Annelida

1
Annelida

• By. Michael Shoro and James Weaver

2
Phylum Annelida

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

3
Segmentation

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

4
Germ layers and Coelom

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

5
Digestive Tract

• 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.
• 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.

6
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)

7
Circulatory System

• 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.
• 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.

8
Respiratory System

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

9
Reproduction

• Reproduction can be either sexual or asexual.
• Asexual reproduction would occur through
  fragmentation, budding, or fission.
• 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.

10
Habitat

• Wide range of geographical environments.
• Some live in semi-arid conditions while some live
  underwater.
• 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.

11
Cephalization

• 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.