earthworm dissection
DESCRIPTION
Earthworm Dissection. Phylum Annelida —segmented worms. Over 1000 species! (earthworms, marine worms, leeches). Segments allow for specialization of tissue and efficiency of movement. “Tube within a tube” digestive system Breath through skin by diffusion Closed circulatory system - PowerPoint PPT PresentationTRANSCRIPT
Earthworm Dissection
•Phylum Annelida—segmented worms
•Over 1000 species! (earthworms, marine worms, leeches)•Segments allow for specialization of tissue and efficiency of movement
• “Tube within a tube” digestive system
• Breath through skin by diffusion
• Closed circulatory system
• 2 kinds of muscle for movement: – Circular (shrink and spread)– Longitudinal (shorten and lengthen)
Step 1-Locate the dorsal, ventral, anterior, and posterior sides
Step 2-Find the sperm ducts and clitellum
Step 3-Find the mouth and anus
Step 4-Place 2 pins in the worm
Step 5-Carefully cut the worm
Why do you think there is a thin, layer here?
•Cut all the way to the clitellum
Step 6-Pin the worm, exposing all internal organs
Step 7-Identify all internal organs
Pharynx—used to suck in food
Esophagus—food travels through this after pharynx
Seminal vesicles—produce sperm***Remove with tweezers
*Crop-stores food*Gizzard-grinds up food (very strong)
crop gizzard
Intestines!!!!!-digestion and absorption of food
What are these small organs???
aortic arches/hearts
This thin dark-red tube extends the entire length of the worm. It is the dorsal blood vessel !!!