Problem 5

Background and context

Microbial mats represent the first form of prokaryotes on Earth. They are the earliest form of cellular life that existed much before from plants and animals. They are the multi-layered sheets of prokaryotes that include both bacteria and archaea. They are only a few centimeters thick and mostly grow in moist places. They have different colors because prokaryotes in them carry out different metabolic pathways. Prokaryotes in them secrete a substance called the extracellular matrix which is a glue-like sticky used to hold them together.