Transcript Chapter 29: Mollusks and Annelids

Chapter 29: Mollusks and
Annelids
What is a mollusk?
What is an annelid?
Mollusks
Objectives:
• Describe the skeletal structure,
fertilization, reproduction, body
symmetry, body coverings and
locomotion for the Phylum Mollusca and
Phylum Annelida
• This will be completed through
spreadsheet notes…..
How are annelids and mollusks
related?
• Both were the first major groups of
animals to develop:
• true coelom. – they have a body cavity,
the gut and the rest of the organs are
cushioned by the fluid in the coelom.
• trocophore: a larval stage develops from
egg, in some species it is free swimming
and propels itself with cilia.
Trochophore: Free swimming
larval stage of mollusks and
annelids
Seven classes of mollusks make
up phylum Mollusca
•
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Three largest classes and examples are:
Gastropods- snails and slugs
Bivalvia- clams, oyster, and scallops
Cephalopoda- octopuses and squids
Know the 6 Key Characteristics
of Mollusks
• 1. Body cavity: true coelom
• 2. Symmetry: bilateral symmetry
• 3. Three-part body plan: visceral masscentral part, mantle- outer layer of body,
foot- muscular region used for locomotion
• 4. Organ systems- excretion, circulation,
respiration, digestion, reproduction
• 5. Shell- one or two shells (most)
• 6. Radula- tongue like organ in the mouth,
thousands of teeth on radula scrap off food
and pull in prey.
Animal
Skeletal structure
Phylum
Mollusks:
3 part body plan most
have shells, (foot,
visceral mass,
mantle)
Fertilization and
Reproduction: Mollusks
has reproductive system, male
and female individuals, some
hermaphrodites
Important Features : Mollusks
organ systems for excretion circulation,
respiration, reproduction, two ends to
digestive tract, radula for feeding
Body symmetry: Mollusks
most bilateral
Body coverings: Mollusks
most have either one or two shells,
mantle of tissue covering body
Locomotion: Mollusks
muscular "foot" used to dig, slide,
jump
Mollusk - Gastropods Examples: snails,
slugs
Fertilization and Reproduction for
Gastropods: same as mollusks
Important Features (look in this column and fill in
for gastropods)
have organ systems for excretions, circulation,
respiration, reproduction, two ends to digestive tract,
radula for feeding
same as mollusks, pair of tentacles on head with eyes
at tips
Body symmetry of gastropods is
bilateral
Body coverings of gastropods are
a mantle of tissue covering the
body, spiral shells
Locomotion of Gastropods:"foot",
secretes mucus it glides on
Bivalves:
Examples: clams, oysters, scallops
(all the notes for the next 6 slides
are in the bivalve row)
Bivalve skeletal structure:
• All have two part
hinged shell
Giant clams can
weigh more than
227 kilograms
(500 pounds),
and are the
largest bivalve
mollusk in the
world.
Fertilization and
Reproduction of Bivalves:
sexually, release sperm and
egg into water, fertilized
eggs become trocophore
larvae
Important features of Bivalves:
filter feeders, through siphon
tube, over gills out other siphon
tube
Body symmetry of bivalves is
bilateral
Body coverings of bivales:
two part hinged shell, two thick
adductor muscles connect shells
Locomotion of bivalves: most
sessile, some swim
opening/closing valves quickly
Cephalopod examples: squids,
octopuses, cuttlefish, nautilus
Cephalopod skeletal structure:
large head attached to tentacles,
lack external shell,
Cephalopod reproduction: Sexual
Cephalopod body symmetry:
bilateral
Cephalopod body coverings: only
nautilus has shell
Cephalopod locomotion: jet
propulsion
Animal
Skeletal structure
Annelids: segmentation, setae:
bristles, some have
parapodia: fleshy
appendages
Annelids:
Fertilization and Reproduction of
Annelids:
hermaphrodites, reproduce sexually
Important features of annelids:
respire through skin, have closed
circulatory system, complex nervous
system
Body symmetry of Annelids:
bilateral
Body coverings of annelids:
setae: bristles, some have
parapodia: fleshy appendages
Body coverings of annelids:
setae: bristles, some have
parapodia: fleshy appendages
Locomotion of annelids: fluid filled
compartment aids with contracting,
stretching to move
Marine worms: Examples feather
dusters, Nereis
Marine worm skeletal structure:
Many parapodia
Marine Worm Reproduction:
Hermaphrodites, sexual
Marine worm special features:
some burrow, others live in protective tubes,
some feed by pumping water through body
Body symmetry of Marine worm:
Bilateral
Body coverings and locomotion of marine
worms: many parapodia, use parapodia to
swim, burrow or crawl
Earthworms skeletal structures:
no parapodia, only setae
Fertilization and Reproduction of
Earthworms
hermaphrodites, reproduce sexually
Important Features of Earthworms:
eat their way through soil
Symmetry, body coverings,
locomotion of Earthworms:
bilateral
few setae on fluid filled
each
compartme
segment
nt aids with
contracting,
stretching
to move
Leeches Skeletal Structure and
Reproduction:
Leeches suckers on both
Exam
ends of body,
ples:
flattened body
hermaphrodi
tes,
reproduce
sexually
Important Features, Symmetry
and Body covering of Leeches
most species bilateral
predators
or
scavengers
lack both setae
and parapodia
Locomotion of Leeches:
contraction and elongation of
body
Let’s Review!
• Get out the worksheet titled
Invertebrate Review: Cnidarian,
Annelids, Molluscs
We have covered the Phylum of
Sponges, Cnidarians, Annelids,
and Mollusks
• Over the next few slides, determine
what phylum the animal is classified.
• Write the name of the animal under the
correct heading on your worksheet.
• Write a sentence about the
characteristics of each animal.
Slide 1: Earthworm- look at the
example of the sentence for
characteristics.
Slide 2: Sea Anemone
Characteristic example: all
polyps, have tentacles
Slide 3: Sponge Characteristic:
Is asymmetrical, is sessile
Slide 4: hydrozoan
has stinging tentacles, radial
symmetry, formed of both polyps and
medusa
Slide 5: gastropod, has a single
shell or no shell
Slide 6: Leech suckers on both
ends of body, segmented
flattened body
Slide 7: cephalopod has 3 part
body plan, organ systems, radula
Slide 8: Feather Dusters have
many parapodia, segmentation,
Slide 9: Scyphozoan has both
polyp and medusa stage, radially
symmetric
Slide 10: Bivalve two part hinged
shell, bilateral, filter feeder
Slide 11: Sponge have spicules
and spongin for support
Slide 12: Sponge have ostia and
oscula as body coverings
The Walrus and the Carpenter
enjoyed Bivalves…..
End of Critter Quiz!
• Pass in your
slide show notes
• Pass in your quiz
• Ready for a
movie and quiz?
Humans are big fans of bivalves
too.
Buried Bivalve
Marine Bivalves
1. What class of animals are they!
Giant Squid – a cephalopod
Nautiluses - Cephalopods
Pearly Nautilus
Cuttlefish
Octopus - cephalopods