EARTHWORMS Science Page EARTHWORMS ARE ADAPTED FOR LIVING IN SOIL

.usbg.gov MOVING w A worm moves through ww soil by using special muscles and hydraulics. An earthworm is divided into segments. Each is filled with liquid, and Hydraulics is the each has its own set of muscles. Long muscles run along the sides of movement of liquids each segment, and circular muscles go around each segment. under pressure.

BREATHING Bristles, called The earthworm’s skin has When long muscles tighten—or contract— segment setae, are located UNITEDSTATES BOTANIC GARDEN

glands that give off the segment is squeezed so it gets shorter. on each segment mucus. This mucus helps The liquid in the segment presses outward, of the earthworm’s making the segment fatter. When circular body. They the earthworm breathe muscles tighten, the segment is squeezed prevent the because it keeps the body around the middle, so it gets thinner. Liquid setae earthworm from moist. The earthworm in the segment is pushed lengthwise, slipping breathes through its thin making the segment longer. The tightening backwards. of one set of muscles and then the other skin. Oxygen dissolves in happens in waves down the segments of the the moisture on the earthworm’s body. This helps to pull and earthworm’s body, and push the worm along. then passes into the body.

FEEDING clitellum The earthworm is 5. The waste material passes out of the specially adapted hearts brain body through the for feeding anus. underground. 4. The ground up food passes into the intestine. Digestive fluids break down 1. A hard area on the the food, and nutrients are head forces open absorbed into cracks in the soil. 2. When the earthworm swallows small the body. The earthworm can particles of soil and bits of dead plants then crawl into the and animals, muscles push the food to cracks in search of a chamber or sac called a crop. The 3. Food enters the gizzard, where it is food. crop stores food for a short time. ground up with the help of tiny stones.

EARTHWORMS CULTIVATE AND FERTILIZE SOIL. As earthworms worm casts move through soi l, they make tunnels. These tunnels let air reach plant roots,

and let water drain through soil. Mucus that earthworms produce helps bind soil particles

together, so that The waste coming out of the earthworm’s body is the tunnels keep called worm casts. Worm casts contain valuable their shape. plant nutrients. They reduce the acidity of soil. Earthworms also Worm casts also soften the soil, so roots can grow more easily. mix soil layers as they burrow.

times, but each time change the direction that the worm’s head is pointing. Which direction WORD SEARCH does the earthworm move?

.usbg.gov Does a worm have a sense of smell? w Find these S I M D J S E T A E earthworm Dip a Q-tip in vinegar. First, wave the Q-tip near ww words in U N O Y R T K K X W the worm’s rear end, and then near its front end. Do not touch the worm with the Q-tip. the puzzle C T O C E A P V O M on the Does the earthworm show any response? right: U E K G R E Z R W H Can an earthworm sense light? crop, Now darken the room, and shine the flashlight M S H T O O M Z T I circular, on the worm. What does the earthworm do? Were your predictions accurate? mucus, A T G V Q C P U I M mouth,

UNITED STATES BOTANIC GARDEN BOTANIC STATES UNITED N I X V A C O V A G anus, SPOTLIGHT

intestine, U N K S X M Y B F X ON RESEARCH gizzard, S E T B U B K Q D G An earthworm has both male and female setae and sex organs in its body worm casts K S R A L U C R I C An earthworm has both male testes and

female ovaries in its body, but it usually needs another worm to mate. Mating worms put their TRY THIS bodies together, and sperm passes from one worm to the sperm storage sac of the other EARTHWORM STUDY worm. After mating, a mucus ring is formed by What you need the clitellum on each worm. As the worm * ruler * earthworm * eyedropper wriggles out of the ring, the ring passes over * Q-tip * paper towels * water the worm’s ovaries and sperm storage sacs. * vinegar * stiff paper * pan Eggs and sperms are deposited in the ring. As * flashlight What to do the ring slips off the worm, both ends of the ring 1. Place the earthworm on a moist paper towel seal to form a cocoon. Inside, the sperm in a pan. Observe the worm for a few minutes. fertilizes the eggs. A short time later, baby How does it move? What muscles are necessary worms hatch. for the earthworm to move? Worm casts makes plants grow faster 2. Roll the worm over and observe what Scientists at Ohio State University wanted to happens. The side that the worm prefers up is know how well vegetables, fruits, and flowers the dorsal or top side. The side it prefers down would grow if worm casts were added to the soil. is the ventral or underside. They fed worms a special diet of pig and cow 3. The body of the earthworm is made up of manure, and then collected the worm casts. segments. At around segment 30 from the front They added the worm casts to some soil, and end of the worm, look for a wide thick band left other soil alone. Then the scientists around its body. This swelling is called the compared the growth of crops planted in the clitellum, and is found on adult worms. The two soils. In the greenhouse, lettuce, tomatoes clitellum is used in mating. peppers, carrots, radishes, onions, marigolds, 4. On the underside of the earthworm are small and petunias grew faster in the soil with the bristles called setae. Put the earthworm on a worm casts added. In fields, tomatoes, peppers, piece of stiff paper. Can you hear it make any strawberries, raspberries, and grapes all grew noise as it moves? Hold the paper up level with faste r, and produced fruits faster when worm your eyes. Do you see the setae? Run your casts were added to the soil. fingers along the underside of the worm. Can Sources: Edwards, C.A. (1998). Vermicomposting’s potential: small to large- you feel the setae? scale operations. Resource Recycling. 5. Study the earthworm’s head. Does it appear Atiyeh, R.M., Edwards, C.A., Subler, S., and Metzger, J.D. (2001). Pig manure vermicompost as a component of a horticul- to have any sense organs, such as eyes, ears, tural bedding plant medium: effe cts on physico- or a nose? Do you think the earthworm is able chemical properties and plant gr owth. Bioresource Technology. 78, 11-20. to sense moisture, light, or odors? Make your predictions, and then find out. Ha! Ha! Can an earthworm sense moisture? Ha! Ha! Place a dry paper towel on one side of the pan RIDDLE and a moist paper towel on the other. Stretch Why did the earthworm cross the road? the worm so that it lays across both towels. Observe the earthworm’s response. Try this ten