Precambrian Plants And Animals
The first one celled organisms formed during the Precambrian period. There were microscopic bacteria, ediacarans, dickinsonia, cyanobacteria, and early algae. There were three main categories for the organism that lived during the Precambrian time. The three main categories were sponges, cnidarians, and annelids. Sponges were soft-bodied creatures that did not have organs or a nervous system. They lived by making water go through their bodies and they filtered out the food particles. Cnidarians had sac-like bodies and a simple digestive system with a mouth but no anus. Examples of cnidarians are sea anemones, corals, and jellyfish. Annelids had fluid-filled body cavities and they breathed through their skins. An example of an annelid is a segmented flatworm.