1. Invertebrates II: Mollusca, Arthropoda, Echinodermata

2. More species (200,000+) than any other animal phylum except Arthropoda More species (200,000+) than any other animal phylum except Arthropoda Soft body – often protected by CaCO 3 shell Unsegmented, typically bilaterally symmetrical I. Phylum Mollusca ©2004 Amanda Demopoulos

3. Fig. 7.19 BODY PLAN: Head (eyes/sensory), visceral mass (organs), muscular foot Mantle – covers visceral mass, secretes shell Radula – Ribbon of small chitin teeth used in feeding Gills (ctenidia-comb like) for gas exchange in mantle cavity

4. Radula – Ribbon of small chitin teeth used in feeding

5. I. Phylum Mollusca Exceptions to basic planExceptions to basic plan Bivalves lack radulasBivalves lack radulas Squids have internal shellsSquids have internal shells Octopuses have no shellsOctopuses have no shells Reproduction (for some gastropods and bivalves)Reproduction (for some gastropods and bivalves) 2 larval forms2 larval forms Trocophore – looks similar to annelid larvaTrocophore – looks similar to annelid larva Veliger – ciliated, wing-like, with shellVeliger – ciliated, wing-like, with shell Trocophore Veliger

6. A. Class Gastropoda (=stomach foot) Largest, most common, most diverse group (40K-75K sp)Largest, most common, most diverse group (40K-75K sp) Coiled mass of vital organs=visceral mass enclosed by a shellCoiled mass of vital organs=visceral mass enclosed by a shell SnailsSnails LimpetsLimpets AbalonesAbalones Nudibranchs – lose shell in larval stageNudibranchs – lose shell in larval stage Ventral creeping footVentral creeping foot DietDiet Many vegetarian (scrape algae off rocks with radula)Many vegetarian (scrape algae off rocks with radula) Some predatorySome predatory Prey on bivalves, worms, fishes, spongesPrey on bivalves, worms, fishes, sponges I.Phylum Mollusca 4 classes ©2004 Amanda Demopoulos

7. I. Phylum Mollusca A. Class Gastropoda –Torsion : –Torsion : during late veliger stage, twisting of visceral mass 180º, counter-clockwise, resulting in coiled shell –Operculum : leathery, trap door –*Drawing: radula slide, live lettuce slugs-order Sacoglossa, marine snails*

8. AbalonesSnails SnailsSnails

9. Nudibranchs

10. Laterally compressedLaterally compressed Hinged, 2-valved shell – (oysters, clams, mussels, scallops) muscles keep closed Hinged, 2-valved shell – (oysters, clams, mussels, scallops) muscles keep closed No head, no radula No head, no radula Sedentary lifestyle Sedentary lifestyle Some have muscular foot for burrowing (e.g., clams) Some have muscular foot for burrowing (e.g., clams) Gills used for suspension feeding (active) & respiration Gills used for suspension feeding (active) & respiration Water enters and leaves through siphons (incurrent and excurrent)Water enters and leaves through siphons (incurrent and excurrent) Some anchor to substrate with byssal threads (e.g., mussels) Some anchor to substrate with byssal threads (e.g., mussels) Scallops – Swim! (repeated clapping of valves) Scallops – Swim! (repeated clapping of valves)Swim *Drawing-Scallop shell, live flame scallop *Drawing-Scallop shell, live flame scallop I. Phylum Mollusca Anterior adductor muscle Posterior adductor muscle Valves Foot Mantle Giant clam B. Class Bivalvia (=2 valved)

11. 1.Octopuses (5 cm – 9 m)– no shell; Cryptic, bite prey with beak-like jaw 2.Squid (giant ~ 1000 kg, 18 m) – Shell reduced to pen made of chitin 3.Cuttlefish – Carbonate shell=cuttlebone, aid in buoyancy 4.Nautilus – Shell with chambers (septa) filled with gas, buoyancy organ Exclusively marineExclusively marine Fast moving, highly mobile predatorsFast moving, highly mobile predators Large eyes Large eyes Shell reduced or absent Shell reduced or absent Foot modified as arms and tentacles bearing suckers Foot modified as arms and tentacles bearing suckers Siphon – Directs water released from mantle cavity Siphon – Directs water released from mantle cavity Move by jet propulsion-move in any direction Move by jet propulsion-move in any direction Ink sac for defense-distractionInk sac for defense-distraction http://www.pbs.org/wnet/nature/octopus/http://www.pbs.org/wnet/nature/octopus/http://www.pbs.org/wnet/nature/octopus/ I. Phylum Mollusca C. Class Cephalopoda (=head footed)

12. I.Phylum Mollusca Class Cephalopoda - Octopus and squid have beak-like jaws - Mouth is central among tentacles Octopus 8 arms, non-retractable w/ 2 rows of suckers Nautilus 60-90 suckerless tentacles Squid 8 arms + 2 tentacles non-retractable w/suckers and hooks Cuttlefish 8 arms + 2 tentacles, retractable w/ suckers, no hooks **Drawing-squid and nautilus**

13. fin mantle funnel eye 2 –extensible tentacle stalks arm tentacle clubs

14. C. Class Polyplacophora (Many-plate- bearing=Chitons, 800 species) Mostly graze algae on rocky shorelinesMostly graze algae on rocky shorelines Exclusively marineExclusively marine 8 overlapping plates8 overlapping plates *drawing-chiton**drawing-chiton* D. Class Scaphopoda (=spade foot, Tusk shells) Predators on foraminifera and juvenile bivalvesPredators on foraminifera and juvenile bivalves Most common in deep water, buried in sedimentMost common in deep water, buried in sediment I. Phylum Mollusca © Charlotte M. Lloyd

15. Most species of any phylum (1 million+), 75% of all animals species describedMost species of any phylum (1 million+), 75% of all animals species described Insects, spiders, centipedes, crabs, lobsters, shrimp, barnacles, etc.Insects, spiders, centipedes, crabs, lobsters, shrimp, barnacles, etc. Segmented, bilaterally symmetrical body Segmented, bilaterally symmetrical body Jointed appendagesJointed appendages Exoskeleton made of chitinExoskeleton made of chitin Growth requires molting - defenselessGrowth requires molting - defenseless Body segments Body segments Head, thorax, abdomenHead, thorax, abdomen Some groups have head and thorax fused = cephalothorax Some groups have head and thorax fused = cephalothorax Discuss 3 subphyla and representative classes Discuss 3 subphyla and representative classes II. Phylum Arthropoda

16. Subphylum Trilobitomorpha Class Trilobita MarineMarine Extinct since 250 myaExtinct since 250 mya Rich fossil history because of exoskeletonRich fossil history because of exoskeleton Dorso-ventrally flattenedDorso-ventrally flattened *drawing-trilobite fossil**drawing-trilobite fossil*

17. A. Class Merostomata (=legs attached to mouth, Horseshoe crabs) Not true crabsNot true crabs Named for feeding appendages – chelicerae Named for feeding appendages – chelicerae Distinctive, horseshoe-shaped carapaceDistinctive, horseshoe-shaped carapace No antennaeNo antennae Benthic predators/scavengers on clams and small invertebratesBenthic predators/scavengers on clams and small invertebrates No jaws - Grind food with bristles on walking legs (must be walking to “chew”)No jaws - Grind food with bristles on walking legs (must be walking to “chew”) Much of what we know understand about vision based on horseshoe crab eyesMuch of what we know understand about vision based on horseshoe crab eyes Blood is used to test injectable pharmaceutical solutions for bacterial contaminationBlood is used to test injectable pharmaceutical solutions for bacterial contamination **drawing-horseshoe crab****drawing-horseshoe crab** Subphylum Chelicerata

18. B. Class Pycnogonida (= thick knees, Sea spiders) All marine All marine Superficially resemble spiders Superficially resemble spiders Mouth at end of large proboscis Mouth at end of large proboscis Carnivores Carnivores Feed on sea anemones, hydrozoans,Feed on sea anemones, hydrozoans, other soft invertsother soft inverts Legs much longer than body, more than 8 Legs much longer than body, more than 8 *Drawing-sea spider* *Drawing-sea spider* Subphylum Chelicerata PHOTO: Bill Rudman

19. Subphylum Crustacea (40K species) Contains majority of marine arthropod speciesContains majority of marine arthropod species Gills + two pairs of antennae (sensory)Gills + two pairs of antennae (sensory) Larval forms – nauplius and zoeaLarval forms – nauplius and zoea A. Class Copepoda (=oar foot, Copepods) Extremely abundant holoplankton (always plankton)Extremely abundant holoplankton (always plankton) Some live on/in substrates (benthos)Some live on/in substrates (benthos) **Among most abundant animals on earth** **Among most abundant animals on earth** Important primary consumers of phytoplanktonImportant primary consumers of phytoplankton Small << 1-2 mmSmall << 1-2 mm Some parasitic formsSome parasitic forms *drawing-copepod slide**drawing-copepod slide*

20. B. Class Cirripedia (= hairy foot, Barnacles) Active suspension feeders (filter feeders)Active suspension feeders (filter feeders) Use feathery cirri (modified swimming appendages) Use feathery cirri (modified swimming appendages) Sessile (attached to surfaces-whales, piers)Sessile (attached to surfaces-whales, piers) Fouling organisms (boats, whales)Fouling organisms (boats, whales) Resemble mollusks superficially – calcareous platesResemble mollusks superficially – calcareous plates *drawing-barnacle nauplii, cypris**drawing-barnacle nauplii, cypris* Subphylum Crustacea

21. C. Class Malacostraca (=soft shell, 75% crustacean species-Discuss 4 Orders) 1. Order Amphipoda (Amphipods) beach hoppers, sand fleas, whale lice Laterally compressed Laterally compressed Generally small (< 2 cm), but larger in deep ocean Generally small (< 2 cm), but larger in deep ocean Head and tail downward Head and tail downward Widespread distribution Widespread distribution Generally free living Generally free living Important scavengers Important scavengers *drawing-Gammarus slide, Daphnia slide* *drawing-Gammarus slide, Daphnia slide* Subphylum Crustacea ©2004 Amanda Demopoulos

22. C. Class Malacostraca 2. Order Isopoda (Isopods-rock lice, fish lice) Dorsoventrally compressedDorsoventrally compressed Generally small (< 2 cm), but larger in deep ocean Generally small (< 2 cm), but larger in deep ocean Related to terrestrial pill bugsRelated to terrestrial pill bugs Widespread distributionWidespread distribution Generally free living Generally free living Important scavengers Important scavengers Some parasites Some parasites Subphylum Crustacea

23. C. Class Malacostraca 3. Order Euphausiacea (Krill) - holoplankton Laterally compressedLaterally compressed Up to 10 cm long (usually smaller) Up to 10 cm long (usually smaller) Head and anterior segments fused to form distinct carapaceHead and anterior segments fused to form distinct carapace Widespread distributionWidespread distribution Important primary consumers and predators Important primary consumers and predators Important prey for larger consumers (whales, penguins, fish) Important prey for larger consumers (whales, penguins, fish) Keystone species in some ecosystems (Polar, Southern Ocean) Keystone species in some ecosystems (Polar, Southern Ocean) Aggregate in schools (billions of individuals)Aggregate in schools (billions of individuals) *Drawing: euphausid (krill) specimens**Drawing: euphausid (krill) specimens* Subphylum Crustacea

24. C. Class Malacostraca 4. Order Decapoda (=10 legs, Crabs, Lobsters, Shrimps) Most species in Crustacea (~10,000) Scavengers/Predators/Both Largest crustaceans Five pairs of walking legs (deca=10) First pair usually modified as claws for feeding/defense Well-developed carapace = cephalothorax Rest of body = abdomen, tail Laterally compressed, except crabs – abdomen under cephalothorax *drawing-crab zoea slide, lobster Subphylum Crustacea

25. Fig. 7.30

26. Phylum Arthropoda Subphylum-Uniramia Class Insecta=Hexapoda (6 footed) 1 million species described to date 1 million species described to date Found in every known terrestrial + freshwater habitat, some marine except deep sea Found in every known terrestrial + freshwater habitat, some marine except deep sea Diversity attributable to Diversity attributable to Feeding specializationFeeding specialization Dispersal capabilitiesDispersal capabilities Predator-avoidance possibilities (flight)Predator-avoidance possibilities (flight) *Drawing-insect leg types *Drawing-insect leg types a) walking legs b) swimming legs

27. 6000 species6000 species Sea lilies, feather stars, brittle stars, sea stars, sand dollars, sea urchins, sea biscuits, sea cucumbersSea lilies, feather stars, brittle stars, sea stars, sand dollars, sea urchins, sea biscuits, sea cucumbers Radial symmetryRadial symmetry Pentaradial symmetry in adultsPentaradial symmetry in adults Oral/aboral Oral/aboral Endoskeleton = hard plates, ~95% calcium carbonate, covered by skin Endoskeleton = hard plates, ~95% calcium carbonate, covered by skin Complete digestive, nervous systems, and reproductive organs Complete digestive, nervous systems, and reproductive organs Regeneration Regeneration Water vascular system = internal hydraulic system Water vascular system = internal hydraulic system Unique to echinodermsUnique to echinoderms Tube feet (podia) extended by pressure from ampullae (muscular sacs)Tube feet (podia) extended by pressure from ampullae (muscular sacs) Tube feet used for locomotion, feeding, sensory functionsTube feet used for locomotion, feeding, sensory functions Connected to exterior through madreporite (porous plate)Connected to exterior through madreporite (porous plate) III.Phylum Echinodermata – spiny skin

28. A. Subclass Asteroidea (=star like, Sea stars) Most species have five arms (some more),Most species have five arms (some more), Tube feet on oral surface in ambulacral groovesTube feet on oral surface in ambulacral grooves Endoskeleton composed of CaCO 3 platesEndoskeleton composed of CaCO 3 plates Flexible skeleton – permits movement Flexible skeleton – permits movement Aboral surface often covered with pedicellariaeAboral surface often covered with pedicellariae Small claws used for grooming surface Small claws used for grooming surface PredatorsPredators Feed on bivalves, snails, barnacles Feed on bivalves, snails, barnacles Pry shells of bivalve apart and insert stomach Pry shells of bivalve apart and insert stomach *drawing-sea star, starfish young slide**drawing-sea star, starfish young slide* III.Phylum Echinodermata Class Stelleroidea = a star

29. Crown of Thorns Acanthaster planci

30. B. Subclass Ophiuroidea (Brittle stars, Serpent stars) Arms long and very flexibleArms long and very flexible May resemble writhing snakesMay resemble writhing snakes Tube feet lack suckers (used for feeding)Tube feet lack suckers (used for feeding) Central disk distinctCentral disk distinct 1 Mouth, no anus1 Mouth, no anus Cryptic – Usually not in open areasCryptic – Usually not in open areas Scavengers/DetritivoresScavengers/Detritivores Particles collected by tube feet and passed to mouthParticles collected by tube feet and passed to mouth (*drawing brittle star*) (*drawing brittle star*) III.Phylum Echinodermata Class Stelleroidea

31. C. Class Echinoidea (=spine like, Sea urchins, sea biscuits, sand dollars), (Echinus = Gr. Hedgehog) Round, rigid test with movable spines and pedicellariaeRound, rigid test with movable spines and pedicellariae Spines and tube feet used for locomotion Spines and tube feet used for locomotion Tube feet in shallow ambulacral grooves (5 rows) along outside of testTube feet in shallow ambulacral grooves (5 rows) along outside of test Complete digestive systemComplete digestive system Mouth on bottom, anus on top Mouth on bottom, anus on top HerbivoresHerbivores Feed on seaweeds and seagrasses (especially drifting) plus attached encrusting organisms Feed on seaweeds and seagrasses (especially drifting) plus attached encrusting organisms Mouth includes Aristotle’s lantern (system of jaws and muscles used to bite off algae, other food from bottom)Mouth includes Aristotle’s lantern (system of jaws and muscles used to bite off algae, other food from bottom) *drawing-sea urchin, sand dollar**drawing-sea urchin, sand dollar* III. Phylum Echinodermata

32. D.Class 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 in skin – soft bodiedEndoskeleton reduced to small calcareous spicules in skin – soft bodied 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 tentacles that pick up food from substrate or filter particles from waterTube feet around mouth modified as branched tentacles that pick up food from substrate or filter particles from water Evisceration as defense mechanismEvisceration as defense mechanism Can eject internal organs through anus to deter predatorsCan eject internal organs through anus to deter predators

33. III. Phylum Echinodermata E.Class 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 mouthCiliated ambulacral grooves transport food to mouth Feather stars – UnstalkedFeather stars – Unstalked Cosmopolitan, but especially abundant in warm waterCosmopolitan, but especially abundant in warm water Capable of swimmingCapable of swimming Sea lilies – StalkedSea lilies – Stalked Uncommon, restricted to deep waterUncommon, restricted to deep water