Friday, September 24, 2010

Why Hyenas Are Exclusively for Africa ?


A team from the National Museum of Natural Sciences (CSIC) has analyzed the impact of climate change on spotted hyena survival in Europe over 10,000 years ago during the Pleistocene period. These changes played a vital role, but the scientist advocate further study to look at the influence made by human expansion and transformation in herbivorous fauna on the extinction of the species across the European continent.
        Generally, the secondary source is a summary of the abstract or the introduction of the primary article.The author of the secondary source has certain word limits to construct the article. So he has to be precise in detail selection. The primary source is a very well organized and descriptive article. Often it is boring to study and won't find much readers other than the peers who review it or other researchers and students from science background. The primary source is easier to read and understand because of the simple approach and not so extensive use of scientific terms.
                           The secondary source starts on with basic terms but the sudden use of the term "Pleistocene" in the last half of the article may surprise the reader. The author could have used the term in the beginning of the article with its relevant meaning. Earlier, the author has been using easy terms  like 10,000 years ago, to refer to Pleistocene period. 
    The secondary source commends the theory but lacks in providing much of the details to prove its point. The secondary source fails to describe about the system used for model projection of various climate scenario's  of  the  Pleistocene . He should have mentioned the system used to provide model projection  which was GENESIS 2.0 General Circulation Model (126 ka, 42 ka, 30 ka and 21 ka). This system has been extensively  used in the study of paleoclimates.
                                         In the secondary source the author describes the role of climate change as a crucial one in the extinction of hyenas from Europe. But he cites the same information twice in the paragraph. The same amount  of words could have been employed to furnish other relevant details like  one  pointed out earlier by me.  At the same time, the author also makes a blunder by citing a wrong information in the article. While earlier in the article  he talks about the climate of southern Europe being extreme for hyenas to survive. Later in the article , he declares that southern Europe always had a climate which was within hyenas' tolerance   range.  This may really confuse the reader about the authenticity of the article. But the primary source put forth that southern Europe was always within hyenas tolerance range.
                                According to primary  source the hyenas inhabited a wide range of annual precipitation and
mean temperature conditions,  although Pleistocene European localities appeared to have lower  temperatures and, to a lesser extent, lower precipitation than current African localities. Present data for Europe during the warm/wet conditions of the Pleistocene 126 ka scenario had different climatic conditions than those from the cold/dry conditions of the last  glaciation. The   geographical projections of the climatic niche derived from all fossil and current data indicated that hyena had suitable climatic conditions in Europe during the last 126 k. The potential climatic distribution of the species covered Europe in the last interglacial age . The research result puts up that the hyenas might have diminished due to extreme cold conditions prevailing during the Last maximum Glacial. But  even during this probability large portions of central and southern Europe would have remained habitable. There are even more evidences which support that climate was not the only crucial and decisive factor. Many cold periods  occurred during the Pleistocene and certain fossil evidence suggest that hyenas existed during Maximum Glacial period in Europe. The secondary source directly puts forward that hyenas became extinct during late pleistocene , coinciding with maximum glacial but the primary source doesn't states this fact. 

                                            The author in the primary source states that is it relevant to study the human effect and herbivore abundance to understand the extinction of hyenas in Europe and its prevalence in Europe.The secondary source expresses the other two reasons casually without putting much emphasis on them. But the primary source put forth the idea of exploring the northern Europe to search for fossil records related to the limited number of Northern European interglacial fossil sites because the spotted hyena European distribution should cover Northern  Europe during the warm periods of the Late Pleistocene.
                                 The author of the secondary source runs through the whole research work in seconds. After finding the research paper. I got to know about the half cooked articles, the  newspapers and internet  serves us. The Primary source provides much details rather than the secondary, but secondary information sources will always connect research work with the common people. A secondary source writer has to be thanked for simplifying the science and to make it available for common people.  But some major flaws in the article, surely questions the credibility of the author in writing the article.

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