Of toads and snakes: Evolution at work
By Thomas73
@Thomas73 (1467)
Switzerland
January 30, 2007 7:45am CST
A recent article in the Proceedings Of The National Academy Of Sciences Of The USA caught my attention. A research group has investigated the snake population of Two Japanese islands -- namely Ishima and Kinkazan -- and has made some interesting findings about their behaviour with respect to toads.
Those snakes, a species of keelback snakes called Rhabdophis tigrinus (tiger grooved-neck keelback, or simply tiger keelback), exhibit a different reaction when attacked. Whereas the snakes on Kinkazan flee, those on Ishima stand their ground and fight, relying on their poison. However, this particular species of snake is unable to synthsise its own venom. But R. tigrinus found on Ishima have been demonstrated to harbour bufadienolide compounds (toad toxins) in their neck (nuchal) glands.
The investigation on the origin of the toxins indicated that they were obtained from the snakes' diet. Whereas most animals, including snakes, avoid eating toads because of the toxins contained in their skin, R. tigrinus on Ishima island not only survive the ingestion of those toxins, but also store them for their own defense. This was confirmed by feeding the snakes a toad-free or a toad-rich diet and measuring the amount of bufadienolide contained in their nuchal glands.
The research team also showed that baby snakes benefit from these toxins too. Snake mothers with high toxin levels were shown to pass on the compounds to their offspring, thus allowing them to enjoy the toad-derived protection.
So snakes of the same species living on different islands exhibit different behaviours that confer them a different survival advantage. Whereas the snakes on Kinkazan will keep on struggling and fleeing, those on Ishima will thrive on a toad diet that will allow them to face predators more efficiently. Like Darwin's account of finches' beaks on different islands, this obervation confirms once again that evolution is a fact, and not a mere theory.
Note: This is an article that I wrote for another website and that I thought I'd share with the myLot community. All constructive comments welcome.
5 people like this
9 responses
@sunshinecup (7871)
•
30 Jan 07
I no doubt, all living things, and as well as us humans have and still do evolve to adapt to our surroundings. It's part of survival and all living things of today must have done so 100's to 1000's of years ago in order to be present now.
However, I never thought "evolution" in regards to some physical changing in order to live in our atmosphere was ever doubted, but the idea we humans changed from a completely different species into another. The claims we were monkeys that turned into humans is odd to me. Especially when we supposable have a lot in common with pigs as well. I honestly think we are our own unique species that did not originate from another animal. In fact the more I learn of the evolution theory, the more convinced I am.
BTW missed you around here, glad to see you visit us. :-)
3 people like this
@Thomas73 (1467)
• Switzerland
30 Jan 07
Thanks for your comment and kind words, sunshinecup.
I know that evolution is quite difficult to understand for non-scientists, but I can assure you that the facts do not point toward any other explanation for all the links between species on Earth... yes, even pigs! :)
3 people like this
@Eskimo (2315)
•
11 Mar 07
I had to study 'The origin of the Species by Natural Selection', and it puts the whole world into perspective, the birds actually evolved differently on thd different islands partly due to the habitat of the island itself but also the birds were blown to different islands by the wind and the distance the birds had to travel from the mainland to the islands. Can't remember offhand how many different islands there are (around 10-12 I think) would need to look it up. The diversity in the birds is very striking and helps prove Darwin's theory.
Incidentally I understand that he actually went on his Beagle expidition to prove Creationism existed, and it takes a good scientist to accept that discoveries show different from your original expectation.
@Thomas73 (1467)
• Switzerland
11 Mar 07
Darwin was indeed a theologian who went on to prove the Bible right, and came back with the knowledge that the story of the Creation -- among many others -- was just a legend. He had a very scientific attitude and, unlike too many people, didn't twist the evidence to fit his views, but developed new ones according to the evidence. A great man indeed!
2 people like this
@Eskimo (2315)
•
11 Mar 07
I often wonder how many other scientists have made amazing discoveries, only to supress them because they didn't fit in with preconceived ideas. (Nicholas Copernicus springs to mind who new the earth revolved around the sun but was forced to publicly recant by the Catholic Church).
2 people like this
@volschenkh (1043)
• South Africa
30 Jan 07
A really nice piece of work here, Thomas73. Great info, I enjoyed reading it!
@ShadowWalker (969)
• United States
31 Jan 07
Interesting. It would seem that these frogs did evolve from an earlier species. And I do believe it is possible. Unlike most Christians I do believe everything has evolved from a earlier species. Including man. I know that other Christians point out the Garden of Eden. I believe that was a parable. Too many facts point to the fact that we did evolve from a earlier species. And that we are continuing to evovle as each year goes by. Anyways, back to your artcile. Sorry, I tend to rant. Once again I found the article interesting and very informative.
1 person likes this
@Thomas73 (1467)
• Switzerland
31 Jan 07
I'm always happy to see open-minded believers who do not take the 'holy' scriptures at face value. I am actually planning to write an article about the future evolution of Man and the apparition of two human-derived species. Or maybe I should also write about this 'life from a rock' theory that seems to indicate that organic life forms originated from mineral templates, more specifically... clay!
@sigma77 (5383)
• United States
30 Jan 07
I read this before and found it to be interesting to say the least. I am wondering if there is some reason for this based on the island itself? Maybe something that one island has and the other doesn't. I don't know, like a different chemical makeup or something we don't know about.
I am not a student of evolution, but I have to agree that this certainly supports the idea. I can't go against evolution and just believe we appeared on the planet in a puff of smoke.
2 people like this
@Thomas73 (1467)
• Switzerland
30 Jan 07
Like most evolutionary processes, this one must have arisen by chance. One snake, one day, had the impulse to eat a toad and to stand up to its predators, which it did efficiently. This allowed it to survaive and reproduce better than the snakes that didn't do that, thus passing on the ability to perform such acts. The rest followed naturally.
As soon as you get a survival advantage, it gets passed onto the next generations. Like the ability the first hominids had to use their intellect to make tools, for instance.
2 people like this
@manong05 (5027)
• Philippines
12 Mar 07
Your posting reminded me of the saying that "Wherever there is life, there is power." Life will always find its way and will continue to adapt and survive in whatever situation whether in the form of allopatric speciation or otherwise. I wouldn't be surprised to see a man like Kevin Costner in the movie Waterworld who developed gills in order to survive in an environment where there is nothing but water.
@arnboy (357)
• India
11 Mar 07
I can understand the sarcasm of a Charles Darwin fan :).
However, the Darwin theory of survival of the fittest is open to valid criticism. It is too general in its nature, what i provided was just an alternative approach to looking at things. I feel Darwin's theory has become plain old vanilla and requires some chocolate sauce. lol...:)
1 person likes this
@arnboy (357)
• India
11 Mar 07
Darwin's theories are excellent, however as far as the survival of fittest is concerned. I think it is something we
all knew, like avoiding the neighborhood bully :).
Basically, this theory was lapped up, because of his previous theories, much like how people buy the latest music
album of their favorite pop star, without even giving a thought about, the fact that the songs may not sound as good
as before.
1 person likes this
@arnboy (357)
• India
11 Mar 07
I read the article and i was surprised how just a simple change of diet can cause such change in the specie. However, similar observations have been made with respect to human being's also, humans living on a diet composed of fruit and vegetables, will have a different body composition when compared to a person who is living on a diet of meat and milk.
Darwin's theory of evolution, can be counterproductive in this case, because the snakes of Kinkazan flee at the first given opportunity whenever they face a hostile predator, unlike a Dodo, a snake can be a very slippery customer who is difficult to catch.
Whereas, the snakes of Ishima, emboldened by the belief that their venom is good enough to get rid of their enemy might actually walk into a trap. If i was a snake hunter, i would prefer the snake to come
onto me, that way i can catch it more easily.
Darwin's theory need's a relook, because according to him the survival of the fittest is the foundation
of the existence of all surviving species. But, then
how can he explain the survival of the domestic cat,
and the near extinction of big cats like Tiger, Lion
etc.
I think Darwin's theory needs a major update, how about including facts regarding Symbiosis (like mutualism),for example the human dog relationship, where the dog, decided to accept the human as the master and was thus saved from a possible extinction.
@Thomas73 (1467)
• Switzerland
11 Mar 07
Wow! I'm amazed to see this discussion re-surface after all this time. Thanks for reviving it!
I must say that Darwin's findings have been only the first step towards understanding evolution better. However, the public mind has misinterpreted what being the 'fittest' means. The fleeing snake is the fittest in its own environment, and a seemingly 'weak' behaviour may constitute the best response for survival.
Likewise, cats and dogs are indeed the fittest due to their association with protective humans. It isn't a full symbiosis, but an inter-species collaboration like the shark and the pilot fish, for instance.
@Thomas73 (1467)
• Switzerland
11 Mar 07
So far, the only species Man has willingly driven to extinction is the virus of smallpox. I won't go into the debate to know whether a virus is actually alive, as it has no metabolism, but let's say that it's officially been eradicated. Well... some strains are still preserved in some centres. You never know, they might be useful in case of biological warfare.
*Cynical grin*
1 person likes this
@arnboy (357)
• India
11 Mar 07
Guten Tag Thomas,
Initially, i just read the discussion and was not surprised with the theory of Darwin, however, after some analysis i felt that the Ishima snakes had a better chance of survival. I revived this thread, because i wanted to stick to science and technology, rather than invoke the wrath of the fundamentalists!.
Also, i disagree with your interpretation of fitness, just like Darwin you are placing the specie under a general category of fitness, although you have specified in this case that the option to flee, or collaborate was also an example of fitness.
Whereas, i believe that the survival of specie depends on how it can outwit the human being's. I feel human beings are the most dangerous predators on the planet, especially when they are armed with their knowledge of science. No, specie which has earned the wrath of human beings can ever dream of surviving. Man has made so much progress, now the
survival of all organisms depend on either ignorance i.e. either the man is not aware of the specie, has not found a solution to deal with that specie or a symbiotic relationship with man.
1 person likes this
