The irreversible increase in the size or mass of an organism as it develops is known as growth. The organisms would be growing as they increase their sizes and masses. Just like a baby, they have all the features of an adult body but they are very tiny. As time passes by, the size and mass of the baby increases and we should take not that this increase is irreversible. As the organisms grow, they enter into another process called aging. As the organism gets close to its lifespan, the ability to carry life functions would also reduce until such time that they could no longer carry life functions resulting to death.