The term for the period of significant evolutionary development of life on Earth is the Biodiversity. This era, characterized by the rapid diversification of species and complex life forms, is often referred to as the Cambrian Explosion. During this time, approximately 541 million years ago, most major animal groups first appeared in the fossil record, leading to dramatic increases in the complexity of ecosystems. It marked a critical point in the development of life that set the foundation for the vast diversity of species observed today.