Purposeful Design or Chanced Processes?

[theStudent]

Evidence of God is everywhere.
The Bible states that truth clearly, when it tells us, "The hearing ear and the seeing eye — Jehovah has made both of them."

The ear consists of three parts: the outer ear, the middle ear, and the inner ear.
The middle ear is a small chamber that begins with the eardrum and leads to the maze of passageways that constitute the inner ear.
Besides its function in connection with hearing, the inner ear also possesses organs having to do with balance and motion.
The use of two ears greatly helps a person to locate the source and direction of sounds.

The human ear detects sounds within the range of about 20 to 20,000 cycles per second.
The ears of many animals are sensitive to tones of higher pitch that are inaudible to the human ear. The range of sound energy perceived by the human ear is remarkable. The loudest sound that the ear can tolerate without danger is two million million times as powerful as the least perceptible sound. The human ear has the maximum sensitivity that it is practical to possess, for if the ears were any keener they would respond to the unceasing molecular motions of the air particles themselves.

The outer ear is precisely designed with a specially designed structure of curves, and an opening designed to catch and channel sound waves into the inner ear.

How the ear works


How the hearing works
[youtube][/youtube]

How your ear works - Inside the Human Body: Building Your Brain - BBC One
[youtube][/youtube]

The eye is a highly efficient, self-adjusting “camera� that transmits impulses to the brain, where the object focused on the eye’s retina is interpreted as sight.
The possession of two eyes, as in the human body, provides stereoscopic vision. Sight is probably the most important channel of communication to the mind.

How the Eye Works Animation - How Do We See Video - Nearsighted & Farsighted Human Eye Anatomy


Anatomy and Function of the Eye
[youtube][/youtube]

A Journey Through the Human Eye: How We See


Eye Animation
[youtube][/youtube]

If the male and the female reproductive organs evolved, how had life been proceeding before the complete formation of both?

An egg from a woman’s ovaries cannot produce life on its own. For this to happen, a sperm cell from the male reproductive system must combine with the nucleus of the egg.
What does the sperm do to make the egg develop?

Differently shaped cells begin to form - nerve cells, muscle cells, skin cells, and all the other types that make up the human body.
Science Digest

No one knows for sure, why certain cells aggregate to form a kidney while others join to form a liver, and so on.

Eventually, the human body reaches full growth, being made up of some 100,000,000,000,000 cells.
What causes the cells to stop dividing at just the right time and why?

How Sperm Meets Egg | Parents
[youtube][/youtube]

The Masterpiece of Nature, by Professor Graham Bell

Sex is the queen of problems in evolutionary biology. . . . It seems that some of the most fundamental questions in evolutionary biology have scarcely ever been asked . . . The largest and least ignorable and most obdurate of these questions is, why sex?

Imo, it is truly mind-boggling how one can say they have no evidence of God.

Do you agree these give evidence of design and purpose?
Is there any chance that these came about through the process described by evolution theorist?
Evidence for arguments required.

[Kenisaw]

There are plenty of assumptions in evolution. Darwin himself assumed that in the future the fossil record should produce the missing fossils he could not find at the time he was formulating his theory.

Darwin didn't assume, he predicted. He said that we should find the missing fossils, and we have. The theory of evolution predicts this. Had we not found the fossils, it would have meant the theory was wrong. The theory was not wrong, and we have billions of fossils at this point, and none of them disagree with what the theory and Darwin predicted.

I don't know of any assumptions in evolution. Evolution became a hypothesis because of the observation in nature that some species resembled others, and also that the level of similarity mirrored how close the species were in proximity to one another on the planet.

It was assumed that our DNA was full of junk and this was shown to be wrong.

Agreed. And this has nothing to do with the theory of evolution, so I fail to understand why you include it in this discussion.

Most of the detail between many of the claims made by evolution are assumptions because they have not been scientifically verified.

Like what specifically? Please list a couple and explain in detail where the assumptions are and what has not been verified or validated.

As time goes by new discoveries expose those assumptions to be incorrect.

Like what specifically?

Are you saying that the claims made by evolution have never been wrong?

If any prediction made by the scientific theory of evolution can be shown to be wrong, it wouldn't still be a scientific theory.

One of the major assumptions is that single-celled organisms evolved into multi-celled life and that natural selection was the driving force. This has not been scientifically verified and is assumed or speculated.

I disagree with your verbiage here. While I completely agree that this is an active area of research and our understanding is far from complete, it is not devoid of evidence. Species like volvox display what is called the colonial flagellate hypothesis - single cells working together. Sponges are another example, as they use large numbers of basically identical cells to live together. Cnidaria (like corals and anemones) are the next step in that - no organized system like blood vessels or a liver or brain, but multiple specialized cells within the group.

Here's a paper on how quickly single cell yeast will create multi cell clusters:
http://www.nature.com/news/yeast-sugges ... ife-1.9810

Biofilms also support the idea of single cell species forming multi-cell structures that become dependent on each other:
http://jb.asm.org/content/182/10/2675.full

Other articles that may interest you:
http://www.nature.com/articles/ncomms3742

Also, don't forget that slime molds, that basically go from unicellular amoeba to a multicellular slug like critter in its lifetime.

There are also statistical studies that show it unlikely that commonality in DNA (which all living things share) could happen unless everything came from a common ancestor:
http://news.nationalgeographic.com/news ... -ancestor/

I'd say "speculated" is not accurate on your part...

In fact, a lot of evolution in the past is assumed because no one was there to see it directly and scientifically verify it.

Oh please, do not be one of those believers that try to play the mythical "observation vs historical science" card in here. I had hoped for better things from you. Fossils are snapshots in time. We are observing the animal's structure at the time it lived. You observe billions of fossils over the history of life and you can see what happened over time. There is no assuming of anything. And we can date things so we know what came when.

Here are more assumptions by evolution,

That Natural selection is able to evolve complex life.

Obviously the links above show you it is possible. Slime molds are living proof.

[stevevw]

[Replying to post 256 by stevevw]

I wasn't specifically talking about beneficial mutations. A mutation can persist throughout a species and have no real benefit or can even be considered negative like blindness for example. However when the environment changes benign or disadvantageous mutations suddenly become advantageous like the blind cave fish.

I would have thought those mutations that take away information from the existing genetic makeup would be a disadvantage even if it appeared to give an advantage on the surface. By eliminating an existing function of a gene, the gene is then not going to work properly despite it appearing to function to a point. Often the mutational effect is slight and can be tolerated but eventually, this can add up to a cost and threaten fitness.

It's a bit like antibiotic resistance in bacteria. Although the mutant bacteria can survive in the environment where it has become resistant to antibiotics, the change has come at a cost. The altered protein is less efficient in performing its normal function, making the bacteria less fit in an environment without antibiotics. The non-mutant bacteria are better able to compete for resources and reproduce faster than the mutant form.

Regardless of how frequent beneficial mutations actually are once a beneficial mutation occurs within a species that helps them leverage the surrounding ecosystem it will eventually persist throughout the species.

I would have though the beneficial mutation frequency was important as there need to be many to account for all of life. If they are very very rare and deleterious mutations are more common then there must have been a multitude of harmful mutations.

[DanieltheDragon]

[Replying to post 260 by stevevw]

I would have though the beneficial mutation frequency was important as there need to be many to account for all of life. If they are very very rare and deleterious mutations are more common then there must have been a multitude of harmful mutations

That is the beauty of natural selection though ain't it? If the mutations become negative and decrease the fitness of the organism then that organism is less likely to pass on its mutated genes through reproduction. An organism with a beneficial mutation will gain an advantage and will be more likely to reproduce.

So you see even when deleterious mutations are more common they are less likely to be passed down. While beneficial mutations bring more rare are more likely to be passed down. This decreases the pervasiveness of the negative mutation and increasing the pervasiveness of the beneficial mutation.

[stevevw]

[Replying to post 252 by stevevw]

"So then you are saying that all learnt tasks are the product of natural selection."

In essence, yes. The fact that humans have greatly expanded on learning tasks, doesn't mean we are outside the realm of natural selection. Humans are part of nature.

That doesn't make sense from the understanding I have of natural selection. I thought natural selection was biological only. Otherwise, this would be expanding natural selections ability beyond the scope of what Darwin and the modern synthesis states. A learned trait is like learning a language for example. But one language is not going to have a real advantage over another so it's not a selectable trait. The ability to communicate through audible means is the selectable advantageous trait regardless of what language it is.

"There is no nurture and nature."

So why is there a difference between a person who is brought up in a stable family enviroment and one that is not. Why is there a difference between someone with education and no education? We are all born with the same brain and if it is not damaged in any way we all have the potential to use that brain power. But education and the way we are brought up will determine what we do with that brain. Nurture, our environment as to whether it is supportive and conducive to learn can bring out the potential of our intelligence. But it can also turn what may have been an intelligent person into an emotional wreck or antisocial person.
https://www.quora.com/Is-intelligence-nature-or-nurture

This is the reason I hate the words "natural" and "unnatural." Humans are still part of nature, so a learned behaviour that is "not always...vital for survival" can still be natural.

But being natural and being something that is biologically inherited for survival in evolution are not the same. A person may be naturally good at singing but that is not vital for survival. Most people can make noises with their mouth through the voice box which is needed as part of communication and survival.

What? Typing isn't a genetic trait, and I never said or implied it was. Adapting your fingers for typing is a LEARNED behaviour that can be TAUGHT. You are mixing up what it means for something to be genetically inherited (your physical fingers) vs a learned behaviour (typing).

Oh I thought you were saying earlier that typing was part of natural selection and that is why I was making the example that if typing was part of natural selection then would not that have to be something that can be passed on and inherited and not learned.

People who can't type today, are at a disadvantage.

Not really for survival because people can survive without typing. If a whole generation eventually did not know how to type then we would still survive. In fact, it was not too long ago that most people could not type. This is only something that has come about in modern times. It may change in a few years when new technology brings out voice recognition in all appliances.

You make a common error in assuming that only things that directly apply to basic survivability are naturally selected for.

Didn't you just say the ability to type is not vital for survival and part of evolution and selection. The ability to type cannot be passed on nor can anyone naturally type at birth so it is not a trait that can be inherited for survival in the first place.

The idea behind natural selection is that traits that improve an individual's chances at surviving and reproducing, will be passed onto to succeeding generations via the offspring. That does NOT mean that any given trait or behaviour will forever be beneficial for survival. Look at polar bears, for instance, they are well adapted to cold climates and hunting on snow and ice. But these adaptations would not confer a benefit to them in an ice-free world.

Yes, this is what selection is about. But that is a biological feature of growing thicker hair and fat layers which can be passed to the next generation as it is a change in the genes which is able to keep that change in the genome. But if it was a learned ability like typing it is not a change in the genes but a learned ability that will be lost to the next generation unless retaught over and over again.

No. Mutations aren't required for a trait to be passed down. De novo structures can be the result of mutation, but we aren't talking about that.

Yes, that's right we are talking about natural selection and random mutations that are said to change the existing features.

Stevevw said
"The single feature of the hands and fingers are that they are a tool for survival as opposed to a wing or fin."

And like many tools, they can be adapted for multiple purposes. Ever used a claw hammer to also remove a nail? Or as a bottle opener?

Yes but that is an extension of the hand. Without the hand, you cannot use a claw hammer. The hand is the biological feature that is said to have been evolved that was necessary for survival.

Stevevw said
" The single feature for the eyes is they see as opposed to not seeing or sensing or using radar."

You have a grossly oversimplified view of how structures work in biology.

Not if I am talking about the difference between learned abilities and biological features as far as being able to be inherited through evolution.

[stevevw]

[Replying to post 260 by stevevw]

I would have though the beneficial mutation frequency was important as there need to be many to account for all of life. If they are very very rare and deleterious mutations are more common then there must have been a multitude of harmful mutations

That is the beauty of natural selection though ain't it? If the mutations become negative and decrease the fitness of the organism then that organism is less likely to pass on its mutated genes through reproduction. An organism with a beneficial mutation will gain an advantage and will be more likely to reproduce.

So you see even when deleterious mutations are more common they are less likely to be passed down. While beneficial mutations bring more rare are more likely to be passed down. This decreases the pervasiveness of the negative mutation and increasing the pervasiveness of the beneficial mutation.

Not really, many deleterious mutations are very slight and are not picked up. The same for the rare beneficial ones which are so slight that they don't get selected. Noy just that the amount of energy used to deal with the multitude of deleterious mutations is a cost to fitness in itself.

[Kenisaw]

I would have thought those mutations that take away information from the existing genetic makeup would be a disadvantage even if it appeared to give an advantage on the surface. By eliminating an existing function of a gene, the gene is then not going to work properly despite it appearing to function to a point. Often the mutational effect is slight and can be tolerated but eventually, this can add up to a cost and threaten fitness.

There's no such thing as mutations = loss of information. That is creationist pseudoscience. And here's a simple way to know that: reversions. A reversion is a reversed mutation, and it is a common event. A DNA base goes from an A to a G, and then back to an A again. According to creationists, the switch from an A to a G is a "loss of information". When the G switched back to an A, they would also call that a "loss of information", since they claim ALL mutations create information loss. Clearly that is moronic.

DNA is not a code. Yes, I know people always say it is like a code, but they use that as a metaphor to help people understand what they are talking about. DNA is just a really complex molecule that is used as a template to make other molecules. When DNA changes, the amount of certain proteins or other molecules that it makes is increased or decreased or sped up or slowed down. There is no genetic standing for the claim that mutations are a loss of information. They aren't. They are simply a change to the DNA molecule.

It's a bit like antibiotic resistance in bacteria. Although the mutant bacteria can survive in the environment where it has become resistant to antibiotics, the change has come at a cost. The altered protein is less efficient in performing its normal function, making the bacteria less fit in an environment without antibiotics. The non-mutant bacteria are better able to compete for resources and reproduce faster than the mutant form.

That's silly. Antibiotic resistant bacteria still live and spread in humans just as easily, but they aren't killed as easily, which means they are more successful at reproducing. If that isn't a benefit to the bacteria, I don't know what is...

I would have though the beneficial mutation frequency was important as there need to be many to account for all of life. If they are very very rare and deleterious mutations are more common then there must have been a multitude of harmful mutations.

Depends of many factors, wouldn't you say? After extinction events, when a lot of niches are opened up in the environment, a lot more mutations would be considered useful since there is more opportunity for that new ability to survive. Some mutations involve hundreds of DNA pairs at a time, which can affect a larger change in one fell swoop. When the magnetic field flips, there is often a reduced strength in the magnetic field which allows for more mutations to happen during that time frame due to increased radiation. There really is no reason to think that mutations rates, beneficial or otherwise, happen at a consistent pace...

[stevevw]

There's no such thing as mutations = loss of information. That is creationist pseudoscience. And here's a simple way to know that: reversions. A reversion is a reversed mutation, and it is a common event. A DNA base goes from an A to a G, and then back to an A again. According to creationists, the switch from an A to a G is a "loss of information". When the G switched back to an A, they would also call that a "loss of information", since they claim ALL mutations create information loss. Clearly that is moronic.

Yeah, the concept of information is hard to pin down when it comes to evolution. It's not just about Shannon information but also about biological function. I am not a creationist so I don't know what they consider info is. Even so, the example you give is really talking about the changing of existing genetic info. Normally if a cell is damaged by a mutation it is harder for it to repair that so it ends up cutting off that function to survive otherwise it will take too much energy to deal with and become a cost to fitness. It's harder for a cell to produce multi-mutations to repair that damage than to produce a single mutation that will disengage that part of the cell.

What I was referring to with antibiotic resistance was how bacteria loses some function to become resistant to antibiotics because mutations harm the ribosome of the bacteria so that antibiotics were not able to attach. The bacteria population has lost the ability to produce individuals that are sensitive to antibiotics. No new genetic information or function was produced rather it was lost and cannot be put back.

DNA is not a code. Yes, I know people always say it is like a code, but they use that as a metaphor to help people understand what they are talking about. DNA is just a really complex molecule that is used as a template to make other molecules. When DNA changes, the amount of certain proteins or other molecules that it makes is increased or decreased or sped up or slowed down. There is no genetic standing for the claim that mutations are a loss of information. They aren't. They are simply a change to the DNA molecule.

Maybe so but there sure is a lot of articles out there saying that DNA is a code or language or an operating system.
Millions of DNA switches that power human genome's operating system are discovered
https://www.sciencedaily.com/releases/2 ... _TrendMD_0

Scientists Discover A Genetic Code For Organising DNA Within The Nucleus
https://www.sciencedaily.com/releases/2 ... 103909.htm

Scientists Discover Parallel Codes In Genes
https://www.sciencedaily.com/releases/2 ... 230116.htm

Stevevw said
It's a bit like antibiotic resistance in bacteria. Although the mutant bacteria can survive in the environment where it has become resistant to antibiotics, the change has come at a cost. The altered protein is less efficient in performing its normal function, making the bacteria less fit in an environment without antibiotics. The non-mutant bacteria are better able to compete for resources and reproduce faster than the mutant form.

That's silly. Antibiotic resistant bacteria still live and spread in humans just as easily, but they aren't killed as easily, which means they are more successful at reproducing. If that isn't a benefit to the bacteria, I don't know what is...

It may be a benefit for resisting antibiotics but that benefit came for the switching off or loss of an existing function, nothing new was added.
Bacterial Adaptation through Loss of Function
The metabolic capabilities and regulatory networks of bacteria have been optimised by evolution in response to selective pressures present in each species' native ecological niche. In a new environment, however, the same bacteria may grow poorly due to regulatory constraints or biochemical deficiencies.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708842/

Stevevw said
I would have though the beneficial mutation frequency was important as there need to be many to account for all of life. If they are very very rare and deleterious mutations are more common then there must have been a multitude of harmful mutations.

Depends of many factors, wouldn't you say? After extinction events, when a lot of niches are opened up in the environment, a lot more mutations would be considered useful since there is more opportunity for that new ability to survive. Some mutations involve hundreds of DNA pairs at a time, which can affect a larger change in one fell swoop. When the magnetic field flips, there is often a reduced strength in the magnetic field which allows for more mutations to happen during that time frame due to increased radiation. There really is no reason to think that mutations rates, beneficial or otherwise, happen at a consistent pace...

Maybe so, but you also have to consider that changes may be the results of other non-adaptive processes besides evolution by natural selection and random mutations. So we have to determine this before we start attributing everything to adaptations. Life may have the ability to tap into vast amounts of genetic info or change through processes such as developmental bias, genetic recombination, gene transference mechanisms, natural genetic engineering, plasticity, niche construction, extra-genetic inheritance etc. So life may use pre-existing genetic info or may have more ability to change without an evolutionary process.

Does evolutionary theory need a rethink?
Missing pieces include how physical development influences the generation of variation (developmental bias); how the environment directly shapes organisms’ traits (plasticity); how organisms modify environments (niche construction); and how organisms transmit more than genes across generations (extra-genetic inheritance). For SET, these phenomena are just outcomes of evolution. For the EES, they are also causes.
http://www.nature.com/news/does-evoluti ... nk-1.16080

Natural genetic engineering in evolution.
https://www.ncbi.nlm.nih.gov/pubmed/1334920

[DrNoGods]

[Replying to post 265 by stevevw]

Life may have the ability to tap into vast amounts of genetic info or change through processes such as developmental bias, genetic recombination, gene transference mechanisms, natural genetic engineering, plasticity, niche construction, extra-genetic inheritance etc. So life may use pre-existing genetic info or may have more ability to change without an evolutionary process.

I would consider most of these as part and parcel of the overall evolutionary process, which is a lot more involved than just random mutations that may or may not be beneficial being selected for or against. Just because pre-existing genetic info is used doesn't violate any principles of evolution by natural selection ... there has to be something to act on that is heritable, and that something is existing DNA.

Do you believe it would be possible (ethics aside for now) to engineer a human capable of living on Mars without any suit or controlled environment? I do, and it would be purely via natural selection over probably a few thousands of generations. The surface pressure on Mars is about 10 mbar, 1/100 that of earth, and the atmosphere is 95% CO2 with little to no O2. So dropping a human into that environment directly would be a very quick death.

To engineer a human to survive in that environment, start with someone from one of the populations of humans on Earth who have adapted to life above 13,000' ... there are several, and each have produced different adaptations for it:

https://en.wikipedia.org/wiki/High-alti ... _in_humans

These humans can tolerate O2 levels only about 60% of sea level, but with similar amounts of CO2. Put them in a controlled environment where the O2 level is reduced to, say, 50% of seal level on Earth and double the CO2 level to 800 ppmv (normal atmospheric levels are around 400 ppmv now ... ppmv being parts per million by volume). These people would have very little problem adapting to that environment (humans start having trouble at about 2% CO2 = 20,000 ppmv, and 15% or higher is lethal), and let them stay for a few generations. Their offspring may show some additional modifications to the even lower O2 levels, and higher CO2 levels, than when they initially started the experiment.

Continue this process where the O2 level is reduced, and the CO2 level increased, every few tens of generations for a few thousand generations, progressively reaching 10 mbar total pressure and 95% CO2 in the "air" they are breathing. Some number of these humans are likely to survive if the process is done sufficiently slowly. Maybe it takes a million years or more ... but do it slowly enough and you are likely to have some survivors that are very different from today's humans. Lungs may have converted back to gill-like structures in order to pull O2 from CO2 (which has 2 oxygen atoms to use). Skin and blood vessels, eyes, etc. would also likely undergo serious physical modifications to handle the low pressures, and no doubt many other physical and internal changes as well. So starting with a perfectly normal human today, it is reasonable to expect that a very different creature could be created that could survive in the Martian atmosphere all from the normal natural selection and adaptation process, starting from just existing genetic material. If Earth's atmosphere changed in this way directly over the next few million years, this experiment would happen whether we liked it or not. There may be no survivors, but there is no reason from an evolutionary perspective to believe that there could not be.

The point being that using only existing genetic material, dramatic changes are possible without violating any evolutionary theory principles. I'd call the Mars human an "arrival of the fittest" that you have mentioned several times, but it happened through a slow process of adaptation that was forced by the environmental change, and may incorporate all of the items mentioned in your quoted section above.

[DrNoGods]

[Replying to post 265 by stevevw]

P.S. In the prior post I meant to imply a large population of starting humans from the high altitude environment ... not just "someone."

[stevevw]

[Replying to post 265 by stevevw]

Stevevw said
Life may have the ability to tap into vast amounts of genetic info or change through processes such as developmental bias, genetic recombination, gene transference mechanisms, natural genetic engineering, plasticity, niche construction, extra-genetic inheritance etc. So life may use pre-existing genetic info or may have more ability to change without an evolutionary process.

DrNoGods
I would consider most of these as part and parcel of the overall evolutionary process, which is a lot more involved than just random mutations that may or may not be beneficial being selected for or against. Just because the pre-existing genetic info is used doesn't violate any principles of evolution by natural selection ... there has to be something to act on that is heritable, and that something is existing DNA.

Most of what I was referring to are non-adaptive mechanisms. They don't rely on natural selection initially or at all in allowing life to change and develop. Natural selection requires extremely rare circumstances to make big changes. Selections role is overstated in how much it can make changes to features and creatures. Not enough credit is given to the ability of life itself to be able to change through non-adaptive mechanisms that can deal with many of the situations creatures find themselves in. Selection and mutation require incredible explanations and a fair degree of assumption and speculation. Whereas some of these non-adaptive processes work with pre-existing genetic info and allow for life to have some control and contribution to the outcomes.

A situation a creature finds themselves in may trigger certain processes that produce certain outcomes which will benefit that creature in that particular environment. The environment may cause certain outcomes in development. Creatures can have an influence on their environments. So rather than the environment dictating how they have to adapt, they can change the environment to suit how they live without having to go through any phenotype changes. Life can work in cohabitation with other life and the environment and share genetic info using micro life and the environment as a conduit.

Processes for change and development of life may follow pre-determined paths and this seems to fit the evidence better. Rather than adaptation having to come up with extraordinary explanations for how life can follow similar development paths even when distantly related it makes more sense to say that life can follow determined processes. For example when two distantly related creatures have the same features even down to the genetic similarities evolution calls this convergent evolution. But this requires extraordinary coincidences rather than pre- determined development processes that all life have such as such as with developmental biases. This means that these non-adaptive processes are more responsible for the big features we see and selection only plays around with fine tuning that.

Do you believe it would be possible (ethics aside for now) to engineer a human capable of living on Mars without any suit or controlled environment? I do, and it would be purely via natural selection over probably a few thousands of generations. The surface pressure on Mars is about 10 mbar, 1/100 that of earth, and the atmosphere is 95% CO2 with little to no O2. So dropping a human into that environment directly would be a very quick death.

To engineer a human to survive in that environment, start with someone from one of the populations of humans on Earth who have adapted to life above 13,000' ... there are several, and each have produced different adaptations for it:

https://en.wikipedia.org/wiki/High-alti ... _in_humans

These humans can tolerate O2 levels only about 60% of sea level, but with similar amounts of CO2. Put them in a controlled environment where the O2 level is reduced to, say, 50% of seal level on Earth and double the CO2 level to 800 ppmv (normal atmospheric levels are around 400 ppmv now ... ppmv being parts per million by volume). These people would have very little problem adapting to that environment (humans start having trouble at about 2% CO2 = 20,000 ppmv, and 15% or higher is lethal), and let them stay for a few generations. Their offspring may show some additional modifications to the even lower O2 levels, and higher CO2 levels, than when they initially started the experiment.

Continue this process where the O2 level is reduced, and the CO2 level increased, every few tens of generations for a few thousand generations, progressively reaching 10 mbar total pressure and 95% CO2 in the "air" they are breathing. Some number of these humans are likely to survive if the process is done sufficiently slowly. Maybe it takes a million years or more ... but do it slowly enough and you are likely to have some survivors that are very different from today's humans. Lungs may have converted back to gill-like structures in order to pull O2 from CO2 (which has 2 oxygen atoms to use). Skin and blood vessels, eyes, etc. would also likely undergo serious physical modifications to handle the low pressures, and no doubt many other physical and internal changes as well. So starting with a perfectly normal human today, it is reasonable to expect that a very different creature could be created that could survive in the Martian atmosphere all from the normal natural selection and adaptation process, starting from just existing genetic material. If Earth's atmosphere changed in this way directly over the next few million years, this experiment would happen whether we liked it or not. There may be no survivors, but there is no reason from an evolutionary perspective to believe that there could not be.

The point being that using only existing genetic material, dramatic changes are possible without violating any evolutionary theory principles. I'd call the Mars human an "arrival of the fittest" that you have mentioned several times, but it happened through a slow process of adaptation that was forced by the environmental change and may incorporate all of the items mentioned in your quoted section above.

I think using the existing genetic material we can make some big changes but I think this works to a limit. For all, we know the ability to live in these other conditions is a capability of the scope we have now. We don't need to go through blind adaptations in a mostly miss and rarely hit the mark process. We have the ability within us now to tap into genetic info that can be switched on to adjust to many situations. That's how our code for life works. As scientists have said they are finding hidden codes within codes and many switches that can change the way our genes are expressed.

Like adjusting to living in colder and hotter climates where humans can do this anyway. But there are limits. Some of these harsher conditions may be tolerated for some time but they may also have an effect on life in the long run. There need to be long-term tests. What we need to consider is that a lot of these changes have a fitness cost to them. We genetically change crops and think we have outsmarted nature and evolved a new species. But this has a knock on effect in changing the way nature works and begins to affect other areas. Most mutational changes have a slight effect on fitness which can build up in the long run. In other words, life is already good enough and equipped to live on earth and has much more hidden ability already built into it to survive and most mutational changes only changes that and will have a fitness cost in the end.