Three Phyla of Worms
Review the Animal Kingdom

4 Major Characteristics?

Multicellular

Eukaryotic
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Heterotrophs

Cells lack cell walls
7 Essential Functions?

Feeding
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Response
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Respiration

Movement
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Circulation

Reproduction

Excretion
Hard Shells
The Anatomy of a Sponge
Water flow
Osculum
Central cavity
Pores
Collar Cell
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
What makes the Porifera phyla the most simple of all animals?
What does the name “Porifera” actually mean?
Cnidarians have two body forms
Polyp - stationary,
vase-shaped
Medusa - swimming,
cup-shaped
Examples: hydra, coral,
sea anemone
Examples: jellyfish,
portuguese man of war
Ecology of Cnidarians
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A. Source of new drugs/chemicals sunscreen
855
B. Provide habitats for marine organisms
C. Source of food for other organisms (like sea
turtles)
D. Symbiotic relationships with other organisms
WORMS
Phylum: Annelida
Phylum: Platyhelminthes
Phylum: Nematoda
What’s a Worm???
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A long, thin invertebrate with BILATERAL symmetry, a
nervous system, and cephalization
Simplest animal to have a true organs like a brain!
Reproduction - Sexual (hermaphroditic – male and female
reproductive organs) and Asexual – Fission (breaking into
pieces)
Many are parasites- (good/bad relationship) live on or in a
host
3 Distinct Phyla
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Platyhelminthes (flatworms)
Nematoda (roundworms)
Annelida (segmented worms)
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http://animal.discovery.com/videos/monstersinside-me-tapeworm-in-my-brain.html
http://animal.discovery.com/videos/monstersinside-me-flesh-eating-hookworm.html
http://planetgreen.discovery.com/videos/gword-red-wigglers.html
http://animal.discovery.com/videos/top-10bloodsuckers-leech.html
Characteristics of Flatworms
(Platyhelminthes)
A. Soft flattened
worms with true
tissues and
internal organs.
B. Simplest animals
to have bilateral
symmetry and
cephalization.
Flatworms carry out 7 essential functions
1. Feeding – some carnivorous,
most parasitic; one opening
into gut; pharynx sucks in
food and releases waste
2. Respiration/ Circulation/
Excretion – No respiratory
No circulatory system,
system; Obtain nutrients
and oxygen by diffusion
directly into cells. Simple
excretory system of
specialized cells.
3. Response/Movement –
ganglia= groups of nerves
in head control nervous
system (like a brain);
“ladder” of nerves run
over body; eyespot
detects light; move by
cilia and squirming using
outer layer of muscle
tissue
Diseases caused by parasitic flatworms
A.
Flukes-Usually infect internal
organs of host – Example: The
blood fluke Schistosoma- causes
tissue damage that could result in
death
Schistosome Life Cycle
Section 27-1
4. Inside the human host, the
flukes produce eggs that clog
blood vessels, causing
swelling and damage to
Primary and/or
host
lungs, liver, spleen,
(human)
intestines
Intermdiate host
(snail)
Primary host
Human
intestine
Flukes mature and reproduce
sexually in the blood vessels
of human intestines.
Embryos are released and
passed out with feces.
Adult
fluke
Embryo
Ciliated
larva
Tailed
larva
After asexual
reproduction, new
larvae are released
from the snail into the water.
They then infect humans,
the primary host, by boring
through their skin.
Once in the water, embryos
develop into swimming
larvae that infect an
intermediate host (snail).
Secondary
host
Diseases caused by parasitic flatworms
A.
B.
Flukes-Usually infect internal
organs of host – Example: The
blood fluke Schistosoma
Tapeworms – Long, flat, and have
adaptations for life inside intestines
of host
Parasitic Flatworms
Head with a scolex suckers and hooks which
attach to the host’s
intestinal lining
Check Your Understanding

What type of symmetry do all worms have?
Bilateral
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Worms are the simplest animals to have
Bilateral symmetry
Cephalization
____________
and ______________.

How do flatworms obtain nutrients and
oxygen? Diffusion
The Characteristics of Roundworms
Phylum Nematoda
A. Body plan- First animals
to have a one way
digestive system with
mouth and anus (tube
within in a tube);
B. First animals to have a
fluid filled body cavity
called a pseudocoelom“false body cavity”
Roundworms Carry Out 7 Essential
Functions
1. Feeding- many are
carnivores with grasping
mouthparts, some
herbivores, many are
parasites
2. Respiration/Circulation/
Excretion- No Respiratory
or Circulatory Systems;
rely on diffusion. Simple
excretory organs.
3. Response/movement -have ganglia (“brain”)and
simple nervous system, have muscular system and
move like snakes
Diseases caused by parasitic roundworms
A. Trichinella causes
painful cysts in the
muscle tissue of
humans and other
animals- transmitted
by eating
undercooked meat
containing worm eggs
Diseases caused by parasitic roundworms
B. Filarial worms cause
Elephantiasis- fluid
buildup that causes
abnormally large
limbs – transmitted
through the bite of
insects like mosquitos
https://www.youtube.com/watch?v=oVuvW5JnYXQ
Diseases caused by parasitic roundworms
C. Ascarids cause
malnutrition in
humans, horses,
cows, etc by filling
the intestinal tract of
its host and
absorbing all
nutrients
Diseases caused by parasitic roundworms
D. Hookworms attach to the
lungs and intestines and
suck blood – common in
humans(1/4 of world
population); larvae pierce
the skin & burrow into the
body. Can severely damage
internal organs.
Transmitted through
humans’ and other
animals’ waste. (Wear
Shoes!)
Check Your Understanding

What is different about the roundworm’s
digestive system as compared to the
flatworm’s digestive system?
A roundworm has a mouth and anus. A flatworm only has one opening
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How are roundworm diseases transmitted?
By eating undercooked meat, walking barefoot, insect bites
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What are ganglia?
Nerve tissue that function as simple brains
Phylum Annelida
Figure 1 – Body Structure
anus
mouth
clitellum
Phylum Annelida
A. Body Plan- tube
within a tube, digestive
system with mouth and
anus; body divided into
sections called septa
that are specialized for
different functions.
First animals to have
true circulatory system
and coelom – body
cavity.
Annelids carry out 7 essential functions?
1. Feeding- predators to filter
feeders; use pharynx to get
food, stored in crop,
ground up in gizzard,
absorbed in intestine.
One-way Digestive System
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Mouth  pharynx 
esophagus (throat) 
crop (storage area) 
gizzard (grinds food)
 intestines
(digestion)  anus
Annelids carry out 7 essential functions?
2. Circulation/ Respiration/
Excretion- closed
circulatory system with
vessels; breath through
gills or through skin; have
excretory organs called
nephridia
Annelids carry out 7 essential functions?
2. Circulation/ Respiration/
Excretion- closed
circulatory system with
vessels; breath through
gills or through skin; have
excretory organs called
nephridia
3. Response/Movement- have
ganglia in each segment
and in the head, nervous
system; move by
contracting and relaxing
muscles
The Anatomy of an Earthworm
Section 27-3
Anus
Setae
Body segments
Gizzard Crop
Dorsal
blood vessel
Clitellum
Mouth
Brain
Ganglion
Circular muscle
Longitudinal
muscle
Nephridia
Ganglia
Ring
vessels
Reproductive
organs
Ventral
blood vessel
Intestine
Gizzard
(grinds)
Clitellum
Dorsal
blood
vessel
Anus
Brain
Crop
(stores)
Aortic
arches
Esophagus
Ventral
blood vessel
Ventral nerve cord
Mouth
Segments
Pharynx
(throat)
Ecology of Annelids
A.
B.
C.
Aerate, mix, and fertilize the soil- have created
some of the most fertile soils on earth!
Tunnels provide passage ways for plant roots and
water
Important in the diets of many other animals such
as birds, toads and snakes; marine annelids
important in the diets of fishes, crabs, and lobsters
Check Your Understanding

Name one characteristic all three worm
phyla have in common

What type of circulatory system do
segmented worms have?
Figure 2 – Reproductive Structures
Sperm
Grooves
Clitellum
prostomium
Male
genital
pores
Earthworm coccoons
setae
Intestine
Dorsal
blood
vessel
gizzard
crop
septa
Seminal vesicles
Aortic arches
pharynx
brain
mouth
Seminal
receptacles
nephridia
Ventral blood
vessel
ovaries
metameres
Ventral nerve cord
esophagus
Review
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What are the three types of worms?
How do worms such as a planarian “see”?
What kind of worm includes leeches and
marine worms?
What makes a segmented worm, such as an
earthworm, different from other worms in
regards to their circulatory system?