Talk:History of Earth

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Former good article nominee History of Earth was a Natural sciences good articles nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

Eras of the Phanerozoic addition?[edit]

I've already added this to the Phanerozoic article, and I'm thinking that I should add it here as well. If you have anything you want to change, either change it directly, or tell me on my talk page. I'd appreciate your input! I'll be adding it tomorrow, but you're still free to edit it further (but if you're going to delete, please tell me why)... Dunkleosteus77 (talk) 03:09, 5 May 2015 (UTC)

Since this is a copy of the Phanerozoic article as it stood a few days ago, I have taken the liberty of putting it in a collapsible box so people can find the discussion. RockMagnetist(talk) 03:40, 7 May 2015 (UTC)
Thank you for your offer. You are welcome to add some material, but you should bear in mind a few things:
  • We have a lot of material on the Phanerozoic already, so you'll need to be careful how you blend the new stuff in.
  • Aside from the largest time divisions, this article is organized by theme, not period, and it would be best to stick to that organization. You might want to look at Geological history of Earth, which is organized more like Phanerozoic.
  • This article is a failed Good Article nominee, but it has been much improved since then, so you need to maintain the high standards. In particular, bare urls for citations will not do. I see that someone has cleaned up your citations in Phanerozoic.
  • RockMagnetist(talk) 05:34, 7 May 2015 (UTC)

I don't know how those bear URL's got in there, but I've added the original copy from my sandbox which (to my knowledge) has no bare URL's. If you wish to edit that section, please do, and then tell me what you did because I'd like to keep my sandbox copy up-to-date. If you wish to delete it, please tell me why (and it better be a good reason...) Dunkleosteus77 (talk) 01:49, 8 May 2015 (UTC)

Remember my points about thematic organization and blending the material in? Please don't just paste it in. You need to read the existing material and see where (and if) your material fits. Much of your text duplicates existing material. RockMagnetist(talk) 02:04, 8 May 2015 (UTC)

I guess I could add the Cenozoic section because the existing one is lacking in information. I don't really know if I can merge the rest though, but I'd appreciate it if anyone could find a spot for it in this article. I also added it to the Mesozoic, but if you want to delete that one, I'd understand. Dunkleosteus77 (talk) 02:17, 8 May 2015 (UTC)

I'm sorry I have to keep reverting your additions, but you need to understand the issues. If it were o.k. to just paste a verbatim copy of Phanerozoic#Cenozoic, then why not also Cenozoic? And why stop there? You could also paste in Paleogene, Neogene, and Quaternary; then Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene; then Gelasian, Calabrian, Ionian, Tarantian, ... and so on. Where would it end? That doesn't make for good articles. Articles on broader subjects should contain summaries of subtopics (see Summary style). I know it's much more work, but there is no substitute for reading this article and thinking carefully about how to add to it. RockMagnetist(talk) 16:03, 8 May 2015 (UTC)

I didn't add the entire "Mesozoic" section, just the Triassic, Jurassic and Cretaceous subsections. You deleted too much and someone's going to have to re-write it... Dunkleosteus77 (talk) 01:46, 9 May 2015 (UTC)

I've re-written the section titled "Diversification of Mammals". Before I add it (in about a week or so), tell me what you think. Dunkleosteus77 (talk) 02:38, 9 May 2015 (UTC)

One last comment here, then I'll move on to diversification of mammals. If you look at the edit summaries, you'll see that I did some work after deleting your material. Some years ago, I pointed out that the organization of the article was inconsistent, with most sections being organized thematically but the Phanerozoic being organized by era. There was some support for changing this, but I never got around to doing it. Now I have done it. RockMagnetist(talk) 02:54, 9 May 2015 (UTC)
Actually, another comment. Would you mind if we deleted the copy of Phanerozoic? We can always look at the article, and the copy puts a large table of contents at the top of this discussion. RockMagnetist(talk) 02:58, 9 May 2015 (UTC)

Go ahead, I have plenty of copies. Dunkleosteus77 (talk) 03:00, 9 May 2015 (UTC)

Diversification of mammals[edit]

Extended content
Further information: Evolution of mammals

The first true mammals evolved in the shadow of the giant reptiles that filled the world during the mid-Mesozoic. Probably the first mammals were nocturnal to escape predation, and rather small. Mammals only began to diversify after the K-T extinction event when the world was left empty of anything over 10 kilograms.[1] The early Eocene was when earth recovered from the extinction, but mammals were still quite small and living in the shadow of the dinosaurs' descendants: birds. Birds, like Gastornis, ruled the earth, and forced some mammals to evolve to escape predation. Creatures like Ambulocetus took to the oceans to eventually evolve into whales [2], whereas some creatures, like primates, took to the trees [3]. This all changed during the mid to late Eocene when the circum-Antarctic current formed between Antarctica and Australia which disrupted weather patterns on a global scale. Prairies (without grass) set out to rule much of the earth, and mammals such as Andrewsarchus rose up to become the largest mammalian predator ever [4] and early whales like Basilosaurus took control of the seas. The Oligocene saw the evolution of grass, and the beginnings of its conquest to rule the world's flora.

The evolution of grass brought a remarkable change to the planets landscape, and the new open spaces created pushed mammals to get bigger and bigger. Grass started to expand in the Miocene, and the Miocene is where many modern day mammals. Perissodactyls like Paraceratherium and Deinotherium (rhinos and elephants) evolved to rule the grasslands. The evolution of grass also brought primates down from the trees, and started the human branch. The first big cats evolved during this time as well, and will eventually branchiate into lions and other large felids [5]. Major tectonic events were occurring alongside these events. The Tethys Sea was closed off by the collision of Africa and Europe [6], and the Isthmus of Panama form between North and South America.

The formation of Panama was perhaps the most important geological event to occur in the last 60 million years. Atlantic and Pacific current were closed off from each other, which caused the formation of the Gulf Stream, which made Europe warmer (winters wouldn't get colder than 10 degrees Celsius). The land bridge allowed the isolated creatures of South America to migrate over to North America, and vise versa [7]. The ancestors of bears, cats, dogs, horses, llamas, and raccoons all migrated across, which is why we have the Spectacled Bear, the Puma (in both of the Americas), and the Llama (which evolved in North America).

Three million years from today was the Pleistocene epoch, probably one of the most famous epochs in geological history. This epoch featured a roller coaster of climactic changes due to the ice ages. The ice ages led to the evolution of modern man in Saharan Africa (which formed due to the Ice Ages) and expansion. The mega-fauna that dominated fed on grasslands that, by now, had taken over much of the subtropical world. The large amounts of water held in the ice allowed for various bodies of water to shrink and sometimes disappear such as the North Sea and the Bering Strait. It is believed by many that a huge migration took place along Beringia which is why, today, there are camels (which evolved and went extinct in North America), Horses (which evolved and went extinct in North America), and Native Americans. The ending of the last ice age coincided with the expansion of man, along with a massive die out of ice age mega-fauna. This extinction, nicknamed "the Sixth Extinction", has been going ever since. In present day, mammals have come a long way from shrews living in the shadows of the Mesozoic forests.

Good choice of subject. It's the part of the existing article that is most in need of help. I think that, with a little cleanup, it would be quite a suitable addition. I'll try to get to it soon. RockMagnetist(talk) 03:00, 9 May 2015 (UTC)

Should I work on a Mesozoic version, or would that be too much? Dunkleosteus77 (talk) 14:06, 9 May 2015 (UTC)

Not much point in that, since the Mesozoic no longer has its own section. RockMagnetist(talk) 23:51, 9 May 2015 (UTC)

Should we re-add the section because that's a fairly important time in earth's history (involving life)? Dunkleosteus77 (talk) 00:20, 10 May 2015 (UTC)

Please read the previous section again. As I mentioned there, that is not the way the rest of the article is organized, and there was a discussion some time ago in favor of using the same organization for the Phanerozoic. I do describe the time divisions at the top of History of Earth#Phanerozoic. RockMagnetist(talk) 14:26, 10 May 2015 (UTC)
Sorry, I forgot about that. Dunkleosteus77 (talk) 19:02, 10 May 2015 (UTC)

On the topic of adding that revised version at the top of the section, should I go ahead and with it, or does it need to be revised? Dunkleosteus77 (talk) 00:47, 12 May 2015 (UTC)

Do you mean the material on mammals? RockMagnetist(talk) 00:52, 12 May 2015 (UTC)
The first two paragraphs of this section; the writing in the collapsible box Dunkleosteus77 (talk) 23:11, 12 May 2015 (UTC)
It does need significant revision to look more encyclopedic, but it is still an improvement over the existing material in that section, so I'd be o.k. with your adding it. RockMagnetist(talk) 02:48, 13 May 2015 (UTC)
One thing you should do first is to convert your bare urls to proper citations. It looks like you can use {{cite web}} for all of them. I have done the first one to provide you with an example. RockMagnetist(talk) 05:36, 13 May 2015 (UTC)
Whoa, that's confusing. Is there some tutorial for proper citations? Dunkleosteus77 (talk) 00:53, 15 May 2015 (UTC)
You could try Wikipedia:Tutorial/Citing sources. Thanks for indenting, by the way. RockMagnetist(talk) 05:01, 15 May 2015 (UTC)
The last two paragraphs of this section need to be (heavily) revised. I have done something about the problem by striking out some extravagant claims: E.g.: "the Pleistocene epoch, probably one of the most famous epochs in geological history." E.g.: "The ice ages led to the evolution of modern man in Saharan Africa (which formed due to the Ice Ages) and expansion." But quite a lot more needs to be done. Filursiax (talk) 23:10, 26 July 2016 (UTC)

Should this article be reorganized by geological divisions?[edit]

I don't know if you've noticed, but everything talking about geological time (which makes up over half of the articles info) is not organized thematically, but rather chronologically. When speaking in terms of geological time, it is natural to order them chronologically, which is why I strongly suggest reorganizing the rest of the article chronologically rather than thematically. Dunkleosteus77 (talk) 17:20, 11 May 2015 (UTC)

By "chronologically" you mean by geological time units. Of course, it is divided into eons. I have some reasons for preferring this organization:
  • There is no single right or wrong approach. This article is intermediate between Geological history of Earth, which organizes time by epoch, and Evolutionary history of life, which is entirely thematic. It seems to me that when there are articles with overlapping contents, it is good to vary the presentation.
  • Since we're trying to cover all of Earth's history, we need to paint with a very broad brush. The article size is already 52kb of readable prose size, with some sections still needing expansion (see the size guideline). I think it is easier to be concise if we keep the time divisions large.
  • This is the way the article has developed, and we have been working section by section to raise it to a Good Article level (see the to-do list at the top of this page for progress so far). You're still relatively new to Wikipedia, so I don't think you realize how much work this involves. A major reorganization would set this effort back.
I have provided a separate section heading for this discussion. RockMagnetist(talk) 19:13, 11 May 2015 (UTC)

635 Ma glaciation[edit]

Well, went through a reference from that section, and found another article there — 'Snowball Earth' hypothesis challenged, dated October 12, 2011: «The hypothesis that Earth was completely covered in ice 635 million years ago has received a serious blow. The atmospheric concentration of carbon dioxide during that period was much lower than previously thought, according to a team of researchers.» There's also this piece, too: «Moreover, this data is consistent with the idea that the atmosphere at the same period was much more oxygen-poor, around 1%, as compared to today's levels of approximately 20%.» — which is utterly interesting and worth considering, etc. Lincoln J. (talk) 16:10, 28 July 2015 (UTC)

It is interesting that Britannica has a separate article on the Slushball Earth hypothesis at [1]. Both this idea and the drastic reduction in oxygen levels are covered in Snowball Earth. I think majority opinion still favours the snowball hypothesis, but I agree that this article is too definite in implying that the snowball is unquestioned fact. Dudley Miles (talk) 16:28, 28 July 2015 (UTC)
@Lincoln Josh: Thanks for the reference. @Dudley Miles: I'm not sure what part of "Some scientists suggest ... a hypothesis called Snowball Earth" is too definite for you. However, this section could be improved with a summary of the pros and cons that are discussed in Snowball Earth. Feel free to tinker with it! RockMagnetist(talk) 17:17, 28 July 2015 (UTC)
Yes I did not read it carefully enough. I will have a go if someone more expert does not take it on - and even better create an article on Slushball Earth. Dudley Miles (talk) 18:03, 28 July 2015 (UTC)
It's unlikely an expert will jump in, so go for it. Just remember that it should be fairly concise since we're covering all of Earth history in this article. RockMagnetist(talk) 19:34, 28 July 2015 (UTC)
I have had a go. Amend anything you are not happy with. I think there is too much on the earlier Huronian episode as it only seems to rarely be described as a Snowball Earth, but I have not taken this on. Dudley Miles (talk) 20:22, 4 August 2015 (UTC)
«I have had a go.» Where? Here? Lincoln J. (talk) 09:38, 20 August 2015 (UTC)
here. Dudley Miles (talk) 09:46, 20 August 2015 (UTC)


Errata and placement in graphic needs correcting[edit]

Errata in the GTS graphic--(top, lede)--are: 1) "Hominids" should read "Hominins"--occurs twice; 2) Hadean color band should end at 4.0 Ga (vice 3.8). Help is requested of any editor to revise the graphic template. (OR: Questions, pls reply here.) Thank you. Jbeans (talk) 05:04, 14 January 2016 (UTC)

The bar for dinosaurs also looks like it's the wrong size (it's hard to tell). And the start of photosynthesis, placed at 3.8 GA, is misplaced by nearly 1 billion years, by most counts. The article otherwise states that it began between 2.4 and 3.2 GA. 135.23.157.250 (talk) 15:30, 25 January 2016 (UTC)
The graphic was created back in 2010 by User:Woudloper, who is no longer active. The label shows photosynthesis as starting at about 3.5 Ga (the continuous bar is for prokaryotes), rather than the more accepted 3.2 Ga. The range of the dinosaurs is about right, unless you feel that the birds should continue this bar up to the present day. I could edit the graphic so that it says "ca. 3500 Ma - earliest start of photosynthesis" or similar. I could also fix the Hadean and the "hominids" while I'm at it. Mikenorton (talk) 16:05, 25 January 2016 (UTC)
I've made those changes and tweaked the main boundaries - end Mesozoic to 66Ma, end Paleozoic to 252Ma and start Cambrian to 541Ma to match the latest ICS products. I will upload that version after a few days, if no-one objects to that approach. Mikenorton (talk) 19:31, 25 January 2016 (UTC)
I think it should be consistent with the Dinosaur article, which includes birds.   User:Dunkleosteus77 |push to talk  23:04, 25 January 2016 (UTC)
@Mikenorton, I support adding a sector for the Cambrian; and I urge that we not "extend the bar" to the present day for dinosaurs-as-birds---the dramatic extinction of the (non-avian) dinosaurs and the literal ending of their era is a touchstone that lay readers especially can relate to. Instead consider this alternative> Revise the current label on the graphic to read: "Non-avian dinosaurs"; then ensure that the end-of-the-bar coincides exactly with the "end Mesozoic" at 66Ma. And please proceed as you indicated. Thank you, and Regards. Jbeans (talk) 03:29, 26 January 2016 (UTC)
OK, changed dinosaur bar as discussed and altered ca. to c. per WP:MOS and uploaded revised image. I can't see the new file yet, but I presume that's just a cache issue. I'm not sure about adding a separate Cambrian sector, so I've left that for now. Mikenorton (talk) 09:54, 26 January 2016 (UTC)
Looks great!--a good improvement, and TYVM. I will return here after I can take time study the new edition--and probably with more "wish list". (My lobby for the Cambrian was from mistaking that you were offering it, but no issues--I still support the idea--as, again, it's a dramatic theme that will, IMO, resonate with lay readers--always a plus for the Wp.)//Jbeans (talk) 00:28, 27 January 2016 (UTC)

I notated the following "punch list" of items (from the old graphic) that still needs correcting>
1. The recent edits show nicely on the new page graphic, BUT, not at all when the graphic is 'clicked' to zoom in---instead the old edition reappears without the new edits.
Items 2 thru 6 are problems with data values, presented per the template that follows:
2. [CURRENTLY READS> "4560 Ma: Formation of the Earth"]-------> {SHOULD READ> "c. 4540 Ma: Formation of the Earth"}
3. ["4527 Ma: Formation of the Moon"]-------> {"c. 4480 Ma: Formation of the Moon"}
4. ["750-635 Ma: Two Snowball Earths"]-------> {"c. 750-630 Ma: Two Snowball Earths"}
5. ["230-66 Ma: Non-avian dinosaurs"]-------> {"c. 230-66 Ma: Non-avian dinosaurs"}
6. ["2 Ma: First Hominins"]-------> {"c. __ Ma: First hominins"}

Items 2, 3, and 5 are corrections that conform their revised values to the article narrative; note, all are "c.", or circa, values--ie, should not be presented as other than approximate, which, again, is consistent with the article narrative. Item 4 is corrected for a significant figure value--in the context of precision, and of adjacent data values. Item 6 is a problem: the value "2" is outdated/wrong, and should be replaced; research homework is due. I volunteer for that task, but meantime let's discuss the above punch list; any additions, objections, comments? //Jbeans (talk) 07:53, 27 January 2016 (UTC)

#1 is not true. I consistently get the updated graphic all the way to largest size on Commons. Maybe purge your cache again? Or maybe it's something to do with Media Viewer, which I don't use. — Gorthian (talk) 18:28, 27 January 2016 (UTC)
Thank you, I'm glad to know it not a broad problem, just my system--(it doesn't appear here to be either glitch you suggested, so I'll have to troubleshoot more).//Jbeans (talk) 00:18, 28 January 2016 (UTC)
Re #6, as I understand it, the first hominin was homo erectus, so the 2 Ma is about right (agree we should add c. to the estimates). Mikenorton (talk) 10:09, 1 February 2016 (UTC)
After looking further into this, it seems that there are a number of candidates for the "earliest hominin", dating back to about 7 Ma, such as Sahelanthropus and Orrorin. Mikenorton (talk) 12:36, 1 February 2016 (UTC)
First, we agree to add "c." to all the event dates, as they all are estimates; and, as there have been no objections, I ask you to proceed with it. And with the changes in the data values if you agree.
There is debate in the industry as to whether Sahelanthropus, Orrorin, Ardipithecus are hominins---and whether they are australopithecines, all members of which are considered hominins. But our quest is actually decided by a larger criteria, namely the definition of hominins that holds broad acceptance among scientists, which is: those species of the (proto-human) tribe Hominini that arose after the split of the human lineage from the chimpanzee lineage, (discussed here); this species can't be named because it is unknown or it is not agreed to at this time.
The temporal range currently debated for this event is from 13 mya to 4 mya---(see here (2nd para.): "Sometime during the late Miocene ..."). My suggestion is that we avoid choosing sides in the debates by posting the earliest date in that range, that is, 13 Ma, then adjust the article text (not the image) to say it is debated---which I will work on and post a proposed edit here soon. //Regards, Jbeans (talk) 20:48, 1 February 2016 (UTC)

Paragraphs[edit]

Undid good faith edit re paragraphs (also per WP:LEAD)> Our priority here should be for the lay reader. Long runs of mashed-up sentences are discouraging to behold. There’s no guiding punctuation space to signal that a new line of thought is happening; no stopping point for the reader to reflect on the material just read; no place for you, reader, to visually ‘hold your place’, should you want to pause---no rest here, jus’ keep reading!

Serviceable paragraphs provide cohering thoughts, separated from the cohering thoughts of adjacent serviceable paragraphs. They are separated physically---a service to the reader---for the advantages of: 1) comprehending a separate component of the larger body of material; 2) to signal a closing of ‘this’ line of thought; 3) and for ease of reading;---and why not? They shouldn’t be jammed together to degrade readability for no perceivable advantage gained.//Jbeans (talk) 05:20, 1 February 2016 (UTC)

Address conjecture in causes of change.[edit]

Re, recent contention, and the addition at some point of "— now dominated by human activity—". "...now dominated by..." is conjecture. Adding the qualification "believed by some ..." improves the accuracy of the statement and lessens the appearance of agenda.

BTW -- new at this -- appreciate the patience. Is "take it to the talk" an asymmetrical activity? ChrisHackett (talk) 00:01, 6 March 2016 (UTC)

Not sure what you mean by "asymmetrical"... — Gorthian (talk) 04:55, 6 March 2016 (UTC)
Who are the "some" who are believing?--Mr Fink (talk) 00:12, 6 March 2016 (UTC)
To Mr Fink's comment, there are some researchers who believe that humans are causing changes in the biosphere, but there are other researchers who believe that there are many other major factors (like CO2 given off by melting permafrost)   User:Dunkleosteus77 |push to talk  04:33, 6 March 2016 (UTC)
Seems to me that however it's phrased, it needs a citation. — Gorthian (talk) 04:55, 6 March 2016 (UTC)

Sourcing problems[edit]

Despite a rather long list of citations, much of the context remains unsourced and several claims lack attribution. :

  • The "Replication first: RNA world" sections starts with a broad statement about the use of DNA in all three domains of the three-domain system and that this in turn leads to prevalent use of RNA. Potentially great staff to include , but there is no mention of any source and how we know it.
  • The introduction of the "Proterozoic Eon" section contains the phrase "About 580 Ma, the Ediacara biota formed the prelude for the Cambrian Explosion." What this means is less than clear and the process is not exlained.
  • The "Emergence of eukaryotes" section includes the claim that "Eukaryotic cells (Eukarya) are larger and more complex than prokaryotic cells (Bacteria and Archaea), and the origin of that complexity is only now becoming known." The increased complexity is not explained by comparison, and the study of the phenomenon is alluded to but not really mentioned.
  • Also in the section, "Emergence of eukaryotes" there is a claim that "Possibly by around 900 Ma true multicellularity had also evolved in animals." The date is sourced, but neither the process nor any supporting evidence is mentioned. The sentence is attached to a well-sourced paragraph about the appearance of multicellular plants.
  • The segment on "Emergence of eukaryotes" concludes with the following sentence: "As the division of labor was completed in all lines of multicellular organisms, cells became more specialized and more dependent on each other; isolated cells would die." This seems to be a key concept in the evolutionary process, but has no source supporting it.
  • The "Late Proterozoic climate and life" segment includes the sentence: "Increased volcanic activity resulted from the break-up of Rodinia at about the same time." And how do we know this?
  • The "Late Proterozoic climate and life" spends a few sentences on new developments of "muscular and neural cells" and that they still lacked hard body parts. No source provided for either claim.
  • The "Phanerozoic Eon" segment includes a sentence on the formation of Pangaea from the union of previous continents. The continents are not named in the text and the description of the process mentions no source.
  • The "Phanerozoic Eon" segment includes a sentence on how "the Cretaceous–Paleogene extinction event ... wiped out the dinosaurs." This is not only unsourced, it is the first mention of the term dinosaur in the text and the term is not defined. By the way, dinosaurs are not really extinct. The theropoda group of dinosaurs has been redefined to include all modern birds. Meaning that there are currently about 10,000 living species of dinosaurs.
  • The "Phanerozoic Eon" includes a few sentence about the survival of "Mammals, birds, amphibians, crocodilians, turtles and lepidosaurs" and that they diversified into their modern forms. This is entirely unsourced. Their survival is well-known but still requires a proper source. Their diversification is much less known and might require additional explanation.
  • The "Tectonics, paleogeography and climate" segment opens with an explanation about the formation of additional oceanic crust by volcanic activity. Then it is explained that the process leads to the rise of the sea level and the covering of continental areas by water. Fascinating stuff, but not sourced.
  • The "Tectonics, paleogeography and climate" segment explains that following a massive extinction events, new species evolve and they are more diverse and better adapted to the new conditions. Fascinating note on the evolutionary process, but actually unsourced.
  • The "Tectonics, paleogeography and climate" segment concludes with Pangaea braking up into Laurasia and Gondwana. This sentence lacks both a source and an explanation of the process.
  • The "Cambrian explosion" segment begins with a rather lengthy explanation of how the new animal life forms of the era developed shells, skeletons or exoskeletons, and these hard party parts have left a larger mark on the fossil record than their predecessors. The entire explanation lacks a source.
  • The "Cambrian explosion" segment covers the appearance of fishes with massive body sizes. The example used is the Dunkleosteus and the segment explains that it could reach up to 7 meters (23 feet) in length. The appearance of the massive sizes is unsourced and the number given for the Dunkleosteus, contradicts our article on the subject. In the specific article, it is explained (with a source) that this fish could reach up to 10 meters (33 feet) in length.
  • The "Evolution of tetrapods" segment briefly covers the divergence of the Synapsids and the Sauropsida. It also mentions the contemporary diversification of fish, insects, and bacteria. Neither the divergence or this diversification is sourced.
  • The "Extinctions" is a lengthy coverage of five different extinction events, each given a different paragraph, some of them giving a statistic on the severity of the event. The problem is that there are only two sources in the entire segment, and they cover rather small portions of the text. Where did the rest of it come from? Particularly the numbers in these statistics.
  • The "Diversification of mammals" segment includes a sentence on how the Archaeoceti managed to take control of the seas. The term is not really defined and this "control" is not sourced.
  • The "Diversification of mammals" segment includes a section of a mass migration of mammal species from North America to South America, with several named examples. The problem is that the entire section has no source.
  • The "Diversification of mammals" segment concludes with a rather lengthy paragraph on the "dramatic climactic changes" of the Pleistocene, a large migration wave over Beringia, and the Holocene extinction. It is entirely unsourced, despite covering some key events. Plus, I am not sure this has anything to do with the diversification of mammals at all. It does not speak about new life forms, but about the extinction of old ones.
  • The "Human evolution" segment is better sourced, but concludes with the following sentence: "Tool use and communication continued to improve, and interpersonal relationships became more intricate." This has more to do with the technology and social life of the various human species than their evolution, and it is unsourced.
  • The "Civilization" segment contains a claim that the various civilizations that adopted agriculture enjoyed relative stability, increased productivity, and an expanding population. This is a major claim on the advantages of agriculture. But it has no source, nor does it address the continued survival of nomadic cultures.
  • The "Civilization" segment includes a sourced segment on the rise of Sumer. That seems nice. It is immediately followed in the same paragraph by the rise of Ancient Egypt, the Indus Valley Civilisation and History_of_China#Ancient_China. None of the three are sourced in the text. The paragraph then continues with the invention of writing and its cultural impact. Again nothing is sourced.
  • The "Civilization" segment includes a sourced section on the state of civilization c. 500 BC. Advanced civilizations in the Middle East, Iran, India, China, and Greece, with periods of expansion and decline. Not too bad as a claim. The rest of the paragraph is a mess. It covers the unification of China and the spread of Chinese culture in East Asia, the impact of the Greco-Roman world on the Western world, the Christianization of the Roman Empire, the Fall of the Western Roman Empire, the Christianization of Europe, the rise of Islam and its dominance of Western Asia, the East–West Schism and its impact on the cultural divergence of Western Europe and Eastern Europe. This covers and mixes up some of the main of a 2000-years period. Without bothering to provide a single source. I am also not certain on the perspective of the paragraph. The Greco-Roman world included areas in three continents (Europe, Asia, and Africa) and there was contact and cultural exchanges with civilizations beyond its borders. See for example the article on Greco-Buddhist art and its impact on China and Japan.
  • The "Civilization" segment includes a sourced section on the Renaissance, the Age of Discovery, and the History of colonialism. While it could use expansion, these seems reasonable. The rest of the paragraph is a mess. It covers the Age of Enlightenment, the secularization of Europe, the World wars, the emergence of the League of Nations and the United Nations, the Decolonization process, the emergence of two superpowers, the Cold War, the formation of the European Union, and the process of globalization. This covers and mixes up the events of three centuries (18th to 20th). But it is entirely unsourced, and a bit too Eurocentric. The Enlightenment also affected the European colonies and the global scene, secularization is not only a European phenomenon, and the article on globalization points that the term is recent but the process is actually centuries-old. What of the effects on every continent?
  • The "Recent events" segment starts with a rather lengthy paragraph on the emergence of nuclear weapons, computers, genetic engineering, and nanotechnology, the effects of economic globalization, the increased influence of democracy, capitalism, and environmentalism, and concerns about disease, war, poverty, violent radicalism, human-caused climate change, and the continued increase of the world population. Nothing is sourced. And I am far from certain that some of these developments count as "recent". Nuclear weapons emerged in the 1940s, the first modern computers emerged in the 1930s and 1940s but their history goes back for millennia, the concept of genetic engineering emerged in the 1950s and the practical aspects of it in the 1970s, the concept of nanotechnology emerged in the 1950s and the practical field in the 1980s. All these events are older than the end of the Cold War, which is covered in the previous section. Democracy (as a system where decisions are taken by election) has appeared in various forms since the 6th century BC and has been on the rise since the 17th century, so I am not sure what "increased influence" means in this case. Our article on the history of capitalism traces the concept to the rise of the merchant class in the 14th century, the emergence of merchant capitalism in the 16th century, and industrial capitalism in the 18th century. It is far from a new system. Environmentalism emerged in the 19th century, out of concerns on the environmental effects of the Industrial Revolution. As for "disease, war, poverty", can anyone point me to a century without these elements. They are far more constant than taxes.
  • The "Recent events" segment concludes with a sourced segment on the Space Age from 1957 to the present. Good idea. Attached to it is an sentence on the emergence of the World Wide Web in the 1990s and its effects on developed world. This remains unsourced, and I am uncertain the effects are limited to a hand full of countries.

That is about it for the problems of the article. I hope I am not being too harsh. Dimadick (talk) 14:40, 6 March 2016 (UTC)

@Dimadick: Thanks for your analysis. Most of this is no surprise - note that your comments are restricted to the unchecked sections in the todo list at the top of this page. So far, as I have added sources section by section, I have found the coverage unbalanced and inaccurate, so instead of just adding citations I have had to rewrite a lot of it. The task only seems to get more difficult as the story progresses forward in time. These days I don't have the time to research such broad subjects properly. I have also looked to the main pages for a few sections, but they often don't lend themselves to clear summaries. If you were to adopt one of these sections and rewrite it, that would be a big help. RockMagnetist(talk) 16:02, 10 May 2016 (UTC)

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