Chapter 35

Section 35.1

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Means “soft body” Most marine, some freshwater, a few

terrestrial

Body divided into 2 main section: head-foot & visceral mass:

Head-foot: head (mouth, sensory structures) and foot (locomotion)

Visceral mass: heart & digestive, excretion, and reproductive organsCovered by the mantle

Mantle: layer of epidermis that excretes a hard shell of calcium carbonate

Mantle cavity: space between mantle and visceral mass that protects the gills

Ganglia: clustered nerve cells that control locomotion & feeding

Radula: flexible, tongue-like strip of tissue covered with abrasive teeth

1. Class Gastropoda2. Class Cephalopoda 3. Class Bivalvia

Examples: clams, oysters, mussels, scallops

All have a two part shell connected by hinge closed by adductor muscles

aged by shell rings sedintary filter feeders

Video

2 siphons at the posterior end: Incurrent siphon = intake of water & foodExcurrent siphon = output of water &

wastes

Clams dig in the soil so only their siphons stick outFilters about 3 quarts an hour!

Video

Video

Calcium carbonate secretion around a foreign objectProtection of the soft visceral massMade by the mantle (just like the shell)

----------- protective outer layer ///////////// prismatic layer

----------- pearly layer

(Snails, nudibranchs, cowries, whelks)

Largest and most diverse group of mollusks Examples: snails, abalones, conchs, slugs Locomotion: wavelike muscular

contractions on mucus slime trail Can withdraw head into mantle cavity when

threatened

Video

Hemolymph: circulatory fluid

Hemocoel: fluid filled spacesA.k.a. blood cavity

tentacles- sense touch & have eyes on ends

respire with gills (aquatic) or exposed blood vessels (terrestrial) by diffusion

we eat muscular foot “escargot”

Examples: octopuses, squids, cuttlefishes, chambered nautiluses

Marine animals, free swimming Meaning “head-foot”

Tentacles have large suction cups Largest invertebrate brain Highly advanced eyes similar to humans Closed circulatory system Many release dark, inky fluid when

alarmed Many have pigment cells called

chromatophores for camouflage

Video

Squid, chambered nautilus, cuttlefish, octopus

He Was Shellfish

Body parts you MUST identify & show me during the lab:UmboValves (shells)MantleGills Incurrent & excurrent siphonsPalps & mouthDigestive gland IntestineGonadsHeart

clam

Oldest part

ANTERIOR POSTERIOR

VENTRAL

DORSAL

Section 35.2

“Few bristles”Few setae and no parapodia

Live in soil or freshwater Example: earthworms

Divided into over 100 segments Movement:

Anchor middle segments with setaeContract muscles in frontElongation of anteriorSetae of anterior grip groundPull posterior forward

Ingest soil as they burrow Digestion path: mouth esophagus

crop (temp. storage) gizzard (releases & breaks up organic matter) long intestine (absorption of nutrients) anus

Closed circulatory system Ventral (toward posterior) & dorsal

(toward anterior) vessels Aortic arches link ventral and dorsal

vessels

Respiration: diffusion of oxygen and carbon dioxide via moist skinSecretion of mucus to keep moist

Excretion: via nephridia (excretory tubules in every segment except first three)

Chain of ganglia connected by a ventral nerve cord

Each segment has a single ganglia Brain = fused ganglia Simple sensory skills

LightTouchChemicals temperature

HermaphroditesCannot fertilize own self

Mating: press ventral surfaces together, anterior ends pointed opposite directionsSetae hold worms togetherMucus secretion from clitellumEach worm injects sperm into mucusSperm going into seminal receptacles of other

wormSeveral days later chitin tube forms picking up

eggs & stored sperm fertilizationYoung worms develop inside tube and hatch 2-

3 weeks later

Examples: earthworms, leeches Annelid means “Little rings” Segmentation allows for division of labor Bilateral symmetry Live in freshwater, marine water, and

terrestrial environments

Setae: external bristles Parapodia: fleshy protrusions on outside of

body

Number of setae and parapodia divides this phylum into three class:

1. Class Polychaeta2. Class Hirudinea

3. Class Oligochaeta

“Many bristles”Number of setae and parapodia

Have anetennae & specialized mouth parts

Most are marine animalsTrochophore larvae

Predatory Largest class of annelids

Video

Smallest class of annelids Example: leeches Live in calm freshwater & moist

vegetation No setae or parapodia Most are carnivores & some are

parasiticSecrete anaestheic & anticlotting factors Ingest 10 times it own weight in blood!

Decomposers of leaves and organic matter

Recycle nutrients Release natural fertilizers (waste)

Aerates the soil

Front of Card:Phylum nameClass name Image of animalCommon name of

animal

Back of Card:SymmetryMobilityFeeding ReproductionDefenseHabitat