Scientists Discover Where Snakes Lived When They Evolved into Limbless Creatures

Penn State ^ | 30 January 2004 | press release

[AdmSmith]

The mystery of where Earth's first snakes lived as they were evolving into limbless creatures from their lizard ancestors has intrigued scientists for centuries. Now, the first study ever to analyze genes from all the living families of lizards has revealed that snakes made their debut on the land, not in the ocean. The discovery resolves a long-smoldering debate among biologists about whether snakes had a terrestrial or a marine origin roughly 150 million years ago--a debate rekindled recently by controversial research in favor of the marine hypothesis.

In a paper to be published in the 7 May 2004 issue of the Royal Society journal Biology Letters, Nicolas Vidal, a postdoctoral fellow, and S. Blair Hedges, a professor of biology at Penn State, describe how they put the two theories to the test. They collected the largest genetic data set for snakes and lizards ever used to address this question. Their collection includes two genes from 64 species representing all 19 families of living lizards and 17 of the 25 families of living snakes.

Genetic material from some of the lizards was difficult to obtain because some species live only on certain small islands or in remote parts of the world. "We felt it was important to analyze genes from all the lizard groups because almost every lizard family has been suggested as being the one most closely related to snakes. If we had failed to include genes from even one of the lizard families, we could have missed getting the right answer," Hedges explains.

"For the marine hypothesis to be correct, snakes must be the closest relative of the only lizards known to have lived in the ocean when snakes evolved--the giant, extinct mosasaur lizards," Vidal says. "While we can't analyze the genes of the extinct mosasaurs, we can use the genes of their closest living cousins, monitor lizards like the giant Komodo Dragon," he explains.

The team analyzed gene sequences from each of the species, using several statistical methods to determine how the species are related. "Although these genes have the same function in each species--and so, by definition, are the same gene--their structure in each species is slightly different because of mutations that have developed over time," Vidal explains. When the genetic comparisons were complete, Vidal and Hedges had a family tree showing the relationships of the species.

"Our results show clearly that snakes are not closely related to monitor lizards like the giant Komodo Dragon, which are the closest living relatives of the mosasaurs--the only known marine lizard living at the time that snakes evolved," Vidal says. "Because all the other lizards at that time lived on the land, our study provides strong evidence that snakes evolved on the land, not in the ocean."

The research suggests an answer to another long-debated question: why snakes lost their limbs. Their land-based lifestyle, including burrowing underground at least some of the time, may be the reason. "Having limbs is a real problem if you need to fit through small openings underground, as anybody who has tried exploring in caves knows," Hedges says. "Your body could fit through much smaller openings if you did not have the wide shoulders and pelvis that support your limbs." The researchers note that the burrowing lifestyle of many other species, including legless lizards, is correlated with the complete loss of limbs or the evolution of very small limbs.

This research was supported by the National Aeronautics and Space Administration Astrobiology Institute and the National Science Foundation.

[Southflanknorthpawsis]

curisosity = curiosity

[VRWC_minion]

didn't know dodo's were still alive

Which proves an example of an unwise creature.

[whattajoke]

Leviticus is a very clearly written book, which contains many "laws" for Jews and Christians to follow. As one who apparently has a firm grasp on the bible, I'm sure you understand that it can't be taken literally.

[VRWC_minion]

How did the Serpent talk? Snakes certainly aren't equipped with the morphology to facilitate speech. Did they lose this ability with the fall of man too? Or, is this (YET ANOTHER) not really literal but still literal biblical story?

Of course snakes don't talk, only donkeys. (Numbers 22:21-41)...

[ZULU]

I'm not calling God's word a lie or God a liar. That's your interpretation.

What I am stating is that some people interpret everything stated in the Bible literally - word for word. They don't examine or think about what they are reading. They never consider the fact that the Bible is full of allegorical and symbolical stories, tales, etc, which are presented to teach some significant or overriding fact involving morality or God or God's relationship to man.

I hardly think reptilian biology, interesting as I personally find it, is a item of pressing importance in God's Biblical message.

[ZULU]

I think you and I disagree about the intrepretation of the Bible.

I don't believe that makes you a bad Christian. We just don't see things the same way.

I believe the Bible is a religous and theological work, not a science textbook. When Science and the Bible contradcit one another on a matter of purely scientific importance, I review the Biblical passage and attempt to interpret its meaning in light of what are proven facts.

When the Bible and Science contradict one another on matters of faith and morality, I look to the Bible.

[VRWC_minion]

Can't argue with that. Adam means "man" dosen't it?

Yes and it also means red (possible metaphor for blood?). But it proves more complex than just two meanings. In some contexts it also means hypocrite and one of the names we translate as Adam (Gen 2:1, when put in a deep sleep) is from a different Hebrew word meaning "first man". The author of gensis moves from one label to another quickly which indicates that they could move from literal to metaphor very easily even within mid verse.

[Southflanknorthpawsis]

The answer to that is simple. Jewish law, etc. became unnecessary with Jesus. But the events of that age are literal and applied to a time before Christ.

[VRWC_minion]

but that doesn't necessarily mean the stories were meant to be taken entirely in a literal sense which is what a lot of Christian fundamentalists believe.

However, just as we would teach using examples from things that have happened, so to would it be likely that God would teach from examples that actually happened.

[VRWC_minion]

(Not saying that there aren't SOME absolutes in the Bible of course, but they aren't as plentiful as others would have us believe, imo)

Jesus did this with the 10 commandments much to the disatification of those listening. He made it clear that our thoughts and feelings applied convict us a sinners as much as doing the literal acts.

[VRWC_minion]

You are, in essence, calling God's word a lie or a fairy tale.

I didn't see him call God a liar. He is simply describing what he sees in God's creation. He is reporting what he and others are observing.

[VRWC_minion]

So, all metaphors are literally false ?

[Southflanknorthpawsis]

I cannot and will not ever judge the authenticity of anyone's Christianity. I will, however, continue to believe that those who want to customize the inerrant Word of God to make it logical to man find themselves in a precarious position.

I have to ask again how you determine what is and isn't literal? I assume you have a criteria or method and I presume it is based on man's pride of his so-called knowledge versus faith.

[VRWC_minion]

What I am stating is that some people interpret everything stated in the Bible literally - word for word

They "believe" they are interpreting literally. They are in fact imposing restrictions on the text that conform with a theology. Like God is liar and death of animals could not occur prior to sin.

[Southflanknorthpawsis]

So, all metaphors are literally false ?

If you can explain how a metaphor is literal, I'd like to hear it.

Again, metaphors are not vague when used in the Bible. They are very clear.

[VRWC_minion]

When Science and the Bible contradcit one another on a matter of purely scientific importance,

I conclude that either the science is wrong or the current literal interpretation of the bible in regards to the science is wrong.

[ZULU]

"As a Christian, Zulu, how do you determine what is literal and what is not?"

When a statement in the Bible totally goes against all scientific knowledge, and when the statement is not really germaine to the main thrust of the idea the Bible is trying to get across, and when the essence of the statement can be viewed as symbolical or allegorical, I choose to do the latter.

"1) The Resurrection "

I think the Bible is especially clear on the issue of the Resurrection. It is a central point in the belief of all or nearly all Christians, unlike whether or not snakes eat dust.

"2) Walking on water"

All Christians concur that Christ performed many miracles in his life and this is one of them. And it is so described as a miracle, i.e. something outside of the natural occurance of things. All Christians should recognize and believe in Christ's miracles as they are a proof of what He said He was, unlike the need to believe that snakes have no limbs because God cursed Satan somewhere back in man's earliest most distant past.

"3) Immaculate conception"

This isn't a trick question is it? All Four gospels, I believe, seem to imply that Mary conceived a Son through the interaction of the Spirit of God and that seems proof enough to me.

"4) Water to wine
5) Multiplying the bread and fish"

See "Walking on Water"

I think, as a Christian, that a good part of what is related in the New Testament can be taken literally. The events occurred relatively recently in time, they are frequently repeated in several sources (the different Gospels) and a good part of them are central to Christian beliefs and the teachings of Christ. The evolution of species is not one of those issues.

A lot of what is told in the Old Testament occurred very long ago, in a society more distant from Christ's time than we are from the time of the Romans. Did Job REALLY exist??
Biblical scholars tell us this, not Genesis is probably the oldest book in the Bible. OR, is it an allegorical or symbolic story designed to convey some truth about human existance and the power of God and the helplessness of man before that Power? Was it important whether or not Job DID exist if you get the message behind the story?

Some parts of Genesis are the same. Sure, miracles can happen, God could have taken a lump of literal clay to make Adam and formed Eve from his rib. BUT, it would seem to me that scientific evidence indicates God used a lower creature to produce th first man. And the serpent in the Graden of Eden was not a real snake, it was Satan in the form of a snake - a very different creature.

[ZULU]

That makes interpreting the Bible in some cases, not a simple literal exercise, doesn't it?

[VRWC_minion]

If you can explain how a metaphor is literal, I'd like to hear it.

Metaphors only work if they are true. If I sow seed in rocky soil will it thrive ? If I sow seed where the thorns and bristles are will it thrive ? If someone sows weeds in my garden after I sow, will my garden contain weeds as well as the plants I am growing ?

[ZULU]

Don't you think though, that whether or not an event related in a parable was real or not is not really important, as long as we "get the message"? In the world in which Christ lived, parables were frequent methods of teaching some priniciple.