The first animals thrived in the ocean
As years passed, eukaryotic cells began forming clusters of cooperating microscopic organisms and eventually started living in groups to feed more efficiently and gain protection. Of course, all the mutually beneficial relationships between these life forms helped them thrive and become something else.
Around 800 million years ago, those groups of clustered cells living together evolved into the first animals, such as sponges. Since none of these organisms didn’t need much to survive, they could easily tolerate the harsh conditions of the prehistoric ocean.
