Sentence examples for brain size and testis from inspiring English sources
Dr Pitnick's project, published in this week's Proceedings of the Royal Society, looked at brain size and testis size in 334 of those species.
And a study with mammals found no relationship between brain size and testis mass [41].
Results from an analysis of variance (ANOVA) derived from multiple regression models with mass dimorphism and male body mass as independent variables, and brain size and testis size as dependent variables, indicated that the level of male competition for mates had a significant association with brain size but not with testis size.
The ANCOVA results estimating the influence of mating system and female promiscuity on primate brain size and testis size were supported by informal visual comparisons of residuals from least-squares regressions of testis and brain weights on body mass (Fig. 1).
A formal comparison across mating systems indicated that there are significant differences in sexual dimorphism and in regression residuals describing relative brain size and relative testis size (Table 2).
Results indicate that there is not a significant relationship between relative brain size and sperm competition as measured by relative testis size in primates, suggesting sperm competition has not played an important role in the evolution of brain size in the primate order.
Brain size and tooth size in hominins.
In order to account for the effect of body size on testis size, we analyzed the variation in male body size and the relationship between body size and testis size.
Body size and testis size were log transformed, and seminal vesicle size was square-root transformed.
The effect of body size dimorphism was examined using multiple regression with brain and testis size as the dependent variables and male body size and mass dimorphism as independent covariables.
However, a later study found that the relationship between testis size and brain size disappeared when morphological adaptation to foraging strategy is included in the analyses [42].
