Phyla Annelida - The Earthworm
Dissection
Activity
WORKSHEET :)
Content Cont.
Moving: Uses segments to contract or relax to cause the body to lengthen in one area or contract in other areas.
Reproducing: Hermaphrodites. During mating, two worms line up inverted from each other so sperm can be exchanged.
Earthworms have a modified external fertilization. After copulating during which each hermaphroditic earthworm exchanges sperm with another, earthworms create a cocoon external to their clitellum.
Respiring: They breathe through their skin. Oxygen and carbon dioxide pass through the earthworm’s skin by diffusion.
Excreting: Has a mouth and an anus.
Responding: They have tissue located at the earthworm’s head that is sensitive to light.
Supporting: Has a coelem with is the hydro skeleton.
Transporting: The intestinal wall contains blood vessels where the digested food is absorbed and transported to the rest of the body. Circulatory System. Three vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels.
Seta
Content
BRISTLES on VENTRAL surface
PROSTOMIUM
http://urbanext.illinois.edu/worms/anatomy/anatomy3.html
- covers/protects mouth opening
senses light and dark/chemicals (food)
CLITELLUM
http://urbanext.illinois.edu/worms/anatomy/index.html
- is the ring
- does not go all the way around
- closest to the anterior end
- makes mucus for reproduction
http://urbanext.illinois.edu/worms/anatomy/anatomy4.html
Phylum: Annelida
Example: Earthworm
Symmetry: Bilateral Symmetry- When you cut it length wise, both sides are equal to each other.
Habitat: Live in most evironments
Organization: Tissues, Organs and Organ Systems
Distinguishing Characteristics: Annelids are cylindrical worms with segmented bodies (they are metameric). Is a two-holed system.
Digesting: The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard.
5 Hearts?
GIZZARD
- All of these hearts pump blood through blood vessels just like our heart.
- used in the digestive system
- grinds food together
- leaves gizzard to intestine
http://urbanext.illinois.edu/worms/anatomy/anatomy6.html
What are Earthworms?
CUTICLE
- non-cellular protective layer
- Its a clear layer on top of the skin layer, you will see it in the dissection
COELOM
Fun Facts
- If an earthworm is split in two, it will not become two new worms. The head of the worm may survive and regenerate its tail if the animal is cut behind the clitellum. But the original tail of the worm will not be able to grow a new head (or the rest of its vital organs), and will instead die.
- O2 is in soil. Healthy soil is aerobic soil, and earthworms are one of the ways that soil stays aerobic.