What is a model organism?

• A. Nonhuman species extensively studied to understand biological phenomena
• B. A species used only for food production
• C. A species with no genetic variation
• D. A species with extreme traits

Answer: (A)

A model organism is a nonhuman species studied extensively to understand biological phenomena because its biology lets scientists reveal general principles that apply across many organisms, including humans. These organisms are chosen for practical advantages—short generation times, easy care, and a rich set of genetic tools and data—so experiments are efficient and findings can be widely generalized. Examples include E. coli, yeast, fruit flies, mice, and the plant Arabidopsis. The other descriptions don’t capture why these species are chosen: being used for food production, having no genetic variation, or having extreme traits aren’t the defining reasons researchers rely on model organisms.