27.3 Annelids Notes
 Nevada State Science Content Standard: L.12.D.1 Students know
organisms can be classified based on evolutionary relationships. E/S
 Objective:
Describe the defining features of annelids.
Identify the characteristics of the classes of annelids.
Describe the ecology of annelids.
 Set: The assessment for this lesson will be a hands on assessment. You will
have the opportunity to dissect and then identify the internal organs of an
annelid.
 Key Vocabulary
Septum – Internal wall between the segments of an annelid’s body (p 694)
Seta – bristle attached to the segments of many annelids (p 694)
Crop –part of the digestive system in which food can be stored in earthworms (p 695)
Gizzard – part of the digestive system in which food is ground into smaller pieces in
earthworms (p 695)
Closed circulatory system – system in which blood is contained within a network of blood
vessels (p 695)
Gill – filamentous organ in aquatic animals specialized for the exchange of gases with water (p
696)
Nephridium – excreatory organ of an annelid that filters fluid in the coelom (p 696)
Clitellum – band of thickened, specialized segments in annelids that secretes a mucous ring
into which eggs and sperm are released (p 696)
What are the defining features of annelids? (p 694)
What are some functions performed by specialized segments? (p 694)
What are the characteristics of the 3 classes of annelids? (p 697 – 698)
What are earthworm castings? (p 697)
Describe the feeding strategies of earthworms and leeches. (p 697 – 698)