Transcript Sponges cnidarians worms mollusks

Kingdom Animalia
INVERTEBRATES: NO BACK BONE
Sponges
Cnidarians
Flatworms
Roundworms
Mollusks
Sponges
 Assymetrical: similar
parts regularly
arranged around a
central axis
 Freshwater or
saltwater
 Sessile – do not move
 Filter feeders: filter
food out of the water
 Body covered with
many pores (openings)
Sponges
 All cells function independently
 Some produce spicules: thin, spiny
structures that form the endoskeleton
 Some produce soft fibers as a
skeleton
 These are the ones people use
Sponge Reproduction:
 Asexually –budding
 Sexually – joining of sperm and egg
Other Sponge Facts:
 Sponges can regenerate – replace lost
body parts through mitotic cell division.
 Commercial sponge harvesting for
personal care industry.
 Used as medicines
Cnidarians – Stinging
Animals
 Radial Symmetry:
similar parts regularly
arranged around a
central axis
 Hollow central cavity
with 1 opening called a
mouth
Cnidarians – Stinging
Animals
 2 body types:
 Polyp: vase shape
that doesn’t move

Medusa: umbrella
shape that moves
around
Cnidarians – Stinging
Animals
 Mostly saltwater
 Corals
 Jellyfish
 Sea anemones
 Hydra
Feeding
 Use tentacles to capture food.
 Tentacles have NEMATOCYSTS –
stinging cells that grab and immobilize
prey using toxins.
 Waste products and undigested
materials are expelled through the
mouth.
Organization
 Nerve net – conducts impulses from all
parts of the body.
 No brain.
 Two layers of tissues derived from
endoderm and ectoderm
Cnidarian Reproduction
 Asexually – budding (polyp form)
 Sexually –produces egg and sperm
Flatworms Platyhelminthes
 Bilateral Symmetry:
body the same on
both sides
 Acoelomate – no
body cavity.
An Important Group
 Free-living in freshwater or parasitic
in a host
 Many nasty parasitic infections.

Dugesia
Tapeworms
 Flukes

Flatworm Feeding
 Free living flatworms are scavengers.
 Parasitic flatworms use specialized
structures (usually with hooks) to
attach to a host.
Flatworm Reproduction
 Sexually - Hermaphrodites – internal
fertilization.
 Asexually – fission – when damaged,
regenerates new body parts.
Roundworms - Nematoda
 Bilateral Symmetry
 Free-living in soil or
parasitic in a host
 Pseudomate – false
body cavity.
 Movement Longitudinal muscles
produce a thrashing
movement
Roundworm Feeding
 Have a simple digestive system.
 Have a mouth and an anus
 Parasitic roundworms use specialized
structures called hooks and suckers to
attach to a host.
An Important Group
 Many nasty parasitic infections in
humans, livestock

Pinworms, Ascaris, hookworms,
Trichinella
Segmented WormsAnnelida
 Bilateral Symmetry
 Body is divided into
segments
 Body covered with
mucus to aid in
movement
 Have tiny setae
(bristles) to pull it
through the soil
Segmented WormsAnnelida
 Have a closed
circulatory system:
all fluids are in
tubes
 Have a simple
nervous system
 Ex. Earthworm
MOLLUSKS
 Soft bodied animals that have an inner
and outer shell
 They have a tube foot to:
 Open and close their shell
 Movement
 Bury themselves in the sand
MOLLUSKS
 They have a head with a sense organ
(like an eye)
 3 Groups separated by shell
characteristics
 Single or no shell
 2- Shell
 Tentacled
Single or No Shell Mollusks
 Ex. Slugs and snails
 Also called
gastropods
 Radula: tongue that’s
used to get food
2-Shell Mollusks
 Ex. Clams, oysters,
mussels, and scallops
 Also known as
bivalves
 Filter feed
 If sand gets stuck
for many years, it
becomes a pearl
Tentacled Mollusks
 Ex. Octopus, Squid,
and nautiluses
 Also known as
cephalopods
 Use tentacles to
catch food