Kingdom: AnimaliaPhylum: Mollusca

Body Plan: Two Main Regions

*Head *Foot

mouth Large muscle used

sensory organs for locomotion

*Visceral mass

contains heart, organs of digestion, excretion, and reproduction

*Mantle - layer of epidermis covering the visceral mass

Phylum: MolluscaClass: Gastropoda

• Stomach Foot

• Conch, snails, abalones (single shell)

• Slugs and nudibranchs (no shell)

• Open Circulatory System – no blood vessels– Organs are bathed in blood

Torsion: during larval development the visceral mass twists around 180 degrees

*allows animal to withdraw inside shell as an adult

• mantle secretes calcium carbonate shell

• Protects gills• Ganglia - paired clusters of

nerve cells• Radula - flexible, tongue-like

strip of tissue covered with tough, abrasive teeth

Killer Cone Snail

• http://www.youtube.com/watch?v=zcBmMPJrrKk&list=PL355D512277EFFA06&index=78

Phylum: MolluscaClass: Pelecypoda• Hatchet Foot

• Clams, oysters, and scallops• Bivalves (two shells)• Adductor muscles that open and close the shell• Open Circulatory• Filter feeders

Shell (consists of three layers)

1. Outer layer protects against acidity of water

2. Middle layer of calcium carbonate strengthens the shell

3. Inner prismatic layer protects the animals smooth body

*Pearl - grain of sand between the mantle it gets coated with the inner layer

Clam• Cilia on gills create water current

– incurrent siphon – excurrent siphon

• Hinge• Umbo• Muscle Scars• Mantle Scar• Foot• Visceral Mass - organs• Gills• Digestive Gland - green• Pedipalps-reproductive organ

Clam vs. The World

• http://www.youtube.com/watch?v=_KVFDfv6R2M&list=PL355D512277EFFA06&index=113

Phylum: MolluscaClass: Cephalopoda

• Free swimming, predatory existence• Circle of tentacles with powerful suction cups• Beak• Brain - largest of all invertebrates• Closed Circulatory System• Chromatophores-pigment cells

•Head Foot

•Octopuses, squids, cuttlefish, and chambered nautilus

Squid• Ten tentacles - longest two used for capturing prey• Muscular mantle propels squid with jet propulsion• The giant squid: Architeuthis may reach 43 feet

Worlds 2nd largest invertebrate• Ink Sac• Siphon• Male/Female• Pen (internal skeleton-remnant of shell)• Beak

Colossal Squid• Worlds Largest Squid Species: 46 feet

Sudden Death Cuttlefish

• http://www.youtube.com/watch?v=E-zodF-XrSE&list=PL355D512277EFFA06&index=3

Class: Cephalopoda• Octopus

eight tentaclesjet propulsion more likely to crawl along bottomno shell

• Chambered Nautilusonly cephalopod with external shellshell with gas-filled chambers for buoyancy

Octopus vs. Shark

• http://www.youtube.com/watch?v=M09sdmIPKto&list=PL355D512277EFFA06&index=138

Kingdom: AnimaliaPhylum: Annelida

Earthworms, leeches, etc.

Segmented Worms

Characteristics• Bilaterally symmetrical

• Segmented worms – allows for efficient movement

(shortening & lengthening of the body)

• Setae – external bristles

• Parapodia – fleshy protrusions

• # of setae and presence or absence of parapodia divide the phylum into 3 classes

Class Oligochaeta “few bristles”• Live in soil or in fresh water• No parapodia• Few setae on each segment• Ex: earthworm

Earthworm: Lumbricus terrestris• Nocturnal

• More than 100 segments

• Circular and longitudinal muscles

• Setae grip the ground

• http://www.youtube.com/watch?v=uO4lkv-jLRs

Feeding & Digestion

• Pharynx esophagus crop gizzard long intestine anus

• Crop – temporarily stores food

• Gizzard – grinds soil up to remove nutrients

• Maintain fertility of soil

• Aerate soil and loosen soil

Closed circulatory system

• Ventral & Dorsal blood vessel

• Aortic arches – five pairs of muscular tubes

Respiration

• Oxygen and carbon dioxide diffuse directly through the skin (moist)

Excretion

• Nephridia – excretory tubules

in each segment except first 3 and the last one

• Chain of ganglia connected by a ventral nerve cord

• Several ganglia are fused in the anterior segments to form the cerebral ganglia (brain)

• process simple senses – light, touch, chemicals, moisture, T, and vibrations

Reproduction

• Hermaphrodites (can’t fertilize own eggs)

• Clitellum – thickened region secretes mucus

• Sperm is secreted into the mucus and travels to the Seminal receptacles (stored)

Class Polychaeta“many bristles”

• Numerous setae & parapodia

• Parapodia function in gas exchange

• Antennae and specialized mouthparts

• Most live in marine habitats

• Some are free-swimming predators

• Others feed on sediment as they burrow for food

Class: Hirudinea (leeches)• Live in calm bodies of fresh water or moist

vegetation

• No setae; no parapodia

• Sucker at each end of their bodies used to attach to surfaces

• Some are parasitic – can secrete an anesthetic and an anticoagulant so

they can feed on blood

• Can ingest 10X their own body weight