The Theory of Evolution is Plausible
Debate Rounds (4)
Hello all, this debate is on whether or not evolution is a plausible scientific theory. This is still a hotly contested topic in this day and age. Despite a virtual consensus within the scientific community to accept evolution as fact, there are many that deny evolution on faith-based grounds, or for other various reasons.
I will be arguing for the plausibleness of evolution, and my opponent will argue the opposite. Here are some definitions:
evolution: the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.
*In this debate, the theory of evolution being considered is Darwinian evolutionary theory.
plausible: (of an argument or statement) seeming reasonable or probable.
R1: Acceptance ONLY
R2: All Arguments Presented
R4: Final Rebuttal/Conclusion
Note: No new arguments may be presented beyond R2.
This debate will consist of well-formatted, extended arguments. Each debater is alloted 9,000 characters per round.
I await my opponent's acceptance!
Nature, and the pure variety of it, is exquisite. We have observed this for countless years. One would think that everyone would come to a consensus on an explanation behind this variety if it was supported by mountains of evidence, tested hypotheses and observations of the natural world, but somehow, the debate still goes on.
I believe that debates like these are a small, yet necessary element of increasing awareness about the truth in evolution. By exposing the lack of evidence and astounding warped logic in denying evolution, and raising the level of recognition and attention paid to evolutionary theory, I think that we can make great strides to improve the use of rational, informed thinking in today's world.
In this debate, I will put forth several widely accepted, factual arguments that support the theory of evolution by natural selection.
I. The Fossil Record and Common Ancestry
A key part of evolutionary theory is the idea that we all descended from a common ancestor, therefore explaining both the similarities between species, and the vital differences that separate us. A crucial supporter of this element of evolutionary theory is the fossil record.
Humans have dug up fossils for years, and we have gained much knowledge from the clues left for us within the record. A fantastic example of such a clue is the Archaeopteryx fossil.
Scientists can identify links between birds and reptiles by analyzing this fossil. The Archaeopteryx was a winged bird about the size of a pigeon, with dinosaurian characteristics that proves its ancestry. Scientists know that this is the missing link between modern-day birds and reptiles; it is undisputed within the scientific community now that birds and reptiles are related.
But the Archaeopteryx is not the only piece of evidence for common ancestry, there are countless other fossils sitting in museums and labs just waiting to be spliced into the great hierarchy of Earth's species of the past.
The amazing thing about the fossil record and the geographic and sedimentary location of specific fossils is that we can track possible influences that caused natural selection to take effect. Geographic isolation that causes natural selection to occur in different ways to different sects of a species is considered. Another example is drastic climate change, which gives certain members of a species an natural advantage (furthered fitness), such as acquirement of food, which triggers natural selection.
II. The Genome and Common Ancestry
The fossil record is a way that scientists can map our past, and prove the relationships different organisms have with one another. But there is, in fact, another way to do this: by analyzing the genetic material within organisms that is inherited from one's ancestor. By identifying the similarity of the gene pools of two different species, or the similarity of one organism versus another of a completely different species, scientists have drawn fantastic conclusions on how closely related species are to one another, even when they appear to be very different.
Pioneering research conducted in labs around the world has mapped the genome of numerous different organisms, and the scientific community has discovered major relationships between species. For example, human and chimpanzee DNA is as much as 98% identical, and science has even progressed far enough so that we can easily point out the genetic differences and when they may have arisen.
This is vital evidence for evolutionary theory, as once again, we can prove the relationships between species across the world. With analysis of both the fossil record and the genomic record, scientists can say with utmost confidence that all of the organisms living today share a common origin and common ancestry.
III. Observations of Evolution by Natural Selection
Since the formulation of the theory of natural selection (introduced most prominently by Charles Darwin in his work On the Origin of Species), natural selection has been observed numerous times by many scientists.
A notable example is Darwin's own observation of the finches of the Galapagos Islands. Darwin observed key differences in the structure of the finches' beaks, and found that these differences were grouped in accordance with the diet of the finch. The finches that ate insects and lived in trees had beaks that were structured differently from the ground-dwelling, seed-eating finch.
But how? How did the finches acquire these different shapes, seemingly ideal to their different diets? The answer is natural selection, and science has confirmed that through further experiments on the Galapagos. To put in simple terms: the finches best adapted to their diet were more successful in survival and reproduction, and therefore their genes became more prominent in the gene pool. The finches evolved to become more fit, more adapted to their environment. They evolved.
We can see that evolution is a plausible scientific theory if we examine the evidence. It is obvious that evolution by natural selection is the best way to explain developments, fluctuations and observations made in nature. Science is wonderful; scientists use evidence to build theories which explain the world around us rationally, logically and astoundingly accurately. As much as 98% of the scientific community believes with the theory of evolution. I side with the scientific community, evidence and rationality, and I believe that evolution is a plausible scientific theory.
Firstly, your argument that the fossil record makes evolution a viable explanation for the great biodiversity we enjoy today. I would view this evidence from a very different perspective. I would, in fact, assert that the fossil evidence runs to the contrary of evolution. Fossil evidence like the archaeopteryx shows that there was once a bird with reptilian characteristics. However, if the theory of evolution was true, there would be evidence of a greater number of transitional species, as the theory of evolution is alleged to be a gradual process. As there is only evidence of one such 'transitional species', a far more rational and evidence based explanation is that the archaeopteryx was a distinct kind of animal, one that shares both avian and reptilian characteristics (though falling into the avian kingdom).
Secondly, your argument that the genetic similarities between certain species proves that they evolved from a common ancestor. I would again argue that this evidence is contradictory. Are we honestly supposed to believe that because species resemble each other they must be descended from a common ancestor? The 'genetic evidence' would show close relation between chimpanzees and humans, yet there is not fossil evidence of such a creature ever having existed. This argument for evolution relies on the premise that similarity between species must mean they share a common ancestry, a pure assumption with little evidence to support it. A far better and more rational explanation would be that species are similiar because they were created similiar.
Finally, your argument that we have observed natural selection. I find this particular argument to be the easiest to dispute. Your evidence was Darwin's finches. However, these finches were not of the same species. There were fifteen separate species of finch on the islands. This argument is very similiar to your second. It assumes that because these species were similiar, they must have had a common ancestor, and that their adaptions to their environment were as a result of isolation. I find this to be preposterous. The idea that different species on different islands must have been the same species and adapted is another pure assumption. It is a flawed notion. Surely, when this 'common ancestor' arrived on a new island with a different method of hunting food required, they would have been ill-adapted, and perished? The evolutionary counter argument to this, that mutations caused one particular bloodline to survive, is equally preposterous. Either evolution is gradual, in which case the minute differences in beak structure of a mutation amongst the colonising population would have made no difference, or evolution is sudden and dramatic, in which case, the creation of an entirely new species occurred in one generation and just happened to coincide with the bird's colonisation of a new island. The former would have led to the death of the birds and so evolution would have been impossible, and the latter is impossible, as we would have evidence of inter-generational speciation in species today, which has never been observed.
Now of course, to assert that evolution is an invalid explanation for biodiversity requires one to provide a different narrative. I would propose that the best explanation for bio diversity, the only explanation in my opinion, is that all species on this earth were created by a supreme being. This explains biodiversity. This overcomes a major flaw of the theory of evolution, namely the origin of life itself. And finally, it is supported by the evidence.
However, this debate is about the plausibility of evolution, not the plausibility of intelligent design. I believe I have, in this round, proven evolution implausible. However, I eagerly await your rebuttal.
I will now attempt to refute my opponent's claims made against my arguments in R2.
This rebuttal will draw from my opponent's claims and present evidence to the contrary.
R1: Prevalence of Transitional Fossils
My opponent claims that there are very few examples of transitional fossils, and therefore there is no sufficient basis for drawing a conclusion on common ancestry. On the contrary, there are many examples of transitional fossils other than the archaeopteryx. One is Tiktaalik, which supports the transition between water-dependent animals, like fish, to land-faring amphibians. Amphisitium, an early type of flatfish, explains the gradual transition to the asymmetrical eye placement of today's flatfish. Australopithecus afarensis represents a change between quadrupedal apes and bipedal humans. Ambulocetus natans supports the phase of transition for cetaceans from freshwater to marine habitats. Need I say more?
It is evident that these transitional fossils are evidence for common relation between all species, and further, a common ancestor. Natural selection, as proven countless times to be true and veritable, is the mechanism for these transitions occurring within the fossil record. Furthermore, it is most definitely true that the fossil record contributes to the plausibility of evolutionary theory and the theory of common ancestry, as the fossil record continues to unveil relationships between different sects of the animal kingdom that point to the credibility of evolution by natural selection.
R2: On Genetic Similarities
This claim rests on the idea that just because there are similarities within the genetic makeup of various species today does not mean that they can be related. However, it is the degree of similarity among more closely related species that proves common descent. For example, bipedal humans and quadrupedal apes have astounding similarities among their genetic pools, with the degree of similarity being 96% or even higher. This degree of similarity is smaller in species which are not so closely related, like the human and the fruit fly, which have a genomic degree of similarity around 60%.
Another vital piece of proving common ancestry through genetic analysis is via phylogenetic reconstruction, allowing geneticists to trace evolutionary relationships by algorithmically sorting genomes by character conflict, transposons, repeats and further criteria. These studies produce beautifully accurate representations of evolution by the use of phylogenetic trees, such as this one: http://www.nature.com...
R3: Darwin's Finches, Common Ancestry and Natural Selection
My opponent fails to account for the basis for natural selection, which is genetic variation within a species. When the common ancestor arrived, there must have been some individuals within the population which were better suited to survive. For example, organisms of a type of finch living in a habitat where nuts are the main food source might be advantageous if they possessed an enlarged, sturdy beak, given the hardships of a finch with a long, thin and flimsy beak in the same situation. It is not just science, but common sense, that the finches with sturdy beaks would have more success in surviving, and therefore their genes would become more prevalent in the gene pool as their reproductive rate is higher than less fit finches. This is an example of directional selection, where an originally scarce trait becomes more common as this trait enables higher fitness than the alternativ(es).
It is clear that my opponent denies obvious evidence supporting evolutionary theory by natural selection. All of my opponent's claims made in R2 against my own arguments have been refuted through the presenting of even more evidence. Therefore, I call on all voters to cast your vote in favor of Pro.
I eagerly await my opponent's response.
Rmcewan15 forfeited this round.
I have no arguments to rebut that I have not already refuted. All of my arguments from R3 extend without a response.
In short, I thank my opponent for this debate, and go science!
Rmcewan15 forfeited this round.
1 votes has been placed for this debate.
Vote Placed by roguetech 1 year ago
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Reasons for voting decision: Fossils: Con simply claimed there aren't enough "transitional fossils". Pro could have dispensed with that by simply pointing out "all fossils are transitional"... But Con ignored a critical point "the... location of specific fossils is that we can track possible influences that caused natural selection to take effect." Genetics (with *slight* advantage to Pro): Tied. Pro failed to address genetics does not predict form, per se. In other words, the DNA of a bat that flies isn't really close to a bird's, simply because it flies (which is essentially Con's rebuttal). Natural Selection: Slight advantage to Pro, due to Con not establishing that evolution could not happen. However, Pro would have been well-served to have demonstrated actual observed evolution, or even the appearance of hereditary genetic mutations among humans. A weak performance by Pro, and a solid effort by Con, but victory must still go to Pro. Waiving a magical "transitional fossils" wand doesn't make them disa
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