There are myriads of arguments that successfully disprove Darwinian Evolution. There are just too many holes in the theory and it does not stand up under intense examination.
It does not stand up under any examination.
One of the basic assertions is that life originated in the water and proceeded onto land via a walking fish that mutated to walk and harvest oxygen from air instead of water. Just bringing up a theory like that draws suspicion.
Under normal atmospheric condition the air is made up of roughly 21% oxygen by volume and 0.03% carbon dioxide by volume. When the diaphragm contracts it moves down and draws air into the lungs by creating a vacuum within the body cavity. Air with this rich partial pressure of oxygen enters the lungs and fills tiny air sacs in the lungs called aveoli. Capillaries surround these aveoli and the thin walls of both allow the free exchange of gases. Now the blood flowing into the lungs is poor in oxygen and rich in carbon dioxide with percentage by volume of 5.3% and 5.9% respectively. With such vast differences in the partial pressure of gasses present diffusion rapidly occurs to equalize the partial pressures of gasses in the lungs and capillaries, so as the blood flows out of the lungs it has suddenly become 13.7% oxygen and 5.3% carbon dioxide by volume. So this is what is occurring – oxygen rich air flows into the lungs and comes into contact with oxygen poor blood. Due to the differences in pressure the oxygen flows into the blood and the carbon dioxide flows out of the blood which is rich in the blood and poor in the atmosphere. Oxygen rich blood is pumped out of the lungs, through the heart and out to the body tissues where it again flows through thin walled capillaries. The amount of oxygen and carbon dioxide in body tissues is 5.3% and 5.9% by volume respectively. Now diffusion occurs again and gas flows freely to equalize the differing partial pressures of gasses. The blood is returned to the 5.3% oxygen and 5.9% carbon dioxide by volume and pumped back to the lungs via the heart.
Now let us look at what happens in the gills of a fish. Water is much harder to harvest oxygen from because salt water only contains 0.4% to 0.8% oxygen by volume. Wow, what a difference from 21% by volume in the atmosphere! Water flows across fine filaments called lamellae where capillaries carry blood flowing in the opposite direction. The direction of flow is important to optimize diffusion in such an oxygen starved environment. Unfortunately I can not dazzle you with fancy numbers as with the human respiratory system, but the principle of blood flow coupled with diffusion remains the same. Newly oxygenated blood flows from the gills to body tissues that have a lower partial pressure of oxygen and a greater partial pressure of carbon dioxide and diffusion again redistributes the gasses.
One of the vital factors of a respiratory system utilizing gills is being immersed in water. Have you ever looked inside a washing machine full of clothes and water? All the clothes are suspended and separated from each other and the ventilation facilitates the removal of dirt from the clothes. When the wash cycle is finished the spun clothes hardly fill the drum, instead they are all pressed up against the sides. Gills can be likened to clothes in a washing machine. When they are fully ventilated, the water suspends and separates the gills allowing oxygen to diffuse across the membranes and oxygenate the blood in the capillaries, but when the fish is out of the water the gills look much like the clothes that have been spun – they hardly fill the cavity, instead they are all pressed together, up against the sides. That does not make for good oxygen exchange, in fact it does not make for any oxygen exchange. How about a human lung, or any mammalian lung for that matter? Water is some what detrimental to its function. Mammals are simply incapable of harvesting oxygen from fluid. Because of the nature of the oxygen demand and the content of oxygen in water, mammals will never be able to draw enough oxygen from water by the same means as from the air. Diffusion would happen in reverse of what it is supposed to!
How does a creature crawl out of the water that is dependant on water for its very life? Granted, there are such things as amphibians which take oxygen from water and from the atmosphere but we will take a closer look at that possibility after we have developed how amphibians do that. My contention is simply that no fish ever crawled out of the water and started living on land. There is a wall of separation between water and air! The mechanisms for oxygen exchange are just too different. On one hand water flows over an appendage type device and on the other hand gasses fill a sac. Could gasses ever flow over gills and oxygenate them? Then could those appendage type devices ever start to fold up into sacs? I find that very hard to believe. It is not something I am capable of taking on faith alone. Even if it did happen, it would have to be guided by something other than chance! A series of random mutations simply can not change gills into lungs. The very thing that would help a fish to survive in the atmosphere would kill it in the water and the thing that allows it to survive in the water kills it in the atmosphere. Because gills need to remain moist to function one of the developments required to allow it to begin to be used as a lung is a mucous membrane. What would the mutation have to be to create one of those out of the blue? It would never happen! Mucous glands are too complex to just appear out of no where and for no reason and DNA mutations are too simple. How can changing a few amino acids develop into brand new organs? Just bringing up a theory like that draws suspicion.
As in mammals and fish, amphibians require a moist surface for the exchange of oxygen and carbon dioxide. Some have lungs and some do not, but all of them have capillaries close to the surface of their skin which has special epithelial cells which function the same as the epithelial cells in the mammalian lung. Some frogs obtain up to 80% of their oxygen through their skin. It does leave us in the same place though – still no possibility of evolution leading fish out of the sea. Gills would never develop into an amphibian form of respiration because the components are too different. How would internal organs ever lead to external organs through the process of natural selection? It becomes yet another example of evolution in reverse. How would it work the other way? Could external epithelial cells ever develop into gills? While I see tremendous benefit to having internal organs I simply can not imaging some sort of mutation that would lead to it! Let us take a look at some of the fruits of DNA mutations in humans – Down Syndrome, muscular dystrophy, chronic myelogenous leukemia and any number of others that lead to miscarriages.
April 19, 2008 at 10:37 pm |
“My contention is simply that no fish ever crawled out of the water and started living on land. There is a wall of separation between water and air!”
Umm . . . ever heard of lungfish?
April 20, 2008 at 12:05 am |
Lungfish only use thier swim bladders for oxygen consumption in an emergency at which time they must bury themselves in mud, keep their skin wet with mucus and slow their metabolism. They are unable to obtain full functioning outside of water, where they do breathe through their gills. The wall of seperation remains between water and air.
April 20, 2008 at 1:07 am |
Some lungfish breathe air regularly and will drown if not able to surface for air. Definitely not a wall of separation. More a continuum–solely gills to gills plus lungs to solely lungs. Not so implausible to suggest tetrapods evolved from fish that developed the ability to breathe air when we have examples of, well, fish that breathe air.
April 20, 2008 at 4:49 pm |
Nimravid, you are right, there is only one brand that normally require gills, but there are still no brands that are able to exist outside of a body of water and function fully, rather they go into a hybernative state. You still have not show what I originally asserted as implausible to be likely, namely a fish crawling out of the water and changing into a mammal.
How do you propose the mutations initially began? Suppose lungs in mammals did change from the swim bladders of fish. How do you propose the circulation system began to change from using the gills as a primary source of oxygenation to the swimbladder? Do you understand that the cells of each must have specific functions? The blood flow from the heart goes first to the source of oxygen then back to the heart and then out to oxygenate the rest of the body. How would cells that were not originally intended for the oxygenation of blood mutate into cells that are? Do you realize that in humans when cells reproduce other cells without their original functionality cancer develops? Why would that be different in any other animal?
April 21, 2008 at 4:05 pm |
“Do you realize that in humans when cells reproduce other cells without their original functionality cancer develops?”
I think you’re confused about the mechanism of evolution. Evolutionary mutations do not resemble cancer. Cancer occurs when somatic cells aquire mutations allowing uncontrolled growth. Evolution occurs when mutations in the germ line are passed on to offspring, expressed, and either selected against or selected for (or the popular third option, don’t have much of an effect at all at first, but later when combined with another change can become useful).
As for the changes and how they happened: slowly. You seem to have this idea that voila! everything happened at once! Evolution goes through stages with gradual modification, each stage being itself viable. We have fish with just gills–viable. We have fish with gills and lungs from modified swim bladders–viable. Once we have a species with lungs and gills, the process becomes pretty trivial. All you need is the slow accumulation of changes that increase the effectiveness of the lungs. Gas exchange is a very simple process. All you need is a large surface area allowing diffusion. Carbon dioxide spontaneously goes out into the air in the lungs because the concentration of carbon dioxide is higher in your blood (or your fish’s blood) than in the air. Oxygen spontaneously goes into the blood because the concentration is higher in the air than in the blood. Conversion to solely air-breathing could occur by an increase in size of the lungs and increase in exposed surface area in the lungs. Simple, just like falling off a log.
April 24, 2008 at 6:18 pm |
Nimravid, sorry about the delay, I have not had computer access. I am not confused about the mechanism of evolution, my assertion is that it is not plausible. Uncontrolled growth is is cancer, but loss of shape and functionallity are also a major part of it. The less functionality and the more deformed the cells, the more agressive the cancer. We have quite an extensive fossil record any more, and the evidence is that change is sudden and dramatic rather than gradual modification. The point is that Darwinian evolution is unsupported by both archiology and biology.
April 15, 2009 at 3:34 pm |
The style of writing is very familiar to me. Have you written guest posts for other blogs?
April 16, 2009 at 4:26 pm |
Six Pack,
I have not written as a guest for other sites but I started out with a blog in which I am the only contibutor. Have you read a lot about evolution?
April 16, 2009 at 4:46 pm |
Joel,
I suspect he is a spambot.
-Rob
April 16, 2009 at 6:13 pm |
There’s an interesting book called “The evolution of a creationist”. I forget who the author is, but the book is a great read on this subject.
Some scientist’s say that humans evolved from apes, yet our “closest relative” in the simian line has an extra pair of chromosomes. Not likely that we could lose an entire chromosome pair and create not only a viable life form but one more intelligent than what came before.
April 17, 2009 at 7:39 pm |
There is only one model of “evolution” which I have come to see as representative of science, reason and theology and it in no way shape or form is controlled by chance.
Nice observation about the genetics of ares and humans. I will look for the book you mentioned. If I have a chance to read it in the near future I will let you know what I think of it.