Phylum Annelida

Question 1

What are some General characteristics of Annelida?

Answer 1

Bilateral symmetry.
3 cell layers (ectoderm, mesoderm, endoderm)
Organ level organization.
Exhibit cephalization.
Complete digestive system (mouth & anus)
Closed circulatory system (blood is pumped & contained in vessels).
Have septa: internal walls walls that separate each body segment

Question 2

How do earthworms reproduce?

Answer 2

Worms attach to each other in opposite directions. They exchange sperm into receptacles

Question 3

What are some unique characteristics of Anelida?

Answer 3

1st animal to have a fully developed body cavity (completely lined by mesoderm).
It is where blood vessels, heart, excretory organs and organs for gas exchange are found.

Have segmentation.

Question 4

What’s the second part in reproduction

Answer 4

Earthworms have a swelling called a clitellum which secretes a mucus ring around the worm. The worm then releases it’s eggs. The worm slides out the mucus ring.

Question 5

What is segmentation?

Answer 5

External segments & internal compartments.
Each “compartment” is filled with coelomic fluid. This partitioning of the coelom permits each body segment to move independently.

Question 6

How does segmentation lead to specialization?

Answer 6

Different segments become specialized for different purposes.