What happens when the ph of a biological system gets too low?

When the pH of a biological system falls at that time the physiological abnormality that is developed is known as acidosis.

Explanation:

Acidosis develops by decrease in body"s pH.To maintain ionic homeostasis buffer system such as bicarbonate buffer system plays a significant role to prevent the further decrease of pH.

         The carbonic acid(H2CO3) that is produced in the biological system is broken down to carbon dioxide and water.Thus the concentration of H2CO3 is reduced to prevent the further decrease of pH.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.