Earthworm Dissection Lab Part A: External Anatomy

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Earthworm Dissection LabPart A External Anatomy
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What you need per group

• Dissecting tray (1 per station)
• Probe (1 per station)
• Earthworm (1 per station)
• Earthworm Lab Worksheet (1 per student)
• Moisten Paper towel lay flat onto the
  dissecting tray
• Place Earthworm on paper towel

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What to do when cleaning up

• Wrap worm and parts in paper towel
• Toss paper towel in trash
• Stack dissecting tray back on cart
• Return probes to Beaker
• Exchange emails to get copy of pictures taken
  from lab
• HW
• a. Complete Prelab Questions on Earthworm
• Dissection Worksheet
• b. Print pictures, Label and bring to class
  on Tues.

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Lab Members Duties

• 1 Dissector
• 1 Helper
• 1 Reader
• 1-2 Camera People

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Disseciton Vocabulary WordsPre-lab Qs

• 1a. Anterior Towards the head
• b. Posterior Towards the tail
• Dorsal Upper back (facing the sky)
• Ventral Belly side

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Part A. External StructuresTake a picture of the
following

• Anterior (Head end)
• Identify the Prostomium (lip of mouth)

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Part A. External StructuresTake a picture of the
following

• Identify Count the of Segments (on body)
  starting from the anterior end
• Record on Worksheet Question 1a
• Every inch 1 year of age (Avg age 6 yrs)

Segments
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Part A. External StructuresTake a picture of the
following

• Identify the Clitellum (thick band)
• Function Location where sex occurs and mucus is
  made.
• What segment is this located? Answer for 1b.

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Part A. External StructuresTake a picture of the
following

• Identify feel the Ventral Side (belly side)
  looks whiter flatter than dorsal side

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Part A. External Structures

• Identify feel the Setaes with your finger (come
  in pairs) along the lateral side of the worm
  (feels like tiny whiskers)
• Function Helps it move through dirt/soil
• Answer 2a 2b on worksheet

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Part A. External StructuresTake a picture of the
following

• Identify the Sperm Ducts (on the ventral side)
  looks like bumps
• This is where sperm is released

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Part A. External StructuresTake a picture of the
following

• Identify the Sperm Grooves (on the ventral side)
  Lines moving from the Sperm Ducts
• This is where sperms travel

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Part A. External StructuresTake a picture of the
following

• Identify the Dorsal (Upper back) side
• Locate the dorsal blood vessel (dark line running
  through the middle of body)

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Part A. External StructuresTake a picture of the
following

• Identify the Posterior End (tail end) anus

Anus
Posterior
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Things to have External Worm

1. Prostomium (lip)
2. Anterior
3. Segments
4. Dorsal
5. Clitellum
6. Ventral Side
7. Sperm Ducts
8. Sperm Grooves
9. Posterior
10. Anus

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Internal Structures Must Have

• Print Pictures and Label the following
• 1. Seminal Vesicles 6. Intestine
• 2. Pharynx 7. Five-ringed heart
• 3. Esophagus 8. Dorsal Vessel
• 4. Crop 9. Ventral
  Vessel
• 5. Gizzard 10. Nerve Cord