Characteristics of Nematoda:-
1)Bilaterally symmetrical, and vermiform.
2) Body has more than two cell layers, tissues and organs.
3) Body cavity is a pseudocoel, body fluid under high pressure.
4) Body possesses a through gut with a subterminal anus.
5) Body covered in a complex cuticle.
6) Has a nervous system with pharyngeal nerve ring.
7) Has no circulatory system (no blood system)
8) Reproduction normally sexual and gonochoristic.
9) feed on just about everything.
10) Live just about everywhere, many species are endoparasites. http://www.earthlife.net/inverts/nematoda.html Cell structure:
Size of phyla:
Nematodes are the most speciose phylum after the arthropods, they occur in nearly every habitat including as parasites in all sorts of plants and animals, (they don't like dry places however). One species is known that can live in old vinegar (Turbatrix aceti)and another that as only been found in German beer mats. Though only about 80 000 species have been described some scientists estimate there may be as many as a million species all told. They can occur in very dense numbers in the soil and rotting vegetation, as many as 90 000 have been found in a single rotting apple, while millions occur in the top 3cm (1 inch) of a square metre of good quality soil. While there are a huge number of free living Nematodes there are also a large number of parasitic species, many of which cause diseases to man and other animals as well as to plants, nearly every living organism has been found to be parasitised by one species of nematode or another. Most nematodes are reasonably small, they range in size from 100 micrometres in length (1/10th of a mm or 1/250th of an in) to the female Giant Nematode Dioctophyme renale which may be up to 1 metre, or 3 ft long.
Nematode Life Cycles
Colours signify:- Blue = Free Living, Red = Primary Host, Green = Secondary Host