model organism
A model organism is a species chosen for study not because it is special on its own, but because what we learn from it applies broadly to other forms of life, including humans. Like learning to drive in a small, simple car before tackling a truck, scientists use easy-to-handle organisms to work out principles that are hard to study directly in people.
Good models share useful traits: they are easy to grow in large numbers, reproduce quickly, have manageable genomes, and can be genetically manipulated and observed cheaply. Crucially, because core biological processes — how DNA is copied, how genes are switched on, how cells divide — are conserved across life, findings in yeast, worms, flies, fish, mice and plants often transfer to humans.
No model is a perfect stand-in. A worm has no bones and a fly has no blood like ours, so results must be interpreted with the species' limits in mind. The art of model-organism biology is choosing the right system for a given question and confirming key conclusions across more than one.
Genes first discovered controlling cell death in the worm C. elegans turned out to have human counterparts central to how our own cells live and die, work later recognized with a Nobel Prize.
Lessons from a millimetre-long worm reaching all the way to human medicine.
Different questions favour different models: yeast for cell-cycle basics, worms for cell lineage, flies for development, zebrafish for vertebrate organs, mice for mammalian disease, and Arabidopsis for plants.