Talk:Evidence of common descent

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What is this article about, exactly?[edit]

I would think that at or near the beginning, there would be a definition or explanation of the meaning of the phrase "Common Descent", and that the rest of the article would somehow contrive to be about that subject. It seems to me it would be a better article if it were about something specific, in this case, the hypothesis of "Common Descent". And, if "common descent" is taken to mean that life originated on this planet, and only once, then it becomes more of a religious doctrine than a provable scientific hypothesis, because if it could arise once, why not twice? Or are we suggesting that all of the plants are related, but not to the animals? Or some similar qualification or constraint on the relatedness of all life? What really is being promoted is the idea that all of the genetic and biochemical machinery is related, in the sense that it is all backwards and forwards and sideways compatible, etc. Theodore Rigley 15:09, 4 January 2013 (UTC) — Preceding unsigned comment added by Trigley (talkcontribs)

I agree that a clear definition or explanation of the phrase "Common Descent" is needed. And we should not seem to be suggesting that plants are not related to animals. Nor should we seem to imply that common descent occurred only on the Earth. Because life formed once, it may have happened more than once on other planets having suitable environments. But that does not imply that advanced life formed more than once on the Earth, because after primative pre-cellular life formed, any later DNA, RNA, amino acids, phospholipids, etc would be consumed by or combined with the existing life forms. Likewise after procaryots developed. Greensburger (talk) 07:57, 5 January 2013 (UTC)

You are correct, the article should not suggest that plants and animals lack common ancestry. And as far as I can tell, it does not. Can you point to where it implies separate ancestry? Guettarda (talk) 16:48, 8 January 2013 (UTC)

Thanks, Greenburger, for the agreement;I hardly ever get that! After I wrote the above, I found the Wikipedia article "Common descent", which seems like it should be combined with this article to make one coherent whole. But I think the pro-Darwinist faction wants the Common Descent speculation to carry more weight than it can or should be asked to. For example, your last sentence above outlines a plausible speculation, and it's probably valid to think that many evidences of evolutionary processes lend it support, but it can't be proven. But so what; the life we have here and now is what requires explaining, and the means are at hand to do so. Theodore Rigley 16:21, 5 January 2013 (UTC) — Preceding unsigned comment added by Trigley (talkcontribs)

You might want to read evolution as fact and theory. Also, a closer read of the list of evidence in this very article, and a honest follow-up reading the related linked articles should demonstrate clearly that the Modern evolutionary synthesis is based on strong evidence and is not a mere hypothesis, and that there is no such thing as a Darwinist religion, considering the scientific method and scientific theory... 70.30.246.149 (talk) 15:07, 8 January 2013 (UTC)
Trigley, the purpose of this page is to focus on specific improvements to the evidence of common descent article. It would thus be useful that you (a) read the article, and (b) focus on specific changes.

The common descent article is linked in the opening paragraph. You are correct that that one and this form a group - this one should rightly be considered a daughter article of that one. As for "pro-Darwinist faction", "plausible speculation" and "it can't be proven" - your choice of language suggests that you haven't read the article. Had you, you'd realise that (as as 70.30.246.149 said) "Darwinism" was replaced by the modern synthesis in the first half of the twentieth century and is really the only game in modern biology. And had you read this article, you'd realise that is anything but speculation. As for "it can't be proven" - that's simply Popperian philosophy...in normal English, if you can demonstrate something with 95% confidence, you've proven it. You can't reject common descent without rejecting almost all of modern biology, because it's all based on the same epistemological underpinnings. Guettarda (talk) 16:48, 8 January 2013 (UTC)

Thanks for responding, folks, I am genuinely interested in learning more about this subject. As your comments above might suggest, I'm not qualified to improve this article, other than by pointing out where a naive reader (me) can't readily make sense of it. The "Common Descent" article begins with this text: "In evolutionary biology, a group of organisms share common descent if they have a common ancestor. There is strong quantitative support for the theory that all living organisms on Earth are descended from a common ancestor." It would seem that this (or a better) definition could start this "Evidence for..." article. Notice that the first sentence seems to provide room for a separate origin for different groups of organisms (i.e., plants vs. animals, or maybe insects vs. molluscs, etc.) but the second sentence basically reduces to a claim for life originating just once on this planet. It seems a different thing to say that "All the organisms within this group are related" vs. "All organisms are related, period, because life originated on Earth, but only once." Now, isn't it possible that if life could have originated once, it could have done so more than once, but the biochemistry and genetics all work together so well because, well, they have convergently evolved to do so? So to me, all of the evidence cited, while compatible with a "Life originated once, etc." hypothesis, does not compel it. Theodore Rigley 16:17, 11 January 2013 (UTC) — Preceding unsigned comment added by Trigley (talkcontribs)

So you are asking that the article show how it is more likely to be common descent than convergent evolution? I would agree that this could be a useful point to bring up, however I would like to hear your suggestions on how exactly to word that and specific examples where you believe that extra step is necessary.--Ollyoxenfree (talk) 20:58, 11 February 2013 (UTC)
My previous comment (from 70.30.246.149), might have been useful, but might also have been hasty. There is evidence of covergent evolution, and hypothesis that life could have originated from space (i.e. via comets). That said, unless I'm mistaken most of the evidence point to common descent. Despite the discovery of covergent evolution in some features of organisms (which features) have developed more than once, those organisms appear to still have common descent. Consider these examples. While flight may have evolved more than once as a feature, those animals in which it evolved appear to still have ancient common lineage. 76.10.128.192 (talk) 02:38, 11 March 2014 (UTC)
  • I don't think definitions are overly important here, I would hope that people read the common descent article before reading the article about the evidence for it, Second Quantization (talk) 08:18, 11 March 2014 (UTC)

Advertisement?[edit]

I noticed the "Evolution - Provided by PBS" link in the External Links section. When visiting, my impression is that it's a link to sell a series. What do other editors think? Thanks. 76.10.128.192 (talk) 17:57, 23 April 2014 (UTC)

Supports and is relevant to the article per WP:ELYES Jim1138 (talk) 19:31, 23 April 2014 (UTC)

Article Title[edit]

I know it has been brought up a thousand times before, but the title is not a descriptor of the material within the article. Instead of reworking the article, I propose that we just rename it to Evidence for Descent with Modification. That is the term Darwin used and it fits better with the common publications relating to the evidence for evolution.

For reasons unknown, the past discussions changed the article name from Evidence of Evolution to Evidence of Common Descent. Sensible but unreasonable in my opinion considering that most of the literature that surveys the subject matter just simply calls it the evidence of evolution. Also, a simple Google search for Evidence for Evolution turns up thousands of results with that title. Even the most well-known publications use the term evidence of/for evolution.

That being said, as per WP:CRITERIA, the current title does not fit the 5 main standards for article titles. Whereas, if the title were simply Evidence of (or for) Evolution or my proposal of Evidence for Descent with Modification, it would be more recognizable (possibly inviting new editors due to the fact that the laymen tends to not know what "common descent" is but definitely has heard of the term "evolution").

In addition, past talk page discussions have commented on the fact that the material is not so much evidence of common descent. Technically it is, but the article encompasses a much broader scope essentially rendering it, in my opinion, obsolete. Why change the material in the article when you can just change the title to fit what the article has evolved into? Of course that logic cannot be used in all circumstances, but in this one specifically, I think it can apply because "common descent" leaves out various other aspects of the evidence for evolution as a whole.

Any thoughts on the matter? A. Z. Colvin • Talk 01:35, 5 April 2015 (UTC)

I noticed that noone answered your question for a while. I like the current name, but I don't personally see a problem with the one you proposed. That said, I don't have any particular authority to decide. It's also difficult to evaluate if no objection implies that others agree... 76.10.128.192 (talk) 23:57, 16 October 2015 (UTC)
It appears to be a dead talk page at this point so I guess the issue is moot. Thanks for your response though. A. Z. Colvin • Talk 05:04, 22 October 2015 (UTC)
I got your message. It seems that this article has been substantially revised since my last comment, several years ago, so that now it focuses a bit more on the actual topic implied by the title, which is the evidence for the common descent of all living organisms. It's no longer just about obvious things, like that humans and chimpanzees are related. Just by reading it, there now seems to be some supporting evidence cited. It's not perfect, but it's significantly improved. ChicagoDilettante (talk) 01:40, 5 March 2016 (UTC)

I propose a discussion and reopening of this topic. I have requested a name change. Input and debate is welcome. A. Z. Colvin • Talk 00:35, 5 March 2016 (UTC)

Requested move 5 March 2016[edit]

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: No move, per WP:COMMONTITLE, and rationales provided below. (non-admin closure) jcc (tea and biscuits) 16:39, 13 March 2016 (UTC)


Evidence of common descentEvidence for descent with modification – See rational: Talk:Evidence_of_common_descent#Article_Title A. Z. Colvin • Talk 00:41, 5 March 2016 (UTC)

  • Oppose – Per book usage, the current title is much more common. And the proposed alternative drops the key concept of "common" that this article is about – that is, a single ultimate ancestor. Dicklyon (talk) 02:53, 5 March 2016 (UTC)
  • Oppose, The rationale above suggests that the title was 'weakened' when it was changed from 'Evidence for Evolution' but then suggests what seems to be a further weakening. Common descent has often been the sticking point for those who can't accept evolution and I think the article now does a reasonable job of explaining it. It's technical enough already and doesn't need more nudges in that direction. Chris55 (talk) 08:07, 5 March 2016 (UTC)
  • Comment. "Common descent" means "Genetically distinct organisms sharing an ancestor." When two genetically distinct populations descend from a common ancestor, this implies that evolution occurred. So evidence for the idea that evolution occurs can be relevant to an article on 'common descent' insofar as common descent (between distinct populations) is always an example of evolution. It can also be relevant insofar as people's doubts about common descent stem from doubts about whether evolution occurs; showing that evolution occurs at all can be a stepping stone to showing that evolution results in separate genetically distinct populations (and species, genera, etc.). If we were going to go with a name change to the weaker idea, then 'Evidence of evolutionary change' is probably a better title than 'Evidence of common descent'. But it's easier to justify discussing evolutionary change in general in an article about common descent, than to justify spending a lot of time on common descent when an article is about evolutionary change in general. Another alternative would be 'Evidence of evolutionary change and common descent', but this might misleadingly imply that common descent isn't an example of evolutionary change. -Silence (talk) 11:11, 5 March 2016 (UTC)
  • Oppose - the article seems very geared towards providing evidence for common descent specifically. There happens to overlap with evidence for 'descent with modification' but if you're using the term 'descent with modification' you might as well just say 'evolution'. If there was a "Evidence for Common Descent by Evolution/Evidence for Common Descent and Evolution" I might consider it. Otherwise there does not seem to be enough reason to specifically justify changing it.--Ollyoxenfree (talk) 21:50, 6 March 2016 (UTC)
  • Comment. Thank you for inviting me to vote. I am still unsure how this article should be named, as per my last comment (under the same IP address above), and I like the current title. Dicklyon and Silence have raised interesting points. I would neither object to "Evidence for descent with modification", nor with "Evidence of evolution" or "Examples of evolution", although the article might then require some adaptations (or fragmentation). As another variant of the aforementioned "Evidence of evolutionary change" idea, I could also propose "Evidence of diversification of life though evolution", or similar, but then again the scope of the article would then change... Sorry for not helping much, I'm ambivalent. 76.10.128.192 (talk) 04:46, 7 March 2016 (UTC)
  • Oppose - Per Dicklyon and Chris55 above. Jim1138 (talk) 08:37, 7 March 2016 (UTC)
  • Strong Oppose there is absolutely no reason why changing to the proposed title would be appropriate. At best this should have been a request back to the original title.InsertCleverPhraseHere 11:31, 7 March 2016 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Image captions[edit]

Is there any reason why the images are numbered off (like the first image caption starts out with "Figure 1a")?   User:Dunkleosteus77 |push to talk  20:38, 17 June 2016 (UTC)

It allows the text to refer to the figure in the proper context. This is done for instance for (Fig. 2b), however it seems that the references are indeed currently lacking for figures 1<x>. 76.10.128.192 (talk) 14:33, 7 July 2016 (UTC)