Earthworm Dissection
PAP-Bio
April 6, 2014 By Jackson Twyman
Objectives
First, you will learn about earthworm dissections, on all of the structures in an earthworm. You will learn about internal and external anatomy of earthworms. You will learn about the earthworms circulatory system.
Internal Anatomy
Brain, ganglion, seminal receptacle, testes, seminal vesicles, ovary, nephridia, ventral blood vessel, dorsal blood vessel, ventral nerve cord, intestine, gizzard, crop, esophagus, aortic arches, pharynx, mouth.
External Anatomy
The earthworm has a segmented body. There are about 100-150 segments, and they all have little hairs called setae on them. The segments help the earthworm move through the soil.
Earthworm and I
Click link for more information on earthworm dissections.
Background Information
The earthworm's scientific name is Lumbricus terrestria. The earthworm lives inside of the dirt, and it feeds on nutrient rich soil. Its predators are many different bird species like the sparrow. The earthworm helps the soil by excreting waste, which helps plants grow well. The earthworm has setae which help it move through soil.
Circulatory System
The earthworm has a closed circulatory system. It sends blood through two major vessels called the dorsal vessel, and the ventral vessel. The earthworm has heart like structures called aortic arches. The dorsal blood vessel sends blood to the heart, and the ventral blood vessel sends blood away from the heart.
Interesting Facts
Some interesting facts about earthworms are that they are perfect baits for fishing. Earthworms are located anywhere that there is healthy dirt. The way that earthworms help out the soil, is by leaving air holes in the soil for water to enter. Also, they leave castings which contain nutrients for the plants.
Earthworm Cladogram
The earthworm belongs to kingdom Annelida.
Earthworm Life Cycle
The earthworm hatches from a cocoon, then becomes a hatchling. Finally, the hatchling grows into a mature earhthworm.
Earthworm Digestive System
Mouth, pharynx, esophagus, crop, gizzard, intestines.
Human Impact
Humans use earthworms in their gardens, to keep the plants healthy. Also, we use earthworm castings as fertilizer for our lawns and gardens. Finally, earthworms are used for fish bait.