Model organism origins

The concept of selecting a common system for in-depth study emerged slowly. In some disciplines it was once considered poor etiquette to work on a colleague's system: if he or she used the toad, you used the frog. That practice led to great inefficiency, because the details of manipulating any system--how to grow the organism, the chemistry of the cell wall, mating habits--had to be worked out over and over again.
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Gradually certain systems became preferred models for biological systems in general, a tendency which has been accentuated as molecular approaches have become the lingua franca of modern biology [1385].

Koshland, Daniel. (1988). Biological Systems. Science 240(4858):1385. PMID: 3375819.