age-and-area hypothesis J. C. Willis suggested in 1922 that, all other things being equal, the area occupied by a taxon is directly proportional to the age of that taxon. Thus in a polytypic genus, the species with the smallest area of distribution would be the youngest in the genus. However, things are rarely ever equal, and Willis's ideas, though much discussed, have never gained acceptance as a law or rule.

age-and-area hypothesis The idea (suggested by J. C. Willis in 1922) that, all other things being equal, the area occupied by a taxon is directly proportional to the age of that taxon. Thus in a polytypic genus, the species with the smallest area of distribution would be the youngest in the genus. However, other things rarely are equal, and the idea has never gained acceptance as a law or rule.

age-and-area hypothesis The idea that, all other things being equal, the area occupied by a taxon is directly proportional to the age of that taxon. Thus in a polytypic genus, the species with the smallest area of distribution would be the youngest in the genus. However, other things rarely are equal, and the idea has never gained acceptance as a law or rule.