Arthropods, Molluscs, Echinoderms

• Largest Marne Phylum, composing about 23% of named marine organisms.
• Include snails, slugs and other gastropods; clams and other bivalves; squids and other cephalopods
• Mantle
• Body Cavity
• Radula
• Some shells, like that of a cowry, was used as currency.

• Physical Adaptations:
• Shells
• Egg case
• Radula
• Colors, patterns, and shapes that help them blend in
• Liquid Propulsion
• Operculum
• Most mollusks have eyes and most have chemoreceptors.
• Oysters can change their sex from male to female to male and so on, throughout their lives.
• Cone shells, a gastropod, carry fast-acting neurotoxic venom.

Arthropod Characteristics

1. An exoskeleton

2. Specialized mouth parts

3. Jointed legs

4. Compound Eyes

5. Segmented body

Echinoderms, Mollusks, & Arthropods

Mollusks

Interesting Facts

Bivalvia. Two shells encase the body. Includes the clams, mussels, oysters, and scallops.

Radula

Echinoderm Adaptations

Gastropoda. Snails and slugs. Snails have a single shell ("univalves') while slugs have none.

Cephalopoda. This marine group includes the various species of octopus, squid, as well as the chambered nautilus. A record 28-foot (8.5 m) octopus and 60-foot (18 m) squid make these the largest of all the invertebrates.

• Radial symmetry, several arms radiating from a central body. The body has five equal segments, each containing a duplicate set of internal organs.
• No heart, brain, nor eyes, but some brittle stars have visual receptors on their arms.
• The mouth is situated on the underside of the body and the anus is on the top (except for feather stars, sea cucumbers and some urchins).
• Tentacle-like structures called tube feet with suction pads on the arms/legs. These tube feet are hydraulically controlled by the vascular system. Locomotion is generally very slow, but certain sea stars can move quickly along the ocean floor.
• Calcitic skeleton composed of many ossicles.

Sea star or starfish (Asteroidea)

Feather stars and sea lilies (Crinoidea)

Brittle stars, basket stars, serpent stars (Ophiuroidea)

Holothurians or sea cucumbers (Holothuroidea)

Sea urchins, heart urchins and sanddollars (Echinoidea)

Resources

http://www.usc.edu/org/seagrant/Education/IELessons/Unit2/Lesson8/CrittersClassified.pdf

http://www.starfish.ch/reef/echinoderms.html

http://www.weblessons.com/Teacher/guide.php?lessonID=546&dallaszoo

http://www.oceanicresearch.org/education/wonders/arthropods.htm

http://www.britannica.com/EBchecked/media/117213/The-horseshoe-crab-has-compound-eyes-that-appear-to-have

http://www.mikedelaney.org/images/Img49.jpg

http://nathistoc.bio.uci.edu/Pycnogonida/Ammothea.htm

Crustacea – crabs & lobsters & shrimp

Arthropods

Pycnogonia – sea spiders

Segmented Body

Merostomara – horseshoe crabs

Compound Eyes

Exoskeleton

Jointed Legs

Specialized Mouth Parts