Which characteristics contribute to the stickleback serving as a model organism for evolution studies?

• A. They are large with long generation times
• B. They are small with short generation times; widespread populations in diverse environments
• C. They have no fossil record
• D. They are difficult to maintain in the lab

Answer: (B)

A good model organism for evolution studies is one that allows observing genetic and trait changes across many generations in a manageable timeframe. Sticklebacks fit this well because they are small and breed quickly, producing many offspring each generation, so researchers can watch evolutionary changes unfold in a practical period. They also inhabit a wide range of environments—from freshwater lakes to coastal systems—providing multiple natural settings in which adaptive differences arise. This combination lets scientists study how selection acts on variation across diverse habitats, and to do so repeatedly. In contrast, traits like being large with long generation times would slow down the ability to see evolution in action; having no fossil record or being hard to maintain in the lab would hinder, not help, experimental work.