Radiometric Dating versus Relative Dating

In palaeontology and archaeology, it becomes necessary to determine the age of an artifact or fossil when it is uncovered. This, of course, is so that it can be properly catalogued, and, if valid, can be related to or associated with other objects from the same era. However, such a task can be quite tricky. Fossils and artifacts don't come with labels attached that clearly state their age. Therefore, scientists need to make use of proper techniques to adequately specify what the age of a fossil or artifact is. Two of the most well-known and most frequently used include radioactive dating and relative dating.

Radiometric Dating

Phrased simply, radioactive dating is the method that uses measurements relating to the radioactivity of the atoms in a fossil or an artifact. How is this done? All things decay. Organic bodies, such as you and me, as well as inanimate objects, such as stone tablets or rocks.
What "decay" means is that the atoms in the object or body become unstable, and, over time, begin to "decompose" by giving off radiation in the forms of subatomic particles (such as electrons and protons). There are different types of radiation: specifically, gamma, alpha and beta radiation. These will be discussed in detail at another time.
This process of radioactive decay eventually leads to the atoms becoming a different element and achieving stability.

For example, in decomposing organic bodies - such as an animal carcass - carbon-14, an isotope of carbon, is present.
Overtime, the C-14 atoms give off radiation, and, eventually, transform into nitrogen-14 atoms.
The term used to define the amount of time it takes for half of the radioactive atoms, such as C-14, in a body or object to decay fully is known as a "half-life."
The half-life of C-14 is approximately 5 730 years. This means that, after 5 730 years, roughly half of the radioactive C-14 atoms in a decomposing organic body will have decayed into nitrogen-14 atoms.
The decay rate, however, is not linear. That is, after two half-lives, 100% of the C-14 atoms will not have decayed into N-14 atoms. The decay rate, rather, is exponential. To put it simply, if one were to draw the decay rate of C-14 on a line chart, it would not be a straight, diagonal line. It would be a curving downward slope.


Scientists can use decay rates to, very roughly, determine the age of a fossil or artifact. If a fossil is found, it means it is organic in nature, and thus has or will have contained C-14 atoms. By using the known decay rate of C-14 as a reference and working out how much of the fossil's composition consists of C-14 and how much of it consists of N-14, they can approximate the age.

But what about inorganic objects, such as, say, stone tablets, or rocks? Some of these objects also contain a radioactive isotope. This time, of the element uranium. This radioactive isotope is uranium-238, and has a half-life of approximately 4.47 billion years (4 470 000 000 years).  This is a very extensive decay rate, but is still useful to scientists. Much in the same way used to approximate the age of organic fossils, scientists use uranium-238's decay rate and the uranium-238 to lead-206 (which it decays into) ratio to approximate an age to assign to the object.

As can be seen, radioactive dating is quite an advanced and sophisticated technique. Unfortunately, though, it is impossible to determine exactly what the age of a fossil or artifact is using it. Why so?
Well, many sources state that a recent test on the accuracy of C-14 dating - and thus, in turn, radioactive dating - attempted to date living penguins. While questionable, it appears as though the living penguins were dated as 8000 years old. Such a massive inaccuracy is inexcusable. There have also been other reported cases.

Aside from these alleged inconsistencies, there is also the assumption that the decay rates of the isotopes is constant, or fixed. If this were not the case, and the decay rate was susceptible to change or was not constant, it would render all ages inaccurate.



Relative Dating

Relative dating is the more conventional of the two. Relative dating is the technique that attempts to roughly determine the age of a fossil using its position or location in relation to other fossils or remains in nearby strata (hence the name, "relative")

In other words, to determine the age of a fossil using relative dating, one would look at the stratum the fossil was found in. Then, one would compare the fossil's position in the stratum to the position of other nearby index fossils or remains. Doing this, one can "map" out where the fossil appeared in the geographic time scale and thus work out a rough estimate of the fossil's age, by comparing it to other fossils (i.e "it came before this fossil, and after this fossil, so therefore it must be an intermediary, and will have appeared in the time period between the two other fossils," or "this fossil was found in the same stratum as this other one, at almost the same depth and in a close radius of each other - therefore, they must have appeared in the same time period.")


Perhaps the most concerning shortcoming of relative dating is how it is incapable of determining an exact or absolute age. In fact, some are of the opinion that its results are actually more of a rough estimate or less trustworthy than the results obtained from radioactive dating. Why is this so? Because the results rely heavily, not necessarily on the position of the fossil or its stratum (which is still an extremely important primary factor), but rather the way in which the scientist interprets it, which means it is vulnerable to bias, miscalculations, and so on. A scientist may present a fossil's position or location in the strata accurately, but then interpret it as only a few thousand years old, whereas another may present it as many millions of years old.

Not only this, but the geological time scale - another fundamental of relative dating - is sketchy and not always linear all over the globe. For example, sometimes the strata of a certain region are in the exact opposite sequence or order to how geologists expect them to be using the geological time scale. Several things may cause this.
A good example would be the eruption at St. Helena, located in the Washington state, U.S.A, in May 1980. The eruption was so intense that many layers of sediment on the volcanic mountain were blown into the air, and settled on the landscape around the volcano. This sediment would form strata. Does the volcanic strata belong where it landed? Of course not! In fact, it may contain coal or fossil fuels - which take, at the very least, thousands of years to form - that now appear near the very top! Such an inconsistency would, logically, confuse geologists in the future if they had no prior knowledge of the St. Helena eruption.
It is known that volcanic eruptions, such as the one at St. Helena, have occurred many times in the past. Not only that, but earthquakes and floods can also sometimes shift and mix strata and sediments.

Relative vs. Radiometric - Which Should Be Used?

It is a gaurantee that different scientists, from different backgrounds, have locked horns over this debate many times, each with their own sets of recorded evidence. But which is truly more efficient?
Each technique has already been discussed in detail above. It is now time to compare the pros and cons.

Radiometric
   Pros

• Capable of providing a reasonably exact age
• Makes use of known and predetermined parameters (e.g amount of radioactive isotopes in fossil)
• Leaves relatively little room for bias
• Is not usually dependant on dynamic or changing factors (e.g few things can change the amount of radioactive atoms in the fossil)

  Cons

•  Not failsafe - can present inconsistencies or confusing results (e.g living penguins dated as 8000 years old)
•  Assumes the rate of radioactive decay is fixed or constant
• Therefore, does not take into account environmental factors that may have affected decay

Relative
   Pros

• Easier and quicker to utilize
• While not exact, does accurately present the fossil's position in the timescale in relation to others

   Cons

• Does not provide an exact or absolute age
• Results can be manipulated according to bias and personal opinion
• Can be interpreted in different ways
• Relies on dynamic or inconsistent factors (e.g assumes geological time scale is linear)
• Other index fossils or remains must be present in order to compare positions

From the above list, it can be seen that both techniques have pros and cons. Both are not entirely inaccurate, but neither are both entirely accurate.
However, it must be noted that radiometric dating seems to emerge as superior. Why so? Even though it is fallible, and a small chance holds that it may even be entirely inaccurate, radiometric dating relies more on fixed or solid variables and factors than relative dating does, thus having a smaller margin for error. For example, radiometric dating dates the fossil as it is individually - relative dating compares it to other fossils in an environment (strata and sedimentary layers) that is certainly not linear.

This is not to imply radiometric dating is immediately superior to relative dating and is fully correct. Rather, this entry wishes to point out that radiometric dating, while certainly not infallible, has less of a margin for error, and thus has a higher chance of being correct.

Still, scientists involved in the dating of fossils and artifacts should retain their freedom to date using the techniques they see fit to use.

Jurassic Park - A Future Reality?

Steven Spielberg's film adaptation of Michael Crichton's techno-thriller novel, Jurassic Park (pub. 1990), struck awe into the minds of many keen audiences at the time of its release. I myself could not help but contemplate just how incredible it would be if dinosaurs - who walked the earth many tens of thousands of years ago - could return to life and walk it once more, as shown in the film. Hypothetically, the possibilities were endless if something like that were to occur. Imagine your very own theme park, exhibiting newly-resurrected prehistoric creatures! Not even the San Diego Zoo or the British Museum of Natural History would be able to rival such grandeur. But then the film reminded us of the implication of the actions of the scientists who had brought the dinosaurs back - it manifested itself in the bloody disembowelment and evisceration of many an unlucky human at the claws of the film's velociraptors (we won't touch on the factual inaccuracies on the film's depiction of them yet!), and all of us who have seen the film can remember the bone-chilling crunch when the fearsome tyrannosaurus rex (commonly shortened the well-known term "t-rex") closed his jaws around the unlucky lawyer. And, no, to those of you who have not seen the film, that is not a joke the scriptwriters came up with.

However, all these thrills and chills were soon overshadowed by a question posed by many in the audience, "is this actually possible? Can dinosaurs really be brought back to life?" With the film and novel's magnificent depiction of science, some may have indeed been fooled into believing such a mind-wracking feat could be accomplished by so little a team of scientists. (If I recall, I spotted just over ten different scientists working at the InGen facility in the film. A little short on funding, Mr. John Hammond?) Still, what about the hundreds of real scientists whose eyes had been caught by the film?

Perhaps the most notable - and one of the first - scientists to have applied his brainpower to tackling the possibility of a genetic reconstruction of dinosaurs would be the microbiologist Dr. Raul Cano, currently a professor at the Biological Sciences Department of California Polytechnic State University. In 1992, Dr. Cano innovated with a technique he believed could be used to extract the DNA of prehistoric specimens from fossil 'containers', such as amber - just like in the film. Dr. Cano noted that amber fossils - which are pieces of fossilized tree resin - contained prehistoric insects that are as old as the dinosaurs, and stated that this could be a step towards the dinosaurs' genetic reconstruction. Why? Some insects, such as mosquitos and fleas, feed off the blood of larger fauna. Many thousands of years ago, there were counterparts to these insects, which could mean, if the correct insect is found, so will a tiny sample of a larger specie's blood be found. Dr. Cano's technique consists of the following steps:
• Sterilize the amber, killing off any bacteria or other micro-organisms that could prove destructive
• Freeze the amber with liquid nitrogen, hardening it and making it far easier to break or shatter
• Meticulously and carefully drill into the amber, cracking it open and exposing the fossilized organic tissue within
• Add chemical compounds to the tissue, which will duplicate or multiply even the tiniest fragment of DNA to make the DNA detectable on a gel.

Should this technique prove successful after an attempt, it means that the DNA - unique genetic material and encoding which is nearly impossible to find of any prehistoric specie - can be gleaned from the fossil, which, in this case, is the most essential step that must be made in the grand, fantastic scheme of recreating a dinosaur specie. Interestingly enough, using this method, Dr. Cano managed to successfully extract the DNA of an ancient bee. The antediluvian insect's body had been encased in amber, providing the perfect test run for Dr. Cano's technique, which proved effective.

After taking note of his success, scientists at the American Museum of Natural History in New York, U.S.A, decided to attempt a DNA salvage of their own, using the method developed by Dr. Cano. Once again, the microbiologist's method proved successful, allowing the scientists to duplicate and salvage the DNA of an ancient termite, which, much like Dr. Cano's bee, had been encased in amber.
With these successes in mind, it would be accurate to say that duplicating, replicating and salvaging the DNA of prehistoric fauna could very well be possible. However, one must keep in mind a grim (or, for those who are not keen advocates of this endeavour, refreshing) reality: despite the above successes, these salvages were performed on ancient insects, not dinosaurs.

 In spite of this, Dr. Akira Iritani, professor emeritus of the Japanese Kyoto University, located in Kyoto, Japan, is spearheading a noteworthy scientific endeavour: he and his team plan to clone, or, in essence, recreate, a woolly mammoth; a pachyderm believed to have been extinct for thousands of years. Much like Dr. Cano and the scientists at the American Museum of Natural History with the case of dinosaurs, this team of ingenious Japanese scientists hopes to resurrect a long-extinct specie, and, interestingly enough, hopes to do so within five or six years. Thus far, minor steps have already been taken, including a mostly-complete mapping of the creature's DNA (obtained from the discovery of keratin in the hair of a perfectly preserved woolly mammoth body), but actually extracting the DNA from the frozen specimen is proving extremely difficult and tedious, and the team are working to overcome the obstacle. Still, the team appears to be maintaining an optimistic and resolute attitude. Should this endeavour prove successful, and a woolly mammoth is actually cloned, it could prove to be an invaluable stepping stone towards the palaeontologist's holy grail: living dinosaurs.

Once again, though, in all fairness, optimism must be contrasted with scepticism:  Time magazine, which took note of this topic, wrote that it is physically impossible to clone or resurrect a dinosaur. To support this statement, the researcher pointed to the claim that there are "pseudo-genes" - that is, obsolete "blueprints" - in the DNA of dinosaur fossils, which make replication or manipulation of the DNA impossible. However, whether these alleged "pseudo-genes" exist or not is debatable, according to some biologists, as it would appear that what is regarded as "pseudo-genes" could very well just be non-encoding DNA, which would still find some importance.

All in all, it would appear that there is an ongoing conflict between biologists regarding the possibility of cloning or resurrecting dinosaurs. And it's not necessarily about the ethics of the issue. Whilst it is viewed as improbable, there are still those who believe it might still be feasible to recreate dinosaurs through manipulation of gleaned DNA, and then there are those who are more skeptical. Currently, the scientific community seems to favour the opinion of the latter.

So, in conclusion, it must be asked: will Crichton's fantasy of dinosaurs being brought back to life ever really come to fruition? In our lifetime, will we get to see the theme park, reminiscent of Jurassic Park, in which we can see the giants of ages past walking once again? Currently, the answer is unclear, if not unlikely, much to the dismay of many enthusiasts. Still, with recent scientific advances, and the firm attitudes of scientists still willing to be innovative in this regard, the fact that "where there is a will, there is a way" must be acknowledged.

Bibliography & Acknowledgements

• Will We Clone A Dinosaur?, by Matt Ridley (April 2000); published by Time [Link]

• Recreating Dinosaurs, uploaded by Discovery TV (February 2009)  [Link]

• DNA: The Secret of Life, by James Watson & Andrew Berry (August 2004, Barnes & Noble) 

• Japanese Researchers Announce Plan To Resurrect Woolly Mammoth Within Five Years, by Dan Nosowitz (January 2011) [Link]

• Profile: Raul J. Cano, Ph.D. California Polytechnic State University. [Link] 

• Dinosaur Resurrection - The Truth, by "Saurian" (2010) [Link]

• Jurassic Park Logo (c) Universal Studios

• Photo Of Amber (c) Amberabg [Link]

Welcome! - An Introductory Post

Welcome to Scientia, my scholarly blog! To those whom it concerns, the word "scientia" is Latin, and can be rendered as science or knowledge, and the Latin word "discipulus" - while it can be rendered as disciple - can also be rendered as student, learner or pupil.


The question I am certain that all newcomers will enquire of is, of course, "what is this blog about?"
My blog, Scientia, will be the medium through which I will convey, not only my personal thoughts and philosophies on the schools of thought revolving around biology - especially palaeontology, zoology and ecology - but also interesting and attention-capturing research, articles and studies involving the subjects fore-mentioned. It is my hope that you find the information being discussed captivating, and as thrilling as I found it when researching.


To be specific, however, here are key topics you may find recurring through the subjects and themes to be discussed and researched: 
• Dinosaurs, and other prehistoric fauna
• The Earth and the general terrestrial environment (and there effects thereon)
• The fossil record
• Animals, and other contemporary fauna
• Plants and flora
• Intelligent design (Although the material will be prepared from and presented in a neutral perspective)

This is not to insinuate that the spectrum of discussion and consideration will be limited to the above topics. Other topics, such as astronomy and chemistry, will also be discussed occasionally.


I, personally, hope you enjoy reading this blog, and find it informative and interesting! Also, if you can, please, feel free to contact me should you have any comments, thoughts or topic suggestions!


Friendly regards,
Discipulus