A Worm with a View
Intended for Grade:
Subject:
Second
Science
Description:
This project is an introduction to earthworm anatomy using
both computer simulations and line drawings as tools for a virtual dissection.
Objective: The student will be able to identify the major parts of the
earthworm.
Mississippi Framework addressed:
•
Science Framework 2a: Identify parts and basic functions of various
body systems (circulatory, respiratory, digestive, skeletal and nervous
systems).
National Standard addressed:
•
Content Standard C: Life Science
Materials:
•
•
•
•
•
Three different colors of paper (e.g. cream, pink, and yellow)
Word Bank
Answer Key
Scissors
Glue sticks
Background:
Biologists classify organisms using an ordered system. The most
general category is kingdom. In descending order from kingdom, the list is
phylum, class, order, family, genus, and species. The phylum Annelida
includes earthworms, leeches, and other segmented worms. Within the
phylum Annelida, earthworms are in the class Oligochaeta and the genus
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Lumbricus. All annelids have an initial unsegmented section, the prostomium,
located at the anterior portion (head) of the body. Segmentation can be
identified easily on the remainder of the body. The rest of the description
that follows concerns earthworms, specifically.
Earthworms move via peristaltic contractions. In this type of
movement, alternating waves of longitudinal and circular muscle contractions
occur that pass towards the rear of the worm. Paired bristles, called setae,
occur on each segment and increase traction for the worm as it moves.
Earthworms primarily feed on decomposing organic matter found in
the soil. The digestive system begins with the mouth. Food enters the
mouth, which is located on the underside of the prostomium. The food then
moves into the small buccal cavity, which produces saliva. Food then passes
to the pharynx. The pharynx pumps food into the buccal cavity, and it moves
food into the esophagus. The food moves down the esophagus to the crop,
which is a small storage chamber. From the crop, the food is ground in the
muscular gizzard. The intestine is a straight tube that leads from the
gizzard to the anus.
There are two major components of the earthworm circulatory
system. Five contractile vessels, commonly referred to as hearts, are found
in earthworms. The blood is moved via these hearts primarily through the
dorsal blood vessel and into the capillaries of the body.
Earthworms are critically important to the soil as their burrowing
increases drainage and aeration. As well, Lumbricus is an excellent soil mixer
bringing deeper soil to the surface and surface organic material to lower soil
levels.
Procedure:
Prior to the Activity:
1. Copy each page of the worm dissection sheets on different
colors of paper (e.g. page 6 on cream, page 7 on pink, and page 8
on yellow). Make enough copies so that each student will have
all three sheets.
2. Make a copy of the Word Bank handout for each student.
3. To create a dissection packet, stack the dissection sheets with
page 6 on top, followed by page 7, and finally page 8. Staple
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the pages together three times on each side where “Staple
here” is written. Be sure NOT to staple the bottom or top.
Activity:
1. To introduce the exterior anatomy of the earthworm and to
help illustrate how it moves, show the following animation:
http://www.biology.ualberta.ca/courses.hp/zool250/animations
/Earthworm.swf.
2. To introduce the parts of the digestive system, use the
following website:
http://www.naturewatch.ca/english/wormwatch/virtual_worm/i
ndex.html.
3. In order to show, how an earthworm digests its food, show this
animation:
http://www.ncsu.edu/scivis/lessons/earthworm/Overview.html.
4. Introduce the term “virtual dissection” to the students.
Explain that it is a way to understand the external and internal
parts of an organism without having the organism at hand.
5. Use the website, http://biog-101-
104.bio.cornell.edu/BioG101_104/tutorials/animals/earthworm.h
tml, to illustrate a virtual dissection of an earthworm. Point out
the major parts (crop, gizzard, hearts, etc.) of the earthworm
by going through the pictures with the students.
6. Explain that each student will now have the opportunity to do
their own virtual dissection.
7. Distribute one dissection packet and one Word Bank handout to
each student. Keep a copy of the Answer Key on hand to
monitor the student’s responses.
8. Have the students cut out all of the words on the Word Bank
handout.
9. Have the students analyze the top page of the dissection
packet. Tell them to glue the appropriate word on each line.
10. Have the students cut the dashed line on the first page of
their dissection packet and fold over the flaps. Be sure that
they only cut the TOP sheet of paper.
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11. On the second page, have the students identify each part of
the worm and glue the correct label on each line. Point out to
the students that the brain is part of the earthworm’s nervous
system, and that the hearts and dorsal blood vessel are parts
of its circulatory system.
12. Have the students cut along the dashed line on the second page
of the dissection packet being careful to only cut the second
sheet of paper. Have the students fold the flaps open.
13. Have the students label each part on the third page by gluing
the correct word on the line. Emphasize that all of these parts
compose the majority of the digestive system of the
earthworm.
14. Trace the path of food from the mouth to the intestine.
15. Use the completed dissection packet to review the anatomy of
an earthworm.
Evaluation:
Using their dissection packet or by looking at pictures, the students
can identify the major parts of an earthworm.
Extended Activities:
A worm farm, such as that made by Worm-Vue Wonders, can be
brought easily into the classroom for further investigation and
observation of earthworms. Students can observe how real worms
move through the soil and dig burrows.
Two other interactive websites about worms that could be used
to supplement the lesson are:
http://www.urbanext.uiuc.edu/worms/index.html and
http://yucky.discovery.com/flash/worm/.
Sources:
Ruppert, E.E. and R.D. Barnes. 1994. Invertebrate Zoology 6th ed.
Orlando, FL: Saunders College Publishing. 506-567.
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Van de Graaff, K.M. and J.L. Crawley. 2005. A Photographic Atlas for
the Biology Laboratory 5th ed. Englewood, CO: Morton
Publishing Company. 157.
Prepared by:
Heath E. Capello
NSF NMGK-8
University of Mississippi
April 2007
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Staple here
6
NSF North Mississippi GK-8
Staple here
Staple here
Fold here
Staple here
Staple here
Staple here
Fold here
Cut here
Fold here
Fold here
Cut here
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Word Bank
Prostomium
Mouth
Segment
Brain
Hearts
Dorsal Blood
Vessel
Buccal
Cavity
Pharynx
Esophagus
Crop
Gizzard
Intestine
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Answer Key
2.
1.
4.
5.
3.
6.
7.
8.
9.
10.
11.
12.
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1.
2.
3.
4.
5.
6.
Prostomium
Mouth
Segment
Brain
Hearts
Dorsal Blood
Vessel
7. Buccal Cavity
8. Pharynx
9. Esophagus
10. Crop
11. Gizzard
12. Intestine
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