals possess lophophorelophophore• Ciliated hollow tentacles arranged in a horseshoeCiliated hollow tentacles arranged in a horseshoe

• Suspension feedersSuspension feeders• Bilateral symmetry, Bilateral symmetry, coelomcoelom (body cavity), U-shaped gut (body cavity), U-shaped gut

A.A. Bryozoa/Ectoprocta – BryozoansBryozoa/Ectoprocta – Bryozoans• Colonies consist of interconnected individual Colonies consist of interconnected individual zooidszooids

• Encrusting and lacy forms (CaCOEncrusting and lacy forms (CaCO33 tests) tests)• Retractable lophophoreRetractable lophophore

B.B. Phoronida – Phoronids, Horseshoe WormsPhoronida – Phoronids, Horseshoe Worms• Worm-shapedWorm-shaped• Agglutinated sediment tubes attached to hard substrate Agglutinated sediment tubes attached to hard substrate

in shallow waterin shallow waterC.C. Brachiopoda – Lamp ShellsBrachiopoda – Lamp Shells

• Abundant in fossil recordAbundant in fossil record• Superficially resemble clams, but shells are dorsal-Superficially resemble clams, but shells are dorsal-

ventral, not left-right as in mollusksventral, not left-right as in mollusks• Many attached to substrate with Many attached to substrate with pediclepedicle (short stalk) (short stalk)

III.III. Chaetognatha (Arrow Worms)Chaetognatha (Arrow Worms)

• Important components of the Important components of the planktonplankton

• Voracious carnivoresVoracious carnivores

• Sit and wait predatorsSit and wait predators• Eat zooplankton (small crustaceans, Eat zooplankton (small crustaceans,

larvae, eggs)larvae, eggs)

Fig 7.41

IV.IV. Enteropneusta (Acorn Worms)Enteropneusta (Acorn Worms)

• HemichordatesHemichordates• Possible evolutionary transition Possible evolutionary transition

between invertebrates and chordatesbetween invertebrates and chordates• Share some but not all characteristics Share some but not all characteristics

with chordateswith chordates

• Deposit feedersDeposit feeders• Many construct U-shaped burrows and Many construct U-shaped burrows and

process large quantities of sedimentprocess large quantities of sediment• Proboscis secretes mucus used to collect Proboscis secretes mucus used to collect

organic materialorganic material

V.V. ChordataChordata

• CharacteristicsCharacteristics1)1) Dorsal hollow nerve cordDorsal hollow nerve cord

2)2) Pharyngeal gill slitsPharyngeal gill slits

3)3) NotochordNotochord

4)4) Postanal tailPostanal tail

• Three subphylaThree subphyla• Urochordata – TunicatesUrochordata – Tunicates• Cephalochordata – LanceletsCephalochordata – Lancelets• Vertebrata – VertebratesVertebrata – Vertebrates

V.V. ChordataChordata

A.A. Urochordata - TunicatesUrochordata - Tunicates1.1. Ascidiacea (Class) – Sea squirtsAscidiacea (Class) – Sea squirts

• Only sessile chordatesOnly sessile chordates• Solitary (single or clumped)Solitary (single or clumped)• ColonialColonial

• Body covered by Body covered by tunictunic (gelatinous outer covering) (gelatinous outer covering)• Active suspension feeders (filter feeders)Active suspension feeders (filter feeders)

• Water pumped in through Water pumped in through incurrent siphonincurrent siphon and out through and out through excurrent siphonexcurrent siphon

• Particles filtered out by Particles filtered out by feeding basketfeeding basket (pharynx)(pharynx)

• Planktonic Planktonic tadpole larvatadpole larva• Possesses all four chordate characteristicsPossesses all four chordate characteristics• Doesn’t feed – resorbs notochord and tail at Doesn’t feed – resorbs notochord and tail at

settlementsettlement

Fig 7.48