Introduction to Animals: Animal Survey Lab
Invertebrates
Name:
Hour:
Objective: In this lab you will look at a variety of animals representing the different invertebrate phyla.
Make clear drawings where instructed and answer all questions asked. This lab is designed to let
you look at the different kinds of invertebrates before learning more about each group from the
student projects.
1. Porifera
What type of symmetry does the sponge have?
The members of this group are sessile, what does
that mean?
Draw a picture of the sponge.
When a sponge dies, usually the part the remains is the spicule. What is the function of
a sponge’s spicules?
2. Cnidarian
The example of cnidarian you will be observing is a small animal called a hydra.
Draw a picture of a hydra as you observe it under a
microscope. Be sure to have the correct number
of tentacles.
What type of symmetry does the hydra have? (hint:
look down on it from above)
Does this cnidarian have a polyp or medusa body
form? (see pg. 670)
What are some other animals that belong in this phylum?
3. Platyhelminthes
What does the term platyhelminthes mean? Why is this an accurate name for this animal?
The example of this group is an animal called a
planaria. Draw it in the box to the left. Make sure
to include any observable structures that you see
on the worm.
Cephalization is when an animal has a concentration of sense organs and nerve cells at one end
of its body, mainly what we call the "head end". Animals with bilateral symmetry usually exhibit
cephalization. How can you tell that this animal has cephalization?
The planaria is a free-living worm. What does this mean?
4. Nematoda
Draw an example of a nematod, a vinegar eel in the box.
How would you describe the movement of the vinegar eels?
Roundworms are considered to be animals that are
“a tube within a tube” Why are they called this?
What type of symmetry do these animals have?
5. Annelida
The term annelida means “little rings”. Why is this a good name for these types of worms?
Feel the underside of the earthworm. There are little bristle-like structures called setae. What do
you think is the function of these little bristles?
Draw an earthworm below and label these parts: mouth, clitellum, setae, septa, anus
List 2 other kinds of annelids: ______________________ and ____________________
How are they similar to the earthworm.
6. Mollusca
The example of the mollusk is the clam. List 5 other animals that are mollusks.
Which class of mollusks does the clam belong?___________________________
Describe how a clam gets its food. (pg.706)
What is the function of these organs in the clams?
gill-
mantle-
foot-
7. Arthropod (class: Insecta vs. class: Crustacea)
What is an appendage?
Looking at the appendages of the grasshopper and the crayfish, how are the grasshopper (insect)
and the crayfish (crustacean) similar?
How are they different?
Because arthropods have an exoskeleton, their muscles are attached inside their skeleton instead
of outside (like on humans) Looking at the picture on page 718, read about how arthropods move
and draw the different muscles when their legs are flexed and extended
Flexed
Extended
8. Echinodermata
The example of the echinoderms is the sea star (starfish). What type of symmetry does this
animal show?
Look at the underside of the sea star under the dissecting scope
and draw what you see. Note the tube feet, what is their function?
List other animals in this phylum.
9. Arthropods (revisited)
The arthropod phylum is the largest of all the animal groups. It is divided into 5 main classes:
Insects, Crustaceans, Arachnids, Chilopods and Diplopods.
Draw examples of the spider, millipede and centipede in the boxes below and label which class they
belong in. Section 28-2 in your biology book will help you.
spider
Class: ______________
centipede
millipede
_________________
_________________
Compare number of body segments with the number of legs.
spider
# of legs_______________
# of body segments _____________
centipede
# of legs________/segment # of body segments _____________
millipede
# of legs________/segment # of body segments _____________
How do the centipede and the millipede compare........
number of legs?
food source?
behavior?