Talk:Timeline of evolution/Archive 2

Some work with the External Links

I added an external link to an evolutionary timeline that's a bit more compact. I also noticed that one of the external links (Palaeos) isn't working so I put it to the bottom. Made some minor edits, including internal linking to monsoon. Kaimiddleton 21:32, 13 December 2005 (UTC)

The timeline exceeds 32K

Well, I've done a bunch of edits tonight, mostly making links, so that mammoth is instead mammoth, etc. And I received a warning that the article, at 40K, exceeds the recommended maximum 32K length.

Personally I like a lot of information on one page. E.g., if I'm reading an FAQ I much prefer to have a multi-hundred KB document because I can page through it quickly with the browser. That's my natural bias. But also, I think this timeline is not easily limited in size. It is natural to expand it with new information as it comes out (e.g. homo floresiensis).

One thing that the Wikipedia:Article_size guidelines suggest is to break the article into sections. I don't know if sections would work in a table. I might try it out to see. If I read it right, then, so long as each section is under 20K we're good. And it wouldn't be hard to make arbitrary sections based on some MYA or kYA number; e.g. we could use these sections: >= 1000MYA, 500-1000MYA, 250-500MYA, 65-250MYA, 30-65MYA, 5-30MYA, 1-5MYA, 100kYA-1MYA, 30-100kYA, 0-30kYA, present. I haven't thought about these numbers much.

What do folks think?

Kaimiddleton 07:56, 17 December 2005 (UTC)

Update: putting sections into the table doesn't work (using double equals around 4600MYA, for example). It seems the table would have to be broken up into smaller tables. In which case it would be good to be more formal about the numbers probably. Or maybe wikipedia just bothers you every now and then about the article size and you can just ignore it.

Kaimiddleton 08:06, 17 December 2005 (UTC)

Also, in the external links section I'd already added a link to another timeline of evolution that is much more compact. I have to say I prefer the long timeline.

Kaimiddleton 08:21, 17 December 2005 (UTC)

Important: The 32k warning is a data relic from earlier versions of MediaWiki. There are no hard and fast rules regarding article length of Wikipedia articles; just use common sense. For example, many featured articles are two or three times over the "limit" (History of Poland (1945–1989) is 73kb, Hugo Chávez is 99kb), but because they're no longer than their subject merits and are already in summary format, it is unnecessary to trim them down further. In fact, almost all featured articles break this arbitrary limit; it's hard to have a good article without going in depth enough to do so. So, don't sweat it—worry about the quality of the article itself, not about blind archaic-rules-following. -Silence 12:02, 17 December 2005 (UTC)

Thanks for the feedback! I agree that an emphasis on quality should come first and have been doing a lot of polishing work, in addition to my minor adds here and there.-Kaimiddleton 01:01, 18 December 2005 (UTC)

I have absolutely no problem with keeping the timeline on one page, but I still think a split into section should be discussed. The earlier mentioned intervals (>= 1000MYA, 500-1000MYA, 250-500MYA, 65-250MYA, 30-65MYA, 5-30MYA, 1-5MYA, 100kYA-1MYA, 30-100kYA, 0-30kYA, present) could be used as section headers (enclosed by ==), while using the current left-side table cells as subsection headers (enclosed by ===). Yes, that would mean we'd drop the table entirely :-) What do you think? --Fred Bradstadt 13:05, 24 February 2006 (UTC)

Y-chromosomal Man before after Modern "race" formation?

The following seems like an error to me:

100 kYA Modern "race" formation begins

60 kYA Y-chromosomal Adam lives in Africa. He is the last male human from whom all current human Y chromosomes are descended.

How do you get racial diversity when everyone is geneticaly related 40,000 years later? 12.20.127.229 17:48, 22 December 2005 (UTC)

The Y-Chromosome has changed in 40000 years, giving genetical diversity, though its ORIGIN is the same. And genitical diversity also, and in a much larger scale, comes from the other 45 chromosomes we have.

Good point. Can anyone from the academic community comment on this? Kaimiddleton 00:13, 23 December 2005 (UTC)

Anyone want to object to my removal of the line:

100 kYA Modern "race" formation begins

? -12.20.127.229 19:06, 6 January 2006 (UTC)

Hmmm: I wouldn't object, per se, but if you remove the sentence "Modern "race" formation begins." then what about the rest: "African populations remain more 'diverse' in their genetic makeup than all other humans, since only a subset of their population (and therefore only a subset of their diversity) leaving Africa. For example, mtDNA shows that an individual with English ancestors is more similar genetically to an individual with Japanese ancestors than are two individuals drawn from two African populations."

I like the reference at 60 kYA because it wiki-links to Y-chromosomal Adam, even though that wikipedia entry describes the time as 60-90 kYA so that 60 kYA is a lower bound.

I don't have a very strong opinion whether to delete or not, but I would suggest a better solution would be to reconcile the entries a bit more thoughtfully. Kaimiddleton 21:02, 6 January 2006 (UTC)

I concur, I think it might be better listed as:

100 kYA - The first anatomically modern humans (Homo sapiens) appear in Africa by this time or earlier; they derive from Homo heidelbergensis. Homo sapiens (humans) live in South Africa (Klasies River Mouth) and Israel (Qafzeh and Skhul), probably alongside Neanderthals. Modern humans enter Asia via two routes: one North through the Middle East, and another further South from Ethiopia, via the Red Sea and southern Arabia. (See: Single-origin hypothesis).

90kYA~60kYA - Mutations causes modern genetic differentation begins. African populations remain more 'diverse' in their genetic makeup than all other humans, since only a subset of their population (and therefore only a subset of their diversity) leaving Africa.

Opinions? I removed 'race' since it is a poor choice of terms, all of the races blend where they overlap making it at best an outdated term. The last sentance was redundant as well, if someone that has read this entire timeline cant figure out what it means for a genetic subset to leave an area and needs an example then they most likely do not understand this article. 12.20.127.229 21:20, 6 January 2006 (UTC)

I think that looks pretty good in terms of an overall approach. Two details: first a minor grammar point: "leaving Africa" should be "leaves Africa". Secondly, if you use a tilde as in "90kYA~60kYA". you're introducting a new notation that hasn't been used in the timeline before. My suggestion would be to use 75 kYA and then note the range of uncertainty in the explanation. I reason that using precise numbers in the left column is legit as they're all approximate anyhow, and over time a better number might be placed there as new archeological results are published. Then if you cover the uncertainty with some comment in the explanatory text you should be fine. Kaimiddleton 23:10, 6 January 2006 (UTC)

I like the idea of a range symbol (~), but it would never work on this timeline after some thought, because 99% of these dates are aproximations, and where would any of the dates get located on the timeline. Are you infavor of the shortining of the one and the splitting of the entry if so I might do that tonight when I get home from work.-12.20.127.229 17:11, 9 January 2006 (UTC)

Sounds fine to me. Thanks for the great work! Kaimiddleton 17:49, 9 January 2006 (UTC)

First footprints 530 MYA, animals invade the land 450 MYA?

I just added an item to the timeline about fossil footprints discovered at 530 MYA in 2002. Yet the timeline has animals 'invading' the land at 450 MYA. That's quite a few MYs in between, there. Can anyone comment on this, especially as we're going on 4 years with this discovery? Kaimiddleton 00:17, 23 December 2005 (UTC)

'Ancient sandstone is notoriously difficult to date.'

That quote from the margin might help explaine. I'd think that the info added might be better left out till it is concrete and less speculative. 12.20.127.229 19:41, 23 December 2005 (UTC)

Explanation for arrival of carnivores on Madagascar

21 MYA: A mongoose-like creature floats to Madagascar from Africa on a raft of vegetation. Becomes ancestor of all carnivorous mammals there.

That's just silly. Someone do something.

And if you know about this subject, please also address this line:

64 MYA Lemurs cross the ocean into Madagascar from Africa mainland.

Kaimiddleton 21:43, 26 December 2005 (UTC)

North America meets South America

Here's another request for someone to make a fix: when does this event occur? The timeline has two entries: 5 MYA: Volcanoes erupt and create the small area of land that joins North and South America 3 MYA: North and South America become joined, allowing migration of animals. Which is it? Can someone work this through? Kaimiddleton 22:06, 26 December 2005 (UTC)

AD 1000 Humans reach New Zealand from where?

This statement about AD 1000 doesn't seem right...

AD 1000 Human population 300 million. Humans reach New Zealand (from Fiji).

Where is the evidence that they came from Fiji? Maori people are said to have arrived from eastern Polynesia. In fact, the Maori language has more in common with the languages of Hawaii and Tahiti. Unless someone can provide some reference for this Fiji claim, we should simply state it was from Eastern Polynesia, not Fiji.

--Xagent86 21:11, 27 December 2005 (UTC)

Seems like you know the issue, and I haven't gone digging around for the info. This page isn't updated too frequently so you might as well just do it. Kaimiddleton 21:19, 27 December 2005 (UTC)

It's not really my field, but I did a little bit of research. There is a good section on The direction and timing of settlement on the Te Ara Encyclopaedia of New Zealand site: http://www.teara.govt.nz/

While Fiji might have been part of the migration route, Eastern Polynesia would seem to be the more correct answer. I'm tempted to change it - however there is quite a debate about the date of first settlement, with tradtional theories suggesting 1250 to 1300 AD, but other research on Rat bones and Rat DNA suggesting an earlier date.

I might try to find a little more information before I make the change. Xagent86 22:14, 27 December 2005 (UTC)

Now updated to refer to Eastern Polynesia. I've left the date at 1000 AD due to conflicting evidence.

• Most researchers agree date between 1250 and 1300
• footprints recorded in ash erupted ca. 1400 AD from Rangitito Island
• genealogical dating based on oral tradition suggests around 1325–1400 AD
• Radiocarbon dating of settlements reliable dates after 1250 AD.
• Rat bones dated 50–150 AD - rats need humans to travel by sea.
• Rat DNA - inconclusive(?) so far.
• Rat gnawed seeds and snails - no evidence before 1250.

Conclusion - although it doesn't appear that there was settlement before 1250, it's possible there might have been visits to New Zealand prior to that date, so leaving at 1000 AD. --Xagent86 04:46, 29 December 2005 (UTC)

I know a little about this issue. Maori oral histories state that the ancestors of the Maori came from "Hawaiki", which isn't all that helpful to us since no-one knows exactly where it is. However they definitely came from the eastern islands of Polynesia, possibly the Cook Islands. I'm certain they did not come from Fiji, which is in Melanesia. As for when... I've read several theories. The earliest possibility seems to have been circa 800 AD, but most put it at a later date, though no later than the thirteenth century. James Belich suggests the mid-eleventh century. Aridd 12:10, 7 June 2006 (UTC)

Speculations removed in the interest of NPOV

'possibly derived from RNA molecules. These molecules copying/reproducing/replicating required resources like energy, space and smaller building blocks, which soon became limited, resulting in competition. Natural selection favors those molecules which are more efficient at replication. The atmosphere does not contain any free oxygen.'

This is pure speculation. It is very interesting science when done in the lab, but very unscientifical, when presented in this way.

'Cells resembling prokaryotes appear'

The best we know, they were prokaryotes. The original NASA press release didn't say things like 'resembling', they said that they had the same chemical ratios as today's prokaryotes.

'These first organisms'

Again, very unscientific. We just have no idea what the first organisms were like. Also, this part refuted an earlier (also removed) paragraph, in which RNA molecules were the first organisms.

'Later, prokaryotes evolve glycolysis, a set of chemical reactions that free the energy of organic molecules such as glucose. Glycolysis generates ATP molecules as short term energy currency and is used in almost all organisms unchanged to this day. Lifetime of the Last universal ancestor, the split between the bacteria and the archaea occurs.'

Pure speculation. Science does not allow unproven statements like that, we have no idea whatsoever, how the original metabolism of organisms evolved.

Please, stick to presenting the scientific facts, and stop pushing your own agenda.

Above umsigned post by anon 62.68.179.65.

reply :If you are right, we should remove Big Bang theory as well. Science can only offer the best educated guess.

250 Myo organism

Quote from the article: "Some spores of bacteria Bacillus strain 2-9-3 (Sali bacillus marismortui) are trapped in salt crystals known as halite in New Mexico. They are re-animated in AD 2000 and have multiplied rapidly. Currently the world oldest living organism" I have read a paper disputing this fact, and I suggest that it is removed. I dont want to do it since I`m not a member yet, though someone read it and make up y`alls minds: http://www.tau.ac.il/~talp/publications/Permian.pdf

Tierra del Fuego

Tierra del Fuego is described as "the last continental region to be inhabited by humans". But surely it's an island (or an archipelago), rather than a continental region. --OpenToppedBus - Talk to the driver 10:13, 22 February 2006 (UTC)

Featured list

I have listed this excellent article/list as a featured list candidate. Please let us know what you think via that link. I've personally had nothing to do with the article's development and congratulate those who have. One concern mentioned already is that some events, particularly in the last 5-10000 years are not strictly evolution events. I've removed a couple but would be interested in what others think. -- —Moondyne 12:55, 22 February 2006 (UTC)

The greatest concern is the scope of the article. The lead makes it clear that we are dealing here with evolution from a biological perspective. For instance, the evolutionary impact of humans reaching the South Pole is minimal (or so far ahead in the future that it is impossible to predict, remember Wikipedia is not a crystal ball). Same with most of the items at the end of this list. A timeline of sociocultural evolution, or similar, would be the perfect place for these items, but their inclusion in this list is, at best, debatable. -- Rune Welsh | ταλκ 14:58, 22 February 2006 (UTC)

I agree. I would vote for removing some of the latter entries. For instance, someone recently added the first monkey in space, although I notice now it's gone. I think too many such entries dilute the topic. Since the last few entries are short and streamlined I don't object too much, although I have some qualms; for example, we still have both earth orbit and moon walking as notable evolutionary events. I think one would be nice, to give perspective, but two seems overmuch. Kaimiddleton 17:29, 22 February 2006 (UTC)

I've been bold and removed a few more. -- —Moondyne 02:27, 23 February 2006 (UTC)

I think this is too narrow-minded. Now is history, history is now. This is as much a living document as any, though I agree it should be from an evolutionary biological perspectives. I have always thought removing things is destructive while adding things is good. Human reaching south pole or the moon is just part of the continuing journey of man starting from 200KYA in East Africa - a story worth telling. The moment you finish reading these words, that is history too until the next version comes!

That's some very pretty and noble-sounding bullshit, but Timeline of human evolution is a page specifically created for listing such momentous (but not directly relevant to the evolution of life in general) events. -Silence 09:51, 24 February 2006 (UTC)

Well if that is the case, those deleted sections should be pasted there. The person who deleted them did not do it. Migrations of human beings are not directly relevent to the evolution of life? Yet when mammals returned to the seas to become whales, when arthropods , fishes and tetrapods went to the land to live, these moments are considered relevant to the evolution of life. This is very strange logic to me.

I think there are some good points on both sides of this discussion. For instance, here are two removed items: the birth of the oldest living tree 4000+ years ago (I put that one up originally), and the first monkey in space (put up recently by someone else). Neither of these is really momentous for the history of life on earth. I put the tree one up in order to give the reader a sense of time scale. I thought the monkey one was silly, personally. On the other hand I liked the one about the moon landing as that was a rather amazing migration for any kind of life on earth. So maybe the monkey entry wasn't too silly? There are a lot of shades of gray here.

Another argument is that humans have had a huge impact on the evolution of life on earth so some human migrations are in fact important. Or notices about human populations (e.g. reaching one billion). I'm going to give a whack at adding a few recent entries (recovered from the article history). I'm only going to to it once so if someone changes it I won't object.

Kaimiddleton 23:54, 26 February 2006 (UTC)

Lots of shades of grey, agreed. Agree some items which are not strictly evolutionary can be useful to give a sense of scale, but cannot see the argument for iron age tools and walk on the moon. To the anonymous editor above: - every single event in life could be argued as a progression in the evolutionary ladder, but we cannot list everything. We should only list events which demonstrate milestones in biological evolution, else where do you stop? -- —Moondyne 01:27, 27 February 2006 (UTC)

Since all these are just shades of grey, shouldn't we err on the side of more details rather than less? We are trying to build a complete encyclopedia, not a nursery book on evolution.

Could you please sign your posts with 4 tildes (~~~~) so readers can keep track of who says what. -- —Moondyne 14:05, 27 February 2006 (UTC)

Personally, up to this point I have been opting for inclusion over exclusion. E.g. when I saw the "first monkey in space" bit I just tried to wiki-link it nicely even though I didn't find it to my taste. However, since over time there has been a certain amount of discussion about removing some of these items maybe it's a good idea. Kaimiddleton 05:00, 27 February 2006 (UTC)

Including only "recent" entries seem to imply that evolution has already stopped. Please also note the quote:

"We are the product of 4.5 billion years of fortuitous, slow biological evolution. There is no reason to think that the evolutionary process has stopped. Man is a transitional animal. He is not the climax of creation."

Carl Sagan, astronomer

Hi sorry; I don't understand your point vis-a-vie what you might be proposing. You're saying evolution is a continuing process, therefore ....

Kaimiddleton 19:48, 28 February 2006 (UTC)

Part of the problem, perhaps, is the title. While most of the major events in Earth's history are related to evolution, there are several which are not. For instance, I'd consider the formation of the Earth, the formation of the moon, some of the major continent formations, the development of agriculture, the first time a species develops space travel, and so on important to Earth's history, although they are not directly related to evolution. Perhaps the title of this article should be changed to Chronology of Earth's history or Chronology of Earth or something like that, or a new article be written at that title. The soope of such an article could be a bit wider than than one focusing solely on evolution. I have been working on a somewhat similar idea at History of Earth. Just a thought. — Knowledge Seeker দ 04:27, 1 March 2006 (UTC)

I think you have an interesting idea, but I like the idea of a timeline of evolution, something showing how life on earth has changed, that gives a sense of when events were happening, and something that either directly or indirectly indicates some of how those changes happened. Thus continent movements are relevant because they cause speciation. If you open up the subject to Chronology of Earth then to me it would be a very different article. See also some of my comments immediately below Kaimiddleton 16:55, 1 March 2006 (UTC)

Moon landing: As I mentioned above I took a whack at the recent events in the timeline. I actually think this would be better:

• 3 kYA Humans start using iron tools.
• AD 1 Human population 150 million.
• AD 1835 Human population reaches 1 billion during the Industrial Revolution.

This omits the moon landing and puts in the industrial revolution. I liked the idea of the moon landing because the reader might infer a correlation with "530 MYA First footprints on land [8]" and also see the rapid evolution (if you will) from "using iron tools" to "humans walk on the moon". However, I think that it's not necessarily clear to draw these inferences, and that the moon landing is not quite thematic with a "timeline of evolution". I think the idea of putting in the industrial revolution to show a) the correlation with using iron tools 5000 years ago, and with the advance of population draws the inference much more nicely. I also mentioned above that I would only touch the recent entries once. So if someone else wants to make this change please do so. Kaimiddleton 16:55, 1 March 2006 (UTC)

It is extremely naive to think that evolution can happen in a vacuum. Any geological event can potentially change the physical environment and thus the direction of evolution. If an organism does change, it is perfectly naturally to ask "Why?". Hence all forms of information, (if correct) are useful for providing the clues and answers, and should not be removed from the timeline. It is strange that anybody can separate the story of life FROM the story of Earth.

One reason why I dislike the Book Of Genesis is the lack of details. Lacking details will only make this document look like another Creation story.

The significance of the landing of Homo sapiens on the moon lies in the possibility that this may be the very first time that the Earth's biosphere extends to another heavenly body 1 light-second away, carrying with it not just the first primates but also the first bacteria and viruses.

Reliability of information

I'm a bit worried about the reliability of some of the information in here. For example, it talks about the extinction of Homo floresiensis, a species discovered only a few years ago. I'm not arguing that the estimated extinction is wrong (that'd be original research), but should something that is still at the bleeding edge of science be included in a timeline like this? Andjam 03:52, 3 March 2006 (UTC)

The date of extinction of H. floresiensis is unknown and probably always will be disputed. Ebu Gogo indicates it may have survived until quite recently. -- —Moondyne 05:30, 3 March 2006 (UTC)

One of the basic tenets( also its strength) of science is that : it is falsifiable. We must be prepared that we are all wrong if new evidence is available. For eg, we are not even completely sure that the creature described is a Homo sapien, Australopithecus or a Homo erectus. We just have to take our safest bet.

Primordial tide pool = primordial sea/ocean?

I found the first term in a book and the second in a footnote of this article. Do they refer to the same thing, the ancient water mass from where (they say) all forms of life started, or are they different? Adam78 19:26, 5 March 2006 (UTC)

Origin of seed reference?

The timeline states 360 Ma as an estimate for when seeds evolved. Does anyone have a citation for this or know where this figure came from? I'd like to use it for History of Earth. Thanks! — Knowledge Seeker দ 05:40, 7 April 2006 (UTC)

Took a quick look at K.J. Willis and J.C. McElwain, The evolution of plants. Oxford: OUP, 2002. Their chart on p. 93, and text, shows seeds present in the geological record from the Carboniferous period onwards, i.e. 354 Ma onwards. The earliest seed plants were the seed ferns (Palaeozoic pteridosperms). So 360 Ma seems an acceptable figure, given that something like a seedcoat was evolving in the Late Devonian (370-354 Ma). Mark Nesbitt 07:20, 7 April 2006 (UTC)

That is extremely helpful. Thanks! — Knowledge Seeker দ 07:14, 8 April 2006 (UTC)

Common Ancestor of Mice & Men

"Humans and mice diverged about 75 million years ago, too little time for many evolutionary differences to accumulate."

Yea, it's what i thought all along. WE ain't that different from mice:) Even seen a few mice that looked like people i knew:)

Title discussion: why not "timeline of life"?

I was just wondering: why not give this article the more broad and simple name of just "timeline of life"? This would help clear up any potential confusing between this article and the "history of evolutionary thought" page, and it would clear up people's misconceptions over the idea that evolution and the history of life are somehow distinct concepts. -Silence 00:41, 20 June 2006 (UTC)

I agree. History of life (currently a redirect) is another alternative, but maybe Timeline is more appropriate given that the article is a list. -- bcasterline • talk 01:09, 20 June 2006 (UTC)

Yes, "Timeline" is fine as-is, since this page is a timeline (and hence a list), not a prose history (unlike History of Earth). So, should I make the move, or should we wait for more feedback? -Silence 00:28, 22 June 2006 (UTC)

Comment: The article seems a timeline of the evolution of life towards us and and some things we care about. Which is fine. People are more interested in lions than in extinct ecosystems and classes. Or even than in all existent insects, or in the plants which dominate our planet. But a timeline format article on life? If it was rewritten as prose, would History of Life be a good title? Maybe. Perhaps a History of when new forms of life showed up? It seems the "evolution" in the title is actually saying something significant about what the article does and doesn't cover. Timeline of life's evolution? I'm not objecting, merely noting reservations. 66.30.119.55 23:13, 9 July 2006 (UTC)

Though if someone wanted to make it more like the history of life, that could be nice. I was just now wishing for more biome information. You can sort of read between the lines ("at N Ma, all the components of a grassland exist, so maybe so does it"). Ie, moving beyond when individual species evolved, to what you would see if you were there. But that might be a different article. And require a lot more work. 66.30.119.55 05:02, 18 July 2006 (UTC)

Add an overview sentence?

I would have more easily understood the timeline if there was an orienting sentence, a mini-timeline, to help provide context. Rather than having to work one out myself. Eg, Basically, since 4000 Ma, simple cells; since 3000 Ma, photosynthesis; since 2000 Ma, complex cells; and since 1000 Ma, multi-cellular life.. 66.30.119.55 23:30, 9 July 2006 (UTC)

Perhaps also: Since 1000 Ma, algae; since 800 Ma, something; since 600 Ma, sponges; since 400 Ma, insects; since 200 Ma, mammals. 66.30.119.55 23:30, 9 July 2006 (UTC)

Hearing no objection, I've added an overview paragraph. All the numbers are from the body of the article. I considered also doing 100 Ma to present in steps of 10 or 20 Myr, but didn't see a nice narrative. 66.30.119.55 04:40, 18 July 2006 (UTC)

Upon being able to see the big picture, the biggest suprise for me was that mammals had been around for 1/10 the time of multicellular life (and 1/3 the time of animals in general). I had thought of them as more recent. 66.30.119.55 04:40, 18 July 2006 (UTC)

Add additional links?

Perhaps more of the text should be turned into links? Many of the concepts mentioned now have their own articles. A higher than usual density of linkage might make for more interesting browsing. Hopefully without significantly reducing clarity. 66.30.119.55 05:22, 18 July 2006 (UTC)

• Do you mean doing more wiki-linking? Sounds like a great idea. That's how I started out editing the page. But do you think it's better to only link the first occurrence of a new word, or all occurrences. E.g., would you want to wiki-link all occurrences of monkey? There might be some guidelines about this somewhere but I don't remember seeing something about that. Kaimiddleton 23:57, 18 July 2006 (UTC)
  • Yes, wiki-linking. Perhaps link one occurrence per time entry (or adjacent set of entries)? Hmm, and, perhaps, it need not be the first occurrence in an entry, if another one would be clearer, as most entries are bite-sized? The motivating story is a user reading some time entry, wants to click on a critter, but it's not a link, so they think "oh drat. was that one of the many many links elsewhere on the page which i've skimmed by? is it linked somewhere else?... who knows. should i page search for it? or search the wiki? do i care enough? ahh... punt.". A timeline seems both more likely to be read non-linearly, and to lack the hierarchical organization which in normal articles provides a way to find the (usually already seen) linked first occurrence when looking at an unlinked one. Timelines may also have to work harder to keep the user interested and engaged, as they look a bit like lists of names, which if linked can be interesting, but if not, can easily become "ok, i've had enough of this now" boring. 66.30.119.55 03:23, 19 July 2006 (UTC)

• Please review WP:MOS-L and WP:CONTEXT. -Silence 03:27, 19 July 2006 (UTC)

• Good stuff from everyone. It is a question that requires some balance. Here's a proposal: make the change all at once (or in two or three steps in the same evening), then ask people what they think. If people don't like it we can revert easily enough, without intertwined changes; otherwise, you've made an improvement. Kaimiddleton 06:45, 19 July 2006 (UTC)

This is an encyclopedia. So this timeline article should be used as a historical reference. For eg, at T=t, what happens to life and its environment everywhere on earth? I should be able to check it out quickly. Whether it is interesting or not is irrelevant.

Cynodictus

I've added Cynodictus, or dawn dog, the progenitor of modern dogs. But I'm not sure of the correct date. I've seen 40 million years ago, but I've also seen 30 million years ago. If someone could narrow it down that would be great. Kaimiddleton 16:00, 9 August 2006 (UTC)

needs intro par. overview/summary main strands

I judge an article by 3 criteria. Does it answer my questions? Does it provide me with new info that deepens my understanding? Is it clearly written and well-organised? Yes, on all 3 points. Don't worry about people who want the Olympic Games in Sydney to be on the list. You can't please everyone. You have made good list choices. The non-bilogical stuff, mainly the origin of Solar System is there to frame and give context to what follows. The extinctions are obviously important, so are tectonic plate splitups.

Naturally, we humans we have a specific interest in the geneology of our own species, and few would expect us to organise such a list from the viewpoint of a gerbil. Development of tools is a must inclusion, and landing on the moon is significant as the first step to a wider colonisation of space prefigured by the earlier ones. The later human stuff too gives a reader a good sense of the vast scale of this timeline, events in Western "ancient history" are but seconds in the grand narrative. And that's a perspective that is well-worth presenting clearly. While we think of history in terms of thousands of years rather than millions and thousands of millions, we cannot grasp the nature of evolutionary history. Altogether, a well-considered and wisely chosen selection.Leave it as it is. Certainly, no nukes, no UN, no Black Death.

This would be set off beutifully with a good overview of what follows. Something that points out life has been on Earth for about one quarter of the time that the Earth has existed, and that for most of this time, that life was of the unicellular type. Then a couple of lines on the reign of the dinosaurs and the emergence of mammals etc. Lists can be great lookup devices, but they tend to atomise info. Typically, and most especially for a novice reader, they require some more discursive background material to tie the whole thing together. Put that in and you've got a winner. abzorba 08:07, 1 October 2006 (UTC)

History of Earth may have some of what you are looking for. — Knowledge Seeker দ 08:27, 1 October 2006 (UTC)

21Mya

Says that all carnivores derive from a common ancestory. Any sources? thx--sin-man 06:42, 4 December 2006 (UTC)

Oldest life

I thought the oldest fossilized life was 3.3-3.5 billion years old in Australia and South Africa. I thought the first photosynthetics were about as old. I also thought the moon formed within 30 million of earth's final form.GetAgrippa 21:57, 24 January 2007 (UTC)

Formation of the Moon

The Hadean eon chart states "4533 Ma The planet Earth and the planet Theia collide, causing rings to form around the young Earth which last for millions of years until they coalesce to form the Moon..."

In a number of articles I've seen recently - including one this year (I think) in Scientific American - there is a growing consensus that the formation of the moon took less than 30 days. Here's a link to one that I googled up quickly (the info is about halfway down):

http://www.dailycamera.com/news/2007/jan/28/cosmic-collisionsx/

And if it's good enough for Robert Redford, its good enough for me! Frunobulax 12:20, 9 March 2007 (UTC)

OK, I made the edit. Three plus months should be more than enough time. --Frunobulax 16:58, 23 June 2007 (UTC)

Someone's reverted your edit — I'm not sure about the best way to phrase this. "Between 30 days and millions of years" doesn't quite sound right... Perhaps a sentence explaining the two different points of view would be appropriate. Given the slackness of much of the information in this article, citing recent sources for each side of the argument would be highly desirable. Verisimilus T 20:43, 23 June 2007 (UTC)

If we look at the Wiki entry on the Giant impact hypothesis [1], it states that "Current estimates based on computer simulations of such an event suggest that some two percent of the original mass of Theia ended up as an orbiting ring of debris, and about half coalesced into the Moon between one and 100 years after the impact." A hundred years is a lot closer to a month than a million years. Your suggestion to explain both views makes sense, but given the nature of the article, wouldn't that complicate the timeline a little? If this article is primarily about life and evolution, determining the length of time it took the moon to form (unless we are talking about billions of years) is almost irrelevant. How about if we leave it purposefully vague: "The planet Earth and the planet Theia collide, sending countless moonlets into orbit around the young Earth. These moonlets eventually coalesce to form the Moon. The gravitational pull of the new Moon stabilises the Earth's fluctuating axis of rotation and sets up the conditions for the formation of life." FWIW, the word 'moonlets' is from the existing PSI reference itself. What do you think?

That sounds good, "eventually" is a very good word to choose. I quite like the word "moonlets" - cute! I do feel that "sets up the conditions for the formation of life" could use some expansion. This phrase essentially justifies the inclusion of this event in the timeline; it might be worth stating why life could not have evolved were the rotation axis not stable. Verisimilus T 15:04, 26 June 2007 (UTC)

Thanks. Re "the conditions...for life" phrase: that was already in place, and I simply let it remain. If one wanted to, one could compare the post-collision setup as being 'gyroscopic' in nature, and that the stabilization allowed seasons as well as a variety of climatic zones (tropical, temperate, and polar, I think) and so on, but I do not know if any of this was a direct result of the collision. Its beyond my paygrade anyway, I'm afraid. For now, I'll add the above to the article and hope no one edits it back.

KY

what does the unit KY stand for, this should be stated in the intro. —The preceding unsigned comment was added by 82.26.102.42 (talk) 04:04, 18 March 2007 (UTC).