Why is apoptosis important?

Apoptosis is important because it helps to eliminate unnecessary and potentially toxic cells, benefiting the organism as a whole. Only cells that should no longer be part of the organism are removed through this process. Two of the most common examples of apoptosis are the formation of fingers and the elimination of potential cancer cells.

While still in the embryo, the hands and feet of a fetus look like a flat paddle-like block of tissues with no fingers or toes. As the fetus develops, several cells receive cues to commit suicide. This whittling away of unnecessary cells is how fingers and toes are formed during the later stages of development. When something goes wrong during development and apoptosis remains incomplete, it may result in fused or webbed digits.  

Apoptosis is also responsible for eliminating toxic cells, such as pre-cancerous cells and cells infected by viruses. These cells pose a definite threat to the body if they are allowed to survive. By removing them, apoptosis removes or minimizes the threat to the rest of the organisms. 

Apoptosis also plays a key role in maintaining homeostasis in the immune system. Immune cells divide extensively when they detect a pathogen. The aim is to overcome the pathogen with their large numbers. After the pathogen has been eliminated, these extra immune cells are killed off by apoptosis to maintain the balance within the immune system.