The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the Choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives. The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the Choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives.