Today's Mendelian Genetics began interestingly with the discovery of the microsope in the 17th and 18th centuries. And primitive doctrines were refined into a scientific school of thought called preformationism, which held that living beings were essentially fully-formed prior to conception.
The doctrine of spermist preformation is exemplified by the famous Homunculus image, drawn by Nicholas Hartsoecker in 1694, and supposedly based on an observation of Anton van Leeuwenhoek. The image shows a spermatozoon containing, within its head, a tiny, but fully-formed, human being, and the implication is that the sperm contains the complete, preformed essence of the unborn person; whereas the egg is merely an inert, nutritive, sheltering matrix.
Opposed to the spermist preformationists were the ovist preformationists of the 18th century, led by Regnier de Graaf, who believed that it was the egg that contained the complete essence of the human being, and that the sperm was merely a triggering mechanism for development.
The entire doctrine of preformationism, however, was completely discredited by the embryological observations of Caspar Wolff in the late 18th century. Any remaining controversy over whether the sperm or the egg was more important was finally settled in 1875 by Wilhelm Oskar Hertwig, who demonstrated that the fertilization process required the fusion of the nuclei of both cells.
Doc Chew's lecture is the most interesting I have heard since school started three months ago. He managed to relate "Mendelian Genetics" which I thought was quite a dead subject involving solving predigrees and crossovers, with some creative thinking components. I managed to stay awake all the way for the 2.5 hours lecture... =) Yah, Im proud of this, LoL! But I bet his test will be zzz (dead). =)
Finally, everything seems to get into order two weeks after the sem break - a short break b4 heading to hell. Reports handed in, projects progressing smoothly, and tutorials done and settled. Phew, finally some leisure time for a gym session this morning, in preparation for the shopping sprees when December arrives.
The doctrine of spermist preformation is exemplified by the famous Homunculus image, drawn by Nicholas Hartsoecker in 1694, and supposedly based on an observation of Anton van Leeuwenhoek. The image shows a spermatozoon containing, within its head, a tiny, but fully-formed, human being, and the implication is that the sperm contains the complete, preformed essence of the unborn person; whereas the egg is merely an inert, nutritive, sheltering matrix.
Opposed to the spermist preformationists were the ovist preformationists of the 18th century, led by Regnier de Graaf, who believed that it was the egg that contained the complete essence of the human being, and that the sperm was merely a triggering mechanism for development.
The entire doctrine of preformationism, however, was completely discredited by the embryological observations of Caspar Wolff in the late 18th century. Any remaining controversy over whether the sperm or the egg was more important was finally settled in 1875 by Wilhelm Oskar Hertwig, who demonstrated that the fertilization process required the fusion of the nuclei of both cells.
Doc Chew's lecture is the most interesting I have heard since school started three months ago. He managed to relate "Mendelian Genetics" which I thought was quite a dead subject involving solving predigrees and crossovers, with some creative thinking components. I managed to stay awake all the way for the 2.5 hours lecture... =) Yah, Im proud of this, LoL! But I bet his test will be zzz (dead). =)
Finally, everything seems to get into order two weeks after the sem break - a short break b4 heading to hell. Reports handed in, projects progressing smoothly, and tutorials done and settled. Phew, finally some leisure time for a gym session this morning, in preparation for the shopping sprees when December arrives.
And there's Taiwan trip for me to look forward to! YeAh! =)
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