Highlights of Poriferan Fossil History

Let's travel through time
Through the waters and waves
And as we pass as fast as lightning
Let's obseve the memories saved

For as does the course of humanity
Possess an extensive history
There is much to learn from the fossils
Submerged beneath the sea

Throughout the millions of years of history that are associated wtih the existance of porifera, geologic phenomena and other occurances have affected differentiations in population and fossil record.  For example, one group of the Demospongiae was able to transfer its habitat from lower depths to shore depths due to a change in energy.  The presence of fossils upon areas that are now land indicates that the levels of the ocean were different.  Also, we may discover when such disasters as meteors may have influenced the geologic history of the earth and other species which we know existed at some point in time but are now extinct.  The porifera are keys to a past that we can only imagine- a past that is our own, but so foreign to us.
    Porifera, originating in the Vendian/Precambrian era, experienced several fluctuations in their population throughout the course of time.  Currently, although they are extremely divserse, this biodiversity is not representative of the peak of their diversity, which was achieved during the Cretaceous period.  While they are still numerous within modern times, this is not a representation of how large the populations previously were.  Decreases in population indicate changes in geologic period.
    Due to the fact that such fossil records are rather ancient, there are holes within its structure.  For example, there is no recorded origin of the sphinctozoans and stromoporids.  These are classifications of the existent/non-existent class of the Sclerospongiae.  This absence has partly contributed to this class's isolation from the taxonomy of sponges, since there is no relation other than certain physical features.  Also, the fossil history of the demosponges is interesting.  Most of the information pertaining to the fossil record of this class is not a representative sample.  While they always represented at least a plurality of the sponges, such a fact may not be true.  Due to their chemical composition, certain demosponges dissolve before they fossilize.
    However, such facts are not completely accurate due to certain factors that may influence the fossil record.  In fact, all of this page is theoretical.  However, all of our theories have been substantiated and are accepted as a common perspective.  Therefore, we would also like to remind you that this information could be altered any day.  It only goes to prove how innovative and dedicated the scientists are that research such cryptic information.