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.

[whattajoke]

Every once in a while I am still shocked at the ludicrous levels to which creationists can stoop. Many times it's simple ignorance or strong faith, which I can not argue against too much. However, to put forth the idea that snakes actually eat dust is hard for me to ignore.

Snakes do not eat dirt any more than you or I. Vertebrates cannot subsist on dust. Surely you understand this. And surely Dr. Weiland understands this... which is the only reason I'm posting this diatribe. He, as "CEO of AiG-Australia" is LYING and OBFUSCATING, directly contradicting one of the clearest Commandments. It burns me up.

Why does it burn me up? Because as an undergrad, I spent many long late night hours actually studying the Vomeronasal Organ in snakes with my advisor who is one of the world's leading experts on snake tongues, feeding, and sensory organs. I have enormous respect for Dr. Schwenk and his work in this specific field of herpetology. To read that some idiot has written some nonsense article to try to fit the VNO into a literal reading of the bible is too much.

If you wish to further discuss the sensory organs and feeding habits of snakes, I'll be more than happy too... it'll be the first time I actually use what I learned from those long hours in his lab.

http://www.eeb.uconn.edu/faculty/schwenk/schwenk.htm

[whattajoke]

OOPS, in my anger and haste I had the VNO in my head instead of the Jacobson's organ in snakes. Sorry.

[ZULU]

The parables may use POSSIBLE real events, but the REALITY of the SPECIFIC event used is IRRELEVANT to the story narrated.

Its NOT IMPORTANT if the "good Samaritan" REALLY existed. The POINT of the story si what is important.

The Bible is full of symbolism. Its a theological work. Its not a biology book. The "Snake" in the Garden of Eden was Satan. The little story about eating the dust of the earth was a symbolic tale of proably what happens to people to lead others into sin. The serpent getting its head crushed by the woman's heel refers to Christ, the Son of Mary destroying Satan, not to a woman stomping a snake. Its symbolical.

St. Patrick and the driving of "snakes" from Ireland is another example. There NEVER were ANY snakes in Ireland. The SNAKES were a symbol of the human-sacrificing pagan Druids.

[ZULU]

That's exactly what I was trying to say. Thank you.

I read that in a book on Phobias.

[ZULU]

"image (of serpent) "

As in symbolical image of a serpent, representing Satan.

Thank you.

[VRWC_minion]

Snakes appeared in the fossil record LONG before modern man did. As a matter of fact, they may have appeared before even our predecessors like the Australopithecines did. The time frames are all wrong!!

What literal passage tells you what the time frame is for this Garden of Eden event. Moreso, what literal place it this where God walks in the garden and which is protected by a Cheribum. You have assumed a time frame and a place.

[ZULU]

Not angry, just disgusted.

I have been a reptile fan and a Christian all my life and I continually have to deal with people who view snakes as "Satanic" . They aren't. They are interesting, beautiful creations of God like all other animals and have an important function in nature.

Studies have indicated that wherever large snake popualtions are decimated or destroyed, rodent popualtions bloom. This has a negative impact on food production and also leads to the transmission of various types of diseases.

Even today, they have "Rattlesnake Round-ups" where gangs of idiots travel into remote areas where are few or any people and gas and kill animals which help keep down the population of injurious rodents.

It makes no sense.

[VRWC_minion]

Snakes do not eat dirt any more than you or I.

First, its dust. Second, how does a creature that eats unwashed food that also is on the ground avoid eating dust ? Does it carry it to the nearest stream and wash it thoroughly ?

[headsonpikes]

One could argue, but one would be wrong.

I like your attitude! How else cling to ignorance but through close-mindedness?

You're a credit to your sub-species.

[ZULU]

No. I'm going by the geological record for fossils. The fossils of the first snakes appeared long before the fossil of the first modern man. "Modern Man", Homo sapiens appears at the earliest about 200,000 years ago in the fossil record. Could H. spaiens have existed a little before that time? Posssibly. We may just have not found the fossil evidence. But as far back as the first snakes?? Impossible. Modern man would have to antedate his predessors - the Australopithicines, and even then, it wouldn't be far enough back in the fossil record.

The first snakes appeared LONG before that time.

[ZULU]

Any dust on what a snake eats is coincidental. And what about aquatic snakes and arboreal snakes? They never get any dust in their food.

The Biblical writer was merely describing what people of the time thought, not biological facts. Are snakes wise??
Are doves "innocent"??

[Doctor Stochastic]

And where is the Elephant Graveyard?

[VRWC_minion]

but the REALITY of the SPECIFIC event used is IRRELEVANT to the story narrated.

But if the scripture is God inspired, the easier path is for God to create a metaphor rooted in fact. The author might play with time seeing that he is unbound by time. To assume that the events described are untrue in nature because the primary purpose is to teach by analogy or metaphor is a mistake in my opinion.

In the case of the snake, its interesting that the bible describes a land creature becoming a snake when its possible that a sea creature could have evolved so. Especially when we think of legs as being a positive adaption.

[patriot_wes]

There was also an attorney somewhere in the evolutionary gene pool...

A Clinton bump here..."still a snake"

[Doctor Stochastic]

Studies have indicated that wherever large snake popualtions are decimated or destroyed, rodent popualtions bloom.

Every time we get another diamondback in the garden, we just give it to the wildlife guys to release in the woods (a long way from town.) We let the other snakes slither and creep anywhere (outside) they please.

[whattajoke]

You: "First, its dust. Second, how does a creature that eats unwashed food that also is on the ground avoid eating dust ? Does it carry it to the nearest stream and wash it thoroughly ?"


I can't believe I'm arguing about how much dust snakes eat. My first answer that snakes eat no more than you or I stands. Is not dirt a bunch of dust?


Because the latest info from the American Dietetic Association tells us that, like it or not, each of us probably eats several pounds of dirt from birth to death, and no matter how well we wash those turnip greens or carrots we’re still going to be putting down some reechy matter.

Since it’s time to start hauling in veggies from our gardens, I thought I ought to alert everybody to this new information, although the old saying “You’ve got to eat a peck of dirt before you die” has been around for generations. Anybody with a baby has quoted that one.

The U. S. Food and Drug Administration says it’s really impossible to get all the dirt and foreign objects (insects, rodent hairs, worms, maggots!) off our food, fresh and processed, but for the most part, the USFDA states, this unappetizing stuff won’t kill us or even make us sick. That’s good to know.

I still have fond childhood memories of pulling radishes straight from the garden, washing those suckers off with the hose, and eating ‘em like candy. Makes my mouth water to think about it. Little did I know I was digesting a palatable portion of grit and grime also, no matter how long I washed those radishes.

And as little bitties, sister Kathy and I had the most adorable playhouse where we spent hours making mudpies and cinnamon “coffee” in dusty bowls and cups. We never partook of our gourmet offerings but fed them instead to baby cousins and dogs. Must not have adversely affected them because they’re still around. (Not the dogs -- but the cousins seem all right.)

Then there are folks who eat dirt on purpose. You read that right. They’re called geophages (from the Greek “geo”--earth and “phagein”--eat).

Trying to explain the attraction of soil gobbling, scientists and sociologists have come up with a bunch of explanations ranging from hunger to cravings to heredity. But when they ask geophages why they eat dirt the main response is that dirt tastes good.

Well . . . I guess so.

One dirt eater in an article written by Associated Press writer Kathy Eyre compared her habit to using a pinch of chewing tobacco every day. I’ll say “Amen” to that.

Another lady claims she eats a cupful every afternoon while she watches TV and works her crossword puzzle. I can hear the conversation now: “Hey, honey, while you’re up would you get me a cup of dirt?”

Dr. Kevin Grigsby, a social worker and professor of psychiatry and health behavior at Medical College of Georgia explains that geophagia exists all over the world and has for centuries, but is especially prevalent in the American South. That’s a lot of dirt excavating. No wonder we need kudzu for soil conservation.

Anyway, I was telling hubby G-Man about all this dirt eating research I was doing and he said he didn’t eat much dirt as a child, but did enjoy munching on chicken feed, the closest thing to junk food his mama kept around the house. He swears the little chicken feed pellets were tasty. (And this is a man who won’t eat English peas.)

But listen, I’ve always maintained “to each his own.” I’m not one to get all up into peoples’ business. They can just proceed if they want to devour stuff like chicken feed and dirt (which, by the way, comes from the Old Norse word "drit," meaning excrement).

Not me. I’ll dish the dirt, but there will be nary a time I'll intentionally eat it.

from: http://usadeepsouth.ms11.net//dirt.html

[Manic_Episode]

"Shoot, the Bible says right in Genesis that God cursed the serpent and said it would from that day forth crawl on its belly."

I always wondered if that meant they used to hop around, straight up like a pogo stick?

[Southflanknorthpawsis]

Unless the passage says otherwise, or is clearly using metaphorical language give Scripture a literal meaning. It is a well stated rule, "If the literal sense makes sense, seek no other sense."

I see, Zulu. Because you like snakes, you find a need to interpret Scripture to suit your personal likes. Hmmmmm!!!!!

Obviously God created snakes and reptiles and they have a purpose. How you translate that fact into denial of the events leading to the fall of man is confusing to me.

[VRWC_minion]

image (of serpent) " As in symbolical image of a serpent, representing Satan. Thank you.

You give the Hebrew people too little credit. They were capable of holding multiple meanings as being true at the same time. Even the names of the characters in the bible demonstrate this. Think of a diamond reflecting light. It catches different light and reflects it back to the viewer. From one angle its white, from another green.

For you to put scripture into a box that says its all one thing and not another is no different an error than those who demand that its all literal.

[VRWC_minion]

I have been a reptile fan and a Christian all my life and I continually have to deal with people who view snakes as "Satanic"

No where does the scriture indicate that snakes are satanic. It merely says that God changed there gentic code, if you will. You have extrapolated or read into a literal view beyond what is there to prove its not literal. God doesn't say the snake is the devil.