Scientific Evidence for Universal Common Descent

[Dan From Smithville]

The thing they come up with is the impossibility of going beyond boundaries, except by some form of unproven genetic change. There are, of course, life forms that have gone extinct in the course of present history. This does not prove evolution. It proves that some life forms go out of existence.

What boundaries are those? Nothing in science is proven. Undiscovered perhaps.

I have not heard of any theories or hypotheses that claim extinction is evidence for evolution. It is of importance to the study and a part of evolution in a sense. Extinction often occurs when selection is so powerful or quick that it outpaces the ability for populations to adapt. Adapt here in the sense of selection driving fixed, heritable traits that convey a fitness benefit. Not in the sense of phenotypic plasticity, physiological versatility or developmental flexibility.

 

[Dan From Smithville]

IF I were to go along with the classifications of evolution, I would agree that I am what you say. On the other hand, apes are still apes and not on their way in any shape or form to either becoming human or another type. Maybe with another eye, etc. You know for its betterment perhaps?

This speaks of the idea of evolution having a goal or that changes indicate some advancement in the progression towards an ideal. Evolution does not work that way. Changes are driven by the environment and the environmental factors are referred to as natural selection.

Most people do not observe living things in the detail that would be necessary to make the observations that scientists make. From a gross, macroscopic view they may seem static, perhaps they are in this time scale, but that does not mean they are not evolving. They are just not going to suddenly start giving birth to a new and different species.

Here is one definition of ape:
"Apes are humanity's closest living relatives. In fact, people are apes; humans share about 98 percent of their DNA with chimpanzees. The non-human types of apes are divided into two groups: great apes — gorillas, bonobos, chimpanzees and orangutans — and lesser apes — gibbons and siamangs.May 29, 2015
Facts About Apes | Live Science"
Facts About Apes
Shall I say from that explanation that apes are not human <smile>, but are "humanity's closest living relatives." And, according to that definition, people are apes. But of course, apes are not people. again -- <smile> Well, there's more. But that they are said to share about 98% of their DNA does not prove that humans evolved from -- apes.

Correct. Apes are not human, but humans are an ape. Of course it does not prove it, but it is strong evidence of a relationship and shared ancestry. If you have cousins, you will naturally share some level of genetic similarity with them. This similarity indicates a common ancestry. It does not prove it in a scientific sense. Other evidence would be examined and added to the list of evidence supporting your relationship with your cousins. As evidence accumulates, the assertion of commonality is strengthened, but it never becomes an absolute in science. New evidence could be found to refute your relationship with your cousin(s). In science, at this point, it would take evidence of incredible robustness to derail the theory of evolution or common ancestry.

The evidence of common ancestry between humans and the other apes is found in morphology, genetics, molecular biology, cytogenetics and genomics and includes, but is not limited to, chromosome fusion, genomic homology, genetic similarity, presence and absence of different ERV's, comparative anatomy, physiology and development.

 

[Subduction Zone]

Apes are not human, but humans are an ape.

I would say that not all apes are human but all humans are apes. Just as not all dogs are beagles but all beagles are dogs.

 

[Jim]

@YoursTrue I said that all I’m objecting to is stigmatizing people who don’t believe that all living creatures have a common ancestor, but that was a mistake. I’m also objecting to some ways that I see people using some words in media stories and Internet discussions, including “science,” “evidence,” “evolution,” “facts,” and labels for people based on what they believe and don’t believe.

 

[Subduction Zone]

@YoursTrue I said that all I’m objecting to is stigmatizing people who don’t believe that all living creatures have a common ancestor, but that was a mistake. I’m also objecting to some ways that I see people using some words in media stories and Internet discussions, including “science,” “evidence,” “evolution,” “facts,” and labels for people based on what they believe and don’t believe.

There is a clear standard for scientific evidence. You do realize that don't you?

 

[Jim]

What might happen, and what I think would be best for human progress, would be that in spite of the stigma and lack of funding, some people will explore the possibilities in theories of evolution in which all living creatures do not have a common ancestor. Eventually the stigma will fade away, and the two ways of thinking will coexist, like what happened with the wave and particle models of light transmission.

 

[Jim]

No one even knows what the word “species” actually means.

Defining ‘species’ is a fuzzy art

 

[Jim]

This is just one of a multitude of ways that I see human progress being impeded by stereotyping and prejudices, especially prejudices across imaginary belief lines, now that national and race prejudices have been widely discredited. Not that those have disappeared. Just that they can’t be used as blatantly and shamelessly as prejudices across imaginary belief lines, to excuse and camouflage unloving attitudes and behavior.

 

[Jim]

A friend of mine thinks that it might be because the book companies don’t want to have to re-write the textbooks.

 

[Jim]

Common ancestry doctrine: “Similarities are evidence of a common ancestor, except when they aren’t, where the only rule for deciding if they are or aren’t is how credibly we can deny that they aren’t.”

 

[usfan]

I have previously posted this a few times. Enjoy!

1) Are you made of complex cells with internal organelles? If so, you are a eucaryote.

2) Do your cells have membranes made of lipids rather than walls made from glucosides and are they surrounded by an extracellular matrix composed of collagen and glycoproteins? Then you are an Animal.

3) During embryo development, does the blastopore (the first opening) become the anus? Then you are a Deuterostome.

4) Do you have a head, backbone, brain, red blood cells, and kidneys? Then you are a Vertebrate.

5) Are air-breathing, have hair, three ear bones, sweat glands, the ability to regulate internal temperature and specialized teeth? Then you are a Mammal.

6) Do you lack an epi-pubic bone and do females like you have a uterus which produces a placenta during pregnancy? Then you are a placental Mammal.

7) Do you have a collar bone, opposable fingers, a flat nail on fingers and toes, eye sockets made from bone, stereoscopic vision, an enlarged cerebral cortex? Then you are a Primate.

8) Do you have a narrow nose and downward pointed nostrils, broad rib cage, a fused frontal bone, convoluted cerebral hemispheres, a large brain for his size of mammal, color vision, a lack of tail, and a lack of cheek pouches? Then you are an Ape.

So, yes, if you are human, then you *are* an ape.

Yes, by arbitrary morphological definition. The visual similarities between chimps and humans are more than between humans and dogs, or bananas. But that 'looks like!' morphological similarity is NOT evidence of common descent. It can also be evidence of common design.

I could draw a graphic, showing the 'evolution' of cars, starting from the most primitive. Or airplanes.. or telephones. Any similarity in visuals or functionality shows the similarity of the design process. Nobody would suggest these things created themselves, or that there was some mysterious inner mechanism causing them to advance in complexity.

We can follow the actual 'evolution' of telephones, airplanes, and cars, and have a real historical timeline, not just an assumed progression. We also have convincing evidence that these things were man made, and did not create themselves.

Calling humans 'apes', may be taxonomically correct, but it also infers common descent. as do almost all taxonomic classifications. But it is an arbitrary biological classification, based on morphological similarity, not descendancy. It is not 'proof of evolution!'

 

[usfan]

The thing they come up with is the impossibility of going beyond boundaries, except by some form of unproven genetic change. There are, of course, life forms that have gone extinct in the course of present history. This does not prove evolution. It proves that some life forms go out of existence.

..it also indicates that living things do not conjure up traits needed to adapt. If they don't have the variability necessary to adapt to changing selection pressures, they go extinct. Low levels of diversity spell extinction for some organisms..

Then, we have low diversity organisms like sharks and cockroaches, that have changed little in their morphology, over (allegedly) millions of years. They did not go extinct, because their basic design included the necessary traits to adapt to a wide range of conditions. Bacteria, as well.

But the unseen, untested, unevidenced 'theory' that all organisms descended from common ancestors is an imaginary fantasy.. it is science fiction, not science.

 

[usfan]

Since he will not respond to logic and evidence not much else is left. Of course then after going out of his way to earn what he calls "heckling" he will complain about that to no end. Is that not more than a little hypocritical?

This is evidence for common descent, to you?


What else do you call someone who disruptes a scientific debate with personal attacks?

Logic? ROFL! You generally use fallacies, not reason, and cannot present a sound scientific case for your belief in common descent. I point this out, and you react with outrage and hostility.

There are too many poo flinging hominids in this thread already. Some rational human beings would be a refreshing change..

 

[usfan]

On that topic I want to say that I don’t see endless, aimless, acrimonious debating about the theory across lines of prejudice, as a way of socializing and passing the time away; or stigmatizing people who don’t agree with the theory , as examples of beneficial uses of the theory.

I have no control over the thinking, etiquette, and civility of other posters. I have offered a civil debate over the theory of common descent, but some are triggered by that, and react in hysterical, religious fervor.

Others probably enjoy ridiculing the beliefs of others.. a very common practice of religious bigotry, in humans.

But i have consistently and CONSTANTLY called for rational, civil, SCIENTIFIC standards of discussion in this thread, from the OP.

I will also point out:
1. This topic is always popular.. threads like this run for years.
2. The posters generally follow ideological lines.. it is somewhat an extension of the 'Atheists vs Christians!' flame war, that typifies forums like this.
3. More heat than light is generated, even though the discussion is about a scientific theory.
4. Facts, reason, and empiricism are not the tools commonly employed by the Defenders of common descent. Fallacies, and righteous indignation are more effective.
5. A dry, fact based 'debate' about actual scientific methodology would bore everyone to tears. The actual facts are not very titillating. Projection, assumption, extrapolation, and personal deflections have much more reality show appeal.
6. People do not change their minds, from forum posts. Their beliefs run much deeper, and are the result of many factors, in their life. Indoctrination from progressive institutions is a major factor for most, in modern western civilization.

 

[Jim]

But the unseen, untested, unevidenced 'theory' that all organisms descended from common ancestors is an imaginary fantasy.. it is science fiction, not science.

I object to your stigmatizing of the common ancestry premise. I don’t think that it’s the premise of common ancestry that needs to be denounced. What I think needs to be denounced is the practice of stigmatizing people for what they believe or don’t believe believe. The problem I see here is not the premise of common ancestry. The problem I see here is stigmatizing people who don’t believe that. Without that stigma, I think that evolution research would be a lot more fruitful and beneficial.

 

[usfan]

I did as you requested, and examined the study linked to.

How did you find this computer model on statistics compelling evidence for common descent? Several people seemed to think it 'proved evolution!' Was my rebuttal off base? Were my points flawed?

If this study is offered here as 'evidence for common descent', then the claims, data, and conclusions can and should be examined, as objectively as possible. I've offered a rebuttal to this 'evidence', but i see no response. Was it a bluff? A proxy argument, with no intent to follow up?

I'm doing my bit, in examining the offered evidence, even though it was just a link, that most do not understand, it seems. My rebuttal stands, unaddressed and unrefuted. So is this 'link' no longer compelling scientific evidence for common descent?

@usfan : care to comment on the details of this paper? It seems to provide exactly what you have been asking for: evidence of common ancestry of humans and other primates.

I will review this study, as a request from you. The poster who originally quoted it has chosen the heckling, ad hom route, which compels me to ignore any rational points

Here's the LINK..

"We find overwhelming evidence against separate ancestry and in favor of common ancestry for orders and families of primates. We also find overwhelming evidence that humans share a common ancestor with other primate species."

This is a statistical study, not a laboratory experiment. But I'll look at the claims, and offer my analysis.

The summary in the abstract is the conclusion of the writers, in this computer model. Is it compelled by the evidence? That's for the reader to judge.

From the abstract:
While there is no doubt among evolutionary biologists that all living species, or merely all living species within a particular group (e.g., animals), share descent from a common ancestor, formal statistical methods for evaluating common ancestry from aligned DNA sequence data have received criticism.

1. The prejudicial bias is clearly stated in the opening paragraph. Common Descent is assumed as 'settled science!'
2. 'Statistical methods', have received criticism, for the very reason mentioned, and this statistical analysis is no different. "..take sequence similarity as evidence for common ancestry while ignoring other potential biological causes of similarity.."
3. 'Sequence similarity' (looks like!) , is a subjective, argument of plausibility. Because of similarity of design, materials, and construction, a conclusion of 'common descent!', is asserted. This is no different than drawing a phylogenetic tree and declaring it as evidence.

So right off, the premise is based on an assumption of common descent. The deck is stacked to deliver the desired results, which is what you get in a computer model.

The conclusion and belief in common descent is asserted often, but the 'evidence' is vague, and only alluded to. Most people seem to be dazzled by their conclusions and forceful assertions, not any empirical evidence.

The most compelling among these objections was that the results of the tests are a trivial consequence of significant similarity among the sequences.

This criticism of another statistical analysis applies equally to this one. How is 'similarity!' of construction or design an indication of common ancestry?

All that is being done here, is taking the building blocks of life.. ALL LIFE.. amino acids, etc, and declaring this lowest common denominator as 'proof of evolution!' This was the earliest argument from Darwin.. similarity of appearance (looks like!) morphology, and arbitrary taxonomic classifications make it seem plausible.

But this is not evidence. It is speculation. It is a belief, repeated as a plausibility until it is accepted as 'settled science'.

..the community remains without a thoroughly convincing statistical method to demonstrate universal CA, whether among all domains of life or for more specific sets of species.

And i see nothing in this study to refute this observation of statistical analysis. Assumptions are made, between chimp and humans, the same as the previous computer models.

The data from the earlier, criticized study appears to be based on:
..used as evidence the highly unlikely topological agreement among the most-parsimonious trees for five separate proteins sampled from the same taxa..

So there were 5 seperate proteins, analyzed for similarity, then plugged into a computer model to calculate the odds of this happening, if you assume common descent.

This computer model is based on another study of primates.. animals assumed to be descended from a common ancestor.

A recent publication (Perelman et al. 2011) contains a molecular phylogeny of primates created using 54 nuclear genes and 191 taxa including 186 primate taxa from an alignment of 34,941 base pairs that the authors reduced from a larger alignment after discarding sites with great alignment uncertainty. Sequence data included roughly equal amounts of coding and noncoding sites, mostly from autosomal regions of the genomes, but with a few thousand sites from both X and Y chromosomes. No taxon was sampled for all 54 genes (humans are the most sampled with 53 genes) and many taxa have long stretches of missing data.

Everything is based on the ASSUMPTION of common descent. The cherry picked samples, the molecular structures, assumed to be related, then coming up with the 'odds', that this is what happened.

..it becomes reasonable to ask the specific question of how strongly molecular sequence data support the inference that the human species shares CA with other primates.

..reasonable, indeed. It is even more reasonable to ask how any statistical or visual 'similarity!' can infer common descent..

That is the crux of this study. It is a computer model, using sampled proteins from chimps and humans, and comparing their structure. Descendancy is assumed, and a calculation is contrived to arrive at a number..

The significance of this number can only be described as 'a trivial consequence of similarity'.

Hopefully, the grant money was good, and the conclusions seem to impress those who already believe strongly in common descent, but i see no evidence of ancestry, other than the age old argument of similarity. Putting a statistical number, from a human programmed computer model, is not a compelling scientific study, to support common descent.

 

[usfan]

I object to your stigmatizing of the common ancestry premise. I don’t think that it’s the premise of common ancestry that needs to be denounced. What I think needs to be denounced is the practice of stigmatizing people for what they believe or don’t believe believe. The problem I see here is not the premise of common ancestry. The problem I see here is stigmatizing people who don’t believe that. Without that stigma, I think that evolution research would be a lot more fruitful and beneficial.

The only 'stigmatizing!' from me is inferred. I am exposing the 'theory' of common descent as an unscientific hoax.. a religious belief, masquerading as 'science'!

My comments are toward the THEORY, or concept of common descent, not those who believe it. I only address them if they attack me with ad hom grenades, and minimally at that.

Is scrutinizing the basis of this belief 'unloving!!?' How does debating a CONCEPT, turn into anthropomorphic projection? How are people personally offended, for scrutinizing a scientific theory? Cannot the scientific methodology for this theory be scrutinized, without True Believers screaming, 'Kill the blasphemer!'?

 

[Jim]

@usfan This might be repeating what I’ve already said, but I’m seeing some things a little differently now, so there might be something new in it.

From the time I first learned about evolution theory until I saw this thread, I’ve always imagined that all life on earth had a common ancestor. My only questions were from curiosity about the “scientific consensus” joker card that I’ve seen people tossing onto the table. One thing led to another, and after some research and asking more questions, now it seems more likely to me that all life on earth is not from a common ancestor.

I don’t see the behavior that is sometimes associated with belief in common ancestry as a reason to stigmatize the belief itself. I think that would be just as harmful socially, and detrimental to human progress as stigmatizing any other view.

 

[usfan]

Some of the evidence, offered up to now:

1. Computer model showing statistical odds of common descent, based on analysis of amino acids and other building blocks of life.
2. E.coli study, showing the ability of bacteria to adapt.
3. Vestigiality
4. The phylogenetic tree graphic
5. Ridicule of 'Mitochondrial Eve!'
6. Canidae study on mtDNA showing genetic evidence of descent among specific canids.
7. Chromosome fusion/split
8. Fallacies.. poisoning the well, ad hominem deflections, straw men, equivocation, and many others.

Is this the compelling evidence for belief in universal common ancestry?

Is there any interest in a critical, fact based examination of these (and other) claims of common ancestry?

 

[Jim]

I am exposing the 'theory' of common descent as an unscientific hoax.. a religious belief, masquerading as 'science'!

My comments are toward the THEORY, or concept of common descent, not those who believe it. I only address them if they attack me with ad hom grenades, and minimally at that.

Is scrutinizing the basis of this belief 'unloving!!?' How does debating a CONCEPT, turn into anthropomorphic projection? How are people personally offended, for scrutinizing a scientific theory? Cannot the scientific methodology for this theory be scrutinized, without True Believers screaming, 'Kill the blasphemer!'?

I’m not objecting to exposing the fallacies, or denouncing some of the behavior, associated with belief in common ancestry. I’m only objecting to stigmatizing the belief itself. I think that to promote free thinking and free exchange of ideas, we need to strictly avoid stigmatizing any views. We need all views on the table at all times.