Evolution question - How did mammals originate ?

Originally posted by KellyJay
Yes, we can agree a cell has life, we do not agree that life started
from a cell.

No responsible biologist believes life "started from a cell." What most biologists DO believe is that cellular life is the most primitive form of life that remains available for us to study. That is, as far as we have yet been able to discover, any more primitive, non-cellular, life forms have been entirely superceded by cellular and are no longer present for us to study. The extinction of any pre-cellular life forms took place at least 3 billion years ago. This fact makes the study of abiogenesis, or the origin of life, a rather difficult subject. I am not convinced that abiogenesis is therefore necessarily beyond the reach of science, but it is certainly very difficult to study.

OTOH, evolution, the study of how life forms change over time, is perfectly well within the reach of science since we DO have numerous life forms that are available to study.

So stating you think you have some explanation as to
how it could go from point A to point B is purely academic on your
part, if there are no real world examples in life, unless of course you
can show me in a lab some where or in nature the grand jump of life
evolving from a single cell into functional complex living creatures
with various organs doing a variety of jobs keeping some life form
alive. I'm speaking of examples of evolution not the programming of
life through the natural processes we see today in biology.

The study of evolution IS "academic" in that it is typically studied at institutions of higher learning, but I suspect that is not what you mean. 🙂

As far as we can tell, the development of single-celled organisms into multi-cellular organisms happened at least twice (possibly only twice) and both of those occasions were at least 600 million years BP (before present). That is, both of them happened following more than 2 billion years after the appearance of single-celled life. (IIRC, sponges are among the few remnants of one of those events and all of the multicelled animals, plants and fungi among the remnants of the other. I could, obviously, be wrong.) Single-celled life still outweighs multi-cellular life by a large margin.

Although it is possible that some collection of single-celled organisms in a laboratory could undergo whatever change it would require to amalgamate and form some kind of multi-cellular life form, I think it is safe to say that the odds are massively against it, judging by how (IN)frequently this particular sort of change has been known to happen in the past. Contrast this with, e.g., antibiotic resistance, which is known to evolve within a homogeneous culture of single-celled organisms with sufficient regularity that it is a standard lab experiment in college biology courses.

I believe that is a matter of faith, for those that cannot abide in the possibility of a creator God.

Considering that I have posted contrary evidence multiple times, I have to consider this statement of yours at least willful ignorance if not a lie. I suppose you may believe what you said (which would make your literal statement about your belief not quite a lie) but evolution is accepted as the mechanism by which life, in its present forms, developed from prior forms, by MANY who do believe in "a creator God."

Paul

Originally posted by KellyJay
I'll leave the word evolution out of this discussion, we can simply deal
with mutations which is a known phenomenon.

You are stating randomness isn't a factor in mutations due to the
fact that there are forces at play which are to varied, complex, or
unknown but do exist? So ultimately our limited grasp of these forces
which all actively help decid ...[text shortened]... ? Much like gravity forces objects to the
ground by the force it exerts upon them.
Kelly

I'm claiming that genetic mutations are not random in the metaphysical sense, because there are causal forces sufficient to bring them about. A metaphysically random event is such that a complete specification of the physical state of the world and the physical laws that govern the interactions of physical systems does not entail that the event will occur. In other words, a metaphysically random event is one that is causally undetermined. Genetic mutations are not like this, they are causally determined. Hence, to the extent that the term 'random' applies to genetic mutations, it only does so in an epistemological sense.

Originally posted by bbarr
I'm claiming that genetic mutations are not random in the metaphysical sense, because there are causal forces sufficient to bring them about. A metaphysically random event is such that a complete specification of the physical state of the world and the physical laws that govern the interactions of physical systems does not entail that the event will occur. ...[text shortened]... he term 'random' applies to genetic mutations, it only does so in an epistemological sense.

I'm not sure I can agree with this. I was under the impression that you (Bennett) admitted quantum events as "metaphysically random". At least those mutations "caused" by radioactivity would then be "metaphysically random" would they not?

Best Regards,
Paul

Originally posted by prn
I'm not sure I can agree with this. I was under the impression that you (Bennett) admitted quantum events as "metaphysically random". At least those mutations "caused" by radioactivity would then be "metaphysically random" would they not?

Best Regards,
Paul

Not all properties of quantum systems are indeterminate. Genetic mutations result when radiation damages DNA by altering nucleotide bases or by breaking the bonds between oxygen molecules and phospate groups. It may be metaphysically random that some particle or other strikes some DNA molecule in this location rather than that location (since location and momentum form a complementary pair of properties, in Heisenberg's sense of 'complementary'😉, but that doesn't entail that the event of a particle strking a DNA molecule is causally insufficient to either damage a nucleotide base or break a molecular bond. Hence, it doesn't entail that the event of DNA damage is metaphysically random. If there were causal forces sufficient to bring about such damage, then the event of such damage being brought about is not metaphysically random.

Best,

Bennett

Originally posted by prn
No responsible biologist believes life "started from a cell." What most biologists [b]DO believe is that cellular life is the most primitive form of life that remains available for us to study. That is, as far as we have yet been able to ...[text shortened]... rior forms, by MANY who do believe in "a creator God."

Paul
[/b]

Let us be careful in what we call facts! Unless you can without a doubt
prove an event took place 3 billion years ago, it isn’t a fact. I agree
that I misspoke about life starting as a cell. However it started, it had
in early stage if evolution is true, we can call our point of origin
anything we want I suppose, if there is a name for it I’m not familiar
with it. I believe for our discussion we can simply look at cellular life
and both acknowledge it is not the starting point of evolutionary
thought, but nonetheless we can look at that point and begin our
discussion on evolution from there. Can we possibly get from point ‘A’
cellular life to the vast array of life we have to today? When it comes
to is it likely or possible given the complexity of the level of life we
see today?

If we attempt to do this discussion justice we must as painful as it is,
make sure we understand our terms. For example my discussion with
bbarr has been over the word random. We have posted several times
just to clear up our meaning of that word, and we are not done yet.
I would also point out that another reason it is quite possible that
there isn't a huge amount of evidence to study abiogenesis in
evolution is, because what is being looked for never happened.

"OTOH, evolution, the study of how life forms change over time, is perfectly well within the reach of science since we DO have numerous life forms that are available to study."

I can buy into evolution at some levels; however, those changes are
limited. If we are saying life forms changing over time do so to the
point of going from a cellular level to those with hearts, brains, eyes,
ears, livers, blood and so on that is different. I believe that to be a
matter of faith. I cannot buy into evolution if that change is so drastic
that we see new organs where there were none before on time line of
life. I can if we limit our changes to type of life we are studying, if it is
dogs we can see changes yes; however, we start with dogs we end with
dogs. We do not start with cells and end with rabbits.

I believe saying events that took place millions or billions of years
ago, are facts again cannot be accepted. If I were to make a claim
that I put a device under a stress for a certain length of time without
documented proof that event took place, and there were decisions that
were going to be made on the outcome. I'd have to have more than
my word to cause those wanting to know the results of that stress to
act. Speculation on what could have happened millions or billions of
years ago is just that, speculation nothing more.

When I state my beliefs, I'm not lying. I agree that there are several
believers that accept evolution. This simply says that with them they
accept the evolutionary process may have been how God did it, it does
not mean much more than that. Evolution is not a point of contention
with me on someone's salvation, meaning if they believe it the go to
Hell. It isn't that important: however, I believe that one is better being
on a solid foundation of truth than one of a falsehood. Which is what
I believe evolution is to the degree that claims are made that life
changed from points like the cellular level to oak trees, jelly fish,
people, and so on. I do believe in changes within kinds or species but
they remain that kind or that species.
Kelly

Originally posted by KellyJay
I do believe in changes within kinds or species but
they remain that kind or that species.
Kelly

Obviously, your use of the term 'kind' isn't synonymous with the biologist's term 'species'. So, when you talk about changes only occuring within a kind, what do you mean? What determines whether two creatures are of the same kind or a different kind?

Originally posted by bbarr
I'm claiming that genetic mutations are not random in the metaphysical sense, because there are causal forces sufficient to bring them about. A metaphysically random event is such that a complete specification of the physical state of the world and the physical laws that govern the interactions of physical systems does not entail that the event will occur. ...[text shortened]... he term 'random' applies to genetic mutations, it only does so in an epistemological sense.

If I understand your point again, please bear with me; the universe
forced all mutations to take place the way they did, the universe is
forcing those taking place now as well, because of the various forces
applied on DNA. So each mutation had to happen the way it did, not
because a will was applied in most cases, but the universe the way it
was setup at the time of each mutation was about to happen forced it.
The universe could do nothing but cause each mutation to occur the
way they did. Everything is predetermined then, there is no
chance involved, random mutations are basically natural fallout of
cause and effect according to factors beyond our understanding?
Kelly

Originally posted by KellyJay
If I understand your point again, please bear with me; the universe
forced all mutations to take place the way they did, the universe is
forcing those taking place now as well, because of the various forces
applied on DNA. So each mutat ...[text shortened]... and effect according to factors beyond our understanding?
Kelly

No, since some systems are metaphysically random, it is not the case that everything is predetermined. Further, the universe does not force anything to happen. The universe isn't an agent or a will that exerts causal influences. The universe is just the set of that which exists. You are correct, however, when you claim that genetic mutations are 'natural fallout'. Genetic mutations are caused by natural phenomena like ultraviolent light, nuclear radiation, exposure to chemicals, etc. Calling such mutations 'random' means only that we can't predict when they will occur, or what their effects will be. But this is because we lack the necessary information, not because genetic mutations are spooky non-natural events (they aren't).

Originally posted by KellyJay
If mutations are not guided, if there is no purpose behind how they
happen, if there are chances of something going in direction X or Y,
and nothing pushes it along to X or Y, it simply happens one way or
another, I'd say that is rando ...[text shortened]... asic point we can hash out without to
much difficulty.

Kelly

Right, mutations are random. Never claimed otherwise, as is clear from my frequent use of the phrase 'random mutation'. And I thank bbar for his description of epistemological randomness.

What I have been saying in every message I posted is that selection drastically reduces this randomness. Some mutations are selected out, some are kept. This selection doesn't happen at random, but favors a certain kind of mutations. Hence the collection of mutations that really matter when considering evolution, the ones that are selected, is not random. What I've been trying to find out is whether you think this collection of selected mutations is random, not what you think of the initial group of all mutations.

David

Originally posted by DdV
Right, mutations are random. Never claimed otherwise, as is clear from my frequent use of the phrase 'random mutation'. And I thank bbar for his description of epistemological randomness.

What I have been saying in every message I posted is that selection drastically reduces this randomness. Some mutations are selected out, some are kept. This selection doe ...[text shortened]... selected mutations is random, not what you think of the initial group of all mutations.

David

When you say that selection "favors a certain kind of mutations" you make it sound as though some mutations are, by their very nature, fitness-increasing. I'm sure you don't intend to be interpreted this way, however.

Originally posted by bbarr
When you say that selection "favors a certain kind of mutations" you make it sound as though some mutations are, by their very nature, fitness-increasing. I'm sure you don't intend to be interpreted this way, however.

I think I'm finding out I can make things more muddled by trying to be as clear as possible. Thanks for the clarification, that was indeed not at all how I intended it to be interpreted. I realise I'm oversimplificating terribly, but I'm just trying to find a way to get my point across.

David

Originally posted by DdV
I think I'm finding out I can make things more muddled by trying to be as clear as possible. Thanks for the clarification, that was indeed not at all how I intended it to be interpreted. I realise I'm oversimplificating terribly, but I'm just trying to find a way to get my point across.

David

The essential point is that no genetic mutation is, by it's very nature, fitness-increasing. Whether a particular genetic mutation is fitness-increasin depends essentially upon the envirmental context in which it is manifested. Whether a particular genetic mutation is fitness-increasing depends upon whether it makes it more or less likely for the mutated organism to successfully reproduce. But successful reproduction occurs within an environmental context, and fitness can only be understood by looking at an organism within its envirmental niche.

Originally posted by bbarr
No, since some systems are metaphysically random, it is not the case that everything is predetermined. Further, the universe does not force anything to happen. The universe isn't an agent or a will that exerts causal influences. The unive ...[text shortened]... se genetic mutations are spooky non-natural events (they aren't).

I'm not sure what you mean by spooky non-natural events.

I'm not sure how to follow your logic in this either.

Somethings are random, others are not. So if there is a mix that
occurs that adds to the unpredictablity of events doesn't it?

Then I'm not quite sure what the difference is between random events
with no causes, and events that are influenced. If these events are so
completely out of our ability to understand, and all the forces behind
them, than even your so called metaphysical random events could
simply be events that have some influences upon them we don't
understand at all. Which would limit your randomness down to one
type. Why it would be thought of as non-random events when the
influences could be so wide and varied the outcome outside of God
looking at them would be beyond anyone's understanding. If I
understand what you said you are looking at the strenght of various
types of light, pressures, thermo, and other forms of influences the
varity of outcomes that could happen would be nearly endless. I still
believe that the word random fits rather nicely.
Kelly

Originally posted by KellyJay
I'm not sure what you mean by spooky non-natural events.

I'm not sure how to follow your logic in this either.

Somethings are random, others are not. So if there is a mix that
occurs that adds to the unpredictablity of events does ...[text shortened]... I still
believe that the word random fits rather nicely.
Kelly

Yes, so do I, which is why I suggested in my previous post that the epistemological notion of randomness was the proper one for this debate. You, however, objected that this entailed that all genetic mutations were predetermined. But since the universe contains metaphysical randomness (since the universe is not completely deterministic), it follows that not all physical events are predetermined, which is what you seemed to be claiming in your post above.

Originally posted by KellyJay
Somethings are random, others are not. So if there is a mix that
occurs that adds to the unpredictablity of events doesn't it?

To a certain extent, yes and to a certain extent, no.

The existence of a "random" component does not necessarily diminish the predictability of the overall outcome. To return to the casino example, the fact that the outcome of an individual spin of the roulette wheel is random, but the distribution of a large number of such spins virtually guarantees that the house will win money. To consider examples with more "realistic" 🙂 numbers, the motions of individual atoms in a glass of water is also random, but the behavior of the liquid that is the sum of these motions is entirely predictable.

Similarly, the occurrence of a specific mutation in a specific organism may be random (in whichever sense) but the overall distribution of variation ensures that some organisms in the population will have a selective advantage over others and that the overall "fitness" of the population will increase.

Best Regards,
Paul