How The Life Begin

Main article:  Cambrian explosion Trilobites  first appeared during the Cambrian period and were among the most widespread and diverse groups of Paleozoic organisms. The rate of the evolution of life as recorded by fossils accelerated in the  Cambrian  period (542–488 Ma).The sudden emergence of many new species,  phyla , and forms in this period is called the Cambrian Explosion. The biological fomenting in the Cambrian Explosion was unpreceded before and since that time.Whereas the Ediacaran life forms appear yet primitive and not easy to put in any modern group, at the end of the Cambrian most modern phyla were already present. The development of hard body parts such as shells,  skeletons  or  exoskeletons  in animals like  molluscs ,  echinoderms ,  crinoids  and  arthropods  (a well-known group of arthropods from the lower Paleozoic are the  trilobites ) made the preservation and  fos...