Transcript Visceral mass - Perry Local Schools

Kingdom: Animalia
Phylum 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: Mollusca
Class: Gastropoda
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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
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Phylum: Mollusca
Class: 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 soft
body
*Pearl - grain of sand between the mantle it gets
coated with the inner layer
• Cilia on gills create water current
– incurrent siphon
– excurrent siphon
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Hinge
Umbo
Muscle Scars
Mantle Scar
Foot
Visceral Mass - organs
Gills
Digestive Gland - green
Pedipalps-reproductive organ
Clam
Phylum: Mollusca
Class: Cephalopoda
•Head Foot
•Octopuses, squids, cuttlefish, and chambered nautilus
• Free swimming, predatory existence
• Circle of tentacles with powerful suction cups
• Beak
• Brain-largest of all invertebrates
• Closed Circulatory System
• Chromatophores-pigment cells
Class: Cephalopoda (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
Class: Cephalopoda
Octopus and Chambered Nautilus
• Octopus
eight tentacles
jet propulsion more likely to crawl along bottom
no shell
• Chambered Nautilus
only cephalopod with external shell
shell with gas-filled chambers for buoyancy
Kingdom: Animalia
Phylum: Annelida
Earthworms, leeches, etc.
Characteristics and Classification
• 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”
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Live in soil or in fresh water
No parapodia
Few setae on each segment
Ex: earthworm
Earthworm: Lumbricus terrestris
• Nocturnal
Structure and Movement
• More than 100 segments
• Circular and longitudinal muscles
• Setae grip the ground
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”
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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