How many animals were there first on the world?

Answer 1

The exact number of animals that first appeared on Earth is difficult to determine, as it depends on how we define "animal" and the time frame considered. The earliest multicellular animals are believed to have evolved around 600 million years ago during the Ediacaran period, with simple organisms like sponges and jellyfish. However, the total number of species and individuals that existed at that time remains largely unknown due to the incomplete fossil record.