cells in the earth - (Sep/15/2004 )

hey..can anyone tell me why there is so many kinds of cells in the world?

specialization, evolution

survival of the fittest in each condition

There are many, many cells in this world because they are small enough to fit on this world. Cells are small in order to retain a small surface area to volume ratio, allowing cells sufficient area to communicate with and exchange molecules with the environment. If cells were any larger, they most likely would not be viable as they would have too little exchange occuring (between the cell and the environment).

This reason alone accounts for the fact that trillions of trillions of cells exist in this world.

There are so many cells in the world because they are all used for specialized tasks