Circulatory Systems:

The circulatory system is made up of the vessels and the muscles that
help and control the flow of the muscles that help and control the flow of
the blood around the body. The main parts of this system are the heart,
arteries, capillaries and veins.

Circulatory System of an Arthropod:
The circulatory system of an arthropod is open. With most of the body
fluid, or hemolymph, occupying cavities of the body and it's appendages.
The three main classes into which the phylum is divided is; insects,
crustaceans, and arachnids. Other classes include; onychophorans,
diplopods, and chilopods. All arthropods have a heart. Crustaceans and
arachnids hae respitory pigments.
Arthropods reproduc sexually for the most part. The males pass a sack
to the females by ether dropping it, or putting it directly into the female.
The female then lays the eggs which will eventually hatch. The hatching
period depends on the arthropod that hatched the eggs.

Cirulatory System of a Nemotode:
Nematodes possess digestive, nervous, excretory and reproductive
systems, but lack a discrete circulatory or respitory system. There are
nearly 20,000 described species classified in the phylum Nemata. They
live about anywhere, and eat about everything. They like dense places,
or rotting vegititation.
Nematodes can reproduce one of two ways. One way would be asexually,
which means they can fertilize the egg themselves. Although a male and a
female could reproduce together.

Circulatory System of an Echinoderm:
Echinoderms do not possess a circulatory system. Instead they have
a haemal system, and in most cases a perihaemal system. Both come
from the coelom, and form a open circulatory system. The greek word
Echinodermata means "spiny skin". All echinoderms live in salt water,
and the phylum comtains about 7,000 different species. Examples would
be star fish, sand dollars, sea cucumbers, and urchins.
Echinoderms can reproduce either asexually, or sexually.

Porifera- Do not technically have a circulation system but use their pores to maintain a constant flow of water through the body. This flow is to remove waste, bring in food, and oxygen. So in theory, their respiratory, digestive, and excretion system is all in one, acting as one huge circulation system.

This species mainly uses diffusion to get a flow of nutrients and food through their bodies. They do not move therefore they just suck in the needed elements from around them. They can also pump water through their tentacles to efficiently use diffusion so that no nutrients they use escapes the body through the mouth. But if an excessive amount of oxygen comes in it could prove toxic, so they use anti oxidants to neutralize that problem.

  • Mollusk
  • A soft bodied organism that has a fluid filled cavity.
  • They are one of the largest phyla of animals.
  • They have an open circulatory system, which does not allow the blood to flow through out the body.
  • The mollusk has a blood cavity, which is also known as a hemocoel.
  • The respiration and circulation helps the mollusk increase in size.

  1. Platyhelminthes is the simplest form of an animal.

    They are also known as flat worms and tape worms.
  2. They don't have an anus for their food to come out of.
  3. The other name for this phylum is (parasite).
  4. external image platyh5.gif
    external image platyh5.gif


All of this species diffuse nutrients through the skin, also through pores. The pores are at the end with the heaviest water flow.