Biologie se uniekheid as substraat vir die tipies menslike funksionering

The biological similarities between humans and apes are great but they should not obscure the differences. Some differences are of such great consequence that man should be considered truly unique kind of organism with a marvellous plasticity of mind. All of the uniquely human traits are adaptations to the environments in which man evolved; these Include profound modifications of anatomy, physiology and behaviour. The morphological differences between man and his nearest relatives are very conspicuous. The form of the skeleton is adapted to fully erect posture and bipedal locomotion. The pelvis is broadened to provide adequate attachment for the powerful striding muscles. The transformation of the tail vertebrae is unique among the vertebrates. The joint for the neck is in the middel of the base of the skull. The hands are prehensile, with a large and strongly opposable thumb. The brain is uniquely large in proportion to the body and has a particularly large and complex cerebrum; the cerebral cortex contains the cent res for memory and complex computation. The enlarged brain requires prolonged infant dependency and high quality nutrition. Differences between humans and animals are grea tes t in the realm of behaviour: Ability to make tools (associated with bipedalism); ability to anticipate the future; development of symbolic communication (associated with expansion of cortex). Direct evidence of man's language capabilities comes form the anatomy of the modern human vocal tract. Man is the only species that succeeded in creating a truly productive language, and it is the scaffolding of human culture and civilization

Development and Evolution of the Muscles of the Pelvic Fin

Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition

The ontogenetic development of the somatic musculature of the trunk of the aglossal anuran Xenopus laevis (Daudin)

Thesis (D. Sc.) -- University of Stellenbosch, 1952.Full text to be digitised and attached to bibliographic record

The ontogenetic development of the somatic musculature of the trunk of the aglossal anuran Xenopus laevis (Daudin)

Originally presented as the author's thesis (D. Sc. -- University of Stellenbosch, 1952).From: Acta zoologica, Bd. XXXIV, 1953.Full text to be digitised and attached to bibliographic record