Mollusks, Annelids, and Echinoderms

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Mollusks, Annelids, and Echinoderms

• Alisha Horst, Cecelia King, and Amber Plank

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Annelidsintro

• Referred to as segmented worms
• Found in deep marine sediments as well as common
  soils
• Split into three groups polychaeta, oligochaeta
  (earthworms), and hirudinea (leeches)
• Polychaeta (live in almost all marine
  environments) is the bulk of the annelid group
  but the other two groups are most familiar for
  humans

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Annelidscharacteristics

• Have three body regions
• Majority of the body is made of repeated sections
  called segments
• Examples earthworms, leeches
• activity earthworm dissection

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Worm Dissection
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Mollusksintro

• molluscus- Latin meaning soft
• Soft bodied with an internal or external shell

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Molluskscharacteristics

• Four body parts
• Shell- made of calcium carbonate (CaCO3) secreted
  by glands in the mantle
• Mantle- thin tissue covering body. Secretes the
  shell
• Muscular foot- mouth and other feeding parts
• Visceral mass- internal organs located here
• Bilaterally symmetrical
• Have 1 or 2 shells
• Produce a trochophore (larva)

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Molluskslife processes

• Respiration
• Aquatic mollusks gills
• Land mollusks mantle cavity lined with blood
  vessels, skin breathing
• Internal Transport
• Sessile and slow moving mollusks open
  circulatory system- blood flows into internal
  body cavities
• Fast moving mollusks closed circulatory system

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Molluskslife processes cont.

• Reproduction
• External fertilization
• Internal fertilization (mollusks with tentacles
  and some snails)
• Cross fertilization (snails that are
  hermaphrodites)
• Mollusk Video Clips

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Mollusks

• Examples Squid, Giant Clams, Octopus
• Vampire Squid
• activity squid labeling paper

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Squid Labeling Key
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Echinoderms

• Groups of animals include
• Starfish, urchins, feather stars and sea
  cucumbers

Sand Dollar Video
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Enchinoderms

• They are simple animals
• They dont have
• A brain
• Complex sensing organs
• Front or back end
• Head

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Echinoderms

• They do have
• Spiny skin
• 5 part radial symmetry
• Internal skeleton
• Central mouth
• Develop sharp spines for protection

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Echinoderms

• They are found in a variety of shapes and colors.
• They cling to coral reefs around the world
• They live entirely in water

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Echinoderms

• What it does
• Feeding, movement, internal transport,
  respiration, and excretion
• Some of these animals are carnivorous, and feed
  and scavenge the ocean floor

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Echinoderms

• All echinoderms move around with the use of
  thousands of tiny tube feet, many of which have
  suction cups on the ends

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Echinoderms

• The most unusual feature to echinoderms is their
  water vascular system. It contains a network of
  fluid-filled canals connected to countless tube
  feet.