biology unit 7 organ systems worm notes
TRANSCRIPT
BIOLOGY
Unit 7:Earthworm Notes
(1) External Parts• Setae:
– Rings / Segments – Contain tiny hairs to help with movement + sex.
• Clitellum:– Knob near center-length of worm.– Secretes fluid to enclose fertilized eggs.
• Mouth vs. Anus:– Mouth = Closer to Clitellum– Anus = Further away from Clitellum
(2) Internal Parts*MOST INTERNAL PARTS ARE BETWEEN
THE MOUTH + CLITELLUM.*
• Ganglia:– Fleshy bit right behind the mouth.– “Brain” of worm.
• Aortic Arches:– Tiny black, finger-nail looking bits.– Circulate blood / nutrients.
(3) Digestive Organs• Pharynx:
– Round Bump behind mouth + ganglia.– Starts to break down food.
• Esophagus:– Wrinkly tube leaving the mouth + pharynx.– Carries food to next organs.
• Crop:– Round lump after esophagus.– Stores food before digestion.
• Gizzard:– Round lump after crop.– Contains stones to break apart food.
Digestive Organs (Cont’d)• Intestine:
– Long skinny tube leaving gizzard.– Goes rest of length of worm.
(4) Reproductive Organs• Seminal Receptacles:
– Fleshy colored lumps/bits, behind the hearts.– Receive sperm for egg fertilization.
• Seminal Vesicles:– Small fleshy lumps/bits, behind hearts.– Release + store sperm.
---Dissection Notes---
1. Lie worm on its belly (rounded/darker side pointed up).
2. Identify clitellum.
3. Carefully cut from MOUTH CLITELLUM
4. Carefully peel back skin.
5. Identify organs.
External Dorsal:
Clitellum
Mouth
Dorsal Blood Vessel(Dark Line) Anus
External Ventral:
Mouth
Clitellum Genital
Setae
Sperm Ducts Female
Genital Pores
Internal:
Intestine Gizzard
Crop
Seminal Vessicles
Seminal Recepticles
Aortic Arches
Esophagus
Ph
arynx
Ganglia
(Brain)
Internal w/o Digestive…
Nerve Cord
(Like our Spinal Cord)
Seminal Receptacles