In the Cambrian world 560 million years ago, there was a species of arthropod. Because their bodies are divided into three parts by two vertical lines. Trilobites are the most representative ancient animals. It was not completely extinct until the end of the Permian, 250 million years ago. They have lived on Earth for more than 310 million years. In ancient times, trilobites evolved into thousands of species.
Scientists have divided the known trilobites into eight categories. There are tens of thousands of trilobites found around the world, the largest of which is nearly 1 meter long and the smallest is only 2 mm long. With their superior adaptability, they are widely distributed in the oceans around the world. It can be said that in the Cambrian, where there was an ocean, there were trilobites.
The largest of these is nearly 1 meter long and the smallest is only 2 millimeters long. Trilobites, widely distributed around the world, developed rapidly due to their superior adaptability, reaching their reproductive peak in the Late Cambrian. Because of the living environment of each region, the forms and forms evolve in a variety of ways. The shell is flat, with horizontal and vertical lines inside, and the head and tail lack obvious decoration, such as a large head. Some heads are wide and large, and the leading edge is surrounded by a flat edge, and the flat edge is lined with neat tumor particles, such as cryptomonitors. Some thoraxes and tails are decorated with pointed needles, such as split-bellied fish, and some shells can be curled into spherical shapes, such as cryptocephalus.
Trilobites are the oldest known single-celled insects on Earth. The earliest trilobites belonged to Hedwig single-celled organisms, and the latest trilobites belonged to Bacchus trilobites. Single cells refer to one-dimensional single-cell biota with many extracellular structures such as vesicles, cysts, connective tissue, mucus, etc. In addition to extracellular structures, they also have some intracellular structures, such as the nerve nucleus and the neural membrane. The earliest trilobites belonged to hedwig single-celled organisms and are now found mainly in the depths of the Pacific Ocean.
After the advent of trilobites, they may be representative of many organisms throughout the Early Paleozoic Era. The prehistoric marine trilobites are no longer seen coming alive. Today, we can only appreciate the charm of this prehistoric animal on the trilobite carcass displayed in the museum, recalling the legendary story of its history. With the advent of large numbers of marine invertebrates, the population of trilobites decreased and eventually became extinct with the arrival of the Mesozoic.