Question

If signaling arose as a solution to the demands of multicellularity, how then do you account for the very similar mechanisms of signaling that are used in animals and the unicellular fungus Saccharomyces cerevisiae?

Answer 1

Unicellular organisms like yeasts also use cell signalling for mating purposes.All cells need to communicate whether unicellular or multicellular. Cell signalling governs the bascic activities of a cell and coordinates the actions, even in unicellular organisms.Yeast cells send a peptide signal to their environment .The mating factor is thought to bind to the receptor of other cells to induce them for mating.Bacteria also use signalling to sense thpopulation cell density in the environment.Signalling is needed not just for multicellularity but for cell communication.This allows populations of cells to work together and co-ordinate each other.