Under the sand on some beaches there are up to 32,000 Annelids per square meter. Also they burrow in all kinds of soild which is where they rework the soil and sediments. Other types are found on other organisms where they live off that current host.
b. Movement
They use longitudinal muscles which when contracted makes the worm shorter. Also another group of muscles is utilized to make the warm skinnier when contracted. when all tehse muscles are used together they can take the worm wherever it wants to go.
c. Feeding/Digestion
The digestive tract of the Annelida is a long tube located inside the body cavity which runs from the mouth to the anus. When food enters the mouth it goes through the gut where it is digested and straight to the anus. In feeding the pharynx is present in both herbivore and carnivorous Annelids. Also some feed by the process of filter feeding.
d. Circulation/Internal Transport
Most Annelids have closed circulatory systems around two blood vessels which stretch the length of their body. As blood moves to the head of the annelid the blood is on the dorsal side of the annelid but as it moves to the back of the worm it travels on the ventral area of the annelide. In earthworms mainly there are several of the ring vessels that are considered hearts because they contract rhythmically and help pump blood through the heart.
e. Respiration
Annelids that live in the water mainly breath through gills. Some Annelids are capable of taking in oxygen through their skin and then giving off carbon dioxide. Some die opf suffocation because their skin drys out and they cannot take in oxygen. To stop or at least slow down the process of drying out and dieing there is a protective called a cuticle which holds in moister.
f. Nervous System
The Brain for all annelids sits at the top of the gut. two nerves connect to the brain. There is an entire nerve cord which runs the entire length of the annelid. Most annelids have sensory objects such as sensory tentacles, statocysts, chemical receptors, and two or more eyes. Some annelids are very simple because they have only tiny sensory objects in the skin.
g. Reproduction
Most annelids produce sexually even though some are capable of asexual reproduction. Annelids can also have the capability of producing sperm and fertilizing an egg. Annelids rarely fertilize their own eggs so its basically like a buddy system. Some annelids have external fertilization where eggs are released into open water and the female worms come into fertilize the egg they want.
h. Excretion
Solid wastes past through the anus but the wastes resulting from cellular metabolism are eliminated by nephridia which is a simple toob-like excretory system. There is a pair of nephridia in each segment of annelids which carry all the wastes that cannot pass through the anus to the outside.