During the Paleozoic Era, a time period occurred called the Ordovician time. During a great part of this time period, the flora and fauna grew a lot. Many of the species dominated their environment at this time. In the Cambrian time, the flora and fauna flourished as well. However, it flourished even more during the Ordovician time. It also became more diverse than in the Cambrian period before.
There also became more animals that would filter when they would eat. However, just like the Cambrian period, the Ordovician period was coming to an end. The animals started dying out. As a matter of fact, lots of the species were facing extinction. Mainly the planktons were very threatened at the end of this time.