What Are Animals? Animals:

1. are multicellular– distinguishes them from bacteria and most

protists

2. have eukaryotic cells without cell walls– distinguishes them from bacteria, fungi, algae

and plants

3. cannot produce their own food, so they depend on other organisms for nutrients

4. can actively move (with the exception of adult sponges)

SpongesPhylum PoriferaBasic characteristics:

simpleasymmetricsessile—permanently attached to a solid

surfacehave many shapes, sizes and colors

Sponge Structure and FunctionBody is built around a system of water canals

ostia—tiny holes or pores through which water enters the sponge’s body

spongocoel—spacious cavity in the spongeosculum—large opening through which water

exits from the spongocoel

Sponge Structure and FunctionLacking tissues, sponges have specialized

cellscollar cells (choanocytes) use their flagella to

provide force for moving water through the sponge’s body

archaeocytes—cells that resemble amoebas, and can move through the body can assume any of the other cell forms, or transport

materials

Sponge Structure and FunctionStructural materials

spicules—skeletal elements that give support to a sponge’s body, which are produced by specialized cells and composed of calcium carbonate, silica or spongin

spongin—a protein that forms flexible fibers

Sponge Structure and FunctionSponge size and body form

size is limited by water circulationasconoid—simplest form; tubular and always

smallsyconoid—sponges that exhibit the first stages

of body-wall foldingleuconoid—sponges with the highest degree of

folding, which have many chambers lined with collar cells

Sponge Structure and FunctionNutrition and digestion

sponges are suspension feeders – they feed on material that is suspended in seawater

sponges are filter feeders – they filter their food from the water

sponges are one of the few animals that can capture particles 0.1 to 1.0 micrometers in size

Sponge Structure and FunctionReproduction in sponges

asexual reproduction budding—a group of cells on the outer surface of

the sponge develops and grows into a tiny new sponge, which drops off

fragmentation—production of a new sponge from pieces that are broken off

sexual reproduction eggs usually develop from archaeocytes and sperm

from modified collar cells larval stage is a planktonic amphiblastula

Ecological Roles of SpongesCompetition

compete for space to attach with corals and bryozoans

Predator-prey relationshipsfew species eat sponges

spicules are like needles some produce chemical deterrents

major food source for hawksbill sea turtle

Ecological Roles of SpongesSymbiotic relationships

sponges are mutualistic or commensalistic hosts to many organisms e.g. mutualistic bacteria

many organisms live within the canals or spongocoel, for protection, water flow

Sponges and nutrient cyclingboring sponges recycle calcium as they burrow

into coral and mollusc shells

Cnidarians: Animals with Stinging CellsPhylum CnidariaNamed for their cnidocytes—stinging cellsCnidocytes are used to capture prey and

protect the animal

Organization of the Cnidarian BodyRadial symmetry—many planes can be drawn

through the central axis that will divide the animal into equivalent halves

Often exhibit 2 body plans within their life cycles:polyp—a benthic form characterized by a

cylindrical body with an opening at 1 endmedusa—a free-floating stage (jellyfish)

Stinging CellsCnida—stinging organelle within a cnidocyte,

which may function in locomotion, prey capture, or defensenematocysts—spearing type, which are

discharged when the cnidocill—a bristle-like trigger—contacts another object

Dangerous speciesPortuguese man-of-war (painful stings)box jellyfish (can kill within 3-20 minutes)

Types of CnidariansHydrozoans (class Hydrozoa)

mostly colonialcolonial forms contain 2 types of polyp:

feeding polyp—functions in food capture reproductive polyp—specialized for reproduction

hydrocorals secrete a calcareous skeletonsome produce floating colonies

e.g. Portuguese man-of-war

Types of CnidariansScyphozoans

true jellyfish (class Scyphozoa) medusa is predominant life stage photoreceptors—sense organs that can determine

whether it is dark or light

Cubozoabox jellyfish (class Cubozoa)

tropical voracious predators, primarily of fish

Types of CnidariansAnthozoans (class Anthozoa)

sea anemones polyps with a vascular cavity divided into

compartments radiating from the central one though sessile, many can change locations

coral animals polyps that secrete a hard or soft skeleton form reefs along with types of algae

soft corals polyps that form plant-like colonies

Nutrition and Digestion of CnidariansGastrovascular cavity—central cavity where

cnidarians digest their preyfunctions in digestion and transport

Many hydrozoans and anthozoans are suspension feeders

Jellyfish and box jellyfish eat fish and larger invertebrates

Sea anemones generally feed on invertebrates

ReproductionHydrozoans

generally exhibit asexual polyp stage and sexual medusa stage in the life cycle

reproductive polyps form medusa-like buds which grow into adults after release

adults release gametes into the water, where they are fertilized and form larvae planula larva—planktonic larva that grows in the

water column, then settles

ReproductionScyphozoans

medusae (sexual stage) release gametes into the water for fertilization

planula larvae settle, grow into polyps, and reproduce medusa-like buds asexually

ReproductionAnthozoans

asexual reproduction pedal laceration—leaving parts of the pedal disk

(base) behind to grow into new animals fission—the anemone splits in two and each half

grows into a new individual budding produces large colonies of identical hard

coralssexual reproduction

larval stage is a planula larva

Ecological Relationships of CnidariansPredator-prey relationships

cnidarians are predatorsstinging cells discourage predation

Habitat formationcoral polyps form complex 3-dimensional

structures inhabited by thousands of other organisms

coral reefs provide a solid surface for attachment, and buffer waves and storms

Ecological Relationships of CnidariansSymbiotic relationships

Portuguese man-of-war and man-of-war fishreef-forming corals and zooxanthellaesea anemones...

and clownfish and the hermit crab

CtenophoresPhylum CtenophoraPlanktonic, nearly transparentCtenophore structure

named for 8 rows of comb plates (ctenes) which the animal uses for locomotion ctenes are composed of large cilia

exhibit radial symmetrybioluminescent

CtenophoresDigestion and nutrition

carnivorous, feeding on other planktonic animals

may used branched tentacles in a net pattern, adhesive cells, jellyfish stingers

Coral AnimalsStony (true) corals deposit massive

amounts of CaCO3 that compose most of the structure of coral reefs

Hermatypic—coral species that produce reefs, found in shallow, tropical waters

Ahermatypic—corals that do not build reefs, which can grow in deeper water from the tropics to polar seasmost do not harbor zooxanthellae

Coral AnimalsCoral colonies

large colonies of small coral polyps, each of which secretes a corallite

a planula larva settles and attachesa polyp develops, and reproduces by budding

to form a growing colonypolyps’ gastrovascular cavities remain

interconnecteda thin, usually colorful epidermis overlies the

colony surface

Coral AnimalsSexual reproduction in coral

mostly broadcast spawners—release both sperm and eggs into the surrounding seawater

spawning is usually synchronous among Pacific reef species, but nonsynchronous among Caribbean species

Coral AnimalsAsexual reproduction

Reproduction by fragmentation some branching corals are fragile and tend to break

during storms if they survive the storm, fragments can attach and

grow into new colonies fragmentation is a common form of asexual

reproduction for branching corals

Coral AnimalsCoral nutrition

symbiotic zooxanthellae supply 90% of nutritional needs of stony coral zooxanthella provide glucose, glycerol and amino

acids coral polyp provides a suitable habitat and

nutrients, absorbed directly through the animal’s tissues

zooxanthellae remove CO2 and produce O2

need of zooxanthellae for sunlight limits depths to which stony corals can grow

Coral AnimalsCoral nutrition (continued)

corals as predators small animals paralyzed by the nematocysts are

passed into the digestive cavity

World of Coral ReefsCoral reefs are highly productive, but occur

in nutrient-poor watersThis is made possible by the symbiotic

relationship between coral animals and zooxanthellae

These symbionts + algae form the basis of the community; other reef animals depend on these organisms

Coral Reef TypesFringing reefs border islands or continental

landmassesBarrier reefs are similar to fringing reefs but

separated from the landmass and fringing reef by lagoons or deepwater channels

Atolls, usually elliptical, arise out of deep water and have a centrally-located lagoon

Reef StructureReef front or forereef—portion of the reef

that rises from the lower depths of the ocean to a level just at or just below the surface of the water, on the seaward sidedrop-off—a steep reef-front that forms a

vertical wallspur-and-groove formation or buttress zone—

finger-like projections of the reef front that protrude seaward; disperses wave energy and helps prevent damage

Reef StructureReef crest—the highest point on the reef and

the part that receives the full impact of wave energywhere wave impact is very strong, it may

consist of an algal ridge of encrusting coralline algae, lacking other organisms, and penetrated by surge channels—grooves of the buttress zone

Reef flat or back reef—portion behind the reef crest

Coral Reef DistributionMajor factors influencing distribution:

temperature – corals do best at 23-25o Clight availability – photosynthetic zooxanthellae

need lightsediment accumulation – can reduce light and

clog feeding structuressalinitywave action – moderate wave action brings in

oxygenated seawater, removes sediment that could smother coral polyps

duration of air exposure – can be deadly

Reef ProductivitySource of nutrients

land runoff for reefs close to landsource for atolls unclearpossible explanations:

nutrients accumulated over time are efficiently recycled

reef bacteria and filter feeders capitalize on nutrients from dissolved/particulate organic matter

nutrients brought from other communities

Reef ProductivityReef photosynthesis

photosynthetic organisms: zooxanthellae, benthic algae, turf algae, sand algae, phytoplankton, seagrasses

Coral Reef CommunitySponges and cnidarians

sessile organisms, though anemones can move if necessary

filter feed; anemones also paralyze and consume small fishes and crustaceans

Annelidssessile filter feeders include featherduster and

Christmas tree wormsfireworms are mobile predatorspalolo worms burrow through and weaken

coral and usually deposit feed

Coral Reef CommunityCrustaceans

shrimps, crabs and lobstersvary from parasites to active hunters

Molluscsgastropods eat algae from coral surfacesgiant clams are filter feeders, but also host

symbiotic zooxanthellaeoctopus and squid are active predators

Coral Reef CommunityEchinoderms

feather stars, sea urchins, brittle stars, sea stars, and sea cucumbers

filter feed, scavenge, or eat sedimentReef fishes

most prominent and diverse inhabitantdiverse food sources, including detritus, algae,

sponges, coral, invertebrates, other fish

Species Interactions on Coral ReefsCompetition between corals and other reef

organisms for space to attachEffect of grazing

grazing of larger, fleshier seaweeds permits competitively inferior filamentous forms or coralline algae to persist

herbivory decreases with depth

Species Interactions on Coral ReefsEffect of predation

predation of sponges, soft corals and gorgonians provides space for competitively inferior reef corals

species that feed on fast-growing coral assist slower-growing species to remain

corallivores seldom destroy reefssmall invertebrates are almost all well hidden

or camouflaged, indicating the prevalence of predation in the reef

Coral Reef EcologyCoral provides:

foundation for reef food websshelter for resident organisms

Reefs form a complex 3-dimensional habitat for many beautiful and strange creatures

Threats to Coral ReefsEffect of physical changes on the health of

coral reefshurricanes and typhoons topple and remove

coral formationsEl Niño Southern Oscillation (ENSO)

changes winds, ocean currents, temperatures, rainfall and atmospheric pressure over large areas of tropical and subtropical areas

can cause massive storms

Threats to Coral ReefsCoral bleaching

a phenomenon by which corals expel their symbiotic zooxanthellae

most often associated with warming of the ocean water by ENSO or global warming

if the stress is not too severe, corals may regain zooxanthellae and recover

if the stress is prolonged, corals may fail to regain zooxanthellae and die

Threats to Coral ReefsCoral diseases

black band disease—a distinct dark band of bacteria migrates across the living coral tissue, leaving behind a bare white skeleton

white pox—characterized by white lesions and caused by Serratia marcescens

other coral diseases: white band disease white plague yellow blotch disease

Threats to Coral ReefsHuman impact on coral reefs

overfishing may occurhuman-sewage bacteria cause white poxnutrient-rich runoff (eutrophication) increases

algal growth, which covers and smothers corals e.g. Kane’ohe Bay in Hawaii

Evolutionary Adaptations of Reef DwellersProtective body covering

tough, defensive exteriors help animals avoid predation, but can limit mobility and growth

Protective behaviorsproducing a poisonous coating of mucusburying the body in sand to hideinflating to appear largerhiding at night when nocturnal predators are

active

Evolutionary Adaptations of Reef DwellersRole of color in reef organisms

color for concealment and protection countershading disruptive coloration camouflage (bright colors in reef environment)

Evolutionary Adaptations of Reef DwellersRole of color in reef organisms

other types of camouflage body shape

warning colorationother roles of color

defending territories mating rituals

Evolutionary Adaptations of Reef DwellersSymbiotic relationships on coral reefs

cleaning symbioses cleaner wrasses, gobies, etc. feed on parasites of

larger fishes cleaning organisms set up a cleaning station

Other symbiotic relationships clownfishes and anemones conchfish and the queen conch gobies and snapping shrimp crustaceans and anemones

MolluscsPhylum MolluscaHave soft bodies, usually covered by a

calcium carbonate shellOne of the largest and most successful

groups of animalsWide range of sizes, lifestyles and

relationships to humans (i.e., some are food, others cause commercial damage)

Ex: Snails, Clams, Squid, Octopus

Molluscan Body2 major parts (mostly for snails and

nudibranchs):head-foot—region containing the head with its

mouth and sensory organs and the foot, which is the animal’s organ of locomotion

visceral mass—body region containing the other organ systems, including the circulatory, digestive, respiratory, excretory and reproductive systems

Molluscan BodyMantle—protective tissue covering the soft

parts, which extends from the visceral mass and hangs down on each side of the body; it forms the shell

Radula—a ribbon of tissue containing teeth (found in all except bivalves) used for scraping, piercing, tearing or cutting pieces of food

Molluscan ShellSecreted by the mantleNormally comprises 3 layers:

periostracum—outermost layer, composed of the protein conchiolin that protects the shell from dissolution and boring animals

prismatic layer—middle layer, composed of calcium carbonate and protein, which makes up the bulk of the shell

nacreous layer—innermost layer, composed of calcium carbonate in thin sheets, with a different crystal structure

Molluscan ShellPeriostracum and prismatic layers form at

the mantle’s margin as the animal growsNacreous layer is secreted continuously

nacreous layer of oysters is known as mother of pearl, which can become layered over irritating particles (such as sand grains) to form pearls

Chitons (class of mollusca)Class PolyplacophoraHave flattened bodies most often covered by

8 shell platesAttach tightly to rocksMost scrape algae and other organisms off

the rocks with radulae for food

Scaphopods (class of mollusca)Tusk shells (class Scaphopoda)Tusk-like shell is open at both ends, with foot

protruding from larger endWater enters and exits at smaller endFeed primarily on foraminiferans, which are

captured with the foot or tentacles emerging from the head

Gastropods (class of mollusca)Class Gastropoda (snails and nudibranchs)May have no shell, or a univalve (one-piece)

shellas the animal grows, whorls of the shell

increase in size around a central axisoperculum—covering over the shell’s aperture

which allows it to be closed

GastropodsFeeding and nutrition

herbivores – most feed on fine algae; some on large algae like kelps

carnivores – usually locate prey using its chemical trail; have evolved various behaviors for capturing/subduing prey

scavengers and deposit feedersfilter feeders

GastropodsNaked gastropods

nudibranchs—marine gastropods that lack a shell

have cerata—projections from the body that increase the surface area available for gas exchange

some feed on cnidarians and then use their stinging cells as defensive weapons in the tips of cerata

bright colors indicate toxicity to predators

Bivalves (class of mollusca)Class BivalviaHave shells divided into 2 jointed halves

(valves)Includes:

clamsoystersmusselsscallopsshipworms

BivalvesBivalve anatomy

no head or radulalaterally compressed bodies shell halves attached dorsally at a hinge by

ligaments umbo—oldest part of the shell, around hinge adductor muscles—large muscles which close the 2

valvesmantle often forms inhalant and exhalant

openings to facilitate filter feeding palps form the food into a mass for digestion

Cephalopods (class of mollusca)Class Cephalopoda (nautilus, squid, cuttlefish, octopus)

Ring of tentacles projects from the anterior edge of the head, for use in prey capture, defense, reproduction and sometimes locomotion

Except for nautiloids, they lack shells or have small internal shells

CephalopodsTypes of cephalopods

nautiloids produce large, coiled shells composed of chambers

separated by septa (partitions) gas-filled chambers aid with buoyancy siphuncle—cord of tissue connecting the nautiloid to

uninhabited chambers (it inhabits the last chamber) which removes seawater from each chamber as it forms

60-90 tentacles coated with a sticky substance function in sensation or bringing food to the mouth

Cephalopodsnautiloids (continued)

move using jet propulsion usually dwell on the bottom during the day and

migrate to the surface at night nautiloids eat hermit crabs and scavenge for other

food on the bottom food is stored in a crop prior to transport to the

stomach for digestion

Cephalopodscoleoids (e.g. cuttlefish, squids, octopods)

cuttlefish have a bulky body, fins, 10 appendages (8 arms + 2 tentacles), and small internal shells

squids have: large cylindrical bodies with a pair of fins derived

from mantle tissue 10 appendages (8 arms + 2 tentacles) arranged in 5

pairs around the head and embellished with cup-shaped suckers surrounded by toothed structures and attached by a short stalk

a pen (a degenerate shell; an internal strip of hard protein) which helps support the mantle

Cephalopodscoleoids (continued)

octopods have 8 arms (no tentacles) with suckers without stalks or teeth, and sac-like bodies without fins

coleoids cloud the water with a dark fluid called sepia containing melanin (a brown-black pigment) when disturbed

swim by jet propulsion by forcing water through a ventrally-located siphon or by fin undulation (in squids)

have the most advanced, complex nervous system among invertebrates

CephalopodsColor and shape in cephalopods

arm/body movements and color changes are used in communication

chromatophores—special skin cells containing pigment granules which are concentrated or dispersed to change color

cephalopods can produce general body color changes or stripes and other patterns

CephalopodsFeeding and nutrition

carnivores – prey is located with highly developed eyes and captured by tentacles or arms

a pair of powerful, beak-like jaws in the oral cavity is used to bite or tear tissues; octopods use radula to drill holes in shells

diet depends on habitat squids are pelagic: fish, crustaceans, squid cuttlefish find invertebrates on the bottom octopods forage or lie in wait near the entrances to

their dens

CephalopodsReproduction in cephalopods

sexes are separatemating frequently involves some kind of

courtship displaymale squid have a modified arm used to

transfer a spermatophore (sperm package) from his mantle cavity to the female’s, near the opening of the oviduct (tube that carries eggs to the outside of the body)

Ecological Roles of MolluscsFood for humans and other animals

snail shells are a calcium source for some marine birds

sperm whales consume masses of squidSome snails are intermediate hosts to parasitesShipworms damage wooden pilings and boat

hulls, but also prevent wood from accumulating in the marine environment

A few bivalves have commensal relationships (attaching to other animals)

Arthropods: Animals with Jointed AppendagesPhylum Arthropoda = 75% of species

Ex: crabs, lobsters, shrimp, crawfishHave exoskeleton—a hard, protective exterior

skeleton composed of protein and chitin (a tough polysaccharide)molting—shedding and replacement of

exoskeleton to permit animal’s growthBody is divided into segmentsUsually, each segment has a pair of jointed

appendages, for locomotion, mouthparts, sensation, ornamentation

Arthropods: Animals with Jointed AppendagesHave highly developed nervous systems

sophisticated sense organscapacity for learning

2 major groups of marine arthropods:chelicerates – have a pair chelicerae (oral

appendages) and lack mouthparts for chewing food

mandibulates – have appendages called mandibles that can be used to chew food

Chelicerates (group of arthropods)6 pairs of appendages; 1 pair are chelicerae

for feedingHorseshoe crabs

3 body regions cephalothorax – largest region with the most

obvious appendages abdomen – contains the gills telson – a long spike used for steering and defense

body is covered by a carapace—a hard outer covering

CheliceratesHorseshoe crabs (continued)

locomotion by walking or swimming by flexing the abdomen

mostly nocturnal scavengerssmaller males attach to females to mate, and

eggs are laid in a depression on the beach; larvae return to the sea to grow

Mandibulates (group of arthropod)Crustaceans—marine mandibulates Crustacean anatomy

3 main body regions: head thorax abdomen

appendages: 2 pairs of sensory antennae mandibles and maxillae used for feeding walking legs, swimmerets (swimming legs), legs

modified for reproduction, chelipeds (legs modified for defense)

Mandibulatesgas exchange

small crustaceans exchange gases through their body surface

larger crustaceans have gills

MoltingCrucial part of the life cycleFrequency of molting decreases with ageControlled by specific hormones produced in a

gland in the head, and initiated by environmental conditions

Decapods (group of mandibulate)Order decapoda; includes animals with 5

pairs of walking legs:crabslobsterstrue shrimp

1st pair of walking legs are chelipeds—pincers used for capturing prey and for defense

Wide range in size

DecapodsSpecialized behaviors

hermit crabs inhabit empty shellsdecorator crabs camouflage carapaces with

bits of sponge, anemones, etc.common blue crabs are agile swimmers

DecapodsNutrition and digestion

chelipeds are used for prey captureappendages are used for scavengingpredation and scavenging are usually

combined some decapods are deposit or filter feeders

DecapodsReproduction

sexes usually separatemales have appendages modified for clasping

females and delivering sperm spermatophores—sperm packages copulatory pleopods—2 pairs of anterior abdominal

appendages that deliver spermmost brood their eggs in chambers or modified

appendages

Cirripedia (class of arthropods)Class Cirripedia – the only sessile

crustaceansMost have calcium carbonate shellAttach directly to a hard surface, or have a

stalk for attachmentFilter feed using cirripeds—feathery

appendages which extend into the water when the shell is open

BarnaclesReproduction

hermaphroditiccross-fertilized using a long, extensible penisbrooded eggs hatch into nauplius larvaenauplius larvae develop into cyprid larvae,

which have compound eyes and a carapace of 2 shell plates

cyprid larvae attach using adhesive glands in antennae, then metamorphose into adults

Ecological Roles of ArthropodsArthropods as food

important food sources for marine animals and humans

copepods form a link between phytoplankton they eat and many animals that use them as a major food source

krill are consumed in large quantities by whales and other organisms

Ecological Roles of ArthropodsArthropods as symbionts

cleaning shrimps remove ectoparasites and other materials from reef fish

Some are ecotoparasites and endoparasitesbarnacles are commensal with many hosts

Ecological Roles of ArthropodsRole of arthropods in recycling and fouling

grass shrimp feed on detrital cellulose material, and so helps break down algae and grasses in tidal marsh ecosystems

barnacles are a serious fouling problem on ship bottoms attached barnacles can reduce ship speed by 30% special paints and other anti-fouling measures

Echinoderms: Animals with Spiny SkinsPhylum Echinodermata (sea stars, sea

urchins, sea cucumbers, brittle stars)Larval forms exhibit bilateral symmetry but

most adults exhibit a modified form of radial symmetry

Mostly benthic, and found at nearly all depths

Sea cucumbers and brittle stars are commonly found in deep-sea samples

Echinoderm StructureEndoskeleton—internal skeleton that lies just

beneath the epidermisSpines and tubercles project outward from

the ossiclespedicellariae—tiny, pincer-like structures

around the bases of spines that keep the body surface clean in some echinoderms

Echinoderm StructureWater vascular system—unique hydraulic

system that functions in locomotion, feeding, gas exchange and excretionwater enters by the madreporitepasses through a system of canalsattached to some canals are tube feet—hollow

structures with a sac-like ampulla within the body and a a sucker protruding from the ambulacral groove

Asteroidea (class of echinoderm)Class AsteroideaTypically composed of a central disk + 5

arms or raysOn underside, ambulacral grooves with tube

feet radiate from the mouth along each rayAboral surface—the side opposite the mouth,

which is frequently rough or spiny

AsteroideaFeeding in sea stars

most are carnivores or scavengers of invertebrates and sometimes fish

prey are located by sensing of substances they release into the water

sea stars envelope and open bivalves, evert a portion of the stomach, and insert it into the bivalves to digest them digestive glands located in each ray provide

digestive enzymes

AsteroideaReproduction and regeneration

sea stars can regenerate rays; some can regenerate themselves from a single ray plus part of the central disc

asexual reproduction involves division of the central disk and regeneration of each half into a new individual

most have separate sexes, which shed eggs and sperm into the water for fertilization and hatching into usually planktonic larvae

Ophiuroidea (class of echinoderm)Class Ophiuroidea

e.g. brittle, basket and serpent starsBenthic with 5 slender, distinct arms,

frequently covered with many spinesLack pedicellariae and have closed abulacral

groovesTube feet lack suckers and are used in

locomotion and feedingBrittle stars shed arms if disturbed

OphiuroidsFeeding in ophiuroids

carnivores, scavengers, deposit feeders, suspension feeders, or filter feeders

brittle stars usually filter feed by lifting their arms and waving them in the water

deposit feeders use their podia to gather organic particles from the bottom into food balls and pass them to the mouth

basket stars suspension feed by climbing onto corals/rocks and fanning their arms toward the prevailing current

OphiuroidsReproduction and regeneration in ophiuroids

autotomize—to cast off, as of an arm, when disturbed or seized by a predator

asexual reproduction by division into 2 halves and regeneration of individuals

mostly separate sexesmay shed eggs into water or brood them in

ovaries or a body cavityplanktonic larvae metamorphose into adults

within the water column

Echinoidea (class of echinoderm)Class Echinoidea – sea urchins and sand

dollarsBody enclosed by test—a hard exoskeletonBenthic on solid surfaces (sea urchins) or in

sand (heart urchins, sand dollars)Regular (radial) echinoids—sea urchins;

spheroid body with long, moveable spinesIrregular (bilateral) echinoids—heart

urchins and sand dollars; have short spines on their tests

EchinoideaFeeding in echinoids

feeding in regular echinoids mostly grazers which scrape algae and other food

materials from surfaces Aristotle’s lantern—a chewing structure of 5 teeth

feeding in irregular urchins irregular urchins are selective deposit feeders some sand dollars are suspension feeders

Holothuroidea (class of echinoderm)Class Holothuroidea- Sea CucumbersHave elongated bodies, and usually lie on 1

sideRespiratory trees—a system of tubules

located in the body cavity which accomplish gas exchange

Sexes are generally separateEggs may be brooded or incubated; larvae

are planktonic

HolothuroideaFeeding in sea cucumbers

mainly deposit or suspension feedersoral tentacles—modified tube feet coated with

mucus which are used to trap small food particles

Defensive behaviorCuvierian tubules—sticky tubules released

from the anus of some specieseviscerate—to release some internal organs

through the anus or mouth

Crinoidea (class of echinoderm)Class Crinoidea – sea lilies and feather starsPrimitive, flower-like echinodermsMost are feather stars, which seldom move

and cling to the bottom with grasping cirriSuspension feedersCan regenerate lost armsSeparate sexes shed eggs/sperm into the

water; larvae have fee-swimming stage, then attach to the bottom and metamorphose into minute adults

Ecological Roles of EchinodermsSpiny skins deter most predatorsPredators of molluscs, other echinoderms,

cnidarians, crustaceanscrown-of-thorns sea star eats coralsea urchins destroy kelp forests

Black sea urchins control algae growth on coral reefs

Sea cucumber poison, holothurin, has potential as a medicine