Review on the Inner Fish Essay
Why Do We Believe in Evolution A Brief Review of Your Inner Fish With his passionate and readable language, Neil Shubin tells us in Your Inner Fish about his adventure to find the fossil of Tiktaalik, an ancient creature believed to be the missing link of trans-specific evolution from fish to amphibian - Review on the Inner Fish Essay introduction. Systematically relating some other evidences, Shubin explains human as an evolutionary product (not necessarily the result, though) of an ancient fish, and argues for the fundamental role of evolution in understanding biological phenomena.
According to their implications, evidences provided in the book can be divided into: similarities of body parts between existing species, and molecular biology evidence; embryonic development; and detailed examination of Tiktaalik fossil. Similarities of body parts between existing vertebrate species indicate a common ancestry of those species, while molecular biology evidence confirm the assumption and extend it to almost all existing species. Significant analogies are found between anatomical characters (for example, structure of bones) of different species.
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Among head, bones in ears, teeth and many other examples illustrated in the book, the upper limb is the most persuasive. No matter what function the upper limb serves for the vertebrate animal (flying for birds and bats, swimming for fish and marine mammals, walking for quadruped, and holding for human), the bone structures are remarkably similar: for nearly all terrestrial amphibian, reptile, mammal and bird, the upper limb is composed of a major bone, two lower bones, and a wrist with five fingers.
Even in species that do not have a functional upper limb, the remnant bones are at the same position with respect to the spine. Molecular biology tells a lot more. Cells in almost all species use adenosine triphosphate as the major coenzyme for metabolism, makes same choices on 20 (or 22) kinds of standard amino acids among thousands of amino acids, and code their hereditary information in precisely identical ways with exactly the same chemicals called DNA (only few virus that use RNA or protein are partially excluded).
Showing the astonishing similarity shared by species on earth, these facts are demonstrated one step further in experiments such as comparing the result of injecting into the embryo of certain species the corresponding DNA (or protein coded by it) of the original species and that of another species. More significantly is that the more two species resemble each other in their genes, the more similar their morphological characters, a fact that strongly supports evolution with the form described in the tree of life.
In conclusion, evidence from both morphology and molecular biology reveal the uniformity of species on earth, and when the two are combined, it becomes reasonable to suggest that all species have a common origin. As for embryonic development, on the one hand it strengthens the common ancestry idea: different multi-cellular species experience comparable phases through parallel process, and the closer the two species are related genetically, the more their embryonic developments resemble each other.
On the other hand, embryonic development itself demonstrates the possibility of a complicated multi-cellular creature stemming from a single cell, though people still don’t fully understand the process. With its morphological characteristics and the approximate time period it lives in, Tiktaalik is believed to be the trans-specific life form that corroborates the evolution from fish to amphibian. Most of the morphological features inferred from its bone structure identify Tiktaalik as a fish. It has four fins, and no bones in the tail for example.
As the only creature known to exist before the first confirmed land-living species appear, however, Tiktaalik has a flat head with neck that allows the head to move separately from its shoulders, a structure never found in fish species. Eyes on top replace the typical side-looking eyes in fish. Spiracle and bones structure show the existence of lung, a rare organ for a fish. In conclusion, it bears most of the characters of fish existing before it, yet also carries primitive features of a typical land creature, suggested to be an evolutionary transition.
Though evolution is widely accepted (especially among scientists), some people favor ideas like creationism or intelligent design. James Patrick Holding doubts the possibility of certain homologous traits (2006). Shaun Doyle asserts that evolution can’t explain upward progress of life from inorganic molecules to simple life forms and then to complex forms (2008). Larry Vardiman questions the radio dating method and the age of the earth, hence supporting that there isn’t sufficient time for evolution to take place (2000).
Bergman, J. objects the interpretation of the evidence we discussed earlier. In his belief, though the evidence works well in accordance on the basis of evolution, nothing conclusively supports trans-specific evolution, and the “homologous traits” between species are proof for a single common designer against multiple designers. For people with the same idea, the amazing molecular biological evidence argues as much (or even more) for common design as for evolution.
To objectively evaluate the argument, one should not simply neglect any opinions because some ignorant (I mean illogical) people hold those opinions. Thus it is valuable to evaluate the reasons behind those doubts and questions above. Observations of artificial selection offer examples of trans-type evolving. The embryonic development and process that inorganic molecules form amino acid with the presence of lightening dismiss to some degree the doubt on upward progress.
More generally, there is a defect within any assertions supporting intelligent design: the power to predict. Well exemplified in the prediction about the existence of Tiktaalik, the time period it lives in, the position where people might find its fossil, and the features of its habitat, thousands of scientists have made strong and precise predictions over the last few centuries. While intelligent design has only the power of explanation, which derives from its continuous revision according to newly discovered facts (that are found by evolutionists, ironically).
To say the least, even if intelligent design is true, there is no point to devote our resources and energy into it nowadays, since it generates no meaningful predictions and thus remains unfalsifiable at least for now. In conclusion, for those believe in evolution and those with an open mind, the consistency of evidences from various disciplines qualifies evolution as a basis for further studies, but until we can replicate the whole process of the evolution starting from inorganic molecules, we should keep our mind open for either revision of evolution or other brand new ideas.
Doyle, S. , Serial cell differentiation: intricate system of design, J. Creation 22(2):6–8, 2008 Holding, J. P. , Not to Be Used Again : Homologous structures and the presumption of originality as a critical value, J. Creation 21(1):13 –14, 2007; <creation. com/original> Larry Vardiman, Radioisotopes and the Age of the Earth: Creationist Research, 2000, ISBN-10: 0932766625, ISBN-13: 978-0932766625 Woodmorappe, J. , Mammal-like reptiles: major trait reversals and discontinuities, J. Creation (TJ) 15(1):44–52, 2001; <creation. com/mammal>