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What is a septa?
Thin membranous fold that separates the coelom into divisions.
What does each segment of an annelid worm contain?
The same organs and structures.
What is metamerism?
Repetition of body segments.
What are the segments in an annelid worm called?
What type of circulatory system to annelids have?
What is the advantage of a closed circulatory system?
Higher metabolic rate for faster movement.
What is metanephridia?
The excretory system in annelids.
What is the excretory system of the annelids called?
What are parapodia and how are they reinforced?
They are appendages that serve in respiration and locomotion, and are reinforced by acicula and setae.
What type of digestive tract do annelids have?
How do annelid worms move?
They have a layer of circular muscles and a layer of longitudinal muscle that create peristaltic waves.
Some worms have parapodia which require oblique muscles to create the elliptical motion for movement.
What are the three classes of annelids?
What class of annelida are the clamworms in?
How does the class oligochaeta move?
Peristalticly, using setae.
What role do setae have in oligochaeta's movement?
They anchor the worm into the ground while they move
What is the clitelum of an earth worm?
A thicker portion of the worm that secretes a mucus-like egg capsule.
Is the earthworm monoecious or diecious?
How does reproduction work for an earthworm?
- Two earth worms meet.
- Sperm from one worm is transferred to the other and stored in the seminal receptacle.
- The clitelum secretes the egg capsule and allows it to harden.
- The worm wiggles backwards out of the egg capsule while eggs are secreted from the oviduct.
- Stored sperm is secreted from the seminal receptacle.
- The worm slides completely out of the egg capsule, creating a cocoon.
- Fertilization occurs while the cocoon hardens.
- Worms grow and emerge from the cocoon.
Where is sperm stored in an earth worm?
How does digestion work in an earth worm?
- Food is sucked into its mouth by a muscular pharynx.
- It is pushed through an esophagus by peristaltic waves.
- Food is stored in a thin walled crop.
- Food is passed to the gizzard which churns the food.
- Digestion and absorption occur in the intestine to the anus.
What type of circulatory system does an earth worm have?
What path does blood take in an earth worm?
- The dorsal vessel pumps blood forward to the aortic arches.
- The aortic arches pump blood to the ventral vessel.
- Blood is distributed through the body via the ventral vessel.
How does an earth worm exchange gasses?
Through its skin.
What does an earth worm use as an excretory system?
How does the metanephridium excretory system work?
- Waste is pumped into the metanephridium.
- It passes through a series of tubes surrounded by blood vessels that reabsorb any wanted material.
- Waste is released through a nephridiopore.
- A: Pharynx
- B: Heart
- C: Seminal Vesicles
- D: Septa
- E: Seminal Receptacle
- F: Crop
- G: Gizzard
- H: Intestine
- I: Dorsal Blood Vessel
What is the distinguishing feature of the class hirudinea?
Anterior and posterior sucker.
What class are the leeches in?