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Coyne describes many ways how there is evidence of evolution. Using one piece of evidence from the book, describe how that piece of evidence links with the "science as a process" theme. Be sure to define what the theme means and make connections to sources other than Coyne's book.
Next, compare and contrast with other responses similarities and differences on how their evidence connect to the theme, and what makes your evidence connect to the theme.
The theme Science as a process can be applied to all realms of biology. This theme describes the process of conducting experiments and evaluating the results to build on other evident scientific truths in order to learn more about the world around us. In, short science as a process deals with how great experimental design can yield new truths time and time again. (Since this theme is all about experimental design and this is already covered in a JAE, thus we are not allowed to use this as an additional theme.)
ReplyDeleteCoyne’s work gives many examples of specific experiments that prove evolution. An example is found on pg. 142 in reference to the evolution of eyes. Nilsson and Pelger of Sweden proved that the eye evolved by experimentally modeling the evolution of the eye in a test tube. The researchers began by allowing tissues surrounding a patch of light-sensitive cells and a pigment layer to grow randomly. The amount of deformation and change was limited by the scientists to 1% of the size of the cell group at each step. At each step, the researcher discarded cells that did not contributed to better vision. By throwing out the cells that didn’t help vision, the researchers mimicked natural selection (only the “most fit” cells for vision survived). In a short time, the scientists observed that their model of cells developed into a complex eye via stages similar to how animal’s eyes were predicted to have developed. Excellent experimental design (while not discussed in detail in the book), allowed the researchers to prove something about evolution. Since science is a process, there are still many experiments that can be performed in the future to learn more about evolution.
Sami’s point about “conducting experiments and evaluating the results to build on other evident scientific truths” is important when discussing science as a process, because we need to keep in mind that this theme does not just relate to sound experimental design. Granted, sound design is essential to gain results that have meaning which we can learn from, but another part of this theme is making connections between results from different experiments to learn even more and make bigger conclusions.
ReplyDeleteAn example of this is seen on pages 129-130, when Coyne discusses the research of Paul Rainey and his colleagues at Oxford. Rainey wanted to find out how long speciation would take in a test tube, so he put a strain of the bacteria Pseudomonas fluorescens in a vessel with nutrient broth that had different environments in different part of the vessel (ex: differences in oxygen concentration). Within ten days (the exact number of generations is not specified in the book), “the ancestral free-floating smooth bacterium had evolved into two additional forms occupying different parts of the beaker.” (130) Further testing proved that the two new forms were different genetically from the ancestor. Here we see new experiments building on old, relating to science as a process. Rainey and his colleagues did NOT set out to prove that bacteria evolve through natural selection choosing the fittest organisms for each environment- a plethora of research and experiments had already proved that. Rainey sought to build off of this scientific truth and find out just how long it took for this evolution to occur in non-changing environments for isolated bacteria. Though like in Sami’s example Coyne doesn’t go into detail about experimental design, we can infer it is sound because all of Coyne’s evidence so far has come from credible, reliable sources, suggesting that this example is no different.
PDF for the journal article for Rainey’s experiment can be found here: http://www.genetics.org/cgi/reprint/161/1/33
(Discussion of methods and experimental design starts at the bottom of p.33 through the top of 35)