biology unit 7 organ systems crayfish notes
TRANSCRIPT
BIOLOGY
Unit 7:Crayfish Notes
(1) External Parts• Carapace:
– Hard, red outer shell– Exoskeleton to protect internal organs
• Chelipeds:– Large pincher-claws– Used to grab prey
• Maxillipeds:– Smaller arms near mouth.– Used to shove food into mouth.
• Swimmerets:– Tiny, feather like legs (along belly)– Used to grasp during sex.
External Parts (Cont’d)• Antennae:
– Long stalks along top of head.– Sensory reception.
• Gills:– White, feathery like layers along sides of head.– Absorb oxygen from water (for breathing).
(2) In The Head• Encephalon:
– Fleshy bit, Directly inside head, by eyes.– (Brain) Control all other organs + respond.
• Green Gland:– 2 small flesh-sticks on either side of eyes.– Secrete enzymes needed to digest food.
• Stomach:– Sack full of bony teeth.– Directly behind head in center.– Breaks apart food.
(3) Chest & Abdomen• Heart:
– Light brown flap behind stomach, along back.– Pump + circulate blood across organs.– Open Circulatory System = No blood vessels,
organs bathe in blood.
• Intestine:– Skinny tube leaving stomach.– Absorb nutrients and excrete waste.
Male Parts• Appearance:
Tiny, bent legs
• Location:Belly
• Function:Insert sperm into female
Female Parts• Appearance:
Swollen hole
• Location:Belly, in between swimmerets
• Function:Take in sperm (like vagina)
--Dissection Notes--
1. Lay crayfish on its belly.
2. Find carapace behind head.
3. Cut along lines + gently remove carapace.
4. Identify internal + external organs.
External Dorsal:
External Ventral:
Sex:
MALE FEMALE
External (Lateral):
Internal (Dorsal):
Deeper Internal (Dorsal):
Internal (Lateral)
Abdomen (Dorsal):