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The study examines the ontogenetic course of the phenotypic covariance structure by analyzing the age-specific covariance matrices of shape coordinates for postnatal craniofacial growth in rats and humans. Results show that age-specific population covariance matrices change through postnatal development in both species, with the time course and pattern of changes illustrating the onset and offset of the developmental processes.

The impact of altriciality, allocare and maternal behaviors on the force of selection acting on age-specific survival and fertility in a model that incorporates the dependence of child survival on maternal survival is studied. The main human life-history traits, a high life expectancy and post reproductive life are due to an increase in child altriciality in early humans.

The reason why mammals have exactly seven cervical vertebrae whereas in other vertebrates, the vertebral number varies considerably was investigated to see whether natural selections constrain the number of cervical vertebrae in humans. Data shows that homeotic transformations that change the number of cervical vertebrae are extremely common in humans and selection is most probably indirect caused by coupling of such changes with major congenital abnormalities.