How would you distinguish the anterior and posterior end of the worm?

How would you distinguish the anterior and posterior end of the worm?

Find the anterior (front) end of the earthworm by locating the fleshy bump over its mouth, called the prostomium. The posterior (back) end has a small hole where solid waste is expelled, called the anus. The length of the worm is made up of many tiny segments, each separated by a thin wall called a septum. 2.

How would you distinguish the dorsal and ventral surface of the worm?

The dorsal surface of some species of earthworms is darker than its ventral surface. The bottom-side of an animal is called the ventral surface. In many animals, the ventral surface is a lighter colour or shade than the dorsal surface. The periproct is the last segment of an earthworm.

What is the purpose of dissecting a worm?

Earthworms are ideal specimens to use for teaching basic anatomy and investigating simple organ systems. Although these annelids, or segmented worms, are one of the simpler preserved invertebrates, the digestive, circulatory, reproductive and nervous systems are well developed and easy to identify.

What is the purpose of studying and dissecting an earthworm?

Purpose: In this lab, you will dissect an earthworm in order to observe the external and internal structures of earthworm anatomy, whilst following the all-important lab safety procedures.

Which reason or reasons would cause an earthworm to leave its burrow?

The theory with the most evidence is that earthworms find it easier to move across the soil surface when it is wet, to find food, new habitats or a mate. When the rain hits the ground it creates vibrations on the soil surface. This causes earthworms to come out of their burrows to the surface.

What is the purpose of the excretory openings of an earthworm?

The process of removal of metabolic waste products including nitrogenous material like ammonia, urea, uric acid, amino acid, etc. from the body is called excretion. Excretory system consists of nephridia as excretory organ which is analogous to kidney of vertebrates.

What do two earthworms exchange during mating explain your answer?

What do two Earthworms exchange during mating? They join at the clitellum to exchange sperm and egg since earthworms have both.

How do you dissect an earthworm for anatomy?

Dissection: Internal Anatomy. 1. Lay the worm on your dissecting tray with its dorsal side facing up. Use dissection pins to secure each end on the tray. Start your dissection about an inch posterior to the clitellum.

How can you distinguish the dorsal and ventral sides of an earthworm?

Notice that the earthworm has a rounded dorsal (back) surface and a flatter ventral (belly) surface. Usually the dorsal surface is darker than the ventral surface (though sometimes this is obscured in the preservation process). Lightly rub your finger along the ventral side toward the posterior end of the worm.

Where can you find the anterior end of an earthworm?

Find the anterior (front) end of the earthworm by locating the fleshy bump over its mouth, called the prostomium. The posterior (back) end has a small hole where solid waste is expelled, called the anus. The length of the worm is made up of many tiny segments, each separated by a thin wall called a septum.

Where are the genital pores on an earthworm?

Near the front end of the worm you should see some larger pores that can be easily seen without magnification. These are genital pores and are important in reproduction. 1. Lay the worm on your dissecting tray with its dorsal side facing up. Use dissection pins to secure each end on the tray.