During the paleozoic era there was explosion of life in the oceans. most of the continents were covered in warm, shallow seas. what is true about life on earth at this time?

The Paleozoic era that spanned from about 542 million years ago to 250 million years ago is considered as the time of enormous modifications on Earth. The era started with the split of one supercontinent and the production of another. The plants became global, and the initial vertebrate species started colonizing the lands.  

The Cambrian period is the initial period of the era and is also known as the age of Tribolites. The explosions of life in the oceans started during this time. The majority of the continents were covered in shallow and warm seas. The dominant invertebrates during this time were tribolites. Fish started emerging during this time, which later led to the emergence of amphibians.  

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.