AnnelidaAnnelida

By. Michael Shoro and James By. Michael Shoro and James WeaverWeaver

Phylum: AnnelidaPhylum: Annelida

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

SegmentationSegmentation

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

Germ layers Germ layers and Coelomand Coelom

Annelids are Annelids are triploblastic triploblastic (three germ (three germ layers)layers)

Due to the fact Due to the fact that annelids that annelids are hydrostatic, are hydrostatic, annelids annelids contain a contain a coelom.coelom.

Digestive TractDigestive Tract The digestive tract is similar to a humans The digestive tract is similar to a humans

by the fact that it is connected from a by the fact that it is connected from a mouth to an anus. mouth to an anus.

The food is sucked into the esophagus The food is sucked into the esophagus and pushed down the through the body.and pushed down the through the body.

A muscular component of the digestive A muscular component of the digestive tract known as a gizzard grinds down tract known as a gizzard grinds down foodfood

Final absorption is done in the intestines Final absorption is done in the intestines and the waste is expelled through the and the waste is expelled through the anus.anus.

Symmetry Symmetry

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

Circulatory SystemCirculatory System Usually, the blood contains hemoglobin, Usually, the blood contains hemoglobin,

an oxygen-carrying pigment.an oxygen-carrying pigment. The system itself is generally closed within The system itself is generally closed within

vessels, but in some species of leeches and vessels, but in some species of leeches and polychaetes, the blood will flow partially polychaetes, the blood will flow partially into the sinuses of their bodies.into the sinuses of their bodies.

Blood flows towards the head and back Blood flows towards the head and back again.again.

The blood flows because of certain blood The blood flows because of certain blood vessels that contract, thus pumping the vessels that contract, thus pumping the blood throughout the body.blood throughout the body.

Respiratory SystemRespiratory System

Aquatic annelids may have feathery Aquatic annelids may have feathery gills that conduct the gas exchange.gills that conduct the gas exchange.

Most annelids breathe directly Most annelids breathe directly through openings on their body.through openings on their body.

ReproductionReproduction Reproduction can be either sexual or Reproduction can be either sexual or

asexual.asexual. Asexual reproduction would occur through Asexual reproduction would occur through

fragmentation, budding, or fission.fragmentation, budding, or fission. Some sexually reproducing annelids are Some sexually reproducing annelids are

hermaphrodites, meaning they have both hermaphrodites, meaning they have both male and female sex organs.male and female sex organs.

Eggs of land annelids tend to be encased in Eggs of land annelids tend to be encased in cocoons, where the baby annelids hatch as cocoons, where the baby annelids hatch as miniature versions of their adult selves.miniature versions of their adult selves.

HabitatHabitat

Wide range of geographical Wide range of geographical environments.environments.

Some live in semi-arid conditions Some live in semi-arid conditions while some live underwater.while some live underwater.

Most terrestrial annelids prefer to live Most terrestrial annelids prefer to live in moist or damp areas.in moist or damp areas.

Earthworms, for example, like to live Earthworms, for example, like to live under rocks or logs, where it is dark, under rocks or logs, where it is dark, damp, and sheltered.damp, and sheltered.

CephalizationCephalization

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

Annelids do have cephalization. Annelids do have cephalization.