Scientific Evidence for Universal Common Descent

[Jose Fly]

@Jose Fly I won’t be replying to your posts any more, except possibly sometimes to disagree with what you say about me. If you say anything to me about evolution or common ancestry, I will read it and consider it.

Yeah, pretty typical creationist behavior....when presented with science that supports evolution, accuse the scientists of wrongdoing, dodge all requests to substantiate the accusation, cry foul when called on it, and run away while playing the martyr.

Seen it a thousand times.

 

[YoursTrue]

I also note that your use of irreducible is plastic and you are using differing versions as if they go back to a single, static definition.

I am using the word to say that a bacteria is not a simple organism, despite the idea that maybe it was the first living thing. It ain't so easy to figure that these elements of a bacteria just kind of came together, with a shell (covering), strands, and whatever else they contain. Whereas I see your point about irreducible, in the long run it doesn't matter because even minerals (said not to be alive) have a format.

 

[YoursTrue]

That’s a good start. Now maybe you’ll start noticing people doing that with some other words, on all sides of all debating.

Who's debating? (Not me...) I'm just trying to explain why I don't believe life just "happened" because I can't even conceive of what simple enough element (1) could just come about (again, not speaking of abiogenesis), and (2) what IS the first living thing? You don't know, and I don't know, no scientist knows. But that isn't the answer or reason for irreducible complexity. It's just that at a certain point, there's nothing there to reason on. Frankly. It's gone. It's nothing. As in -- nothing there from non-life to life. And again, I'm not speaking of abiogenesis. I'm speaking of what possibly could be the first living item? They say bacteria. Bacteria, I ask? How simple or complex are they? If, in fact, they are the first living things, what happened? Did a covering, or form just come about with little hairs emerging or developing from that -- form??

 

[YoursTrue]

Yes, and.........?

You seem to think it significant that science has yet arrive at a tested theory for how it happened. Do you imagine your god lurks in such gaps, the ones that have steadily grown fewer over time?

What I imagine is that science will never arrive at a tested theory to figure how life and the first forms of what is considered living matter might have come about on the earth. You may think science will. I do not.

 

[Dan From Smithville]

That’s a good start. Now maybe you’ll start noticing people doing that with some other words, on all sides of all debating.

But I do notice it. It is not unusual at all to see it happen. Words often have multiple meanings and varying connotations. It is the nature of communication. It is why scientists seek clarity and consistency in terminology, so that comprehension can be optimized.

 

[YoursTrue]

Well, we know simple bacterial existed 3.8 billion years ago. What sort of life existed prior to that, we do not know.

There are also definitional problems for the very early stages (what, precisely, does it mean to be alive?).

Yes, what does it mean to be alive? Good question, I suppose. I believe I am alive. I wonder if bacterium believe or think they are alive. Perhaps someone with credentials in the scientific world perhaps will communicate with a bacterium to learn if they think.

 

[Dan From Smithville]

I am using the word to say that a bacteria is not a simple organism, despite the idea that maybe it was the first living thing. It ain't so easy to figure that these elements of a bacteria just kind of came together, with a shell (covering), strands, and whatever else they contain. Whereas I see your point about irreducible, in the long run it doesn't matter because even minerals (said not to be alive) have a format.

It is still possible that the first life on earth was created. I cannot deny that, but there is no evidence to support that hypothesis either.

Finding something is incredible to a person is evidence of how that person feels about something. it is not evidence that is attributable to what is found to be incredible to them. I find insects incredible, but that is my feeling about them and not a property determining anything about their origins or the validity of hypotheses on those origins.

 

[Jim]

The first - fossils - has been by far the most impressive. Even in Darwin's time the understating that different layers of sedimentary rock represented different time frames in earths history which correlated so well with the types of fossils found. The fact that our dating techniques of sediments is so accurate considering the length of time that has passed, it gives us a powerful tool to compare sediments around the world and the findings are consistent. The findings are clear - simpler structured organisms come first. There is a progression from that point onward with increasing diversity with time. This is exactly what is predicted from common descent.

Multiple descent first must come up with how many different forms of descent were formed and how to distinguish them from each other so they do not share characteristics. Second is determining how each of the multiple descent lines formed and when. Now we are going from a simple to a complex explanation without supportive evidence. Why create something far more complicated to explain when a better supported and simpler explanation already exists.

The second - similarities. Genetics has shown that the genetic codes for basic physiological functions are extremely well preserved throughout living things. Thus we even share genetic similarities with plants. The closer in form and function the more similar genetic material. This is entirely in harmony with common descent. Multiple descent lines would not necessarily have to share any genetic material and certainly not in the pattern we see when we compare the genetics of different organisms that correlate with the history of the fossil record.

What is amazing is just how supportive all the information actually is. All other views do not fit with what is found. I hope my simple explanation will help. The scientific evidence can get quite complex.

I love that response from you. Thank you.

I want to review and update my thoughts about evolution theory. I agree with teaching all of evolution theory, including common ancestry, in public schools, and I’m opposed to teaching Intelligent Design, now that I see that it’s explicitly opposed to evolution theory.

All things considered, it still makes more sense to me to think that there have been many, possibly thousands or even millions, of lines of ancestry going back to the beginning of life. That doesn’t mean that I would not want any research, theories or teaching to be based on a premise of common ancestry. I would not want to discourage any of that. What I think will be better for research and human progress will be for some research and theories to happen without a premise of common ancestry. I think that will happen someday, when research is not influenced as much as it is now by factional and monopoly interests. The reason I think it will be better is because the more lines of investigation there are, the more fruitful and beneficial the results will be.

 

[Dan From Smithville]

Yes, what does it mean to be alive? Good question, I suppose. I believe I am alive. I wonder if bacterium believe or think they are alive. Perhaps someone with credentials in the scientific world perhaps will communicate with a bacterium to learn if they think.

Bacteria operate on stimulus/response mechanisms that are not thinking. Thinking appears to be confined to multi-cellular organisms that have tissue specialization that includes complex nervous systems. Bacteria are single-celled organisms, thus a nervous system is out of the question.

There is no indication that they think.

 

[Jim]

But I do notice it. It is not unusual at all to see it happen. Words often have multiple meanings and varying connotations. It is the nature of communication. It is why scientists seek clarity and consistency in terminology, so that comprehension can be optimized.

What I mean is, the same person shifting back and forth unpredictability from one meaning to another, one meaning to validate what they’re saying, and a different meaning to make it say what they want it to say.

 

[Dan From Smithville]

Yes, what does it mean to be alive? Good question, I suppose. I believe I am alive. I wonder if bacterium believe or think they are alive. Perhaps someone with credentials in the scientific world perhaps will communicate with a bacterium to learn if they think.

Remember back to your basic high school biology or science class. There should have been mention of the criteria for life. These criteria have been established, based on observations, to define what is alive and what is not. It is through those criteria, that viruses are not considered to be alive.

These are some of the basic criteria for life.
respond to their environment
grow and change
reproduce and have offspring
have a complex chemistry
maintain homeostasis
are built of structures called cells
pass their traits onto their offspring

I learned this so long ago, I cannot remember when. This particular list, I found with Google.

 

[Dan From Smithville]

What I mean is, the same person shifting back and forth unpredictability from one meaning to another, one meaning to validate what they’re saying, and a different meaning to make it say what they want it to say.

I mean that too. It is not uncommon. A lot of people use that as a tactic. It is dishonest, but that does not seem to stop some people.

In the particular instance, I do not see it as the use of a tactic and that it was an honest mistake. If it wasn't, then our new friend is very good and can make things like that look like mistakes.

 

[YoursTrue]

It is still possible that the first life on earth was created. I cannot deny that, but there is no evidence to support that hypothesis either.

Finding something is incredible to a person is evidence of how that person feels about something. it is not evidence that is attributable to what is found to be incredible to them. I find insects incredible, but that is my feeling about them and not a property determining anything about their origins or the validity of hypotheses on those origins.

What do you mean by evidence? By that, just so we're not confusing, do you accept as true the presumed evidence (yes, I believe it's presumed evidence in this case) that evolution stemming from one or several organisms (such as bacteria) moving into (and I'll keep this succinct, shall we say) plants, eventually trees, birds, and so forth, is a fact? I don't want to leave out dinosaurs.
It's late -- time for this being to chill out. When I'm sleeping, I can't tell myself or generally feel that I'm alive. Body goes to sleep. Brain functions, but I don't know it's functioning, in general, when I'm asleep. Thankfully I usually don't remember my dreams.

 

[Dan From Smithville]

What do you mean by evidence? By that, just so we're not confusing, do you accept as true the presumed evidence (yes, I believe it's presumed evidence in this case) that evolution stemming from one or several organisms (such as bacteria) moving into (and I'll keep this succinct, shall we say) plants, eventually trees, birds, and so forth, is a fact? I don't want to leave out dinosaurs.
It's late -- time for this being to chill out. When I'm sleeping, I can't tell myself or generally feel that I'm alive. Body goes to sleep. Brain functions, but I don't know it's functioning, in general, when I'm asleep. Thankfully I usually don't remember my dreams.

If you say that you find something incredible, that fact is evidence of how you feel. Or claim to feel.

I am not sure I am following what you are saying. Are you talking about more complex life evolving from simple, single-celled life or something else?

I accept the evidence and the theory of evolution. I would accept the evidence even without the explanation. The change over time has been observed. The features that support common descent have been observed. Natural selection has been observed. Do I accept these facts? Yes.

 

[Jim]

The first - fossils - has been by far the most impressive. Even in Darwin's time the understating that different layers of sedimentary rock represented different time frames in earths history which correlated so well with the types of fossils found. The fact that our dating techniques of sediments is so accurate considering the length of time that has passed, it gives us a powerful tool to compare sediments around the world and the findings are consistent. The findings are clear - simpler structured organisms come first. There is a progression from that point onward with increasing diversity with time. This is exactly what is predicted from common descent.

Multiple descent first must come up with how many different forms of descent were formed and how to distinguish them from each other so they do not share characteristics. Second is determining how each of the multiple descent lines formed and when. Now we are going from a simple to a complex explanation without supportive evidence. Why create something far more complicated to explain when a better supported and simpler explanation already exists.

The second - similarities. Genetics has shown that the genetic codes for basic physiological functions are extremely well preserved throughout living things. Thus we even share genetic similarities with plants. The closer in form and function the more similar genetic material. This is entirely in harmony with common descent. Multiple descent lines would not necessarily have to share any genetic material and certainly not in the pattern we see when we compare the genetics of different organisms that correlate with the history of the fossil record.

What is amazing is just how supportive all the information actually is. All other views do not fit with what is found. I hope my simple explanation will help. The scientific evidence can get quite complex.

Incidentally, what I’m thinking would not exclude the possibility of all life having a common ancestor. There could be many lines of ancestry going back to the beginning of life, and any number of the first life forms could be common ancestors for all current ones. Besides, what do “common ancestry” and “separate ancestry” even mean, when inherited characteristics have aways been able to move back and forth all across the whole range of life forms?

 

[ratiocinator]

What I imagine is that science will never arrive at a tested theory to figure how life and the first forms of what is considered living matter might have come about on the earth. You may think science will. I do not.

The history of this sort of (god of the gaps) belief does not look good for you.

I imagine the the biggest problem is going to be not so much that we can't work out how life could have formed, but working out if that was the way it actually happened (possibly amongst more than one possibility).

As I pointed out on another thread, this also seems a very odd way for a god to go about things. We have copious evidence of how life evolved afterwards, and there is no need for magic there, so why would a god use magic to kick it off and then leave it to natural processes thereafter?

 

[Jim]

This looks something like what I’ve been thinking:

Ancient horizontal gene transfer and the last common ancestors | BMC Evolutionary Biology | Full Text

“Therefore, one cannot assume that the last common ancestors of each gene were all present in the same cell representing the cellular ancestor of all extant life.”

 

[Jim]

And this:

Perspectives on the Phylogenetic Tree | Boundless Biology

“The hypothesis is that eukaryotes evolved not from a single prokaryotic ancestor, but from a pool of many species that were sharing genes by HGT mechanisms. Some individual prokaryotes were responsible for transferring the bacteria that caused mitochondrial development in the new eukaryotes, whereas other species transferred the bacteria that gave rise to chloroplasts.”

 

[Polymath257]

Yes, what does it mean to be alive? Good question, I suppose. I believe I am alive. I wonder if bacterium believe or think they are alive. Perhaps someone with credentials in the scientific world perhaps will communicate with a bacterium to learn if they think.

Life is a different phenomenon from consciousness. I'm not sure why you are bringing up the second when we are discussing the first.

 

[YoursTrue]

When you claim "believe" and associate it with the theory and facts of evolution, what do you mean by that?

I mean conclusions claiming that evidence such as fossils, proves evolution.