Vladimir Ivanovich Vernadsky (1863-1945) was a prominent Russian and Soviet scientist known for his contributions to the fields of geology, biogeochemistry, and the philosophy of science. He is best recognized for his work on the biosphere, which he defined as the global sum of all ecosystems, emphasizing the interconnectedness of life and the environment. Vernadsky was also a pioneer in the study of radioactivity and the role of living organisms in shaping the Earth's geological processes. His ideas laid the groundwork for modern environmental science and influenced various disciplines, including ecology and geochemistry.