http://memapindex.org Development and functions Sat, 19 Dec 2009 13:41:14 +0000 http://backend.userland.com/rss092 en When amphibians left the water, they had a great many problems to face. In particular, their sense of smell became less acute. Fishes can perceive the odours of substances dissolved in water. In order to differentiate between smells on land, the pioneering amphibian had first to dissolve the odorous substances ... http://memapindex.org/brain-of-amphibians-and-mammals.htm The nervous system of the ganglionated type proved to be very convenient. In Annelida, which must have descended from the flatworms, all the nerve cells are concentrated in the ganglia, while the nerve strands connecting them hold only the long processes of these cells. Practically every segment of the worm ... http://memapindex.org/ganglionated-type-of-nervous-system.htm The nerve cells in primitive Coelenterata are joined together by their processes to form a nerve network, the most primitive type of nervous system. The next improvement was the emergence of separate clusters of nerve cells, with their subsequent development into more organized and more compact nerve strands. These came ... http://memapindex.org/nerve-cells-and-nerve-strands.htm When reading the works of the ancient scholars, one cannot help being surprised at the number of scientific discoveries that were made merely as the result of observation and subsequent conjecture. More than two thousand years ago, scholars and physicians possessed quite a profound knowledge of how most of the ... http://memapindex.org/long-evolution-of-human-brain.htm