using a novel taxonomic hypothesis without ..
Other adaptive explanations for chin shape variation have also been suggested, most notably the masticatory stress hypothesis . According to this hypothesis, the chin functions as a buttress against mechanical stress caused by chewing. However, recent research suggests that this hypothesis is no longer viable since stress resistance is uncorrelated with chin shape in fossil and recent humans , –. Furthermore, the masticatory stress hypothesis does not explain the presence of sexual dimorphism in chin shape . If chin shape differences were caused by differences in mechanical stress associated with different diets, then why would males and females differ significantly in chin shape within geographic regions? To our knowledge, there is no evidence suggesting that males and females from the same population eat foods that differ in their mechanical properties. Thus, we consider the masticatory stress hypothesis to be an unlikely alternative to region-specific sexual selection as an explanation for geographic variation in chin shape.
GEOGRAPHIC VARIATION IN THE EVOLUTION AND …
Geographic variation inLoligo forbesiin the ..
Geographic variation in calcium and clutch size - …
Coefficients that are not significantly different from zero as indicated by insignificant t-statistics at a 5% level are dropped from the regression model.