November 15, 2009
Bio 111 MWF
Universal Genome in the Origin of Metazoa
By Michael Sherman
This article basically talks about the emergence of new complex system and the appearance of large taxons. It stated that during the Cambrian period which was around (510-550) Metozoan plyla emerged. The appearance of these plyla was said to be very random. In addition to this more advance forms were discovered called Crustaceae. Because of this information the scientist has came to a conclusion that Metazoa started way before Cambrian period. Although back than it was invisible. How did they get this idea? Well they got this based on the study of putative trace fossils. In addition there was frustration to this idea because they wondered why fossilizable forms of various phyla appeared almost simultaneously and wrong. This means that there was some mistake that the scientist has made with their hypothesis about the origin of Metazoa since the information did not fit like a puzzle. In addition it stated that “ It appears that there was no sequential appearance of the major Metazoan taxon from simpler to more complex phyl, as would be predicted by the classical evoluionary model” ( Sherman 3). There was also other questions that was raised relating to genomes of existing phyla. It said that when multicellular animals emerged it made a radical increase in genome complexity in gene number and appearance of entirely novel gene families. In addition the primitive roundwarm had about 19,000 genes, cnidaria with 20,000, and lastly the sea urchin with 24,000. It also stated that the families of genes are genes that has a relation with the body plans, organ development and cell-cell communications. This apparently means that the families of genes are very important because if that does not function well than we would not have some of the things we have in our body, or any living things body. Basically a lot of things contribute to living things...
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