Cells are the basic unit of life. Atoms make up molecules. molecules make up cells. cells make up tissues. tissues make up organs. organs make up organ systems and organ systems make up the human body. therefore, without cells, there is no life.
That would be animals getting isolated into different groups in different locations. These animals would have to breed AND adapt to that location, otherwise they will become extinct. When each species adapts and breeds to agree with a different location, that would be called speciation.
