Chapter 23.2, Problem 3LO

Summary Introduction

To describe: The three domains and argue against and for classifying organisms in these domains.

Introduction: Till mid 19^th century, organisms were divided into Animalia and Plantae kingdoms. However, after the development of microscopes, many organisms could not be assigned to any of these two kingdoms. In 1866, Ernst Haeckel proposed Protista as the third kingdom. Edouard Chatton in 1937 suggested procariotique and eucariotique terms to describe bacteria and all other cells respectively. In 1969, Robert Harding Whittaker proposed a classification system with five kingdoms based on the structure of cells and the way organism obtain nutrition from its surroundings.