DNA replicates so that new cells can be created; the replication allows old or damaged cells to create replacement cells that support the life of the organism. DNA replication permits the new cells to have the same genetic material as the parent cells. This genetic material informs the cells of their role in helping the organism live.
DNA replication is also necessary for reproduction. The reproductive cells, or gametes, contain the DNA of the parent that is to be passed on to the offspring. Without DNA replication, the production of gametes would be impossible and the species would cease to exist.
Errors in DNA replication can cause serious consequences. If the DNA is not correctly replicated, the cell will not perform its intended function. Some errors in DNA replication are believed to cause cancer.