Evolution
The significant increase in the size of the cerebral hemisphere through evolution has been made possible in part through the evolution of the vascular pia mater, which allows nutrient blood-vessels to penetrate deep into the intertwined cerebral matter, providing the necessary nutrients in this larger neural mass. Throughout the course of life on earth, the nervous system of animals has continued to evolve to a more compact and increased organization of neurons and other nervous system cells. This process is most evident in vertebrates and especially mammals in which the increased size of the brain is generally condensed into a smaller space through the presence of sulci or fissures on the surface of the hemisphere divided into gyri allowing more superficies of the cortical grey matter to exist. The development of the meninges and the existence of a defined pia mater was first noted in the vertebrates, and has been more and more significant membrane in the brains of mammals with larger brains.
Read more about this topic: Pia Mater
Famous quotes containing the word evolution:
“As a natural process, of the same character as the development of a tree from its seed, or of a fowl from its egg, evolution excludes creation and all other kinds of supernatural intervention.”
—Thomas Henry Huxley (1825–95)
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“The more specific idea of evolution now reached is—a change from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity, accompanying the dissipation of motion and integration of matter.”
—Herbert Spencer (1820–1903)