Download Biology 213, Lab 4

Biology 212
Animal Diversity 1
What will be turned in (beginning of next lab period)
1. Labeled sketches of cross-sections and longitudinal sections examined
a. If you would like more time to examine the slides,, they will also be available during non-lab
times (M,W,F all day).
2. Essay comparing the key features of the invertebrate phyla examined in class today.
NOTE: You will also begin to complete table 18.1, but this will not be turned in
I.
Laboratory Objectives
A.
To become familiar with the key characteristics of the following animal phyla: Porifera,
Cnidaria, Platyhelminthes, Nematoda and Annelida.
B.
To compare the basic body plans of these phyla in terms of symmetry, embryonic tissue
layers, body cavity, digestive system, circulatory system, nervous system.
C.
To understand the significance (i.e. functions, limitations) of these features.
II.
Methods
A.
We will examine slides of each of the phyla, proceeding in order from the most simple to
the most complex. For each group (Porifera, Cnidaria, Platyhelminthes, Nematoda and
Annelida) you will sketch a cross section (except for the sponge, in which you will sketch
a longitudinal section) and label the following. Note the most simpler animals will have
fewer structures to label.
1.
Embryonic tissue layers and what they become
a)
ectoderm: epidermis
b)
endoderm: gastrodermis (lining of digestive system)
c)
mesoderm: muscles

NOTE: you will have to label these for both the main body and for
the pharynx in the Platyhelminthes (Planaria)

For the earthworm (Annelida), be sure to indicate circular vs.
longitudinal muscles.

Which muscle type is in the Nematoda? Label it correctly.
2.
Body cavity
a)
Is there one?
b)
What type: pseudocoelom or coelom?
c)
Be sure to indicate the muscles surrounding the gastrodermis of the gut if it
is a true coelom.
3.
Digestive system
a)
Is there one?
b)
Label as “digestive tract”
4.
Circulatory system
a)
Is there one? If so, label blood vessel(s)
b)
Open or closed?
5.
Nervous system
a)
Is there one? If so, label nerve cords (if seen)
6.
Reproductive system
a)
Label parts as seen
7.
Specialized cell types?
a)
Label with correct name (i.e. choanocyte, cnidocyte)
8.
Other specialized sructures
a)
Example: Eversible pharynx of Platyhelminthes.
B.
You will also examine the longitudinal section of the planaria (Platyhelminthes). Be sure
to label:
1.
Eyes
2.
Auricles
3.
Eversible pharynx
4.
Digestive system
5.
Any other features of note.
C.
You will write a paragraph for each of the features listed in part a, comparing the five
phyla in terms of the presence of the feature, the significance of the feature in terms of the
functioning of the animal and any other special aspects of note.
D.
Fill out as much as you can of Table 18.1 based on what you have learned in this lab.
Phylum Porifera, longitudinal section
Phylum Cnidaria, cross-section
Phylum Platyhelminthes, longitudinal section
Phylum Platyhelminthes, cross-section through
pharynx
Phylum Nematoda: cross section of female
Phylum Annelida: cross section