Transcript Mollusks, Annelids, and Echinoderms

Alisha Horst, Cecelia King, and Amber Plank
• 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
 Have three body regions
 Majority of the body is made of
repeated sections called segments
 Examples: earthworms, leeches
*activity – earthworm dissection
Worm Dissection
 molluscus- Latin meaning soft
 Soft bodied with an internal or
external shell
 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)
 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
 Reproduction
 External fertilization
 Internal fertilization (mollusks with
tentacles and some snails)
 Cross fertilization (snails that are
hermaphrodites)
Mollusk Video Clips
Mollusks
 Examples: Squid, Giant Clams, Octopus
Vampire Squid
*activity – squid labeling paper
Squid Labeling Key
 Groups of animals include:
 Starfish, urchins, feather stars and sea
cucumbers
Sand Dollar Video
 They are simple animals:
 They don’t have
 A brain
 Complex sensing
organs
 Front or back end
 Head
 They do have:
 Spiny skin
 5 part radial
symmetry
 Internal skeleton
 Central mouth
 Develop sharp
spines for
protection
 They are found in
a variety of
shapes and colors.
 They cling to
coral reefs around
the world
 They live entirely
in water
 What it does:
 Feeding, movement, internal
transport, respiration, and excretion
 Some of these animals are
carnivorous, and feed and scavenge
the ocean floor
 All echinoderms move around with the
use of thousands of tiny tube feet,
many of which have suction cups on
the ends
 The most unusual feature to
echinoderms is their water vascular
system. It contains a network of fluidfilled canals connected to countless
tube feet.