V. E. Shelford

V. E. Shelford was an ecologist who studied how animals and plants survive in different environments. He introduced the idea of the "law of tolerance," which states that every organism has a range of environmental conditions—such as temperature, moisture, and food availability—within which it can live. If conditions fall outside this range, the organism struggles or cannot survive. Shelford’s work helps us understand how ecosystems function and how species adapt or fail in changing environments, highlighting the importance of suitable conditions for maintaining healthy ecosystems.