# Evolution and science... **URL:** \ **Category:** Great Debates\ **Created:** [February 26, 2005, 5:18am UTC](https://boards.straightdope.com/t/evolution-and-science/291979 "2005-02-26T05:18:08Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![Nolies](https://avatars.discourse-cdn.com/v4/letter/n/45deac/32.png) [@Nolies](https://boards.straightdope.com/u/Nolies)\ **Post date:** [March 1, 2005, 7:21pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/101 "2005-03-01T19:21:44Z")
Moderator, I have a request, that there be a moderated debate on this issue. It would be simply one on one with with 10 rounds of posts. Any other posts would be deleted. Each debater would be given 48 hours to reply to the previous post. The readers of this site could then read and make a decision for themselves as to which is more palusible God did it, or Chance + time did it… The number of absoultely incredibly false scientific claims made by those in favor of the Chance + time scenario is to great to address with the number of posters. This one posted by **Twoflowers** > [@](#): > > The evolutionary time scale is based on extensive analyisis of the fossil record, **radiocarbon dating,** and a whole slew of corroborating data from various disciplines. Go take a geology class. If this is a site truly to fight ignorance then let the fight begin… Radio Carbon Dating; a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14; **believed** to be reliable up to \*\*40,000 years \*\* Radio Carbon Dating is not a way to date a fossil. Since a Fossil is either an impression left in rock or mineralized bone. :smack: This and many others will be exsposed in a moderated debate. I await your response. NoLies 🙂 ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [March 1, 2005, 7:30pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/102 "2005-03-01T19:30:44Z")
Well, there’s one minor point in your favour, Nolies; sometimes people arguing on behalf of science get some of the details wrong. Congrats. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [March 1, 2005, 7:33pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/103 "2005-03-01T19:33:30Z")
May I just put a small bug in your ear, **Nolies**? There aren’t a whole lot of undecideds here. Really. There is no huge group of posters watching the Dope hoping to have someone sit them down and go over the pros and cons of evolution vs. Creation. Honestly. We’ve HEARD about the Creationist account. We know about it. Hell, most of us grew up in families that believed it to be literally true. And yet, somehow, most of the Dopers land squarely on the side of science. Wonder why that is? I would, on the other hand, LOVE to see you try to stand up to a biologist like Darwin’s Finch, who knows his/her evolutionary chronology inside and out, in a structured debate where each has to address the opponent’s points as well as make their own. ---
**Author:** ![Nolies](https://avatars.discourse-cdn.com/v4/letter/n/45deac/32.png) [@Nolies](https://boards.straightdope.com/u/Nolies)\ **Post date:** [March 1, 2005, 8:01pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/104 "2005-03-01T20:01:09Z")
> [@jayjay](#): > > May I just put a small bug in your ear, **Nolies**? There aren’t a whole lot of undecideds here. Really. There is no huge group of posters watching the Dope hoping to have someone sit them down and go over the pros and cons of evolution vs. Creation. Honestly. > We’ve HEARD about the Creationist account. We know about it. Hell, most of us grew up in families that believed it to be literally true. And yet, somehow, most of the Dopers land squarely on the side of science. Wonder why that is? > > I would, on the other hand, LOVE to see you try to stand up to a biologist like Darwin’s Finch, who knows his/her evolutionary chronology inside and out, in a structured debate where each has to address the opponent’s points as well as make their own. > [@](#): > > I would, on the other hand, LOVE to see you try to stand up to a biologist like Darwin’s Finch, who knows his/her **PRESUMED** evolutionary chronology inside and out, in a structured debate where each has to address the opponent’s points as well as make their own. If you presume it is true, then when you find a fossil, you place it in the presumed evolutionary time line. If any evidence, where it is found in strata or near by fossils (index), is found that the fossil is out of the presumed time line then the PRESUMED time line always overrides. Funny how that works… 😉 ---
**Author:** ![Apos](https://avatars.discourse-cdn.com/v4/letter/a/838e76/32.png) [@Apos](https://boards.straightdope.com/u/Apos)\ **Post date:** [March 1, 2005, 8:04pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/105 "2005-03-01T20:04:16Z")
> [@](#): > > Radio Carbon Dating; a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14; believed to be reliable up to 40,000 years Just so you know, carbon dating isn’t really the radio-dating method most common to the evolutionary timescale. As you note, carbon dating has a fairly limited range (though it’s really closer to 50,000 years). Interestingly, it also isn’t reliable for the last 150 years, because humans have altered the atmospheric carbon in particular places enough to make a difference. Carbon dating also isn’t as interesting as some of the other dating methods that actually we do use for evolutionary ages. Much more powerful are methods like Argon, and, most impressively, the Rb/Sr isochron method, in which several minerals from the same rock formation can be sampled for their ratios of Sr and then cross-compared. While the actual math is a bit complicated (graphs and ratios and different isotopes and so on), the great thing about this technique is that it’s self-checking: the several minerals within the rock all “agree” on the age of the same rock, even though each has a different way of measuring the same date. > [@](#): > > Radio Carbon Dating is not a way to date a fossil. Since a Fossil is either an impression left in rock or mineralized bone. That depends on what the fossil contains, but sure, we often date fossils using nearby rocks in the same formation too. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [March 1, 2005, 8:16pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/106 "2005-03-01T20:16:42Z")
> [@Nolies](#): > > If you presume it is true, then when you find a fossil, you place it in the presumed evolutionary time line. If any evidence, where it is found in strata or near by fossils (index), is found that the fossil is out of the presumed time line then the PRESUMED time line always overrides. Funny how that works… 😉 As opposed to assuming that the words handed down orally from illiterate nomadic sheepherder to illiterate nomadic sheepherder over 4,000 years ago are literally true? Even IF you could prove evolution false, you would have to also provide evidence that your Creationist hypothesis is true. The absence of an accepted evolutionary theory doesn’t automatically create a vacuum that only Theistic Creation (or Intelligent Design, its superficially more sophisticated sibling) can fill. Do you have any positive evidence of the accuracy or truth of the biblical story of Creation that doesn’t depend on 4,000-year-old oral tradition? Or do you only have what you consider to be negative evidence against evolution (which, incidentally, is not negative evidence so much as a complete misunderstanding of evolutionary evidence)? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [March 1, 2005, 8:26pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/107 "2005-03-01T20:26:24Z")
> [@Nolies](#): > > Funny how that works Well, you admit it works. Debate over. ---
**Author:** ![I\_Love\_Me\_Vol.I](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/i_love_me_vol.i/32/521_2.png) [@I\_Love\_Me\_Vol.I](https://boards.straightdope.com/u/I_Love_Me_Vol.I)\ **Post date:** [March 1, 2005, 8:27pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/108 "2005-03-01T20:27:21Z")
Why not let this **Nolies** guy have his debate? What could it hurt? A new thread could be started with only **Nolies** and say, \*\*Darwin’s Finch \*\* actually posting replies. They could agree on some terms (10 answers only, or a 1 month time limit, for example) and the rest of us could be passive observers (but active participators in a companion thread). Maybe Ignorance will be successfully fought one way or the other at the conclusion of the debate. Personally, I think the SDMB would benefit greatly from occasional “structured” debates limited to a small number (usually 2) of people and bound by precise rules agreed upon beforehand. These things could start out in a Great Debates thread with a comment such as, “ **Nolies**! I demand satisfaction! I challange thee to a debate!” ---
**Author:** ![Twoflower](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/twoflower/32/22_2.png) [@Twoflower](https://boards.straightdope.com/u/Twoflower)\ **Post date:** [March 1, 2005, 8:35pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/109 "2005-03-01T20:35:52Z")
> [@Nolies](#): > > Radio Carbon Dating; a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14; **believed** to be reliable up to \*\*40,000 years \*\* > > Radio Carbon Dating is not a way to date a fossil. Since a Fossil is either an impression left in rock or mineralized bone. :smack: 1. See post #53 of this thread, where I long ago corrected my terminology. 2. You are correct that fossils generally cannot be dated directly. However, the presence of datable geologic formations above and/or below a fossil can be used to establish a range within which the age of a fossil must fall. 3. As also noted throughout this thread, the ages of fossils and geologic layers have been deduced though a number of different methods, which provide multiple corroborating lines of evidence. Even if creationsts were to succeed in undermining the credibility of any one dating method, the overall change in our understanding of the history of the earth and the devlopment of life forms would be exactly zero. 4. If the earth is only 6,000 years old, as is typically claimed by those espousing literal creationism, how do you correlate that with radiocarbon dating being reliable to 40,000 years??? Once again you choose to pick a nit and have provided no substantiation at all for the numerous claims in your OP, every one of which has been repeatedly refuted in this thread. If you want an actual debate, I suggest you go back to your OP and provide us all with valid scientific references to back up your claims. Your repeated failure to do so only serves to emphasize the weakness of your argument. ---
**Author:** ![Nolies](https://avatars.discourse-cdn.com/v4/letter/n/45deac/32.png) [@Nolies](https://boards.straightdope.com/u/Nolies)\ **Post date:** [March 1, 2005, 8:38pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/110 "2005-03-01T20:38:43Z")
> [@](#): > > the Rb/Sr isochron method, in which several minerals from the same rock formation can be sampled for their ratios of Sr and then cross-compared. While the actual math is a bit complicated (graphs and ratios and different isotopes and so on), the great thing about this technique is that it’s self-checking: the several minerals within the rock all “agree” on the age of the same rock, even though each has a different way of measuring the same date. Not every one is so high on this silver bullet of dating rocks… > [@](#): > > “…Some of the basic assumptions of the conventional Rb-Sr isochron method have to be modified and an observed isochron does not certainly define a valid age information for a geological system, even if a goodness of fit of the experimental data points is obtained in plotting 87Sr/86Sr vs. 87Rb/86Sr. This problem cannot be overlooked, especially in evaluating the numerical time scale. Similar questions can also arise in applying Sm-Nd and U-Pb isochron methods. [p. 14] …As the method was gradually applied to a large range of geological problems, it soon became apparent that a linear relationship between 87Sr/86Sr and 87Rb/86Sr ratios could sometimes yield an anomalous isochron which had no distinct geological meaning. A number of anomalous isochrons have been reported in the literature and various terms have been invented, such as apparent isochron, mantle isochron and pseudoisochron, secondary isochron, inherited isochron, source isochron, erupted isochron, mixing line, and mixing isochron. Even a suite of samples which do not have identical ages and initial 87Sr/86Sr ratios can be fitted to isochrons, such as areal isochrons. [p. 1] …The theoretical basis of the classical Rb-Sr isochron is being challenged and some limitations of its basic assumptions are being revealed. [p. 2] As it is impossible to distinguish a valid isochron from an apparent isochron in the light of Rb-Sr isotopic data alone, caution must be taken in explaining the Rb-Sr isochron age of any geological system.” [from Abstract, p. 1] > > [Y.F. Zheng, “Influences of the Nature of the Initial Rb-Sr System on Isochron Validity,” Chemical Geology, Isotope Geoscience Section, Vol. 80, No. 1 (December 20, 1989), pp. 1-16 (emphasis added).] > [@](#): > > Interestingly, it also isn’t reliable for the last 150 years, because humans have altered the atmospheric carbon in particular places enough to make a difference. I watched the show on the Propaganda Broadcasting System AKA PBS about the supposed origins of earth. What they showed was a plant that was so caustic and full of all different chemicals that life, as we know it could not exist. Now since we know that the earth is not a closed system, which is what Argon dating and other methods must assume. With the presumed nature of the earth in the beginning how can you even begin to say that you have some sort of scientific method to date rocks? If you are wrong about what it was like then and make a model based on that all your data will be skewed. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [March 1, 2005, 8:43pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/111 "2005-03-01T20:43:14Z")
> [@Nolies](#): > > If you presume it is true, then when you find a fossil, you place it in the presumed evolutionary time line. If any evidence, where it is found in strata or near by fossils (index), is found that the fossil is out of the presumed time line then the PRESUMED time line always overrides. Funny how that works… 😉 Ah. I’ve seen this argument before. Let’s say you have a (physically) depressed area on your property – not quite a gully or something of that sort, but a dip in the contour of the land. And there’s a tree growing down in the bottom in it. You don’t want that dip there, and you don’t have much use for the tree either. So you take a chain saw and cut down the tree. But, being cheap, you don’t hire several truckloads of gravel and topsoil brought in; you merely clean up sand and dirt that end up on your property and, whenever you have a wheelbarrow load, say once every few months, you dump it in the depressed area. How long is it going to take you to cover up that tree stump? On the other hand, Great-Grand-Daddy Henry died in 1850 and was buried on the river bank, with a brand new double eagle in his hand. (He’d always claimed, “You **can** take it with you,” and asked to have that coin placed in his hand as he was buried.) But the great flood of 1930 washed away the riverbank, and exposed his remains. And the family reverently reburied him, a ways back from the river. Okay, when did Henry die? When was he buried? Have I forestalled your “evidence”? Index fossils are so designated because they are found over a wide area in sediments that are believed to have been laid down at the same time. In cases where that assumption can be tested, it proves out accurate. (E.g., a layer of sediment between two layers of dateable volcanic ash.) The assumption is that if whenever this can be tested, it works, it’s very likely to be true in the cases where it can’t be tested, or where only one end of a range can be given. And no, people don’t date fossils by the “presumed evolutionary time scale” – they do it by stratigraphy. There was quite a bit of to-do a while ago about a supposed bird that would substantially predate Archaeopteryx – not because it was misdated, but because it would change our understanding of the evolution of birds significantly. (It turned out to be a hoax, as it happens.) There’s a fair amount of dinosaur fossils found in early Tertiary strata. The problem is, either the fossils are misidentified (a couple of types of extinct crocodile have teeth difficult to distinguish from theropod teeth), or it’s a case of reworked sediments (like Old Henry’s reburial). I think most paleontologists would like few things better than to find evidence of dinosaur survival past the K-T interval. Unfortunately, the occasions they have, it turned out they hadn’t. ---
**Author:** ![Apos](https://avatars.discourse-cdn.com/v4/letter/a/838e76/32.png) [@Apos](https://boards.straightdope.com/u/Apos)\ **Post date:** [March 1, 2005, 9:15pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/112 "2005-03-01T21:15:55Z")
> [@Nolies](#): > > Not every one is so high on this silver bullet of dating rocks… You’re quote mining now. That article discusses exactly how to detect and account for false isochrons. It doesn’t at all conclude that isochron dating is ineffective or unreliable as a method: in fact, it shows how to make it MORE reliable. Part of the power of isochrons is that we can directly detect if something anomalous happened before the formation of the rock that would throw off the date. That’s exactly what this article discusses. > [@](#): > > I watched the show on the Propaganda Broadcasting System AKA PBS about the supposed origins of earth. What they showed was a plant that was so caustic and full of all different chemicals that life, as we know it could not exist. Er, what are you talking about? > [@](#): > > Now since we know that the earth is not a closed system, which is what Argon dating and other methods must assume. With the presumed nature of the earth in the beginning how can you even begin to say that you have some sort of scientific method to date rocks? If you are wrong about what it was like then and make a model based on that all your data will be skewed. Again, you aren’t being specific enough here for me to understand what your criticism is. ---
**Author:** ![Nolies](https://avatars.discourse-cdn.com/v4/letter/n/45deac/32.png) [@Nolies](https://boards.straightdope.com/u/Nolies)\ **Post date:** [March 1, 2005, 9:17pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/113 "2005-03-01T21:17:09Z")
> [@](#): > > However, the presence of datable geologic formations above and/or below a fossil can be used to establish a range within which the age of a fossil must fall. Datable HOW? There is not and acurate way. They are dated by the presumed evolutionary time line of simple to complex… > [@](#): > > the ages of fossils and geologic layers have been deduced though a number of different methods, which provide multiple corroborating lines of evidence. Here again you make the same claim all based on the presumed evolutionary time line. > [@](#): > > If the earth is only 6,000 years old, as is typically claimed by those espousing literal creationism, how do you correlate that with radiocarbon dating being reliable to 40,000 years??? You must assume that the c14 was at the same ratio in the atmosphere and that all plants take it up at the same rate. So you can get very wildly different times if your presumptions are wrong. It isn’t that tuff… And who ever said that I would be the one who do the moderated debate. I have a person in mind to defend the young earth creationist position if I can convince him to do it. 😃 ---
**Author:** ![Apos](https://avatars.discourse-cdn.com/v4/letter/a/838e76/32.png) [@Apos](https://boards.straightdope.com/u/Apos)\ **Post date:** [March 1, 2005, 9:19pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/114 "2005-03-01T21:19:10Z")
You know, nolies, it might be nice if you actually outlined your whole critique on a particular, rather than parseling it out piecemeal so we have to jump from subject to subject. It would also help the “oh yeah, well what about THIS” pattern I’ve seen way too often in these debates. There’s no need to be cryptic. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [March 1, 2005, 9:21pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/115 "2005-03-01T21:21:02Z")
> [@Apos](#): > > There’s no need to be cryptic. There is when you’re trying to defend the indefensible. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [March 1, 2005, 9:24pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/116 "2005-03-01T21:24:31Z")
> [@jayjay](#): > > I would, on the other hand, LOVE to see you try to stand up to a biologist like Darwin’s Finch, who knows his/her evolutionary chronology inside and out, in a structured debate where each has to address the opponent’s points as well as make their own. Just as a point of clarification, while I have a Bachelors degree in biology (with an empahsis in evolution an paleontology), I am not a biologist in any professional sense. I am but an amateur, at best. > [@Nolies](#): > > If you presume it is true, then when you find a fossil, you place it in the presumed evolutionary time line. If any evidence, where it is found in strata or near by fossils (index), is found that the fossil is out of the presumed time line then the PRESUMED time line always overrides. Funny how that works… No presumption is necessary. A fossil is not found just lying about anywhere - it is found in direct association with a rock or sediment layer. IF the fossil is known, then the rock layer in which it is found will be either 1) too old, relative ot other rock layers in which this fossil is found, 2) too young, relatively speaking, or 3) the same age as the rock layers for other specimens of the same fossil. Obviously, if #3 is the case, there is no problem. In the case of either #1 or #2, further examination is required to determine if there was an error in dating, or if there is a geological explanation (e.g., reworking of the fossils into newer sediments). In the cases of dinosaur bones found in post-Cretaceous sediments, for example, the error has almost always been the result of incorrect dating methods (and I only qualify that with “almost” because I do not claim absolute knowledge of all instances). If the fossil is unknown, then there is no reference point regarding its “correct” position in the geological table, and there is little reason to doubt that the rock layer in which it was found is the correct one. Future finds would then either confirm or deny the proper placement. In any case, when an anomolous fossil is found, you can bet that scientists are going to be scrutinizing the anomoly and the methods of collection and dating. It is not the case that there is some grand conspiracy determined to maintain the purity of the geologic, and associated evolutionary, timeline. ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [March 1, 2005, 9:27pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/117 "2005-03-01T21:27:32Z")
> [@Nolies](#): > > Radio Carbon Dating is not a way to date a fossil. Since a Fossil is either an impression left in rock or mineralized bone. Um, it’s not not really that limited. Paleontologically speaking, a fossil is any remains you dig up, not just what has been petrified. Were I to dig up **Polycarp** ’s Great-Grand-Daddy Henry he would be a “fossil” and that double eagle would be an “artifact.” Okay, were _ **I** _ to dig him up the double eagle would be inexplicably lost during the excavation, but you know what I’m getting at. That nit picked, I find your debate idea interesting. However, true debate can only take place when both parties agree on the meanings of terms used in the debate so that would have to be established first. ---
**Author:** ![Apos](https://avatars.discourse-cdn.com/v4/letter/a/838e76/32.png) [@Apos](https://boards.straightdope.com/u/Apos)\ **Post date:** [March 1, 2005, 9:32pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/118 "2005-03-01T21:32:04Z")
> [@](#): > > There is not and acurate way. They are dated by the presumed evolutionary time line of simple to complex… Er, no, they are not. They are dated directly by a range of different and indepedant methods. Its these dates that established the evolutionary timeline, not the other way around. Certainly, currently, this timeline has been shown to be so reliable that one can easily use it to quickly estimate dates for strata (for instance, if we find a trilobite fossil, then we can bet that the rock is going to date older than, say, the Ordovician. And, in fact, it does). But that doesn’t mean that that’s the ONLY way to date the rock! > [@](#): > > You must assume that the c14 was at the same ratio in the atmosphere and that all plants take it up at the same rate. So you can get very wildly different times if your presumptions are wrong. It isn’t that tuff… I think you’ll learn that the whole point of science is that scientists don’t just go “oh, well, this is only true if certain assumptions are made” and then go sit on their hands. They instead go out and find ways to TEST those assumptions. First of all, carbon dating can be tested against tree ring data, and when it is, it proves to be both accurate and consistent with the assumptions being made. Second of all, we can historically judge the amount of carbon that was in the atmosphere directly (for instance, as found in preserved in lake sediments), and we find that the amounts did not vary enough to matter. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [March 1, 2005, 9:32pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/119 "2005-03-01T21:32:49Z")
> [@Nolies](#): > > Datable HOW? By dating the surrounding rocks, using radiometric dating. Index fossils are a secondary means of dating, obviating the need to crank up the spectrographs and chromatographs every time a fossil or rock layer is unearthed. If there is any question about the dates, radiometric dating is used to establish the date ranges. ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [March 1, 2005, 9:35pm UTC](https://boards.straightdope.com/t/evolution-and-science/291979/120 "2005-03-01T21:35:49Z")
BTW, Darwin, and I know this is a question that has no place in GD and I shouldn’t ask it, but for some reason I’ve always assumed you were female. Is that true or just another of my many misapprehensions? [Previous page](https://boards.straightdope.com/t/evolution-and-science/291979.md?page=5) [Next page](https://boards.straightdope.com/t/evolution-and-science/291979.md?page=7)