Name: Date:

Phylum Annelida: Segmented Worms

Domain: Kingdom:

References: Text 681-683. This is required reading!

Shape of Life, Chapter 4: Annelida Body Plan

-Segmented worms belong to Phylum Annelida, which means ____________________

in Latin.

-Annelids are different from other worms we have talked about because their bodies are

segmented and they possess a true coelom.

Biology 11 AP: Annelida Page 1

Annelida Common Characteristics and Evolutionary Advances

a) Segmentation

-In Annelida, the basic body plan is divided

into segments with external body rings and

internal septa. What is segmentation an

evolutionary advantage?

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b) Coelom Development

-Annelids have a fluid-filled coelom, which functions in:

i) Movement: ____________________________________________________________

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ii) Protection: ____________________________________________________________

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c) Movement

-Locomotion involves the alternation

of two muscle groups. Each segment

has its own circular and longitudinal

muscles.

d) Embryological Development

-Annelids are protostomes because ___________________________________________

Biology 11 AP: Annelida Page 3

Annelida Classes

1. Class Oligochaeta: Earthworms

- Earthworms are classified as Oligochaeta because they have relatively few __________

Biology 11 AP: Annelida Page 4

Use the diagram to comment on

earthworm respiration.

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Comment on their digestive system.

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2.Class Hirudinea: Leeches

*Use text page 683 to write your own notes about leeches

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3. Class Polychaetes: Bristle Worms

Polychaetes are often called bristleworms because each of the body segments has an upper and lower bundle of bristles (called setae or chaetae) on each side. In free-living polychaetes, the bristles, combined with snake-like body waves, help the worm to move along. In Fireworms, Eurythoe spp (A), the bristles have evolved into defensive organs. They are fragile, hollow tubes filled with poison. They are easily broken when the worm is touched and the pain they cause when they pierce the skin makes their common name very appropriate.

The bristles found in worms that live in tubes or burrows (sessile or sedentary) have often evolved hooks to help anchor the worm in place. Sedentary worms make a whole variety of homes. Many make a hard calcareous tube (C-Spororbis), which is attached to a hard surface or even large algae. Other sedentary worms have a leathery tube, sometimes decorated with pieces of broken shell, or sand and mud particles.

Free-living worms include carnivores, herbivores and scavengers. Some, such as the fireworms, are active carnivores feeding on colonial animals eg: sponges and ascidians). On the other hand, sedentary worms, (which cannot move about), usually feed on microscopic plants and animals or fine particles. Many sedentary worms filter plankton out of the water by a crown of feathery tentacles that surround their mouth and give them their common name of 'fanworm' or 'feather duster' worm (B)

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