EARTHWORM DISSECTION
INTRODUCTION
BACKGROUND
The earthworm is from the world of Animalia. Earthworms, members of the phylum
Annelida (segmented worm), are among the most familiar invertebrate species. An annelid's
body is generally split internally and externally into well-defined segments, which can be
divided by membranous partitions from each other. Bilateral symmetry and a body plan for
'tube-within-a-tube' are available for earthworms. A distinguishing feature of this phylum is
the division of the body into divisions. This segmentation is external and internal with several
structures or organs repeated in each segment. The body has three layers of ectoderm,
mesoderm and endoderm tissue. The coelom is a space in the layers of mesoderm. The
circulatory system is a closed circulatory system, ensuring that the blood remains within the
vessels. Earthworm has a digestive system, reproductive system, simple circulatory system
and nervous system
Earthworms live in the soil making their way through it to consume and eat organic
matter within the soil. Earthworms exchange oxygen through their moist skin so that if a
worm dries out it does not get air other than the risks of dehydration so that it dies. They
intend to play an important role in soil aeration and fertilisation. However, earthworms will
also not survive underwater, and if the soil they live in becomes completely flooded with
water after a heavy storm, they will all come to the surface so that they do not drown.
Earthworms are hermaphroditic and with a pair of worms, fertilise each other.
OBJECTIVE
1. To identify the parts of an earthworm and their respective functions
2. To understand the anatomical and physiological characteristics of an earthworm
PROBLEM STATEMENT
What are the anatomical and physiological characteristics of earthworms?
HYPOTHESIS
Dissecting an earthworm specimen helps us to identify their internal organs and it functions.
, APPARATUS & MATERIALS
• Dissecting pins
• Gloves
• Forceps
• Dissecting scissors
• Scalpel
• Dissecting probe
• Preserved earthworm
• Dissection tray
• Hand lens
• Lab coat
PROCEDURE
1. The anterior and posterior ends are identified. The anterior end is located close to the
clitellum.
2. The dorsal and ventral surface of earthworm (The ventral side is lighter in color)
identified.
3. The pin is attached to the worm's side and the pin is pushed into the pad beneath the
worm to prevent damage to internal organs.
4. The worm is stretched in a straight line and the pin is attached to the posterior and
anterior regions of the worm.
5. A short transverse incision in the dorsal surface just behind the clitellum is made
using a scalpel.
6. The medial incision to the interior is made using scissors, the epidermis and cuticle
are cut without cutting too deep to prevent damage to the internal organs.
INTRODUCTION
BACKGROUND
The earthworm is from the world of Animalia. Earthworms, members of the phylum
Annelida (segmented worm), are among the most familiar invertebrate species. An annelid's
body is generally split internally and externally into well-defined segments, which can be
divided by membranous partitions from each other. Bilateral symmetry and a body plan for
'tube-within-a-tube' are available for earthworms. A distinguishing feature of this phylum is
the division of the body into divisions. This segmentation is external and internal with several
structures or organs repeated in each segment. The body has three layers of ectoderm,
mesoderm and endoderm tissue. The coelom is a space in the layers of mesoderm. The
circulatory system is a closed circulatory system, ensuring that the blood remains within the
vessels. Earthworm has a digestive system, reproductive system, simple circulatory system
and nervous system
Earthworms live in the soil making their way through it to consume and eat organic
matter within the soil. Earthworms exchange oxygen through their moist skin so that if a
worm dries out it does not get air other than the risks of dehydration so that it dies. They
intend to play an important role in soil aeration and fertilisation. However, earthworms will
also not survive underwater, and if the soil they live in becomes completely flooded with
water after a heavy storm, they will all come to the surface so that they do not drown.
Earthworms are hermaphroditic and with a pair of worms, fertilise each other.
OBJECTIVE
1. To identify the parts of an earthworm and their respective functions
2. To understand the anatomical and physiological characteristics of an earthworm
PROBLEM STATEMENT
What are the anatomical and physiological characteristics of earthworms?
HYPOTHESIS
Dissecting an earthworm specimen helps us to identify their internal organs and it functions.
, APPARATUS & MATERIALS
• Dissecting pins
• Gloves
• Forceps
• Dissecting scissors
• Scalpel
• Dissecting probe
• Preserved earthworm
• Dissection tray
• Hand lens
• Lab coat
PROCEDURE
1. The anterior and posterior ends are identified. The anterior end is located close to the
clitellum.
2. The dorsal and ventral surface of earthworm (The ventral side is lighter in color)
identified.
3. The pin is attached to the worm's side and the pin is pushed into the pad beneath the
worm to prevent damage to internal organs.
4. The worm is stretched in a straight line and the pin is attached to the posterior and
anterior regions of the worm.
5. A short transverse incision in the dorsal surface just behind the clitellum is made
using a scalpel.
6. The medial incision to the interior is made using scissors, the epidermis and cuticle
are cut without cutting too deep to prevent damage to the internal organs.
