+ Annelida Nadine Thomas, Elizabeth Skuriat, Julia Woynar, and Johanna Murray

+ Species Medium sized phylum with more than species of worms Freshwater, marine, or terrestrial 3 Major Classes of Annelida: Polychaeta Hirudinea Oligochaeta This specimen is an Oligochaeta.

+ Characteristics Bilaterally symmetrical Body has three separate sections – prostomium, trunk, and pygidium Body has more than two cell layers, tissues, and organs Live in most environments This specimen is a Polychaeta.

+ Characteristics cont’d Major invertebrate phylum Life span – months to years Size – millimeters to meters Movement assisted by lobes and bristles Ability to regenerate

+ Segmentation Each organism has segmentation Allows movement and protection Other phylum with segmentation include Anthropoda and Chordata Segmentation in Annelida can be either external or internal Segments separated by septums Segments can be used for specialization This specimen is a leech.

+ Biological Systems Annelida have a closed circulatory system Simple diffusion is used for gas exchange Have a digestive system that passes from mouth to anus Crop, gizzard, typhosole Also have a nervous system

+ Evolution Evolved from the sea Oligochaetes developed from polychaete stock Leeches and oligochaetes have clitellum in common Evolution relations between marine to freshwater.

+ References TEXT PICTURES

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