A discussion of turtle and tortoise evolution- ONLY.

Madkins007

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Darn it, I let niggling things like 'real life' get in the way of monitoring this thread and it slips away again as evolution threads tend to do. Ah well, it was a fun experiment but no one seems to ever budge on their views and no one ever seems to offer anything really new or different.

I do appreciate that it remained nice and polite- thank you everyone for that!

If something interesting does not happen soon, on the theme of turtles, I'll close the thread.
 

Levi the Leopard

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Re: RE: A discussion of turtle and tortoise evolution- ONLY.

Madkins007 said:
. Speculation is 'forming a theory without firm evidence'. What is the strong evidence that one type of animal DID NOT, over time, become another type?

The strong evidence? I'd say:
The fact that it's never happened or been witnessed.
The fact there are no real connecting links.
The fact we've never seen new data appear, ever, in genetic code. Something can only get wings if wings was in the code to begin with.

I say evolution from single cell organism into everything that exists is speculation.
 

cdmay

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Yvonne G said:
Gotta' hand it to Mark. He starts a thread that says "ONLY" talk about the subject at hand, then he doesn't stay here and monitor that you all follow his rules! Where the heck are you, Mark?

Lighten up Yvonne. The thread went just fine and the members are happy.
 

zenoandthetortoise

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"The strong evidence? I'd say:
The fact that it's never happened or been witnessed.
The fact there are no real connecting links.
The fact we've never seen new data appear, ever, in genetic code. Something can only get wings if wings was in the code to begin with.

I say evolution from single cell organism into everything that exists is speculation."

Gomberg,

You clearly don't like evolution, don't believe in evolution and if your recent musings on snowball thermodynamics are any indication of your science literacy, don't understand evolution. So, why are you commenting on an evolution thread? Wouldn't that be the equivalent of jumping into a discussion of say, pancake tortoises to mention that you have no interest or experience? At some point it's a matter of decorum.


Moving on. In the article Madkins quotes by Vargas-Ramirez, et all, it states:

"Based on fossil calibration, we dated divergence times for the C. carbonaria clades using a relaxed molecular clock, resulting in average estimates ranging from 4.0–2.2 mya."

This an amazing number. It would place the MRCA of the carbonaria clades as contemporaries of Australopithecus. Additionally, the formation of the oldest of the Galápagos Islands (Espanola?)is approx 4-3 mya, indicating carbonaria was well established well before elephantophus was even getting established.

Great read madkins. Thanks
 

Levi the Leopard

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Anyone with a brain can (and should) hold an opinion on how they think they got that brain.

You can think it miraculously formed out of nothing by chance.
I can think it miraculously was designed and given to me.
We can each look at evidence to support our theory. I was an evolutionist for many years until I was convinced by enough evidence to believe I was intelligently designed.

You might understand more about snow properties and pancake tortoises.
I might understand more about the differences in historical science and observational science.

To say one has a right to discuss their view over another is intolerant.

Back to turtles, I'll be attending a live debate between Bill Nye the Science Guy and Ken Ham next week. I'm hoping to talk to them about turtles afterwards.
 

zenoandthetortoise

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"To say one has a right to discuss their view over another is intolerant."

Reread my post. I never said you don't have a right to your own opinion or that you don't have the right to express it. I was questioning why you think it's relevant or productive to redirect a thread by repeatedly questioning its premise. You don't like it. Point taken. Now would it be ok with you if those of us that are interested in discussing the biological nuances proceed? Perhaps you could start your own thread called "I still don't believe in evolution.


"I might understand more about the differences in historical science and observational science."

This seems dubious, at best
 

Levi the Leopard

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What about carbon dating.
Can I discuss the method of carbon dating in this thread? How it allegedly works and point out it's false assumptions and flaws?

You see, if the method is flawed, the results from such a method no longer hold any value.
 

zenoandthetortoise

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"What about carbon dating.
Can I discuss the method of carbon dating in this thread?"

Well I'm not the OP, but this too seems like it would be more impropriate for you to expound your philosophy on your own thread. Common courtesy, I suppose.
Incidentally, you might find more people interested in your take on carbon dating (or snowball melting ) if you described your expertise on the subject. While you get to have your own opinion, regardless of qualifications, it's awfully easy to disregard as inconsequential as presented.

Incidentally, carbon dating, if memory serves, if of utility for only about the last 45K years, thus not relevant to the topics at hand.
 

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“The oldest turtle fossils go back to the Late Triassic, about the time of the first dinosaurs. Among the Triassic turtles the best known is Proganochelys, found in Thailand and in several parts of Germany, where the context is sandstone and shale deposits interpreted as brackish or marginal marine. The turtle was probably washed down to its resting place by coastal rivers. As well as the characteristic carapace and plastron, Proganochelys had toed feet, palatal teeth, a spiky neck and a club-like tail, and both its forelimb dimensions and heavy armour show that it lived on land (Joyce & Gauthier 2003).
Some of its features, for example its teeth and long tail, hint at an ancestry among non-turtles. Many more were unique......
Equally old, but somewhat more advanced in the family tree, are Proterochersis, also from Germany, and Palaeochersis, from Argentina. We know less about Proterochersis because, although more than two dozen shells were recovered, all from stream deposits, the skulls were not preserved. Palaeochersis was buried in a mud layer within a wadi, along with a number of other land animals. It too shared a number of features with non-turtle amniotes.
Another key fossil is the recently discovered Odontochelys, from China. Odontochelys is both slightly older and more basal in form than Proganochelys – for example, it had teeth on both upper and lower jaws, and its overall shape was distinctly elongate. Most significantly, it lacked horny scutes, suggesting that the outer carapace consisted of non-bony tissue, as with modern leatherbacks, and was not preserved. The lack of a hard protective shell agrees with evidence that it lived in a coastal marine environment.
Other Late Triassic specimens have been recovered from Skye (British Isles) and North America. From their first appearance turtles were already global.
Turtles are the only living tetrapods without temporal openings in their skull, and they have sufficient features in common to substantiate the view that they have a common ancestor.”
An interesting read …
http://www.earthhistory.org.uk/transitional-fossils/origin-of-turtles
 

Madkins007

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Team Gomberg said:
Madkins007 said:
. Speculation is 'forming a theory without firm evidence'. What is the strong evidence that one type of animal DID NOT, over time, become another type?

The strong evidence? I'd say:
The fact that it's never happened or been witnessed.
The fact there are no real connecting links.
The fact we've never seen new data appear, ever, in genetic code. Something can only get wings if wings was in the code to begin with.

I say evolution from single cell organism into everything that exists is speculation.

1. Never happened? We see it all the time. We DO it to plants and animals all the time. http://listverse.com/2011/11/19/8-examples-of-evolution-in-action/ and http://www.cracked.com/article_19213_7-animals-that-are-evolving-right-before-our-eyes.html are small examples of this.

2. Connecting links? This one amuses me. The claim is made that fossils don't really show much, then people expect that the fossils should reveal the sorts of minute differences that evolution creates. Looking at the above examples, how many of those changes will show up in the fossils?

3. No new data in DNA? See the above links. Things are showing up in the DNA.

Looking at how things are now and saying 'this is the way is HAS to always have been' is not speculation, but you know it is not true. The idea that 'things change' is one of the most reliable constants in the world.

A rebuttal to what I just wrote would be something along the lines of 'well, yeah, but climate or plant progression, etc. are not the same thing as DNA' to which I would ask why DNA cannot change if other things can?

DNA is obviously mutable. It is affected by so many other things, and it itself shows a lot of evidence of evolution insofar as there is a lot of 'old' stuff in our DNA. I WISH DNA was not subject to change or mutation- it would eliminate a lot of human suffering.


Carbon dating- if someone introduced carbon dating in the thread as evidence, then discussing its validity would be appropriate in this thread. I don't remember, but may have missed, any previous comment.
 

N2TORTS

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Excellent Idea Mark ........
"As a rule, carbon dates are younger than calendar dates: a bone carbon-dated to 10,000 years is around 11,000 years old, and 20,000 carbon years roughly equates to 24,000 calendar years
Carbon dating is used to work out the age of organic material — in effect, any living thing. The technique hinges on carbon-14, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate. Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive. By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be worked out, thereby giving an age for the specimen in question. But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock. The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the 1960 Nobel Prize in Chemistry. But even he “realized that there probably would be some variation”, says Christopher Bronk Ramsey, a geochronologist at the University of Oxford, UK, who led the latest work, published today in Science. Various geologic, atmospheric and solar processes can influence atmospheric carbon-14 levels."
http://www.scientificamerican.com/article/carbon-dating-gets-reset/
 

Madkins007

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A (probably poorly articulated) thought about a common anti-evolution comment- "We have never seen big changes- we don't see half and half forms, etc".

The thing is, we are looking at that point though the lens of time. We've only been watching closely for a few thousand years. There are a lot of species that push the boundaries of their genera. Cheetahs don't meet many of the 'rules' for being a cat, there are fish that breathe with lungs and walk, salamanders and lizards with nearly no legs, birds that don't fly or have non-typical feathers, and to bring the discussion back on target, turtles and tortoises with atypical features, like soft shells or articulating shells. For all we know, these and lots of other examples are in the middle of a transition that will not reveal itself for thousands of more years.

Obviously I cannot use these as proof of evolution since we see them frozen in time and they are not displaying changes in the short time we have watched- but that does not mean it isn't happening. The fossil record seems to support this process.
 

enchilada

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We should all be honest with ourselves that fossils can't provide as much information as we would like to act like they do.

Consider this. Let's say that all modern dog species went extinct 20 million years ago and we never witness a single live canine of any kind. All we had were dog fossils to go by in building the "story" of dog evolution. If we found skulls of Chihuahuas on another continent from Great Dane skulls then modern science would NEVER EVER EVER CONCLUDE that they were from the exact same species. And to say otherwise is being silly. The only reason we know that all dogs are of the same species is because we have WITNESSED their incredible genetic diversity ALREADY BUILT IN to their genetics. But if dogs had went extinct millions of years ago we would have modern scientist building multiple elaborate "stories" of how different dog species were connected.

I believe the same unfortunate thing happens with all other families of animals......even turtles and tortoises. I don't doubt for a minute that hingebacks and redfoot/yellowfoots came from a common ancestor. How and why that happened will always be somewhat of a mystery.That much we can undoubtedly conclude. But to go any further than that and say that tortoises evolved from a "non tortoise" animal is to jump right into total speculation and not real science.

http://creationrevolution.com/2010/10/dogs-big-problem-for-fossil-record/
actually, Chihuahua and Great Dane are the SAME SPECIES. All dogs are the same species.
Chihuahua and Great Dane are actually different "BREED".
 

enchilada

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I am christan and I believe Evolution. most stories in Bible are metaphor. Its ok to believe there is God and jesus, but if you also believe everything in the book literally happend, like Adam making Eve out of his rib or flying talking snake make you eat some apple or pairs of animals on Noah's Ark having no inbred problem ...etc, that is stupid and makes you a fundamentalist.
Maybe God just plant some "seed of life " on earth couple billion years ago, and let it bloom, or, we can say "evolution"
 

Yvonne G

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Remember, folks...please don't get into a religion debate. This topic is about tortoise evolution only!

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smarch

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I'm really happy this thread exists, since I have a very scientific thinking mind.. and accidently asked on the forum once to explain where Russian torts came from without even realizing the debate that would have ensued.
Unfortunately I am nowhere near the level of knowledge of all the posts here so don't have valid input to contribute, but I figure I'll ask here since we're already in the evolution talk so its already being watched closely for arguments to start.

Can you guys tell me whats the best way to start research? Such as key words and stuff to search through google scholar and my schools databases? I'm specifically hoping to look up the Testudo and back, and eventually link things together.
Or even just a few basic sites or authors to get my search going, since once I start i'll be able to go off on a research tangent, but I need a good foundation.

Can you tell i'm on summer school break and deperate for knowledge? :oops:
 

smarch

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Heres a start
http://m.rsbl.royalsocietypublishin...ract?sid=40b6b6c5-dda8-4499-8a7a-352b555c62e9

Most journals require a subscription , but I recently discovered the Royal Society allows access.
Thanks :) I have a bunch of scholarly journals through a database at school that I have instant access to with my email and password so I get free access to journals that people otherwise wouldn't. But when I get home tonight i'll definitely be starting my research, notes and all :) if this thread stays available when I get more knowledgable I'll put in my input, but if its locked you wont see me starting one lol.
 

zenoandthetortoise

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For what it's worth, I hope you do start your own thread. That way maybe you can avoid the metaphysical rambling comments (see previous posts) and focus on what you're reading and interested in. Radiation of the Testudo for example. I, for one, would appreciate more technical posts on the forum and frankly, had somewhat tired of TFO because of the lack. Post what you find, I'd love to discuss.
 
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