Fossils: Tools in Uncovering Our Past
Fossils are preserved remains of creatures that once inhabited the earth a very long time ago. The earliest fossils found are aged to about 600 million years old. Fossils are formed in different ways; one is permineralization or petrification (the original tissues are replaced with minerals), another is unaltered preservation (the organism is preserved in the original form), another is carbonization or coalification (all the elements are removed except carbon), another is authigenic preservation (casts and molds of the organism), and last is recrystalization (crystals replace the original structure). Whatever the case is, fossils are formed when they are buried immediately after they die (Discovering Fossils, 2008).
Fossils are significant tools in determining the geologic history of the earth. When fossils are found, paleontologists determine the areas where it is commonly found, its distribution and the time span it lived. These are then used to determine geologic periods or the time intervals when the organism lived. When these geologic periods are sequenced, they form the geologic column. These columns then explain the order of existence of various organisms in the past. Index fossils are used as indicators of the specific geologic period some other fossils have existed. When new fossils are found, index fossils determine its geologic period which makes it possible to explain the manner of living of that creature in the past. The significance of fossils is not just to determine the geologic period but also to explain evolution and mechanisms that could have triggered this evolution (Plaisted, 2005).
In the case of the 3.3-million-year-old fossilized child in the Dikika region of Ethiopia, this find is significant in explaining the origin of the present man. The fossil is almost complete and the information about the location of the fossil could explain the past living of man. Through studies like this, human evolution could clearly be explained (National Geographic, 2006).
Discovering Fossils. (2008). What is a Fossil? How do they form?. Retrieved June 5, 2008, from http://www.discoveringfossils.co.uk/Whatisafossil.htm
National Geographic. (2006, November). Meet the Dikika Baby, a Three-year-old from the Dawn of Humanity. Her Discovery Holds Clues to the Origin of Childhood. Retrieved June 5, 2008, from http://ngm.nationalgeographic.com/ngm/0611/feature6/index.html
Plaisted, David. (2005, December 27). What Significance do Index Fossils Have?. Retrieved June 5, 2008, from http://www.cs.unc.edu/~plaisted/ce/indexfossils.html