Trilobites are extinct arthropods. One of the closest living relatives to the a trilobite is the Horseshoe Crab. The bodies of trilobites are divided into three parts: a cephalon (head), a thorax (body) ; and a pygidium (tail).Trilobites are often found curled up like now day sow bugs for protection. Trilobites range in length from one millimetre to 70 cm. Trilobites lived in the marine waters. Most could swim, but some couldn't so they just crawled around on the ocean floors. They are not quiet sure why they became extinct yet. Most scientists think that Trilobites might have been that they became a main source of food when the first sharks came to being. Others like myself think it was because of Noah's flood and their bodies were just too weak to handle all the rough seas.
All trilobites have the same body parts, a head (cephalon), a body (thorax) and tail (pygidium). The body can also be divided in three length-ways, that's what the name trilobite is based off of. The thick dorsal exoskeleton is composed of a complex structure of chitin and protein, thickened and hardened by calcite. Modern arthropods have an open circulatory system. Trilobite eyes are the most ancient visual system known. The eyes are compound like the eyes of crustaceans and insects now day. They are made up of many tiny lenses. Some trilobites were blind. 
Trilobites were the first group of animals in the animal kingdom to develop complex eyes. The trilobites of the Cambrian already had a highly advanced visual system. The number of lenses in a trilobite eye varies, some trilobites had only one, while some had thousands of lenses in a single eye. There lenses are shaped like hexagons, six sides.
There are three types of the trilobite eye system:
The Holochroal eye
the Schizochroal eye
the Abathochroal eye
The first two are the major types, the great majority of trilobites have the holochroal eyes. Some Trilobites don't have any lenses at all. In fact some don't even have eyes.
This is a major part of proving creationism and that Noah's ark was real. Their eyes are so complex that they can't just simply be like that, they had to have been created by someone (God). Evolutionists can not explain why their eyes are so complex because they know that they can not be so primitive, without having a creator. 
Trilobites have only been found in oceanic fossil beds. No freshwater forms have ever been found. They occupied many different ocean environments, from shallow flats and reefs, to deeper ocean bottoms, and even the water column, as floating plankton or free-swimming forms. Trilobites from different habitats often had specialized forms. Food particles were stirred up by the legs and passed forward to the mouth, and since they didn't have a very big lower jaw, they are obviously pretty sure that they weren't usually the predator, and were only allowed to have soft food. 
Scientists think that Trilobites reproduced sexually,so do mostly all arthropods now day. No-one is quite sure how trilobites reproduced, although some fossils have been found that appear to have egg sacs attached to their bodies. other fossils have been found that show trilobites shed their exoskeleton several times as they grew up, adding a new segment to their abdomen and getting bigger each time, they molted their exoskeletons as they grew, as all arthropods today do. 
There are three development stage periods for the trilobite.
1. A Protaspid Period
This is the Larva stage. It is composed of and uncompleted exoskeleton.
2. The Meraspid Period
This is when the body is only complete with two united segments. Every time it molts it will add another one or two.
3. The Holaspid Period
This is when no more of the segments can be added during molts. After this is completed it now is called a Holaspis. The major change is not in what it looks like, but if it will increase in size. 
The Trilobites were said to have become extinct around 550-750 million years ago. They were said to have become extinct when the first sharks and other early fishes in the Silurian and Devonian periods. Trilobites may have provided a main source of food for them. Their low numbers and diversity at the end of the Permian, which probably added to their extinction during that great mass extinction event. There is also the possibility of it being from Noah's flood and that there little and weak bodies were to weak to handle the rough waters of the flood.
Trilobites appear to have been only marine organisms since the fossilized parts of trilobites are always found in a rock with fossils of other salt-water animals like brachiopods, crinoids, and coral, and they are found in a range of environments from extremely shallow water to very deep water. The tracks left behind by trilobites crawling on the sea floor are sometimes kept as trace fossils. Trilobite fossils are found worldwide. They were one of the first fossils to get attention, new species are being discovered every year. The Native Americans gave a name for the trilobite which means "little water bug in the rocks." A famous location for trilobite fossils in the United Kingdom is Wren's Nest, Dudley in the West Midlands.
The fossil is now on display to the public. Dr Graham Young said: "We have found a very unusual specimen that illustrates some of the diversity and weirdness of ancient life. A trilobite of this size really is an amazing discovery." In July 1998, a team of scientists went out to northern Manitoba hoping they would find fossils similar to the ones uncovered by the previous digs, like the 43-cm (17-inch) long trilobite found in the area a decade before. 
The evolutionist believe that the Trilobites were alive millions of years ago (around 550-750 million years ago). They also believe that it had nothing to do with Noah's flood, which is one of the highest possibilities.
They don't really have an explanation to the complexity of the Trilobite eye. They think that as time goes on that creatures will get more and more complex and complicated, but that is not true. It really already began that way, we can tell because of the trilobite eye. They have a lot to do with how life began.
The creationists believe that the Trilobites became extinct because of Noah's flood, they think that their bodies were to small and weak to curl up and defend themselves from the rough seas.
Most people think that the Trilobite is a very simple creature but it is not in fact. It is a very complex creature, especially it's eye which is so complex that it could not have evolved,especially since there are no transitional fossils that indicate an evolution. This goes to show that it must have had a Creator. This has only been discovered a couple years ago.  Evolutionists try to say that now the creatures are getting more and more complex and complicated as life goes on, but really it already had started out that way. 
Kurt Wise believes that the best extra-biblical evidence for creation would come from the design of a Trilobite eye and that this creation by God is the most reasonable hypothesis for the reason of the complexity of the trilobite’s schizochroal eye. 
- Trilobite Reproduction and Development Last revised 08 November 2007 by S. M. Gon III
- Trilobites David L. Alles Western Washington University Trilobite: Eyewitness to Evolution, Vintage Books (2000).
- Guide to Trilobites A Guide to the Orders of Trilobites Dr. Sam Gon III
- The Fossil Record Technical Journal 14(1):110–116 April 2000 by John Woodmorappe
- Trilobite technology: Incredible lens engineering in an ‘early’ creature by Charles Stammers. Creation 21(1):23–0. December 1998
- Un-Bee-lievable Vision by Frank Sherwin, M.A. February, 2006
- ‘My favourite evidence for creation!’ by Kurt Wise. Creation Ex Nihilo, Sept.-Nov. 1989, Vol. 11 No. 4, p. 29
- Invertebrates: animals without backbones by Dr. Gary Parker. Facts of Life Chapter 3: The fossil evidence