Annelida By. Michael Shoro and James Weaver

Phylum: Annelida Annelida or more commonly known as ringed worms, contain leeches, earthworms, marine worms and many more.

Segmentation Annelids have multiple segments. Each segment contains the same set of organs which allows it to multiply if cut in half. Annelids have multiple segments. Each segment contains the same set of organs which allows it to multiply if cut in half.

Germ layers and Coelom Annelids are triploblastic (three germ layers) Annelids are triploblastic (three germ layers) Due to the fact that annelids are hydrostatic, annelids contain a coelom. Due to the fact that annelids are hydrostatic, annelids contain a coelom.

Digestive Tract The digestive tract is similar to a humans by the fact that it is connected from a mouth to an anus. The digestive tract is similar to a humans by the fact that it is connected from a mouth to an anus. The food is sucked into the esophagus and pushed down the through the body. The food is sucked into the esophagus and pushed down the through the body. A muscular component of the digestive tract known as a gizzard grinds down food A muscular component of the digestive tract known as a gizzard grinds down food Final absorption is done in the intestines and the waste is expelled through the anus. Final absorption is done in the intestines and the waste is expelled through the anus.

Symmetry Annelids are bilaterally symmetrical and can be found from lengths of a few hundred microns in length (Neotenotrocha) to 3 meters in length (Eunicida)

Circulatory System Usually, the blood contains hemoglobin, an oxygen- carrying pigment. Usually, the blood contains hemoglobin, an oxygen- carrying pigment. The system itself is generally closed within vessels, but in some species of leeches and polychaetes, the blood will flow partially into the sinuses of their bodies. The system itself is generally closed within vessels, but in some species of leeches and polychaetes, the blood will flow partially into the sinuses of their bodies. Blood flows towards the head and back again. Blood flows towards the head and back again. The blood flows because of certain blood vessels that contract, thus pumping the blood throughout the body. The blood flows because of certain blood vessels that contract, thus pumping the blood throughout the body.

Respiratory System Aquatic annelids may have feathery gills that conduct the gas exchange. Aquatic annelids may have feathery gills that conduct the gas exchange. Most annelids breathe directly through openings on their body. Most annelids breathe directly through openings on their body.

Reproduction Reproduction can be either sexual or asexual. Reproduction can be either sexual or asexual. Asexual reproduction would occur through fragmentation, budding, or fission. Asexual reproduction would occur through fragmentation, budding, or fission. Some sexually reproducing annelids are hermaphrodites, meaning they have both male and female sex organs. Some sexually reproducing annelids are hermaphrodites, meaning they have both male and female sex organs. Eggs of land annelids tend to be encased in cocoons, where the baby annelids hatch as miniature versions of their adult selves. Eggs of land annelids tend to be encased in cocoons, where the baby annelids hatch as miniature versions of their adult selves.

Habitat Wide range of geographical environments. Wide range of geographical environments. Some live in semi-arid conditions while some live underwater. Some live in semi-arid conditions while some live underwater. Most terrestrial annelids prefer to live in moist or damp areas. Most terrestrial annelids prefer to live in moist or damp areas. Earthworms, for example, like to live under rocks or logs, where it is dark, damp, and sheltered. Earthworms, for example, like to live under rocks or logs, where it is dark, damp, and sheltered.

Cephalization Cephalization is when there is a concentration of nervous tissue along with other internalized organs located by the head of the creature. Cephalization is when there is a concentration of nervous tissue along with other internalized organs located by the head of the creature. Annelids do have cephalization. Annelids do have cephalization.