Molluscs. Molluscs/Mollusks Over 200,000 species of molluscs More marine species than any other Phylum Most have soft bodies enclosed in calcium.

MolluscsMolluscs

Molluscs/MollusksMolluscs/Mollusks Over 200,000 species of molluscsOver 200,000 species of molluscs More marine species than any other More marine species than any other

PhylumPhylum Most have soft bodies enclosed in Most have soft bodies enclosed in calcium calcium

carbonate shellcarbonate shell..

StructureStructure Body covered by Body covered by mantlemantle, thin tissue that , thin tissue that

secretes the shellsecretes the shell Have ventral, muscular Have ventral, muscular footfoot, for , for

locomotionlocomotion Have head w/ eyes & sensory organsHave head w/ eyes & sensory organs RadulaRadula

unique to molluscsunique to molluscs ribbon of small teeth used to feedribbon of small teeth used to feed made of chitin (highly resistant carbohydrate)made of chitin (highly resistant carbohydrate)

Body FunctionsBody Functions Nervous SystemNervous System - well-defined with a primitive - well-defined with a primitive

brain; ganglia = “local brains” in different parts of brain; ganglia = “local brains” in different parts of bodybody

Circulatory systemCirculatory system – blood vessels & 2- – blood vessels & 2-chambered heartchambered heart

Digestive systemDigestive system - usually includes a jaw, - usually includes a jaw, salivary glands, pharynx, esophagus, stomach, salivary glands, pharynx, esophagus, stomach, intestine and anusintestine and anus

Reproductive systemReproductive system – separate sexes & – separate sexes & external fertilization  external fertilization 

Respiration systemRespiration system –gills –gills

Types of MolluscsTypes of Molluscs All molluscs have basic body plan but All molluscs have basic body plan but

greatly modified depending on class.greatly modified depending on class. 3 Main Classes:3 Main Classes:

CephalopodaCephalopoda (Cephalopods) (Cephalopods) GastropodaGastropoda (Gastropods) (Gastropods) BivalvesBivalves (Bivalvia) (Bivalvia)

CephalopodsCephalopods Name means “head-footed”Name means “head-footed” 650 species, all marine650 species, all marine Predators specialized for locomotionPredators specialized for locomotion Includes: octopus, squid, cuttlefish, & other Includes: octopus, squid, cuttlefish, & other

fascinating molluscsfascinating molluscs

Class Gastropoda Class Gastropoda

Largest and most varied class of molluskLargest and most varied class of mollusk 90,000 species90,000 species Gastropod (stomach foot)Gastropod (stomach foot) Foot on ventral side (stomach)Foot on ventral side (stomach) Examples: Snails, limpets, abalones, Examples: Snails, limpets, abalones,

nudibranchsnudibranchs

SnailsSnails

NudibranchsNudibranchs

Class BivalviaClass Bivalvia

Body compressed and enclosed in a Body compressed and enclosed in a two two valved shellvalved shell

Very small head, no radulaVery small head, no radula Gills expanded and folded and used to Gills expanded and folded and used to

filter out food particles as well as gas filter out food particles as well as gas exchangeexchange

Strong muscles are used to close the Strong muscles are used to close the valvesvalves

ClamsClams

Giant ClamGiant Clam

MusselsMussels OystersOysters

ScallopsScallops

ArthropodaArthropoda

ArthropodsArthropods

Arthropoda = Arthropoda = jointed footjointed foot Largest phylum Largest phylum Includes insects, spiders, centipedes, Includes insects, spiders, centipedes,

millipedes and crustaceansmillipedes and crustaceans Inhabit almost every environment on EarthInhabit almost every environment on Earth

Arthropod Characteristics Arthropod Characteristics

Segmented BodySegmented Body Bilateral symmetryBilateral symmetry Jointed appendagesJointed appendages: mouth parts and legs: mouth parts and legs Compound eyesCompound eyes ExoskeletonExoskeleton: hard, chitonous external : hard, chitonous external

skeletonskeleton Limits growthLimits growth Must Must moltmolt

ClassificationClassification

Biology of ArthropodsBiology of Arthropods

FeedingFeeding Can be parasitic, filter feeders, or detrivoresCan be parasitic, filter feeders, or detrivores

RespirationRespiration Do Not have LungsDo Not have Lungs Tracheal TubesTracheal Tubes – extend through body – extend through body Air transferred through Air transferred through SpiraclesSpiracles Marine arthropods have Marine arthropods have gillsgills or or book lungsbook lungs

CirculationCirculation Have Have gangliaganglia or many hearts run along body or many hearts run along body

Subphylum Crustacea Subphylum Crustacea

The majority of The majority of marine arthropodsmarine arthropods Includes: shrimps, lobsters, crabsIncludes: shrimps, lobsters, crabs 68,000 species68,000 species

GillsGills Skeleton hardened by calcium carbonateSkeleton hardened by calcium carbonate Appendages used to swim and/or crawlAppendages used to swim and/or crawl 2 pairs of antennae = sense2 pairs of antennae = sense ““Green” gland = salt regulationGreen” gland = salt regulation Ventral Ventral nerve chordnerve chord Complete digestive systemComplete digestive system

Subphylum Subphylum Chelicerata Chelicerata All have All have pinchers pinchers

Mouthpart called Mouthpart called chelicerateschelicerates Two body sections: Abdomen & CephalothoraxTwo body sections: Abdomen & Cephalothorax Nearly all have four pair of legsNearly all have four pair of legs Include:Include:

Spiders, Horseshoe Crabs, Scorpions, TicksSpiders, Horseshoe Crabs, Scorpions, Ticks

Insecta Insecta (Insects)(Insects)

Body divided into Body divided into 3 parts3 parts: : Head, Thorax, & AbdomenHead, Thorax, & Abdomen

Three pairs of Three pairs of legs attached to the thoraxlegs attached to the thorax Have compound eyesHave compound eyes Sense taste & smellSense taste & smell Growth involves Growth involves metamorphosismetamorphosis

Eggs Eggs Nymph Nymph Adult Adult Eggs Eggs Larva Larva Pupa Pupa Adult Adult

Form Form societiessocieties: closely related animals; same : closely related animals; same speciesspecies

Subphylum Uniramia Subphylum Uniramia

InsectsInsects Have jawsHave jaws 3 pairs of legs3 pairs of legs One pair antannaeOne pair antannae Examples: Examples:

Centipedes Centipedes : 1 pair of legs per segment: 1 pair of legs per segment MillipedesMillipedes : 2 pair of legs per segment : 2 pair of legs per segment

Echinodermata

Sea Stars, Brittle Stars, Sea Urchins, Sea Cucumbers, & Crinoids

Echinoderm Characteristics Echinodermata = spiny skin Endoskeleton

Secreted within the tissues Water vascular system

Madreporite = where water enters Tube Feet

Muscular extensions of canals End in Suckers Used for attachment, locomotion, & sensing stimuli

Pentamerous symmetry = 5 part Larvae = bilateral symmetry

Behavior

Carnivorous, detritus foragers, planktonic feeders

Reproduce by Spawning & Asexually Regeneration Protection = Spiny skins and spines Predators:

Mollusks Fish Crabs and shrimps Other echinoderms

Ecology and Range

Only marine Various habitats

Intertidal zone to bottom of the deep sea trenches

Sand to coral reefs Cold and tropical seas

Classes of Echinoderms