Acknowledging Annelids

Background

Annelida is a phylum in the kingdom Animalia. Animals in the phylum Annelida--or Annelids are also known as "segmented worms". Annelids can be terrestrial, freshwater or marine and vary in size from a few millimeters to over a kilometer. The distinguishing characteristic of annelids is metamerism or the division of the body into several similar parts or segments. In this lab you will explore the characteristics of annelids.

Materials

PART I: HYPOTHESES

On an attached sheet of paper draw a picture of a worm as accurately as you can based on your present knowledge of worms. Be sure to label any structures that a worm uses for the functions of life.

Answer the following questions based on your present knowledge of segmented worms:

1.Can you distinguish between the anterior and posterior ends of a worm?

If so, how?

2.Can you distinguish between the dorsal and ventral surfaces of a worm?

If so, how?

3.Describe how a worm moves

Does a worm have any special structures for moving?

If so, what are they?

4.Can you distinguish between a male and female worm?

If so, How?

5.How do you think a worm protects itself from predators?

PART II: OBSERVATIONS

Now that you have made several hypotheses about segmented worms, use observations and see whether your hypotheses are supported or not. You may use a dissecting scope or hands lens to view your worms more closely.

1.Observe the skin of your worm. Does it have any markings on its surface?

If so, what?

2.How can you distinguish between the anterior and posterior ends of a worm (other than observing which direction it is moving?)

3.Run your fingers gently over the top and bottom of the worm. Describe how the skin of the worm feels

4.How can you distinguish between the dorsal and ventral surfaces of a worm using your vision?

5.How can you distinguish between the dorsal and ventral surfaces using your sense of touch?

6.Describe how a worm moves?

Can you see any structures used for moving?

7.Can you distinguish between male and female worms?

8.Describe how your worm reacts as you try to pick it up and hold it in your hand

9.Fill a plastic container with soil. Allow your worm to burrow half of its body into the soil and then try to pull it out. Describe what happens when you try and pull your worm from the soil

How do you think this behavior might help protect it from predators?

10.What are three new things you learned about segmented worms from your observations?

Conclusions

Now that you have observed a segmented worm closely, on an attached sheet of paper draw a picture of a segmented worm and be sure to label any structures that a worm uses for the function of life

How are your before and after diagrams similar?

How are your before and after diagrams different?

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