Why do living organisms need to be able to grow and develop?

All life evolves. Thus evolution is a ubiquitous character from prokaryotic bacteria to eukaryotic amoebae to eukaryotic animals. All life contains DNA or RNA and characters are heritable due to the generation-generation passing on of that nucleic acid. In the case of DNA, the enzymes that govern DNA replication replicate the DNA imperfectly and thus mutations arise. Not negative mutations that kill the offspring, note with attention. The mutations are what is called genetic drift, the random change of DNA across time. DNA codes for the phenotype of an organism and so this changes with the changes of the DNA 'code'. Those phenotypes that emerge that cannot survive in the environment around them die, those that can survive do so. The survivors pass on their genes, perpetuating the newly emerged phenotype and perhaps producing such radically different individuals that they are unable to reproduce with organisms from the original population from whence they came. This happens with all life as all life shares these characters with DNA-replication. There is also evidence for the adaptation-ability of species from all 6 different kingdoms. Evolution of DNA is important as it brings about new phenotypes which may be able to survive in different environments than its original progenitor, thus perpetuating the existence of any taxon in its current form.