This document discusses milestones in biological classification, focusing on four famous scientists: Aristotle, Charakan, John Ray, and Carl Linneaus. It summarizes their key contributions to early systems of classifying organisms. Aristotle was the first to classify organisms into plants and animals. Charakan classified over 200 animals and 340 plants. John Ray published works rejecting dichotomous classification and advocated classifying based on observed similarities. Carl Linneaus developed the system of binomial nomenclature still used today and published works classifying thousands of plant and animal species. Overall, the document outlines the early history and development of biological taxonomy and classification systems.