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Off-Topic Discussion => General Discussion => Topic started by: Wild Fragaria on September 27, 2005, 01:51:58 pm
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Evidence of evolution ;)
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Published online: 21 September 2005; | doi:10.1038/news050921-6
Ants make 'devil's garden' of Eden:
Ants use natural poison to kill all but their host plant.
Andreas von Bubnoff
Researchers have found an earthly cause for a phenomenon that Peruvian locals call 'devil's gardens' in the Amazonian rainforest. These gardens consist of just one type of tree (Duroia hirsuta). This is such an eerie and unusual sight in the otherwise diverse Amazon that locals presumed there to be a supernatural cause. But US researchers say it's ants, not the devil, that make this tree bloom.
The ants (Myrmelachista schumanni) live inside the trees' hollow stems, safe from predators and the environment. They kill all plants other than their host plant by injecting formic acid into the leaves. In this way, they help their host plant, and their own colony, to spread. Such gardens can hold more than 300 trees and millions of ants, and can be hundreds of years old.
"It's amazing that the ants exert so much control over their environment," says Deborah Gordon of Stanford University, California. "They create a single species stand of plants in one of the most diverse places on the planet."
Some previous studies have suggested that ants or the trees themselves were killing the surrounding plants, but no one could explain how. Now Megan Frederickson of Stanford University and her colleagues, including Gordon, report in Nature1 that the ants do it through injecting a natural poison.
The researchers planted saplings of a common Amazonian cedar tree (Cedrela odorata) inside an ant-infested forest. When they kept the ants away, the cedar trees thrived. But when ants had access to the young trees, the cedars all shed leaves after about five days.
It seems that the ants bite a hole in the leaves and deliver a droplet of formic acid from their abdomens. The plant's vascular system then spreads this acid throughout the entire plant. Within hours of the attack, brownish areas appear along the veins of its leaves.
"In hindsight it's obvious," says Susanne Renner of the University of Munich, Germany. She studied devil's gardens in Ecuador seven years ago, but was unable to explain how the ants killed the plants.
Formic acid is very common among ants: about one-quarter of the 15,000 ant species produce it, says Jack Longino, an ant researcher at Evergreen State College in Olympia, Washington. Many ants use it to defend themselves against animal or insect attack. But this is the first time that ants have been seen using it as a herbicide, he adds.
The devil's garden relationship joins a growing list of partnerships between plants and ants. Some plants have evolved to grow food for resident ants, which protect their host in return. Other ants physically cut away at neighbouring vegetation to help their host plants spread.
But how can an ant tell whether a plant is the same species as its host or different? That's the next mystery Frederickson wants to solve. She also wants to see whether the ants can kill mature trees as well as saplings, and find out how widespread devil's gardens are in the Amazon.
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That is awesome.
You probably have the coolest habit (Posting these articles) of any of the new people I've seen coming in here in a long time (with the possible exception of BR's "Releasing campaigns" habit). :D
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yes! go new guy! your doing much better than cobra or charismatic ever could have!
(no I'm not being sarcastic)
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Originally posted by Bobboau
yes! go new guy! your doing much better than cobra or charismatic ever could have!
(no I'm not being sarcastic)
Agreed.
I enjoy reading the articles. Keep it up WF. :)
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Awesome read, but I don't understand how this is evidence for evolution any more than it could be evidence for intelligent design. :confused:
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BAM
I love ants. They go agricultural... amazing.
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NB: see below.
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Ok, so from your post, I get the impression that this behavior in ants was observed not to exist at some point in the past, and then observed to have developed to take advantage of the surrounding environment, correct? Because from the quoted article, I got no impression that the behavior in question had "recently" developed.
EDIT: Additionally, I think one of us is misunderstanding the article. I understood that the plants which have that vascular system are being attacked by the ants, with the vascular system allowing the spread of the ants' formic acid throughout the plant, causing its death. You seem to imply the opposite; that plants with the vascular system are the ones with the advantage.
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Originally posted by Sandwich
Ok, so from your post, I get the impression that this behavior in ants was observed not to exist at some point in the past, and then observed to have developed to take advantage of the surrounding environment, correct? Because from the quoted article, I got no impression that the behavior in question had "recently" developed.
It's not the recency of the behaviour that matters, it's both the disparity (from other ant species) and the environment of it; not only is it tailored to a specific environment (the host tree) and thus conveying an advantage of survival, it's a different behaviour from other known ants. Which is indicative of it being developed through natural selection within that region, and quite possibly developed for a specific host plant.
Originally posted by Sandwich
EDIT: Additionally, I think one of us is misunderstanding the article. I understood that the plants which have that vascular system are being attacked by the ants, with the vascular system allowing the spread of the ants' formic acid throughout the plant, causing its death. You seem to imply the opposite; that plants with the vascular system are the ones with the advantage.
Yup, i misread/misunderstood it. :o
http://news.bbc.co.uk/1/hi/sci/tech/4269544.stm clarified it for me.
http://dsc.discovery.com/news/briefs/20050919/ants.html
http://www.livescience.com/animalworld/050922_ant_gardeners.html
The plants...don't really matter. They're just selected by the ants it would seem; unless there's a (unmentioned here) specific adaptation the plants have developed in reciprocity, of course.
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what, no. the ants bite the other plants leaves, and they die from it. right?
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Originally posted by kode
what, no. the ants bite the other plants leaves, and they die from it. right?
Yup. i've (tried) to correct me previous post/s. Albeit a bit of doublethink could be useful........
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Originally posted by Sandwich
Awesome read, but I don't understand how this is evidence for evolution any more than it could be evidence for intelligent design. :confused:
Evolution is the wrong word. Natural Selection would be the proper phrase instead. Look at it this way: in a given area of the forest, one particular type of plant flourishes. Why? Ants kill the rest. Environmental factors have selected one organism out of many to survive.
Unfortunately, this form of natural selection likely will not be signifigant in the overall evolution of the forest system or the species (of which these trees are members) as a whole, because there's nothing here that indicates that different group sof ants always select the same sort of tree, no matter where they are. This selection is purely local to the section of the forest in which a given group of ants live.
Proof of evolution? No. Proof of natural selection? Absolutely.
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You don't think instinctive behaviour can evolve within a fixed population? If this local population has developed the ability to chemically detect a specific type of host tree, and to 'weedkill', I'd say that it had evolved; I don't see how being confined to a specific territory would restrict a species from changing into a different form, especially if they would seem to have the Amazon rainforest as that territory.
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Originally posted by mikhael
Evolution is the wrong word. Natural Selection would be the proper phrase instead. Look at it this way: in a given area of the forest, one particular type of plant flourishes. Why? Ants kill the rest. Environmental factors have selected one organism out of many to survive.
Unfortunately, this form of natural selection likely will not be signifigant in the overall evolution of the forest system or the species (of which these trees are members) as a whole, because there's nothing here that indicates that different group sof ants always select the same sort of tree, no matter where they are. This selection is purely local to the section of the forest in which a given group of ants live.
Proof of evolution? No. Proof of natural selection? Absolutely.
Natural selection is a mechanism of Evolution. It is a process that occurs over successive generations. Which means that a generation has to survive and reproduce that some day they will overrun the earth. In this case, the ants (Myrmelachista schumanni) is our focus, not the jungle. The ants eliminate other plants apart from their host plants so their survival chance becomes greater for having a shelter - to get the the protection the ants needed to a place to reproduce. What makes it intersting is that not all the ant species behave in the similar way, especially not in such a rich and diverse environment. I like to think that in way we are probably witnessing the 'beginning' of an evolution of an organism.
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Black Wolf, Bobboau & Falcon
I am glad that you guys like reading the article (and the other scientific articles I posted). I thought they are something a little different that some of you will appreciate.
And Bobboau, I do not mind being called the 'new guy' but for your info I am a girl ;)
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Originally posted by Wild Fragaria
I like to think that in way we are probably witnessing the 'beginning' of an evolution of an organism.
That's what it strikes me as. You look at hummingbirds that can only get nectar from one particular kind of flower etc and wonder how they get so specialised well something like this is one of the first steps down the path.
The plant and the ant have gotten themselves into a symbiotic relationship but neither is dependant on the other yet. There's a fair selection pressure in favour of the two becoming further intertwined though.
Originally posted by Wild Fragaria
I am a girl ;)
Prepares for stampede :D
Then again this is a fairly scientific thread so far. You might get away with it :)
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:hopping:
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karajorma is most likely correct. The people who would jump into the conversation and go crazy due to the prescence of a girl would most likely avoid this sort of thread.
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Originally posted by Wild Fragaria
I am a girl ;)
That explains it then.
Originally posted by Bobboau
your doing much better than cobra or charismatic ever could have!
(no I'm not being sarcastic)
Great article. :yes:
Is there an original link though?
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I suspect that this is something from Nature or another Journal that Fragaria has institutional access to.
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If we go back to the subject:
I really don't believe that we can even think this as a beginning of that ant species evolution. Even in the article the researches mentions having studied similar 'gardens' (which may be hundreds of years old) elsewhere in the South America, so this doesn't seem to be a new phenomenon. Rather only recently discovered (big difference). And just think about any species that grow to be dependant on other species (for example koala). What if the host plant is diseased and in some areas totally wiped out?
BTW. Different plants species have very different chemical compositions (in VOCs or volatile organic compounds, the ones which smell), how hard can it be for an ant to id different plant species perhaps by tasting or by smell? Even human can recognize certain odours (even when encountering these in extremely low concentration), so i would suppose that ants have evolved to recognize the host plants species also by these compounds, in other words like tuning their senses for the compounds that are most likely vital for their survival => if they take down a wrong plant, the whole ant colony might be destroyed (again, natural selection)...
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Originally posted by BlackDove
That explains it then.
What explains it?
Originally posted by BlackDove
Great article. :yes:
Is there an original link though?
Nope, you won't be able to go on to the link if you're not the journal's subscriber. I did enclose the date and publication info of the article at the beginning so people could refer to the hard copy if they wanted to.
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Originally posted by Wanderer
If we go back to the subject:
I really don't believe that we can even think this as a beginning of that ant species evolution. Even in the article the researches mentions having studied similar 'gardens' (which may be hundreds of years old) elsewhere in the South America, so this doesn't seem to be a new phenomenon. Rather only recently discovered (big difference). And just think about any species that grow to be dependant on other species (for example koala). What if the host plant is diseased and in some areas totally wiped out?
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Well, to be completely crystal clear: You cannot really think of this as a "beginning of an evolution".
You can always backtrack and find small, clinal changes in the species. Over time these accumulate. Point being - species don't just pop out of nowhere, and this kind of wide behaviour suggests that this gene has been active in this ant specie's genome for a long time - maybe effectively preventing hybridization with other near relative ant species (where it would be yet another species mark..).
What we can observe, anyways, is how fast this changes the species. Some people have theoretized that the evolutionary unit in many social hymenopteron's is not an individual or even a queen. It's the hive. The same holds kinda true to ants which are pretty unique group. We can observe the evolution (usually indirectly), of course, but we cannot just sprout out: "This is the beginning of the evolution" - it's false.
edit: OK then. :)
VVVVVVVVVVVVVVVVVV
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Well i tried to say that but in more polite manner :D
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Originally posted by Wanderer
I really don't believe that we can even think this as a beginning of that ant species evolution. Even in the article the researches mentions having studied similar 'gardens' (which may be hundreds of years old) elsewhere in the South America, so this doesn't seem to be a new phenomenon. Rather only recently discovered (big difference). And just think about any species that grow to be dependant on other species (for example koala).
You don’t have to believe that it is the beginning of an evolution of that ant species. No one claimed that as a fact in the article anyway. The research has been conducted in the South America which is where the Amazon Rainforest is. It was not the first time they encountered the phenomenon but no one could explain why the ‘Devil’s Garden’ contained only one type of plant when the garden was discovered. But now, scientists have an explanation on how the ants are responsible and the gardens are being created.
Originally posted by Wanderer
What if the host plant is diseased and in some areas totally wiped out?
It would be bad for the ants of course. They will probably go extinct because their habitat no longer available. Take the Ivory-billed woodpeckers for example, they disappeared when their forest habitat was destroyed decades ago. Another example, during the English Industrial Revolution in the 19th Century, soot and other industrial wastes darkened tree trunks and killed off lichens. The light-colored morph of the moth became rare. Anyhow, if some ants do survive, they will probably evolve to adapt to something new.
Originally posted by Wanderer
BTW. Different plants species have very different chemical compositions (in VOCs or volatile organic compounds, the ones which smell), how hard can it be for an ant to id different plant species perhaps by tasting or by smell? Even human can recognize certain odours (even when encountering these in extremely low concentration), so i would suppose that ants have evolved to recognize the host plants species also by these compounds, in other words like tuning their senses for the compounds that are most likely vital for their survival => if they take down a wrong plant, the whole ant colony might be destroyed (again, natural selection)...
That’s the next thing scientists hope to find out.
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Originally posted by Janos
Well, to be completely crystal clear: You cannot really think of this as a "beginning of an evolution".
You can always backtrack and find small, clinal changes in the species. Over time these accumulate. Point being - species don't just pop out of nowhere, and this kind of wide behaviour suggests that this gene has been active in this ant specie's genome for a long time - maybe effectively preventing hybridization with other near relative ant species (where it would be yet another species mark..).
What we can observe, anyways, is how fast this changes the species. Some people have theoretized that the evolutionary unit in many social hymenopteron's is not an individual or even a queen. It's the hive. The same holds kinda true to ants which are pretty unique group. We can observe the evolution (usually indirectly), of course, but we cannot just sprout out: "This is the beginning of the evolution" - it's false.
But you can not ignore the facts that the ants have gained so much ‘control’ over their living environment and even some new plants have evolved to grow food for the insects. Variants do not arise unless they are needed. These phenomenons fits nicely as the beginner elements of evolution.
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I think it's worth suggesting evolution doesn't exactly 'begin' as such, at least not in an easily quantifiable way, and is more of a constant process taking place since the first single celled organisms (and even the amino acids that formed them)
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Originally posted by Wanderer
And just think about any species that grow to be dependant on other species (for example koala). What if the host plant is diseased and in some areas totally wiped out?
Then the species is f**ked.
Thing is that is the sort of consideration that only an intelligent designer would care about. Natural selection can only work on what it has right in front of it. If tighter integration is good for the species for the next 10,000 years that's where it will go. It doesn't matter in the slightest that 15,000 years from now a new virus could arise and wipe one of the species out.
We can all see that this could be a very bad thing for the ants but evolution simply doesn't care. If the selection pressure is rolling downhill towards a cliff then they'll all go off the edge.
Times like this that I'm really glad that humans are a generalist species rather than specialising.
EDIT : Actually I suppose any intelligent tool user is going to be a generalist to some degree. Lets say instead that I'm glad we evolved from a generalist rather than having as specialist traits still in us like a dependance on a certain kind of animal or tree.
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Originally posted by karajorma
Times like this that I'm really glad that humans are a generalist species rather than specialising.
[color=66FF00]Not to be intentionally funny but surely we specialise at generalising.
There's not a lot of creatures that can exist in all of the places we can.
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After all, you can't naturally select based upon what's not present......
Thinking about it, the dependency state is kind of another factual contradition to creationism; it assumes species are (well, must be) designed to fail. I kind of like an analogy I read in the paper (http://www.theherald.co.uk/features/47818.html) today; he ID challenge to evolutionary scientists and evolutionary theory is not unlike a pacifist challenging the SAS to a game of tiddlywinks.
Although even having (or feeling we need to) to mention ID in this sort of a discussion is sort of an insult to proper scientific exploration.
Originally posted by Maeglamor
[color=66FF00]Not to be intentionally funny but surely we specialise at generalising.
There's not a lot of creatures that can exist in all of the places we can.
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No, we're generalized specialist generalizers. :D
Originally posted by Wild Fragaria
What explains it?
The username, presumably. AFAIK most blokes wouldn't select 'strawberry' as an alt-name on the electroniinterweb.
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Originally posted by aldo_14
I think it's worth suggesting evolution doesn't exactly 'begin' as such, at least not in an easily quantifiable way, and is more of a constant process taking place since the first single celled organisms (and even the amino acids that formed them)
Actually that depends on how you're looking at it. Punctuationism basically states that evolution isn't constant but instead has reasonable long plateaus where there is no change followed by sharp intervals where change occurs. The start of a period of change could quite fairly be described as the start of a period of evolution.
Incidentally there was a big argument about punctuationism in scientific circles a while back until the side that had proposed it realised that the other side had never said it didn't happen, they'd simply assumed everyone knew that it must be true :lol:
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Originally posted by karajorma
Actually that depends on how you're looking at it. Punctuationism basically states that evolution isn't constant but instead has reasonable long plateaus where there is no change followed by sharp intervals where change occurs. The start of a period of change could quite fairly be described as the start of a period of evolution.
Incidentally there was a big argument about punctuationism in scientific circles a while back until the side that had proposed it realised that the other side had never said it didn't happen, they'd simply assumed everyone knew that it must be true :lol:
I dunno. I knid of thought of the process of staying the same being part of evolution; I'd (personally) include the suppression of negative traits (which is still natural selection acting) as part of the process, although I guess it's not strictly or technically evolving if there's not a positive change.
EDIT; i.e. what I meant is that organisms are constantly undergoing natural selection. I'm not sure if you define the start of an evolutionary process (i.e. from one species towards another) as when a natural pressure first exerts itself, or when the first beneficial traits under that pressure emerge and are selected.
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Evolution is a dynamic process. The beginning is when basic amino acids formed in the primordial soup, and the end is when all terrestrial life dies.
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Originally posted by aldo_14
I dunno. I knid of thought of the process of staying the same being part of evolution; I'd (personally) include the suppression of negative traits (which is still natural selection acting) as part of the process, although I guess it's not strictly or technically evolving if there's not a positive change.
Actually I wouldn't agree with that. It's quite frequently stated that sharks for instance evolve slowly or that they've hardly evolved in the last 100 million years or so. The fact that any new mutations are selected against in sharks is actually stated as the reason why they evolve so slowly.
Originally posted by aldo_14
EDIT; i.e. what I meant is that organisms are constantly undergoing natural selection. I'm not sure if you define the start of an evolutionary process (i.e. from one species towards another) as when a natural pressure first exerts itself, or when the first beneficial traits under that pressure emerge and are selected.
Doesn't really matter as both events occur so close together that on the timescale we're talking about they're virtually instantanious. After all if there is a selection pressure that suddenly arises then the selection of animals with benifitial traits will begin as soon as the next generation is born at the latest.
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Originally posted by Wild Fragaria
Natural selection is a mechanism of Evolution. It is a process that occurs over successive generations. ... I like to think that in way we are probably witnessing the 'beginning' of an evolution of an organism.
It drives me nuts when people point to something and say, "See! Evolution!" and what they're actually seeing is natural selection.
Natural selection is a short term observable (subject population X is in event Y. Subpopulation X' survives. Subsequent observation reveals a genetic trait that allowed X' to survive.) Evolution is the summation of all the short term observables that occured in the genetic history of a population with a particular genotype. Thus, evolution is an abstract that cannot be observed, but only inferred through induction.
That's why I say that this is an example of natural selection (the trees the ants 'like' are being selected for and the trees they 'dislike' are being selected against). In a million years, someone can look back and see this as a one point on the mathematical curve of evolution. This point is NOT evolution, but evolution is made up by many of these points. The point does not define the curve, but exists within it.
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Originally posted by Maeglamor
[color=66FF00]Not to be intentionally funny but surely we specialise at generalising.
There's not a lot of creatures that can exist in all of the places we can.
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With the exception of Antartica and the Artic, ants exist everywhere. Everywhere humans have cities, there are roaches.
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we are specalised tool makers, environment modifiers (we don't adapt to the environment, we adapt the environment to us), and socal animal. we have a lot in common with ants actualy, the biggest diference is we aren't as socalised and are far more developed in tool makeing. ants are cool, one of my favorite animals.
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Originally posted by mikhael
It drives me nuts when people point to something and say, "See! Evolution!" and what they're actually seeing is natural selection.
Natural selection is a short term observable (subject population X is in event Y. Subpopulation X' survives. Subsequent observation reveals a genetic trait that allowed X' to survive.) Evolution is the summation of all the short term observables that occured in the genetic history of a population with a particular genotype. Thus, evolution is an abstract that cannot be observed, but only inferred through induction.
That's why I say that this is an example of natural selection (the trees the ants 'like' are being selected for and the trees they 'dislike' are being selected against). In a million years, someone can look back and see this as a one point on the mathematical curve of evolution. This point is NOT evolution, but evolution is made up by many of these points. The point does not define the curve, but exists within it.
Actually I think you're making assumptions without the data to back it up.
Fact is that if there are other Myrmelachista schumanni who don't show this behaviour with the trees they nest in even if it's the same type of tree then there is a before and after you can point at and say See! Evolution!
If the ants that live in these gardens show a type of behaviour that other ants of the same species don't when placed in the same conditions then you definately have evidence of an evolutionary change.
You're making the assumption that all ants of this species show the same behaviour when you say that there is only one point on the curve. I've not seen you provide any evidence to back this up and none of the articles say anything about it in either direction.
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http://mit.biology.au.dk/~biojmo/pdf/Olesen%20et%20al.%20duroia.pdf
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Originally posted by karajorma
Actually I think you're making assumptions without the data to back it up.
*** Much blathering about ants removed ***
Um, Kara, I wasn't talking about the ants. Go and reread what you quoted very carefully, with particular emphasis on the third paragraph there.
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You're missing the point too. If you can point to ants in all the stages between them ignoring all the forest plants all the way up to making these devils gardens then you can say it.
Instead of transitional species in this case you could possibly point to a line of transitional behaviours.
That's why I'm saying you're making assumptions. You've assumed that there are no transitional forms based on no data whatsoever.
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Originally posted by aldo_14
The username, presumably. AFAIK most blokes wouldn't select 'strawberry' as an alt-name on the electroniinterweb.
So how long did you take to figure that out? And how many of you knew that before my announcement yesterday? :)
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Originally posted by Wild Fragaria
So how long did you take to figure that out? And how many of you knew that before my announcement yesterday? :)
Errr.... I didn't actually.
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Originally posted by mikhael
Natural selection is a short term observable (subject population X is in event Y. Subpopulation X' survives. Subsequent observation reveals a genetic trait that allowed X' to survive.) Evolution is the summation of all the short term observables that occured in the genetic history of a population with a particular genotype. Thus, evolution is an abstract that cannot be observed, but only inferred through induction.
So according to your proposal, when does evolution begin?
Originally posted by mikhael
That's why I say that this is an example of natural selection (the trees the ants 'like' are being selected for and the trees they 'dislike' are being selected against). In a million years, someone can look back and see this as a one point on the mathematical curve of evolution. This point is NOT evolution, but evolution is made up by many of these points. The point does not define the curve, but exists within it.
But you can not say it like that either because there isn't a standard 'point' when evolution begins, and how many points/ stages you will have to have to claim that evolution title.
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I think some of you might be interested in the following abstract.
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Oecologia. 2005 Apr;143(3):387-95. Epub 2005 Feb 12.
Frederickson ME
The dynamics of mutualistic interactions involving more than a single pair of species depend on the relative costs and benefits of interaction among alternative partners. The neotropical myrmecophytes Cordia nodosa and Duroia hirsuta associate with several species of obligately symbiotic ants. I compared the ant partners of Cordia and Duroia with respect to two benefits known to be important in ant-myrmecophyte interactions: protection against herbivores provided by ants, and protection against encroaching vegetation provided by ants. Azteca spp., Myrmelachista schumanni, and Allomerus octoarticulatus demerarae ants all provide the leaves of Cordia and Duroia some protection against herbivores. However, Azteca and Allomerus provide more protection than does Myrmelachista to the leaves of their host plants. Although Allomerus protects the leaves of its hosts, plants occupied by Allomerus suffer more attacks by herbivores to their stems than do plants occupied by other ants. Relative to Azteca or Allomerus, Myrmelachista ants provide better protection against encroaching vegetation, increasing canopy openness over their host plants. These differences in benefits among the ant partners of Cordia and Duroia are reflected in the effect of each ant species on host plant size, growth rate, and reproduction. The results of this study show how mutualistic ant partners can differ with respect to both the magnitude and type of benefits they provide to the same species of myrmecophytic host.
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Originally posted by karajorma
You're missing the point too. If you can point to ants in all the stages between them ignoring all the forest plants all the way up to making these devils gardens then you can say it.
Actually, no. If I were to discuss all the ants in all the stages, etc, I would be talking about evolution of a system involving ants and trees. I am, however, talking about any single devil's garden made by any single ant colony. Each one of those is a case of natural selection.
Now, since the article was about how ants kill off trees they "dislike", I'd have to say that's what we were talking. I'm pretty sure I'm not making any assumptions.
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Originally posted by Wild Fragaria
So according to your proposal, when does evolution begin?
But you can not say it like that either because there isn't a standard 'point' when evolution begins, and how many points/ stages you will have to have to claim that evolution title.
Where does a parabola begin?
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(-∞,-∞) or (-∞,∞).
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Originally posted by mikhael
Actually, no. If I were to discuss all the ants in all the stages, etc, I would be talking about evolution of a system involving ants and trees. I am, however, talking about any single devil's garden made by any single ant colony. Each one of those is a case of natural selection.
Now, since the article was about how ants kill off trees they "dislike", I'd have to say that's what we were talking. I'm pretty sure I'm not making any assumptions.
Since the article is the abstract from a scientific paper I think you're making an assumption that the rest of the paper doesn't include data on the ants in other stages.
It's quite possible that the rest of the paper does contain that data which simply wasn't posted because it's dry boring scientific stuff that would be out of place on this board. It's also possible that Fragaria simply didn't notice that the abstract didn't mention those facts.
So it comes down to one of two things
1) The paper doesn't mention ants showing other forms of behaviour (In which case Fragaria was wrong).
2) The paper does mention them in which case the paper is proof even if the abstract isn't.
That's what I mean about making assumptions that the paper doesn't contain other details pertinent to the discussion.
Secondly my real beef is with your claim that evolution is unobservable and especially that it takes millions of years to occur. That's of course utter nonsense. As you've just stated above you can see evolution of a behaviour simply using the animals of a species that are around today.
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Originally posted by Grey Wolf
(-∞,-∞) or (-∞,∞).
Showoff. Isn't that CP's line?
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Yet another finding, read this. (http://news.bbc.co.uk/2/hi/science/nature/4296606.stm). Though is only the first observed gorillas tool usage.
Is this 'just another point on the parabola' or 'the point where evolution began'? Though it may be neither as other great apes have been seen using tools even earlier. However i think the former is a better description of evolution and different stages in it. Evolution is a dynamic and continous process (IMHO).
Copy-pasted:
BBC-News
Wild gorillas seen to use tools
What's fascinating is the similarity between what these creatures have done and what we do
Thomas Breuer
Gorillas have been seen for the first time using simple tools to perform tasks in the wild, researchers say.
Scientists observed gorillas in a remote Congolese forest using sticks to test the depth of muddy water and to cross swampy areas.
Wild chimps and orangutans also use tools, suggesting that the origins of tool use may predate the evolutionary split between apes and humans.
Gorillas are endangered, with some populations numbered in the hundreds.
'Valuable insights'
"We've been observing gorillas for 10 years here, and we have two cases of them using detached objects as tools," said Thomas Breuer, from the Wildlife Conservation Society (WCS), who heads the study team in Nouabalé-Ndoki National Park in the Democratic Republic of Congo.
"In the first case, we had a female crossing a pool; and this female has crossed this pool by using a detached stick and testing the water depth, and trying to use it as a walking stick," he told the BBC.
Gorillas use nature's toolbox
In pictures
The second case saw another female gorilla pick up the trunk of a dead shrub and use it to lean on while dredging for food in a swamp.
She then placed the trunk down on the swampy ground and used it as a bridge.
"What's fascinating about these observations is the similarity between what these creatures have done, and what we do in the context of crossing a pond," observed Dr Breuer.
"The most astonishing thing is that we have observed them using tools not for obtaining food, but for postural support."
In the family
This discovery makes the gorilla the last of the great apes to be documented using tools in the wild.
Chimpanzees use stone tools to process food, and their close relatives bonobos will use the mashed ends of sticks to soak up liquids.
Orangutans - the only Asian great ape - use branches to forage for food, and leaves to modify their calls.
Though some monkeys and birds also use tools, Thomas Breuer believes that the great apes are special.
"We have now seen tool use in all the great apes in the wild," he said.
Chimpanzee Ai sits in front of a computer monitor. Image: AP/Tetsuro Matsuzawa, Kyoto University Primate Research Institute
The chimp Ai can count and recall numbers, recognise characters
"That now makes us think that it might be the case that tool use has been an ancient trait of all great apes before the human lineage split away."
Current scientific orthodoxy holds that the separation between the chimpanzee and human lines came about six million years ago.
Research has shown that in captivity, apes can learn a range of skills including number and character recognition.
They can also learn tool use and transmit their acquired skills to other members of their social group.
The Congo team, drawn from the WCS and the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany, believes that the tool traits they have observed in the wild may also be shared and learned across gorilla social groups.
They publish their findings in the online journal Public Library of Science Biology.
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Originally posted by Sandwich
Showoff. Isn't that CP's line?
Damn! I forgot to account for parabolas defined as X=Y^2!
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I have the original paper of the article I posted. The research was done to investigate the mutualistic interactions involving two Myrmecophytic plants (neotropical myrmecophytes): Cordia Nodosa and Duroia Hirsuta and three ant species: Myrmelachista schumanni, Azteca spp., and Allomerus octoarticulatus demerarae. Apparently, not all the plants in the 'garden' are dwelled by the ants and there are 'competition' between ants and plants. For instance, the Duroia actually grow more fruits when Myrmelachista ants occuppied them. Another interesting fact that was not mentioned in the article, is the ants patrol their host plants to protect their hosts from herbivores. Some ants do better than the other in protecting their plants, others are just lazy. I enclose some data and facts from the paper below so you could have some references :)
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Quote:
Ant species did not inhabit equal shares of the host plant population
20 % of Cordial and Duroia are unoccupied
3 - 4 % of plants other than Cordia and Duroia
Cordia -
Myrmelachista = 7%
Azteca = 19%
Allomerus = 51%
Duroia -
Myrmelachista = 65%
Azteca = 11%
Fruiting and flowering
Duroia fruits more
95.8% of them occupied by Myrmelachista
4.2% of them occupied by Azteca
Behavior of ants
The ants patrol their host plants (Myrmelachiats and Azteca).
Allomerous workers do not actively patrol the trunks of their host plants, where beetles attack.
Myrmelachista clears vegetation from around Duroia and Cordia, not Azteca.
Azteca provides the most protection of leaf herbivore to Cordia and Duroia. A proposal – Azteca ants are common plant-ants because of their highly carnivorous diet makes them very effective guards.
Myrmelachista provides the most favorable light environment, and the data is biologically significant. The first documented ant species to use their poison, formic acid as herbicide.
Variation in host plants
Azteca occupied Cordia are larger, more growth, more frequent fruiting and flowering than Alleomerus occupied Cordia.
Myrmelachista occupied Duroia were larger and more fruiting and flowering but less growth than Azteca occupied Dutoia.
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Kara, can you show me an example of evolution "we can observe" happening?
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Bacteria. Even the creationists don't try to deny it happens there.
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evolution isn't as continuous as a porabala, it has incroments, if you have two or more genorations the acumulated natural selection is evolution. bam.
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Micro evolution...sure.
But even with all the amazing adaptations and natural selected diversifications, an observed case of MACRO evolution have yet to be reported. Now if these crazy ants were to one day grow to extra legs and become arthropods... then I'll start taking the "evidence for evolition" more seriously. I'm not going to jump to conclusions on a scientific theory just because I dont LIKE, or refuse to believe other avenues of thinking.
This debate needs to be silenced already. Both sides seems to be taking to the offensive so agressively because both sides think they are seeking to destroy one an another's way of perceiving this universe. Both sides should acknowledge both the differences AND practical benefits each side offers.
I personally think that this universe contains many things both explainable and mysterious. I don't believe that everything in this universe is explainable, predictable, and controllable. But I am not condemming science's role in trying. We humans have been gifted with brains whose perceptions transcend that of any other creature on this Earth. To not use it is... well, stupid. But even the brain has so many different levels of thought that should not be easily dismissed.
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I very much doubt that Mikhael is going to make the claim that macro and micro evolution are different things.
Only creationists ever make that claim.
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well the problem of the whol "macro evolution" thing is that 'macro evolution' is just a whole bunch of 'micro evolution' so you will never have an ant 'one day' growing anything spectacular, they change slowly over a long time, so much so that youd never see it within your life.
though honestly I'm starting to seriosly consiter getting two little animal cases and and growing a colony of fruit flys in each, trying to give as diferent an environment as posable to each and letting them grow for a few decaes to see what happens. hopefully they'll change so much that they'll become geneticly incompatable with each other.
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Originally posted by karajorma
Bacteria. Even the creationists don't try to deny it happens there.
Bacteria is a hard one to claim as evolution. Its one of the rare cases where organisms use each other's DNA, regardless of species. One bacteria can toss some DNA that another bacteria--unrelated--can then use.
As for micro vs macro evolution: WTF? I could no more make a distinction there than I could state, with honesty and integrity, that Creationism is a valid theory.
Bob: you won't get incompatible strains. That experiment has been tried (albeit unintentionally). The animals used have included dogs, cats, horses, cows, chickens, etc.
Kara, my point was that evolution is a process that is not fractal. You can't point to a bit of evolution and say "that's evolution". You can only point at a bit and say "that contributed to the overall evolution of the species as we know it". Kind of like when you have an accelleration curve, you differentiate it and get a speed at a given moment in time. The speed of the car doesn't really tell you anything about its accelleration, but the accelleration can tell you about its speed.
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Originally posted by mikhael
Bacteria is a hard one to claim as evolution. Its one of the rare cases where organisms use each other's DNA, regardless of species. One bacteria can toss some DNA that another bacteria--unrelated--can then use.
Nonetheless evolution of bacteria can be observed under laboratory conditions where care is taken to ensure that no foreign DNA is available to cause contamination.
Originally posted by mikhael
As for micro vs macro evolution: WTF? I could no more make a distinction there than I could state, with honesty and integrity, that Creationism is a valid theory.
I knew you couldn't. Omni was trying to say the two things were different but the point I was making is that if I can point out any incidence of evolution you wouldn't care whether it was macro or micro. Both would be equally
Originally posted by mikhael
Kara, my point was that evolution is a process that is not fractal. You can't point to a bit of evolution and say "that's evolution". You can only point at a bit and say "that contributed to the overall evolution of the species as we know it". Kind of like when you have an accelleration curve, you differentiate it and get a speed at a given moment in time. The speed of the car doesn't really tell you anything about its accelleration, but the accelleration can tell you about its speed.
I disagree. Punctuationism states that there are actual steps in evolution and that it's not a continuous process like a curve. There are long periods when nothing happens and short ones where a lot of change occurs.
If you catch the right species at the right time you can actually find a time when a change is occuring and then you can say look evolution without needing to wait a million years for it.
That was the point I was making about the ants. The ones which make the gardens are obviously very different from those which don't yet since they are the same species they must have accumulated that change since speciation.
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I don't buy into punctuationism, mainly because it seems to assume a time scale small enough that statistically irrelevant variances are signifigant. Again I must reference the accelleration curve problem: while indeed my individual speed at any given point may or may not fit the proposed curve precisely, my overall accelleration does fit it reasonably well. In other words, on long enough time scales, evolution will be smooth. I'd say 4.5 billion years, plus or minus 20 million is a long enough time scale to smooth things out. Hell, even 3.5by is enough (if we go with the earliest stromatolites as the first life).
As for the bacteria study, can you show me where this has led to distinct speciation? If it doesn't result in speciation, is it really, in the end, evolution?
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Originally posted by mikhael
I don't buy into punctuationism, mainly because it seems to assume a time scale small enough that statistically irrelevant variances are signifigant.
The fact is that there isn't a single evolutionary biologist who doesn't buy into some form of punctuationism. The only difference between the theories is how large the plateaus are and how short the periods of change are.
Originally posted by mikhael
As for the bacteria study, can you show me where this has led to distinct speciation?
Yep I can. Not a bacterium in this case but I'm sure that speciation in an alga is good enough for you.
Coloniality in Chlorella vulgaris
Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.
Boraas, M. E. 1983. Predator induced evolution in chemostat culture. EOS. Transactions of the American Geophysical Union. 64:1102.
If you want more than that I suspect I'm going to need to ask Fragaria to look up the paper for us.
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has anyone tryed the specisation experiment I sugested with something that has a very short maturation? you say it's been done with dogs and hoarses, but they take sevral years to reach maturity, if some insect with a very fast reproduction rate was used then I think it might have a posibility of working within a human life, assumeing they were given sufficent stress.
I'm thinking doing a full environmental stress test would work, get a collony of fruit flies, sence they have a life cycle of 2 weeks, you can get thousands of generations within a single human life.
you take population A and saturate its food with sevral acidic chemicals, not enough to kill them, but enough to make them unhealthy, keep the atmosphere very dry and the food not overly moist.
population B's food gets saturated with sevral alcaline chemicals a super humid atmosphere and the food is almost desolved completely in water saturateing the botom of the enclosure.
you could also have populations with other varialbes, maybe haveing heavy exposure to petrolium chemicals, but the general idea is just to streas diferent populations diferently in hopes that it will cause cellular level evolution that causes the diferent populations to diferentiate, every year you could take a few males and females from the diferent populations and see if they are able to mate with members of the other population.
unfortunately the 2 week life cycle would ultimately be long, my estimate based mostly on fosil record secisation and life cycle lengths of the exsisting decendendts is that it takes somewere between 50,000 and 200,000 generations for a speciese to diferentiate, even assumeing the diferent hostile environments accelerated the proces by an order of magnatude (meaning it would take 5,000 generations) it would take about 350 years for the experiment to work useing fuit flys that have 14 generations per year.
in order to get a diferent species within a decade you'd need an organism capable of a new generation 10-40 times a day. and it'd need to be complex enough to reproduce via some form of sex.
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Originally posted by mikhael
As for micro vs macro evolution: WTF? I could no more make a distinction there than I could state, with honesty and integrity, that Creationism is a valid theory.
Macroevolution is somewhat different, but only in the fact that it takes specific mutations to trigger it. You need to manipulate Hox genes or alter embryonic developmennt, or some other relatively major change. At it's core though, it's all still the same stuff.
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Why do we have two of these threads active at once? :wtf:
As I posted in the other evolution:no evolution thread, bacterial evolution is different from that of more complex organisms. There's no denying that. Of course, bacterial reproduction is also quite different from higher-order reproduction. Sexual reproduction should have a fairly stabilizing and slowing effect on evolution, if just because the whole population, or at least a significant subset of it, must share genes and thus will have to be on the same evolutionary path. (Never mind the longer life cycles and slower reproductive rates that the more complex organisms require). Bacteria can share their DNA with other species, which means it only takes one strain of one species to develop a new trait and then every bacteria exposed to it could potentially pick it up. But what really drives the speed of "micro-evolution" is that it really only takes one bacterial cell to undergo a mutation and all of the bacteria that arise from it will have the same mutation. Plus, other bacteria can pick up the mutation and thus become the same strain while they are still alive (very much a difference between bacteria and multicellulars). If that leads to a novel benefit over other bacteria of the same species, then the new strain will out-compete (and/or assimilate) the old in VERY short order. The difference in the method of genetic transfer alone accounts for the ability to observe differentiation in human years (well, defining differentiation on bacteria is dicy anyway, since the "can it mate with subspecies x" test doesn't exactly work). And of course there's the fact that most cells in a sexually reproducing organism don't get passed on to offspring; reproductive cells specifically (or an embrio, but only very early in development) must be the ones on the recieving end of a mutation in order to be passed on to children. Because of the stabalizing effect of the means of reproduction (and of course the complexity of the organism) it takes millions of years to accomplish what a bacterial colony could in months, there is absolutely no reason that the same guiding forces acting on bacteria do not also apply to multicellular organisms. A hypothesis stating otherwise carries the burden of proof, not the other way around.
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Originally posted by StratComm
Why do we have two of these threads active at once? :wtf:
We don't - this one is about evolutionists disagreeing with evolutioists on points of detail within the theory. The other is more or less your bo standard HLP evolution/creation thread.
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Ah, I saw Omni's post, which on reading back, really doesn't fit the rest of the thread well. My bad. My rant can actually be transferred to the standard HLP debate thread as it's really more a matter of common sense than anything else.
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Originally posted by karajorma
The fact is that there isn't a single evolutionary biologist who doesn't buy into some form of punctuationism. The only difference between the theories is how large the plateaus are and how short the periods of change are.
Which ignores the fact that in the 3.5by curve, it all will tend to even out (which would be a short plateau, short period of change, for those keeping score).
Yep I can. Not a bacterium in this case but I'm sure that speciation in an alga is good enough for you.
If you want more than that I suspect I'm going to need to ask
Fragaria to look up the paper for us.
That works. Good stuff that. What about more complex organisms? Bob's insects would work (though I'm pretty sure the whole fruitfly experiment cycle, which has been repeated by every college biology student since the seventies rules out simple breeding leading to speciation).
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Originally posted by Bobboau
has anyone tryed the specisation experiment I sugested with something that has a very short maturation?
Yep. And it resulted in speciation too.
In a series of papers (Rice 1985, Rice and Salt 1988 and Rice and Salt 1990) Rice and Salt presented experimental evidence for the possibility of sympatric speciation. They started from the premise that whenever organisms sort themselves into the environment first and then mate locally, individuals with the same habitat preferences will necessarily mate assortatively. They established a stock population of D. melanogaster with flies collected in an orchard near Davis, California. Pupae from the culture were placed into a habitat maze. Newly emerged flies had to negotiate the maze to find food. The maze simulated several environmental gradients simultaneously. The flies had to make three choices of which way to go. The first was between light and dark (phototaxis). The second was between up and down (geotaxis). The last was between the scent of acetaldehyde and the scent of ethanol (chemotaxis). This divided the flies among eight habitats. The flies were further divided by the time of day of emergence. In total the flies were divided among 24 spatio-temporal habitats.
They next cultured two strains of flies that had chosen opposite habitats. One strain emerged early, flew upward and was attracted to dark and acetaldehyde. The other emerged late, flew downward and was attracted to light and ethanol. Pupae from these two strains were placed together in the maze. They were allowed to mate at the food site and were collected. Eye color differences between the strains allowed Rice and Salt to distinguish between the two strains. A selective penalty was imposed on flies that switched habitats. Females that switched habitats were destroyed. None of their gametes passed into the next generation. Males that switched habitats received no penalty. After 25 generations of this mating tests showed reproductive isolation between the two strains. Habitat specialization was also produced.
They next repeated the experiment without the penalty against habitat switching. The result was the same -- reproductive isolation was produced. They argued that a switching penalty is not necessary to produce reproductive isolation. Their results, they stated, show the possibility of sympatric speciation.
Rice, W. R. 1985. Disruptive selection on habitat preference and the evolution of reproductive isolation: an exploratory experiment. Evolution. 39:645-646.
Rice, W. R. and G. W. Salt. 1988. Speciation via disruptive selection on habitat preference: experimental evidence. The American Naturalist. 131:911-917.
Rice, W. R. and G. W. Salt. 1990. The evolution of reproductive isolation as a correlated character under sympatric conditions: experimental evidence. Evolution. 44:1140-1152.
There are some more examples of speciation etc here (http://www.talkorigins.org/faqs/faq-speciation.html) Most of those are due to artificial selection pressures but in this case the pressure is closer to that seen in nature.
Originally posted by mikhael
Which ignores the fact that in the 3.5by curve, it all will tend to even out (which would be a short plateau, short period of change, for those keeping score).
But we're not talking about the evolution of every single creature that has ever existed so I really don't know why you're going for such an absurdly large timescale.
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Originally posted by mikhael
I'm pretty sure the whole fruitfly experiment cycle, which has been repeated by every college biology student since the seventies rules out simple breeding leading to speciation
collage students don't keep two isolated populations alive for fifty years in systematicly diferent environments.
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Originally posted by karajorma
But we're not talking about the evolution of every single creature that has ever existed so I really don't know why you're going for such an absurdly large timescale.
Because I was making a distinction between the overall (Evolution) and the immediate (natural selection, mutation, artificial selection, etc). Given that the first fossiles, so far, are 3.5by old, I use that as a good first milestone on the evolutionary curve. There is, of course, some evidence of prior organisms that may go back as much as 250-500my more, however.
Now, for these flies, in the study you mentioned: what criteria are used to determine speciation between the environmentally unique groups? That wasn't really addressed in the abstract.
Bob: college students may not, college biology professors and their labs DO.
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So what is being said here is that Evolution has been a smooth progression on average despite the fact that individual creatures within the sphere may evolve in fits and starts?
I suppose that makes sense, since not all environments change simultaneously, an increase in salinity of the sea would eventually lead, most likely, to an increase of precipitation (assuming that increase is by a reduction in water and not an increase in salts), but I suspect seaborne creatures would feel, and be start to evolve around, the effects of that long before land-based ones do etc.
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That's my view, yes, Flipside.
I can't make any claim as to what function that smooth curve approximates. It could have inflection points. It might be logarithmic. It might be exponential. I'm pretty sure its not factorial though. ;)
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Originally posted by mikhael
Because I was making a distinction between the overall (Evolution) and the immediate (natural selection, mutation, artificial selection, etc). Given that the first fossiles, so far, are 3.5by old, I use that as a good first milestone on the evolutionary curve. There is, of course, some evidence of prior organisms that may go back as much as 250-500my more, however.
This whole debate is based around whether or not you can point to something and say See! Evolution! Not whether you could see the whole of evolution. If speciation has occured you can definately say that.
*Points at the alga* See! Evolution!
Originally posted by mikhael
Now, for these flies, in the study you mentioned: what criteria are used to determine speciation between the environmentally unique groups? That wasn't really addressed in the abstract.
Unfortunately that abstract is all I've got since I don't have access to the journals.
In the case of the alga the fact that it's now in a different family let alone species should be sufficient to say that it has evolved though.
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The second part of that is critical to the first part of that, Kara.
Trees and ants are not algae.
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Who said they were? But if you can observe evolution in fruit flies (and the link I posted has several examples of that) then ants are not too large a stretch, especially if we're not talking about speciation but much quicker behavioural changes.