CHAPTER 12 INTRO TO ANIMALS
(p. 330)
There are over one million
species and nine phylums.
ANIMAL CHARACTERISTICS
1) cannot make their own food (must eat
other organisms).
2) must digest their food.
- food must be broken down for the
body to use.
3) Must move from
place to place.
- find food, escape
predators, migrate,
find mates, etc.
- called locomotion.
4) must be multicellular.
- many types of different cells.
5) eukaryotic
- must have a
nucleus.
6) does not have
cell walls.
Vertebrates
- animals which have
a backbone.
- provides support.
The backbone also
protects the spinal
cord.
- nerves which
connect the body to
the brain.
Invertebrates
- animals without a
backbone.
- 97% of all animals
are invertebrates.
Some invertebrates
have a hard shell
for protection and
support.
Ex. clam
Some have a
hard outer
skeleton for
support.
Ex.
grasshopper
Symmetry (P. 335)
- the balanced arrangement of body parts
around a center point or line.
Radial Symmetry
-arranged in a
circle.
Ex. jellyfish
coral
Bilateral Symmetry
- it can be divided
into two equal
halves.
- each side is the
same
All vertebrates
and most
invertebrates
are bilateral.
Dorsal
- upper side
Ventral
- bottom side
Anterior
- front end
Posterior
- hind end
Asymmetry
- no way to divide
the animal into
halves
Ex. sponges
ASSIGNMENT:
READ PP. 336 - 340.
SIMPLE INVERTEBRATES (p. 346)
Phylum Porifera Sponges
- ‘pore-bearing’
- found mostly on the bottom
of shallow waters.
- mostly salt water.
- cannot move - sessile.
Not a real sponge…
- has pores
- water enters and the sponge filters out
unicellular organisms.
- expels water thru a different pore - osculum
- are called filter feeders
- oxygen is absorbed
the same way.
- The simplest of
animals.
- two layers of cells.
- no organs or
tissues.
Some once thought
that sponges were
plants.
How my brother scratched my
Dad’s 1960 Buick Electra
Spicules
- used for support.
- a simple skeleton.
Collar cells
- pull water and
food into the
sponge.
ASSIGNMENT
WORKSHEET:
“What is an Animal?”
Asexual Reproduction in Sponges
Regeneration
- small parts break off
and can grow into a
‘new’ sponge.
Asexual Reproduction in Sponges
Gemmules
- are a hard outer
covering with
sponge cells inside.
- created during
harsh periods.
- no food, low
water levels.
- when conditions
improve, the
gemmule breaks
open and a ‘new’
sponge forms.
(freshwater only
- ocean conditions
rarely change).
Sexual Reproduction in Sponges
- some species have
separate sexes but most
are hermaphrodites.
- both male and
female.
-
Sperm and eggs are
released into the
water where
fertilization occurs.
-it develops into a
larva (young
sponge) which has
cilia to swim and
find a spot to attach
-- then it grows into
a sponge.
ASSIGNMENT
WORKSHEET
“SIMPLE ANIMALS”
Phylum Cnidaria “stinging cells” (p.
339)
Ex. jellyfish, coral,
sea anemones.
- once called
Phylum
Coelenterata
- “hollow body”
- more complex than
sponges - but still
simple.
- no tissues or
organs.
- all have radial
symmetry.
- most have arm-like
tentacles.
- the tentacles have
stinging cells called
nematocysts.
CORAL
NEMATOCYSTS
- the prey bumps into
the nematocyst and
is stunned.
- the tentacles pull the
prey into the mouth.
Can be dangerous to
people.
Ex. Portuguese
man-o-war
Portuguese Man-o-war
CORAL
- have a hard outer
skeleton.
- when it dies, a new
coral grows over the
dead one building a
reef.
Cnidarians are the first animal to have a
simple nervous system.
- called a nerve net.
- carries impulses and
connects all parts
of the organism,
Cnidarians can have two body plans.
(p. 339)
1) medusa
- free-floating and
often umbrella
shaped.
Ex. jellyfish
2) Polyp
- attached to a hard
surface.
- often tube shaped.
Ex. sea anemone,
coral
Polyp
Medusa
Some species can alternate
between body plans.
ASSIGNMENT:
WORKSHEET
“Stinging Cells”
Phylum Platyhelminthes
“Flatworms”
- flat bodies.
- bilateral symmetry.
- simple animals but more complex
than cnidarians.
- absorb oxygen thru
their skin.
- most are parasites - but some are
free-living.
Ex. planaria (p.
345)
- free-living
- has an eyespot.
- can sense
changes in light.
A planaria can regenerate body parts.
- it has a simple
nervous system
in the shape of
a ladder.
A tapeworm is another example of a
flatworm. (p. 346)
- are parasites.
- can enter the body by eating grass or
uncooked meat which holds the tapeworm
eggs.
Tapeworms have hooks and sucker
to attach to the intestine.
- it absorbs the
host’s digested
food.
- its ‘head’ is
called a scolex.
Each section is
called a
proglottid - and
is full of eggs as
it matures.
ASSIGNMENT:
QUESTIONS
P. 335 2 - 3
P. 342 1
P. 349 2 - 3
Phylum Nematoda
“Roundworms”
- largest worm phylum.
- more complex than
flatworms.
- has a continuous
digestive tract.
“tube within a tube”
mouth
anus
- excrete waste
- some are parasites
Ex. hookworm
- it enters thru the
skin - its larvae are
very small.
- it travels the blood
system into the
lungs.
- A cough brings it up
into the mouth
- it is swallowed into
the digestive system.
- feeds on blood.
Ex. Heartworm
Ex. Trichinella worms
- causes trichinosis
- from eating
uncooked pork.
Another parasite is ascaris
ASSIGNMENT:
WORKSHEET
“SIMPLE CREATURES’
Phylum Annelidia
“Segmented worms”
“little rings” (p. 365)
Ex. earthworm, leech
-most advanced of the
worms.
- has a body cavity
that holds organs.
Earthworm Anatomy (p. 366)
setae
- tiny hairs on each
segment.
- for movement
- to ‘hold on’ to the
soil.
Clittelum
-thick band
- used for reproduction.
DIGESTIVE SYSTEM
- they ‘eat’ soil.
mouth
intestine
crop
gizzard
anus
Crop - storage area.
Gizzard - grinds the
soil/organics.
crop
Intestine - breaks
down food/absorbs
nutrients.
gizzard
intestine
Earthworms have a closed
circulatory system.
- the blood is
contained in
vessels.
It has five ‘hearts’
called aortic
arches to pump
blood.
- absorb oxygen thru their skin.
- has a nervous
system with a
brain and a
main nerve
cord.
ventral nerve cord
intestine
- are hermaphrodites.
- have both male and female parts.
- but must receive sperm from another
worm.
- it cannot fertilize itself.
ASSIGNMENT:
WORKSHEET
“ANNELID ANATOMY”
Leeches
- are a parasitic
segmented worm.
- produce an
anesthetic.
- the host cannot
feel the bite.
A LEECH “MOUTH”
- were once used to ‘bleed’ people with
illnesses.
- used today to
keep blood
flowing to
reattached body
parts.
- Leeches have an anticoagulant in their
saliva.
-stops blood from clotting.
ASSIGNMENT:
WORKSHEET
‘CHAPTER REVIEW’