Chp 13 Annelida The Metameric Body Form

Dissection of Earthworm The earthworm belongs to a group of animals called annelids (segmented worms). The earthworm belongs to a group of animals called annelids (segmented worms). The body of an annelid is usually divided internally and externally into well-defined segments which may be separated from each other by membranous partitions. The body of an annelid is usually divided internally and externally into well-defined segments which may be separated from each other by membranous partitions. Except for the tail and head regions, all segments are essentially alike. Except for the tail and head regions, all segments are essentially alike.

Others Others members of this group include the clam worms and tube worms and tube worms, which live in the ocean, and the leeches. Others members of this group include the clam worms and tube worms and tube worms, which live in the ocean, and the leeches.

Feeding The earthworm hunts food at night and thus has been called a “night crawler.” The earthworm hunts food at night and thus has been called a “night crawler.” It usually extends its body from the surface opening of a small tunnel which it makes by “eating” its way through the soil. It usually extends its body from the surface opening of a small tunnel which it makes by “eating” its way through the soil. The rear end of the worm’s body remains near the opening while the head end forages for decaying leaves and animal debris. The rear end of the worm’s body remains near the opening while the head end forages for decaying leaves and animal debris.

Where To Find Earthworms It has been estimated that an acre of good soil contains over 50,000 earthworms. It has been estimated that an acre of good soil contains over 50,000 earthworms. By their continuous foraging and tunneling these worms turn over 18 to 20 to tons of soil of soil per acre and bring over one inch of rich soil to the surface every four to five years. By their continuous foraging and tunneling these worms turn over 18 to 20 to tons of soil of soil per acre and bring over one inch of rich soil to the surface every four to five years. Thus, indirectly the earthworm enriches farmland and provides for more food in a rapidly expanding population. Thus, indirectly the earthworm enriches farmland and provides for more food in a rapidly expanding population.

Parts of the Earthworm At the anterior (front) end is a small fleshy projection over the mouth. This is the prostomium. It is not considered to be a segment of the worm. At the anterior (front) end is a small fleshy projection over the mouth. This is the prostomium. It is not considered to be a segment of the worm. The anus, the opening at the end of the digestive tract through which solid wastes are exposed, will be found at the posterior (hind) end. The anus, the opening at the end of the digestive tract through which solid wastes are exposed, will be found at the posterior (hind) end. About one-third of the way back from the mouth region is a thick cylindrical collar---the clitellum. This structure, involved in reproduction, will be considered later. About one-third of the way back from the mouth region is a thick cylindrical collar---the clitellum. This structure, involved in reproduction, will be considered later. If you lightly stroke the ventral surface in an anterior direction, the bristles you feel are the setae and are the setae and are used by the worm in movement. If you lightly stroke the ventral surface in an anterior direction, the bristles you feel are the setae and are the setae and are used by the worm in movement. Each segment (except the first three and the last 1) have pores. Each segment (except the first three and the last 1) have pores. The small openings connect with the metanephridia which are the primitive kidneys of the earthworm. The small openings connect with the metanephridia which are the primitive kidneys of the earthworm. Each segment of the worm is separated from the next one by a thin wall called a septum. Each segment of the worm is separated from the next one by a thin wall called a septum.

Digestive System Mouth: the opening is located just below the overlapping prostomium. Mouth: the opening is located just below the overlapping prostomium. Esophagus: passes food with muscular contractions Esophagus: passes food with muscular contractions Crop: stores food Crop: stores food Gizzard: grinds up food Gizzard: grinds up food Intestine: digestion and absorption Intestine: digestion and absorption Anus: expels waste Anus: expels waste

Parts of the Earthworm Cont. Shantell T. Roberson do not want to disect worms Mr. Davis. Shantell T. Roberson do not want to disect worms Mr. Davis.