Viewer Discretion Advised: Images to come that may gross you out Biology 11 Kingdom Animalia: Phylum Annelida: The Segmented Worms Viewer Discretion Advised: Images to come that may gross you out

Coelomates At this point in animal evolution, a true coelom developed. So there is ____________________________ - and __________________________________ - around the skin and the gut It also marks the point where two great lines of animal evolution diverged: the Protostomes and the Deuterostomes

The Protostomes Contain three major phyla of animals (Annelida, Arthropoda, Mollusca) While considered less advanced than the Deuterostomes, these phyla are the dominant animals on Earth today

Phylum Annelida Objectives By the end of the lesson you should be able to: State the advances over Nematodes Describe all the body systems and structures (specifically on the Earthworm) Describe the 3 classes and their example animals (and adaptations)

Phylum Annelida The Segmented Worms – From the Latin Annellus ”little ring” Characteristics and Advances: 1. Their ___________________________results in muscle around the gut and more _____________________________. Specialization of the food tube begins 2. Nervous system has a single ____________________________________with an anterior brain

Phylum Annelida 3. First phylum to have a __________________________- frees them from diffusion of materials - can grow larger. Also have “hearts” 4. Respiration through skin (land forms) by diffusion so must stay moist 5. Sexual reproduction (limited regeneration) 6. Unspecialized segmentation separated by __________________________ (dividing wall)

Phylum Annelida 7. Have specialized excretory units called ______________in pairs in each segment Used as a kidney to get rid of metabolic wastes

Annelid Classes There are three major classes of Annelids: Class ____________________: the ___________________ Class ____________________: the ____________________ Class ___________________: the ____________________

Class Oligochaeta “few hairs” Contains the earthworm Move using __________________ (bristles) Fairly well adapted to land but must stay in moist environment Head is reduced as are obvious sense organs

Class Polychaeta Tube Worms Contains _____________________that are modified setae Used as paddles (thus this class is marine) to move about - beginning of appendage development Also used as crude gills - beginning of respiratory system Include sandworms and tubeworms Tube Worms close up of mouth Cluster

Class Polychaeta The sandworm shows the parapodia development

Class Hirudinea _________________ These are _____________________that feed upon the blood of vertebrates including us. Most common in fish Can be used for medical purposes A leech in a persons eye

Annelids Video