Earthworm Dissection Lab Part A External Anatomy What

Earthworm Dissection Lab Part A: External Anatomy

What you need per group § § Dissecting tray (2 per station) Probe (2 per station) Earthworm Lab Worksheet (1 per student) 1) Moisten Paper towel & lay flat onto the dissecting tray 2) Place Earthworm on paper towel

What to do when cleaning up § § § Return worms to bucket 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 and bring to class on Weds.

Part A. External Structures Take a picture of the following § Anterior (Head end) § Identify the Prostomium (lip of mouth)

Part A. External Structures Take a picture of the following § Identify & Count the # of Segments (on body) starting from the anterior end § Record # on Worksheet Question 1 a § Every inch = 1 year of age (Avg age 6 yrs) Segments

Part A. External Structures Take 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 1 b.

Part A. External Structures Take a picture of the following § Identify & feel the Ventral Side (belly side); looks “whiter” & “flatter” than dorsal side

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 2 a & 2 b on worksheet

Part A. External Structures Take a picture of the following § Identify the Sperm Ducts (on the ventral side); looks like “bumps” § This is where sperm is released

Part A. External Structures Take a picture of the following § Identify the Sperm Grooves (on the ventral side); Lines moving from the Sperm Ducts § This is where sperms travel

Part A. External Structures Take a picture of the following § Identify the Dorsal (Upper back) side § Locate the dorsal blood vessel (dark line running through the middle of body)

Part A. External Structures Take a picture of the following § Identify the Posterior End (tail end) & anus Anus Posterior