How birds influence the evolution of snails
We went up together in the elevator to the airport terminal. It was a long road, but when with me, one of my good friends asked me to drive him to Israel, how could I refuse him?
"Are you sure you want to do this?" I asked him, not for the first time.
He doesn't blink. "I made a decision. I need this freedom. The Far East will do me good, after the divorce and the betrayals and everything. Poor Esty. She did not deserve such treatment. I just want to get on the plane and forget about everything, find myself again in Kashmir, India or anywhere far from here. Wash your head for a few months, and when I come back I will try to restore everything with Esti."
"Oh." I said "Like a snail." He looked at me surprised. "Haven't you heard of the wonderful flying snails from the Japanese islands?"
He shook his head in the negative. Well, that needs to be fixed.
"They were discovered this year," I expanded, "on the island of Hahajima in Japan. The researchers found fragments of shells in the droppings of birds on the island, and wondered if snails could survive the journey through the bird's gut. They decided to let the birds eat snails, checked how many of them emerged alive from the other side of the bird, and found that 15% of the swallowed snails managed to survive the trauma. And on the way they also received air transportation, because the birds re-ejected them in different parts of the island."
"Strong, little bastards." said with admiration. "You see, that's how I want it. To go through the stinking part of life and... to be reborn somewhere else, with all the lessons from the past."
"Not just to be reborn," I said with a raised eyebrow, "the researchers saw that at least one of the snails even managed to reproduce inside the bird's intestine, and hypothesized that the passage through the intestine provides the signal that the snail needs to... well, "horny" it, in layman's terms. And so when the airborne snail reaches the other side of the island and meets a different population of snails, it can immediately bring new offspring into the world. Therefore, the genetic variation between the separate snail populations on the island is also smaller than we would expect."
"It's nice." said with me distractedly. I followed his gaze, and reached the young blonde standing in line at the check-in counter. Shapely, beautiful. Just the kind he likes.
"Listen," he said, "I have to move." Thank you so much for being a good friend, and I love you despite all the weird talk about the snails. I will be back. different."
We hugged goodbye. He stepped into the long line and found his place next to the young woman. I watched him and kept thinking to myself. I thought about the snails flying from place to place on the little island that is their whole world. And I wondered about the price they pay. We know today that evolution works much more quickly and easily on small, isolated groups of members of the same species. Such groups acquire new and different characteristics, until they split into different species and separate from each other. But in the case of the snails on Hahajima Island, the physical distance between groups of snails had no real meaning. The birds bridged between them incessantly and turned them into one big group. If, for example, an unusual snail is born that is especially poisonous to birds, it and its offspring will not easily take over the gene pool of the small groups from its own group, because snails from all the other groups on the island will always reach them.
I took one last look at Eti. He was engrossed in conversation with the young woman next to him. She smiled, and so did he. Before I turned my face and made my way to the car, to return home to my wife, I still managed to see him adjusting the straps of her backpack.
I wondered if it was possible that in the current state the birds were actually stopping the evolution of the snails. Ostensibly, the flight of the snails to the ends of the island allows for a quick and substantial change, but in fact it is a change only with regard to those snails that moved from one area to another. But the deeper change, at the genetic level, fails to occur precisely because of this incessant shuffling of snails. Snails find it difficult to evolve, they are unable to change.
And I hoped I was wrong.
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And more on the subject
Snails can survive passage through a bird's digestive system. S. Wada, K. Kawakami and S. Chiba, In Journal of Biogeography. Vol. 38 no. 9 (2011), doi: 10.1111/j.1365-2699.2011.02559.x
37 תגובות
xianghua,
"But for the sake of it, let's assume that I accept that it is indeed possible in bacteria." So if you accept that it is indeed possible, does it imply that your intelligent creator created only the complex organisms and not the bacteria that you agreed to evolve? If so, who created them? Do you think there is a fundamental difference between bacteria and eukaryotic cells?
In light of the enormous similarity, is it possible that bacteria were formed by one (evolutionary) mechanism and the eukaryotes by another (creative) mechanism?
R.G
If you follow with such devotion you might see where insults were hurled? In my opinion and I think that xianghua will agree with me at least on this issue, the discussion was very matter-of-fact.
R.G.
Chingue is just a troll and has never (but never!) answered anything that contradicts his claims.
He's just annoying and you probably don't understand the material enough to notice that.
It is not enough to use the words of science.
You also need to understand them.
Those who use words without understanding them do so only to deceive people like you.
As someone who follows the discussions with great interest, Xingua is the one who tries to keep calm and discuss
My point is, when insults are hurled at him that are irrelevant and to the uninformed reader, this sounds preachy and arouses suspicion.
Why discredit and talk patronizingly? If you have something to say, say it to the point and don't attack the speaker. It just demotivates you.
It's actually very clear to me!
What we do here is exactly what we did with the birds and the snails.
After all, the plane is the bird and the blonde is the snail. And everything is done for the sake of reproduction and evolution.
Travel and hiking have always been good for evolution.
Contrary to your opinion, I think the article is very nice.
Shabbat Shalom
Sabdarmish Yehuda
I really don't understand why the man with the blonde and the betrayals had to be pushed into the whole description.
What exactly does this add to the understanding of the phenomenon?
And anyway, he really pissed me off. Why does he need/want to "rehabilitate" his relationship with his ex-wife?
He wants to start with blondes anyway... and it's great to start with blondes, but why be married?
Why take advantage of someone, while he himself is alive?
Do not understand. Hates such needy and desperate creatures. Ugh.
RH, I don't think anyone is suffering from anything here. The discussion at the moment is about point mutations and not the formation of complex systems. In the past I brought here a link to a study that showed that even in bacteria it is not certain that this is possible in certain cases.
But for the sake of it let's say I accept that it is possible in bacteria. Well, what does it help if the discussion at the moment is about more developed creatures? Do you agree in principle, that as far as developed creatures are concerned, the calculation I gave is correct? If so, their evolution is probabilistically ruled out.
xianghua,
Either you or I suffer from reading comprehension difficulties (well maybe both of us). I answered you that in bacteria all your assumptions are null and void and therefore the chances of the formation of two mutations in the same gene are low and this can be seen every day in thousands of laboratories around the world.
You said "all this may be true for bacteria" meaning, as I understand it and correct me if I'm wrong, you agreed that in bacteria there is a reasonable chance of two mutations in the gene. This implies that there may be "big" changes in bacteria (according to your definition, not my invention) and this implies that there is evolution in bacteria according to your own conditions, again, note that I did not set the conditions.
parable
As I already wrote to you above, don't you think it is ridiculous to convince someone that there is no chance that something that happens every day will happen?
In my opinion, there is no chance that it will rain this winter in Israel, I calculated and if you want I will present you a detailed calculation on the condition that you agree to my starting assumptions. Want to see how?
RH, it seems to me that there is a problem with the comment system.
RH, where did I claim that I accept evolution in bacteria? I have already presented refutations to the evolution of bacteria here before and this is not the topic at the moment.
Do you accept the claim that I demonstrated above, that the chance that two or three mutations will accumulate in highly developed organisms is extremely small? Because if so, that's already something.
Amit:
Rest your mind.
Khingou doesn't understand anything about the subject either.
I am not trying to argue with him because in previous discussions he has already proven that he does not pay attention to what he is told.
This is indeed a necessary quality for those who have taken it upon themselves to ignore reality, but I am not interested in it.
For some reason, even though I check the little box, I don't receive email notifications in comments in discussions.
I really enjoy reading a discussion in which I understand almost nothing....I just understand that essentially a learned and educated believer like Shingo who would have made me so small in the discussion between us (in light of my ignorance in the fields of science in general and evolution in particular) receives learned and educated answers from scientists who do not fall into delusions of belief And in religious freedom and keep being free. Thanks to Kamila, R.H. Probably to Rothschild (who is not participating in the discussion here).
Just know and remember that many (and I am an example of this) who do not respond much here (due to ignorance and lack of education in the field...) follow, read, enjoy and strengthen your hands as the knights of science, the keepers of the seal of reason, science and rationality who dedicate resources for the important cause.
While we are fighting the culture war against the religious who threaten to destroy every good part (or at least most of the good parts...) in the country, it is good that he who keeps the seal and protects, in a war gathers what is worthy of protection.
So thank you and that's why. In appreciation from me the little layman.
xianghua,
You say: "All this may be true for bacteria, but according to evolution, thousands of different genes have developed in developed creatures such as reptiles, mammals, etc. So the calculation I gave is very relevant."
Good, so we made progress. You finally accept that there is evolution and now we are just arguing where. So in your opinion, scientist, evolution only applies to bacteria? Does that mean your intelligent creator only deals with complex creatures and leaves the bacteria to evolution? Do you understand the absurdity?
RH, all this may be true for bacteria, but according to evolution, thousands of different genes have developed in developed creatures such as reptiles, mammals, etc. So the calculation I gave is very relevant.
"Thirdly, under certain conditions, it is possible to reach more than 100 mutations in a cell" - maybe, but this is only in very specific cases. And from my side you can allow 1000 mutations per birth. It will still be too little.
"As for creatures with sexual reproduction, the story is a little different. Calculate how long it will take until two mutations that are independent of each other are created and what is the chance that after they are created you will meet in one creature following mating? A billion years?”-You mean two new alleles will meet each other?
"In any case, I told you to get off of it, this is not where your salvation will come from. There are mutations, both in the same gene and in different genes. There are recombinations, fusions, frameshifts and other types of bishine that create "new things" according to your definition.
This argument is a bit chewy, isn't it?" - Not at all. After all, the researchers themselves rely on point mutations. Frameshift won't help here.
xianghua,
Certainly in the same garden. Look again at Roy Kishoni's article in the link I gave earlier. This is a one in a million example.
When it comes to bacteria all your assumptions are null and void. First of all, a short generation time of about 30 minutes, secondly, 9^10 cells in one colony and not 1000. Thirdly, under certain conditions, it is possible to reach more than 100 mutations in a cell (for example, in the presence of mutagens that also exist in nature), so I assume you will not argue that there is no evolution or Mutations are not cumulative.
Regarding creatures with sexual reproduction, the story is a little different. Calculate how long it will take until two mutations that are independent of each other are created and what is the chance that after they are created you will meet in one creature following mating? A billion years?
In any case, I told you to get off of it, this is not where your salvation will come from. There are mutations, both in the same gene and in different genes. There are recombinations, fusions, frameshifts and other types of bishine that create "new things" according to your definition.
This argument is a bit chewy, isn't it?
RH, I don't think you got to the root of my opinion. I'm talking about mutations in the same gene. So what do you want to claim, that some 4-5 mutations occurred simultaneously on the same gene? If you have evidence of such an event, I will indeed withdraw from the above argument. But you also have to take into account that this is not a "hot spot" but cases that can be repeated in every possible garden.
xianghua,
Alas, what a far-fetched calculation. I don't have the strength or time to even begin to explain how many errors there are in it, starting with the basic assumptions of what you are doing, the fixation of a neutral mutation, and ending with the calculation itself...
Please read the link already given earlier: http://en.wikipedia.org/wiki/Mutation_rate And understand how to calculate the mutation accumulation rate.
Besides, there is a simple matter called the result test which is there to judge and italola all your glorious calculation. Since I have personally encountered with my own eyes, hundreds if not thousands of times, the different cells with two mutations and more than their parent cell then:
1) Or I'm over a billion years old.
2) Or you are wrong
It's like you coming and trying to convince me that there's no way the sun rises in the east. But my brother, I saw!
Get, for example, an article from last week that shows an accumulation of mutations - http://www.ncbi.nlm.nih.gov/pubmed/22081229 How many billions of years do you think it took?
Leave it, it is better that you try the direction of the fish that is more like people than fish, it seems to me that it is more promising for you than to claim that it takes a billion years for the accumulation of two mutations.
Shabbat Shalom and in the building of Jerusalem we are comforted
Hingua is quite simple, God made a doll out of clay and blew it and the doll came to life, it's quite clear.
OK. Given a small genome with a length of 9^10 bases (three times smaller than the human genome). Given the fact that the chance of fixation of a neutral mutation is one of the parts of the population size and the number of generations required for this is also the number of individuals in the population:
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.section.1402
Given about 100 mutations in each birth and given that a generation is a year, and if we take into account an average population size of 1000 individuals, given all of this it would be argued that it would take over a billion years to change two specific bases on a specific gene. How do you solve this?
Shingo,
I started reading the article in the link you provided and I see that you have once again twisted information and conclusions from studies, just as you have done in the past (even after it was made clear to you why you are wrong and that the researchers' conclusion was the opposite of what you claimed to be inferring from the article). I'm already tired of showing you where you're wrong, because you seem to be able to take anything and twist it enough for it to "present" what you seem to need to present. Since there are countless ways to distort reality, I know what will happen even when I explain to you where you are wrong here.
You are still invited, as you have been asked many times and ignored, to present an explanation (an explanation! and not nonsense like God Almighty or anything like that!) for the variety of phenomena we know about both at the molecular level (genetic, biochemical), both at the anatomical and physiological level, and at the behavioral level, and of course the The paleontological knowledge, which all point to a common origin for the animals and small changes that accumulate. If you have another explanation please show it now and if you don't it's time you stop being a troll grasping at straws, especially in the probabilistic context.
xianghua,
what are you playing games Discounts, desire? How did they say the good, the bad and the ugly?
if you want to shoot, shoot!
For two mutations in a specific location, absolutely. Want to see how?
OK, let's say, how long do you think it takes to get two mutations? A billion years?
RH, before that, I need to know if you agree with the following premise-
In many cases, at least 2 mutations are required to obtain a new function, with the first being neutral. The evidence for this is from studies like this one for example:
http://www.nature.com/nature/journal/v461/n7263/full/nature08249.html
The researchers found that at least a few mutations are required to convert enzyme A to enzyme B. and more in a homologous enzyme. And this is not an isolated case.
Many functions require at least a few mutations (eg, to create a new promoter).
You can't argue with a biologist that's his job.
As for the rabbis, don't be naive, these calculations appear in the lectures of Zamir Cohen and his friends (who in turn copy them from the Discovery Institute, perhaps following this copying they will also decide to become Protestant Christians?)
xianghua,
Maybe enlighten us about your calculation? A billion years??
See here for example: http://en.wikipedia.org/wiki/Mutation_rate
Father, which rabbis are you talking about?
Are my calculations based on an error? They take books and professional articles in biology and biochemistry. Rather, I would like to see how RH presents a model for changing 2 specific nucleotides (when the first is neutral) in less than a billion years.
Xinghua,
R. H. already wrote to you that in his laboratory it took two weeks. You forget (or your chaplain or rabbi told you to forget) that evolution is not only random change but also the preservation of successful variations and thus change in a gene can accumulate very quickly (depending of course on the lifespan of that creature).
Conclusion, the theory of evolution that you think you know from the rabbis is a distortion of the true theory of evolution and therefore your calculations are based on false assumptions and therefore come out wrong. But the response is not to you but to those who are in the middle of the pan brainwashing process and can still return to sanity.
Kamila and RH, so when the pace is too fast it's okay and when the pace is too slow it's also okay?
I did my own calculation and found that to change two or three bases in a specific location would require at least a billion years. How exactly does this fit with the evolutionary model? Any possible plausibility? According to evolution tens to hundreds of bases in the same gene were changed in only a few million years. Something is very wrong here. Anyone have any suggestions?
Xinghua,
Indeed, evolution works at a rather impressive speed, sometimes very impressive speed. See here a video that deals with this topic:
http://davidson.weizmann.ac.il/online/maagarmada/life_sci/%D7%A2%D7%95%D7%91%D7%93%D7%95%D7%AA-%D7%A2%D7%9C-%D7%90%D7%91%D7%95%D7%9C%D7%95%D7%A6%D7%99%D7%94-4-%E2%80%93-%D7%94%D7%9E%D7%9B%D7%A0%D7%94-%D7%94%D7%9E%D7%A9%D7%95%D7%AA%D7%A3-%D7%9C%D7%9B%D7%9C-%D7%94%D7%9E%D7%99%D7%A0%D7%99%D7%9D-%D7%95%D7%A7%D7%A6%D7%91%D7%99-%D7%94%D7%AA%D7%A4%D7%AA%D7%97%D7%95%D7%AA
Roy Cezana,
There is no such thing as "stopping evolution", the fittest survives the most. In this case, perhaps the most suitable are snails that survive and breed best in birds? Or those that have developed a smell/color that attracts the birds to them?
In general, such systems are too complex to determine who will survive and how much and many times they are chaotic and therefore very sensitive to initial conditions (see predator/prey equations) and therefore produce surprising and unexpected results.
xianghua
There are many evolutionary mathematical models. The problem with them is that beyond two or three variables they become too complicated. It is easy to prove that they are true in closed systems containing few species.
It seems to me that a small and isolated group of the same species reaches infidelity faster than a large and diverse group. And incest is the death of evolution. Or I didn't understand something.
Does evolution work fast? Is there any mathematical-evolutionary model that confirms the scientists' opinion?
Anat
Instead of saying that it's all nonsense, then maybe tell us what the nonsense is here, otherwise we will come to the conclusion that your response is one big nonsense.
Good Day
Sabdarmish Yehuda
"fails to occur precisely because of this incessant shuffling of snails. Snails find it difficult to evolve, they are unable to change."
Every word in the summary sentence is wrong and the connection between the words raises a claim that is denied to the point of gibberish.
Why should evolution stop? After all, snails that survived the hardships of life on the island are eaten anyway. The birds are only a tiny part of the breeding process.
Why is this similar?, that we say that the bees that fight plants, harm the evolution of the plants.
Of course this is not the case.
Of course, the evolution of the blonde flying in the belly of the bird-plane may not be affected because of this.
Of course not the evolution of the human species either.
Roy, I enjoyed the article/story!
Good Day
Sabdarmish Yehuda
Outstanding
Memento