The following assignments are to be completed in your lab notebooks. All notes, diagrams, observations and responses are to be recorded in your lab notebooks.
Earthworm Dissection Pre-lab
Complete the questions and diagrams using the diagrams and Reference websites.
PART I: EXTERNAL ANATOMY
Draw and label the following parts of an earthworm in your lab notebook.
a. __ Dorsal End
b. __ Ventral End
c. __ Setae
d. __ Metameres
e. __ Clitellum
f. __ Anterior “head” region
g. __ Caudal Region
PART II: INTERNAL ANATOMY
Draw and label a diagram of the internal anatomy of an earthworm.
A. Internal Organs
a. __ Aortic arches
b. __ Seminal Vescicles
c. __ Crop
d. __ Gizzard
e. __ Intestine
f. __ Dorsal Blood Vessel
B. Cross Section
a. __ Coelom
b. __ Ventral Nerve Cord
c. __ Dorsal Blood Vessel
PART III: Respond to the following questions in your
lab notebook. Use the links in the Reference section to help you research the answers. Please watch the Earthworm Dissection video before responding.
1. What is the scientific name of the earthworm? What phylum does the earthworm belong to?
2. Describe the characteristics of Annelids.
3. Explain the difference in the dorsal and ventral sides of the worm.
4. Describe the function of the clitellum.
5. How many pairs of aortic arches does an earthworm have? Describe the circulatory system of an earthworm.
6. What is the name of the earthworm’s brain?
7. Explain the habitat in which earthworms live and what they eat
1. Notice the space between the body wall and the internal organs. What do we call this space?
2. What is the benefit of the space listed in #1?
3. What is the function of the pharynx?
4. What is the function of the crop?
5. What is the function of the gizzard?
6. How many pulsating blood vessels or aortic arches (hearts) are present?
7. What is the function of the seminal vesicles?
8. What is the function of the seminal receptacles?
9. What is the function of the nephridia?
10. How does the difference in wall thickness of the crop and gizzard relate to their respective functions?
Illustrated Guide to Earthworm Dissection
The Phylum Annelida
All About Earthworms - Discovery Kids
Earthworms - National Geographic
Anatomy of an Earthworm - Discovery Kids
My Anatomy - Basic Earthworm Anatomy