# Chapter 20: How to become a model...in biology

We live in a complicated world. The role of scientists, citing Francis Bacon (1561 – 1626), is to be “merchants of light and to promote relief of human’s estate”. To this end, scientists collect data, formulate possible explanations (hypotheses) of the corresponding phenomena and then subject them to rigorous experimental testing. Hypotheses that fail the experimental test are replaced by those that are more viable. As a result, they propose models that not only explain the available observed data, but also predict previously unknown properties of the given phenomenon. The crucial role in understanding basic principles governing life was (and still is) played by so-called model organisms. Each model organism exhibits unique characteristics, but at the same time illustrates the unity of life, which works on the same principles, regardless of whether it is a bacterium, fungus, plant, or animal. This chapter provides :

1. a description of a "good model organism";
2. rules for choosing a model organism suitable for the study of a relevant biological phenomenon;
3. examples of conventional as well as “exotic” model organisms with their advantages and limitations.

While it is only a superficial overview of the topic, it should persuade the reader that model organisms are not only instrumental in understanding the general principles of the complicated living world we live in but can help us in gaining insights about ourselves as a distinct species.