Objective: To learn the anatomy of the Earthworm through dissections. Materials Needed: -15 pins
- Dissection tray
- Hand lens
1) Gather your materials; dissection kit, dissection tray, and the earthworm.
2) Lay the earthworm onto the dissection tray dorsal side up. 3) Place a pin through the side of the third segment from the mouth, and another pin through the side of the third segment from the caudal end. 4) Draw a diagram of the external anatomy.
5) Define the terms of the external anatomy.
6) Make a T-shaped incision with your scalpel from the clitellum down the middle of the mouth. 7) Use the forceps to gently separate the skin from the body wall so that you can see the internal organs. 8) Place two pins on both sides of the earthworm to hold down the separated skin. 9) Draw a diagram of the internal anatomy.
10) Define the terms of the internal anatomy.
11) Draw a diagram of the respiratory and circulatory systems. 12) Define the terms of the respiratory and circulatory systems. 13) Draw a diagram of the digestive system.
14) Define the terms of the digestive system.
15) Draw a diagram of the nervous system.
16) Define the terms of the nervous system.
17) Using your scalpel separate one metamere from the caudal end of the earthworm to get a cross cut. 18) Draw a diagram of the cross section.
19) Define the terms of the cross section.
20) Dispose of the worm properly, and clean the tray and materials.
Observations: External Terms (Drawing 1):
Mouth: Opening at the anterior end in which food enters.
Setae: Hair-like structures that help the worm move.
Clitellum: Glandular organ that produces mucus for coplulation and secretes the cocoon.
Metameres: Linear series of body segments.
Ventral side: The bottom side of the worm, lighter than the dorsal side.
Dorsal side: The top...