The primary way that animals grow and develop is by building more cells. When an animal eats food, its body breaks the food down and uses it to fuel its energy requirements and build new cells through the process of mitosis. These new, or daughter, cells are often similar in size to the old, or parent, cells.
In order to produce more cells, animal cells divide in two. The process is a complex one since the parent cell has to produce new organelles for each resulting daughter cell. It then has to copy the genetic code as accurately as possible and transfer both copies of the genetic code into the nuclei of the daughter cells. In science, it’s called mitosis.
However, mitosis requires a lot of energy that comes from food, along with the raw materials for constructing more cells. The food that animals eat is then transformed into usable energy for cells or can be used to build new cells, which form tissues like skin and muscle. The process of growth involves eating food, breaking down food through digestion, absorbing nutrients from food, and building tissue.
The rate of growth of an organism has a direct impact on its ability to adapt to the environment. For instance, an increase in the rate of growth of fleshy parts of the fish fin would provide an opportunity for the fish to adapt more easily to terrestrial locomotory life than could a fish without this modified fin. Scientists believe that hence, it may play a role in evolution.
