The big balls split from the freshwater raftballs. Big balls no longer stick together as it is no longer needed. The big balls are larger then their ancestors so they can produce many smaller balls which grow inside them. When a big ball is mature, it will burst open and these small balls will float away. They then will grow into another big ball. Because the big balls can float separately, they were able to float to the ocean. Some died because of the saltwater, but some were able to adapt. Because they had much more space to grow in, they can now be found in all oceans.