Final answer:
Darwin's work shows that organisms are constantly evolving, adapting to their environment through natural selection, and survival is influenced by reproductive success.
Step-by-step explanation:
Darwin's work, which encompasses the concept of evolution, offers insight into the living world by demonstrating that organisms are constantly evolving. The diversity of life on Earth is the product of mutations and the ability for organisms to adapt to a changing environment. This adaptation leads to greater reproductive success and, through natural selection, to the evolution of species.
Over time, what was once an undesirable trait can become a favorable one, and vice versa, as environments change. Darwin's theory of evolution by natural selection has provided a unifying framework for understanding the interconnectedness of all living organisms and their shared ancestry, shaping the field of biology and our understanding of the processes that have shaped life on Earth.