Geology Paper on Evolution – Your Inner Fish

Evolution – Your Inner Fish


For decades, there has been an ensuing debate between theology and science regarding the true origins of man. In addition to the resultant controversy aforementioned, there is a continuous character of the evolutionary process of man in scientific terms relating to the Homo sapiens as well as the understanding of creation as placed by theologits. In most religious faiths, human beings are but a creation of a higher power and the origins of man have seen psychological as well as social changes relation to one another.  On the other hand, scientists believe that human are an evolutionary spices that has gone through years of biological changes that has made it become highly adoptive to its environment. A number of scholars including Charles Darwin have put across several theories regarding evolution, and how humans as well as other organisms have adopted to their surrounding environment to become the superior being seen today. This paper while using the ideology of evolution as presented by Neil Shubin as presented in his manuscript ‘Your Inner Fish’ elaborates on the scientific perspective in reference the process of human evolution.



Theologians believe in the existence of a superior being that determine the existence of mankind throughout human history. According to the bible, man is created in the image and likeness of God suggesting every feature of the human anatomy is a derivative of ‘the works of the almighty’. On the other hand, scientists believe that human beings are a complex genus of multiple organisms that has evolved over a number of years in order to survive the current environmental conditions. The most recognized manuscript about evolution known to the scientific world is “On the Origin of Species” that was presented by Charles Darwin in 1859. According to Darwin evolution is the course which organisms naturally take over time to change physically in order adopt to their surroundings in the process avoiding extinction. Other numerous scholars one of whom is Neil Shubin famously known for his ‘Your inner fish’ ideology that suggests that humans are a genetic result of evolution of other numerous organisms (Shubin, 2009) also share the ideology of evolution as based on natural selection.

Written in the Rocks

Since ancient times fossils have been known as good mediums of recording history. The dinosaur Protoceratops have been suggested to have given rise to the epic griffin represented by the Greeks and this is a result of fossil history. According to Naff (2005), fossil formation is a forthright process that requires the remains of an animal or plant to be deposited in water; sink to the bottom and covered by mud (sediment) consequently avoiding decay and scattering of bones. The resultant product is an almost 3-D imagery of the spices left behind (Futuyma, 2013). The biggest critic against the use of fossils in a historical context is that the total estimated number of species that have ever lived range between 17 and 20 million. A research by Coyne (2009), shows that only 250,000 different species have ever been found through fossils making up only 0.1% to % of all species. This is scarcely a sample that would be used in a historical perspective. However, highlighting on the ancestry between two groups of species does not necessitate the complete fossils of a single species to show a connection or direct decent. Rather, what is required is fossils that have similar traits as well as a dating mechanism that would show that the fossils occurred chronologically in geological records. An ‘ancestral species’ is not similar to a traditional species considering the former only shows a combination of qualities of living organisms that existed before and after it (Naff, 2005).

In reference to the inner fish, the fossils or the written on the rocks ideology helps explains Shubin’s premise of how parts of the human body appear as they do. When exploring the early forms of vertebrae life as shown in a variety of fossils the existence of similarities between the ancestral species between the vertebrae and early human forms (Shubin, 2008). The Tetrapod species are land based and represent the ancestral species that were formed from the fish. The fossils of the Tiktaalik shows the intermediary between a land animal with  specialized limbs, ribs, a neck as well as flat head that originated from a fish showing how a fin turned to limbs. From this the evolutionary traits retrieved from Acanthostega, Ichthyostega, as well as Tulerpeton fossils it is can be argued that the living tetrapod have ancestral connections with fish (Futuyma, 2013).


As earlier explained evolutionary tendencies take a physical nature, hence species develop features that aid them in their survival. However, some of these features with time lose their usefulness to the point where the adaptation is rendered more of a liability than an asset consequently being called a Vestiges limb. According to Shubin (2009), the limb is considered vestigial based on the fact that it is functionless however, it serves as a reminder of evolution. An example of the vestigial feature is the human appendix that was highly useful to the early leaf eating human ancestors this is in addition to what humans call a coccyx a feature used by animal ancestors for balance. Vestigial features not only exist in bodily functions but also by trait; for instance, for the ostrich lost its ability for flight to direct the expensive resources dedicated to fly towards reproduction (Shubin, 2008).

In selective cases, organisms develop an anomaly where they develop characteristics that once belonged to their ancestors; for instance, some horses are born with an extra limb (toe) or human babies with a tail. These features are what are called atavisms and though they share a similar perspective to vestigial limbs their main difference is that they do not occur on every individual of a particular species. According to Zimmer (2006), the movement of evolution makes a vestigial limb become an atavism over time.

It should be noted that both features named above are a sign of evolution as explained by Neil Shubin. As one species transforms and adopts a feature from its ancestor and over time either loses it or makes it vestigial this shows the connection between interspecies and more particularly the fish. It can be argued that as the Tertrapods became more adopted to the land they grew more dependent on longer limbs to the point the being upright became an extra evolutionary feature leading to humans losing their need for tails. Nonetheless, Neil Shubin goes further to explain the existence of dead genes using the above notion. Much has been published in the genome field about dead or silenced genes, which are defined as genes that were once useful to a species but no longer serve their purpose through evolution. In other words they can be highlighted a vestigial genes. In the human genome system, there are thirty thousand genes; however, there are about two thousand pseudogenes that are dead and some of them can be found on other not only living primates but also fish.  For example, the human species has a ‘fish embryo’ stage, a feature even natural selection has failed to eliminate considering the combination of fish like gill arch, circulatory system as well as tail is not needed in a human embryo but still all the above exist. The reason for this existence can be explained through the perception of accessorial gene existence. However, unlike the above explanation though the feature of fish embryo does not affect growth of a human fetus some evolutionary traits are a sign of imperfection.


Bad Design

Evolution allows an organism to thrive in their environment the feature of adoption is not a derivative of perfection but trial consequently giving rise to the idea of ‘bad design’. The evolutionary process takes a similar track to that used by medieval English writers who used skins since paper had not been invented yet (Coyne, 2009). In order to find space for a new manuscript the scrubbed of the oldest data and wrote over it. Evolution takes up the same replacing the old changes with new once that are more effective suggesting organisms though further placed away from their ancestors are not new. The biological building block such as nerves or bone structures have a resemblance. This resemblance might be disadvantageous for instance evolution has transformed the human testicles from fish a feature that is the cause of hernias considering the weakness of the abdominal cavity. The urethra is also poorly designed considering that it runs through the prostate gland.  From the above information, it is evident that the human ancestry form fish has imperfections of poor designs that cause evolutionary defects that do not aid the humanoid species in anyway.

The Geography of Life

Biographic evidence is placed to explain reasons why animals existing in very different environments may share similar traits regardless of their difference in spices. Creationist may argue against the idea of evolution; however, there are a variety species thriving in dissimilar environments; however, they share some similar traits. From the evolutionary theory showing a connection of species though similar ancestor species, it is plausible for scientist to explain this. With issues such as molecular taxonomy as well as continental drift it can be explained how animals with similar traits live in different regions. On the other hand, with the explanations offered by ‘convergent evolution’ theorists such as Futuyma (2013), it can be explained how species that thrive in similar habitats may develop comparable evolutionary traits considering they are exposed to the same pressures of their habitats consequently making them behave or even look alike though they are unrelated.  According to Shubin  (2009), Convergent evolution elaborates on how three major evolutionary theories namely common ancestry, speciation as well as natural selection take place.

The Engine of Evolution

Dorwin in explaining the rules of natural selection stated that the theory was based on the environment allowing the best adopted spices a chance to thrive as it caused the lesser animals to go extinct. Evolution is not voluntarily, it is not a process that gives a species a chance to develop an advantage, but adopt to prevailing conditions in order to survive (Naff, 2005). The notion that things or changes in species features in species happens by chance or accidentally is highly incorrect. The three factors that lead to evolutionary changes first of which is the population of the spices, which is set to keep the class of plant or animal alive throughout the evolutionary period. The second is genetic variation suggesting that true evolution should be derived genetic causes that would transfer the evolutionary tendencies to next of kin generation. The third factor is reproduction, which would be the ability to give birth to genetically advanced offspring allowing the species to thrive (Coyne, 2009).

How Sex Drives Evolution

The idea of male domination as well as female choice in mating is a factor that is known to biologists and is a derivative of evolution. In the African Savanah, the view of a lion crushing the heads of cubs belonging to an overthrown lion, is considered brutal; however, it is part of nature ending the lineage of a weak predecessor and allowing the existence of a more powerful clan. The scenario above is part of evolution here the strongest survive, a factor that is influenced by sex. In birds such as the peacock or widowbird, beauty in form of a long or colorful tail is used to attract the opposite.

On the other hand, in animals such the Elk or the Elephant the longer the horns or tusks the more damage it can inflict on its opposing male compatriot winning over the female allowing reproduction of a highly a superior offspring. From the above explanation sex though in a simple manner has already made evolutionary choices where the female chooses which of its male species is worthy of having offspring which as explained above is a determinant factor of evolution. According to Zimmer (2006), this is a derivative of investment considering the female goes through a longer process of reproduction than the male such as providing a conducive environment for the embryo to develop and become an progeny as well as taking care of the young one to the age of self-dependency.  Consequently, the males have to fight or flirt so to speak to gain the privilege of having their own young ones. One other explanation of how sex determines evolution is through a model known as the sensory-bias model that states that females determine their mates through the nerves system, which is an evolution by-product.

The Origin of Species

Darwin’s manuscript though highlighted as the origins of species explains more about evolution through natural selection and only travels half the journey of explaining how organisms have grown to what they are now. A better tittle for the book would be the origins of evolution considering the manuscript does not explain how a single species transforms to two or many others. In order to explain the origins of species one has to go further than explain species traits. According to Shubin (2009), as species is defined as a naturally reproducing population that is isolated from such other groups.  This would then be a good reason of explaining why lions though living in the same plane as other cats such as leopards are different species though they are of the same classification. Darwin only explains how a leopard are differently modified from lions but not how the two originated from one organism. Genetics is the only field that explain the origin of species.

What About Us?

A variety of technocrats; for instance, paeloanthropologists, geneticists, as well as molecular biologists have gathered significant information from fossils and DNA to show the position held by humans in the evolution tree. Human beings are descendants of apes with the closest being chimpanzees who we share highly similar genetic makeup (Shubin, 2008). From the explanations presented above evolution is a gradual process and there is usually a link between species; however, with humans finding this link that separates us from apes has proved hard to find.  The best possible outcome is to use the inner fish perspective, which is to find evolutionary cousins that share a number of traits with humankind. A look at the collection of the early man fossils shows that humans (Homo erectus) are a descendant of apelike dynasties

Evolution Redux

The process of evolution is evident through a number of different fields from fossil recording, genetic analysis, embryology, as well as vestigial structuring has proved the evidence of evolution however there are still sceptics on the matter. Proving that evolution exists goes beyond proof, it is hard for any average creationist no accept humans are descendants of fish. The ideology of human beings having similar ancestors in evolutionary standards is more acceptable than fish considering because of the emotional consequence of having to look at different organisms from man being in direct relation to man. There is much to be done to convince a variety of individuals to accept the existence of true evolution.



Evolution is regarded as the sequential changes that are observed through the existence of a species in reference to their surroundings. Charles Darwin through his manuscript the origin of spices states that through natural selection organisms physically change on order to thrive in their environments. However, the process of evolution is not voluntary but a procedure of the environment selecting the best species to inherit the earth.  Neil Shubin as presented in his manuscript ‘Your Inner Fish’ shows that humans are descendants of fish considering the human libs seen today are derivatives from fins. Other than the limbs, other features have outlived their usefulness such as the coccyx or appendix in humans. From this, it is evident that evolution is not perfect considering some evolutionary features are not well designed and causes weakness other than advantageous adaptation.


Coyne, J. A. (2009). Why evolution is true. Oxford: Oxford University Press.

Futuyma, D. J. (2013). Evolution. Sunderland, MA: Sinauer Associates, Inc.

Naff, C. F. (2005). Evolution. San Diego, Calif: Greenhaven Press.

Shubin, N. (2009). Your inner fish: A journey into the 3.5-billion-year history of the human body. New York: Vintage Books.

Shubin, N. (2008). Your inner fish: A journey into the 3.5-billion-year history of the human body. New York: Pantheon Books.

Shubin, N. (2009). Your inner fish: The amazing discovery of our 375-million-year-old ancestor. London: Penguin.

Zimmer, C. (2006). Evolution: The triumph of an idea. New York: HarperPerennial.