Species

A perennial topic. The organisms we see cluster around specific, distinct types. We can identify an individual as belonging to that type because it has the distinctive characteristics of that type. We know what the characteristics are because we see a lot of such individuals.

To the some Creationists, those types represent essential, immutable forms, perhaps with some post-Ark latitude, and a bit of variation around the ‘norm’. It is as if those forms were cast from a mould, with small manufacturing defects. The mould is eternal, unchanging.

To the Evolutionist, those types are simply the current form of a changing lineage. Lineages can branch and diverge leading to an increase in the total numbers, offset by extinction. The branching process is somewhat extended in time, so species are not only malleable but somewhat blurry around the inception of a bifurcation. Intraspecific variation does not become interspecific variation overnight.

The Creationist demands to know how one type can ‘become’ another – how one unchanging essence can become another unchanging essence. The Evolutionist answers that their conception of ‘species’ is awry – one type becomes another, or two, gradually, changing like minimalist music. The type ‘floats on the breath of the population’, as Dr Johnson said of the unwritten Erse language. The Creationist responds that this is begging the question – defining species in evolutionary terms is an attempt to prove evolution by definition.

Nonetheless, if you are talking of evolution, your species concept needs to take account of it. An essentialist conception is no use in an evolutionary framework. There is, in my opinion, no non-arbitrary means of distinguishing species from other taxonomic ranks while interbreeding (and hence gene flow) is possible. This is the limit of the Biological Species Concept – a biospecies is the set of all the individuals which can create viable fertile offspring with at least one other member of the set. This can frequently be far too broad – maples separated for 20 million years can interbreed, and fertile hybrids between morphologically distinct types, even those assigned to different genera, are common. It is also difficult practically to assess whether the sets are ‘really’ separate yet. At the extreme, a single introgression among billions of incompatible pairings would indicate incomplete speciation, to a BSC pedant.

Creationists claim an objective means (as they do in other arenas …) but take them out in the field and I suspect their hypothetical methodology would fail them. If we base it on ‘morphology’, just how does one rank characters objectively? A wing-bar, beak colour, gregarious, particular mating dance, blue eggs, prefers shrimps … how many characters, which ones are more important, and by how much?

I would take as an example the Spotted sandpiper and Common sandpiper. These are held to be an example of parapatric speciation – they occupy different but contacting ranges, and within those ranges, for reasons unknown, gene flow in a single ancestral species between the ranges gradually diminished. Potential causes include a temporary ‘firebreak’ where no individuals penetrated, dichotomous mate preference, or ecological specialisation. Now, again for reasons not entirely obvious, they do not penetrate each others’ ranges except in narrow contact zones. At these zones, hybrids frequently occur. So on the BSC, speciation is not complete (indeed, the Common also interbreeds with sandpipers of a different genus, so on the BSC they join in too). But they are clear morphological species. Are they Platonic? Were they both on the Ark?

477 thoughts on “Species

  1. petrushka: How not so?

    I don’t know. Perhaps because after 20 years and 44,000 generations the bacteria still have not crossed Behe’s edge?

    The experiment did lend credence to the idea that bacteria are adaptable critters but antibiotic resistance had already demonstrated that.

    peace

  2. You seem familiar with Behe’s Edge and Lenski. How does Behe respond?

    What exactly is the Edge, if a tiny population can, in a few years, accumulate multiple unreinforced mutations before they enable a useful function?

  3. petrushka:

    What exactly is the Edge,if a tiny population can,in a few years,accumulate multiple unreinforced mutations before they enable a useful function?

    If I understand him

    The edge according to Behe is something like more than two unreinforced but necessary mutations present in the same organism and the same generation.

    peace

  4. I think you need to clarify that. As written it makes no sense. Perhaps a hypothetical history would help.

  5. In the Lenski experiment, two unreinforced mutations had to accumulate, followed by one that resulted in the enhanced metabolism.

    This happened in a tiny, bottlenecked population, in a couple of decades. Outside the laboratory, new protein domains seem to take about a million years each.

    I think perhaps Behe needs to rethink his argument. There is no barrier to the accumulation of unreinforced mutations, even slightly detrimental ones.

  6. Petrushka, you had better hope Behe is right.

    Behe’s edge is the only thing that gives Man ..ehem…an edge against disease. It is what allows us to make vaccines that work.

    Game over when viruses and bacteria figure out how to outfox the Behe.

  7. But they wont. That’s the wall that separates micro from macro.

    The micro maintains stasis.

    The macro has been on the lam for quite awhile now, waiting on the apocalypse.

  8. Hi Allan Miller and Alan Fox,

    Sorry for not getting back to you sooner. Thanks very much for the links to the articles on cichilds and sticklebacks.

  9. Steve:
    Petrushka,you had better hope Behe is right.
    Behe’s edge is the only thing that gives Man ..ehem…an edge against disease. It is what allows us to make vaccines that work.
    Game over when viruses and bacteria figure out how to outfox the Behe.

    Behe is wrong and microbes evolve quickly.

  10. vjtorley:
    Hi Allan Miller and Alan Fox,

    Sorry for not getting back to you sooner. Thanks very much for the links to the articles on cichilds and sticklebacks.

    No problem. Been following your exchanges with Larry Moran (here and on) with interest. If I can find time, I’ll put up an OP on micro, macro, edges and explanations (unless another participant would be interested in posting an OP) for those, like me, who are unwilling and/or unable to comment there. Uncommon Descent has a reputation for interrupting discussions that get uncomfortable for the ID movement. I get the impression your view on these matters is evolving.

  11. fifthmonarchyman: The edge according to Behe is something like more than two unreinforced but necessary mutations present in the same organism and the same generation.

    And what would you expect to see had that “edge” been crossed, exactly?

    Steve: That’s the wall that separates micro from macro.

    Yet we know that even Behe’s “edge” can be achieved by evolution, or is that news to you?

    Therefore you acknowledge the reality of macro evolution, by your own criteria.

  12. Steve,

    Steve: “Behe’s edge is the only thing that gives Man ..ehem…an edge against disease. It is what allows us to make vaccines that work.”

    Then how do you explain things like the cold and flu viruses that often “evolve” too quickly to develop effective vaccines?

  13. Steve:
    But they wont. That’s the wall that separates micro from macro.

    Really? So speciation is due to double-mutations? Got any evidence for that claim? Clearly you’re just making shit up as you go along.

    Steve: The micro maintains stasis.

    This isn’t just false, it is nonsensical. Micro doesn’t “maintain” stasis, since stasis doesn’t refer to speciation, but to morphology.

    It is entirely possible that multiple speciation events could transpire but it’d look like “stasis” in the fossil record because it wasn’t accompanied by any appreciable anatomical changes one could infer from fossils alone.

  14. petrushka:
    In the Lenski experiment, two unreinforced mutations had to accumulate, followed by one that resulted in the enhanced metabolism.

    This happened in a tiny, bottlenecked population, in a couple of decades. Outside the laboratory, new protein domains seem to take about a million years each.

    I think perhaps Behe needs to rethink his argument. There is no barrier to the accumulation of unreinforced mutations, even slightly detrimental ones.

    On a related note, I know of no speciation event that required the evolution of a new protein fold. And I have this nagging suspicion that most of those who think it does don’t even know what a protein fold is. In fact as I documented extensively over on Larry Moran’s blog (in the comments section to one of the posts regarding Meyer’s book), Stephen Meyer, D Axe et al. go to great lengths to invent this lie in Meyer’s book “Darwin’s Doubt”, that the diversification at the cambrian required vast new amounts of new protein folds. Yet if one bothers to trawl through the references given (and there are suspiciously few, most of them being to “Bio-Complexity” publications that just cite each other), one eventually comes up empty handed. There are no known examples of speciation or macroevolution requiring new protein folds to evolve.

    In fact I doubt there’s much macroevolution requiring new proteins at all (not to mention entirely new folds). Rather, as we know from evo-devo, the vast vast majority of the diversification of multicellular life we see, ever since the cambrian, has been due to rearrangements and changes to developmental timings. Most of the core proteins (and their folds) were established in single-celled colonies over 2 billion years before anything like a sponge or a jellyfish ever managed to emerge on the scene.

    Take the pertinent example, the evolution of Homo Sapiens and Pan Troglodytes from our common ancestor about 6 million years ago. Can any of the ID guys around here tell me what new proteins, or new protein folds, or new organs or “bio-systems” were required for this macroevolutionary event? With evidence to back up the claim of course.

  15. petrushka: There is no barrier to the accumulation of unreinforced mutations, even slightly detrimental ones.

    wow this natural selection thingy must be a pretty week mechanism.

    OMagain: And what would you expect to see had that “edge” been crossed, exactly?

    speciation perhaps? Maybe the arrival of IC structures?

    Rumraket: In fact I doubt there’s much macroevolution requiring new proteins at all (not to mention entirely new folds).

    I would not disagree here. Just because Behe is trying to quantify a particular edge does not mean that his edge is the only one that exists

    peace

  16. fifthmonarchyman,

    wow this natural selection thingy must be a pretty week mechanism.

    That depends on its strength … ! There is a continuum (yes! I know!) of possible selection coefficients – that being the exponent of differential reproduction, ie the strength of selection. When they hover around zero, even dipping somewhat into the detrimental, selection is indeed week. Or even fortnight. Selection is not the only mechanism of evolutionary change.

    OMagain: And what would you expect to see had that “edge” been crossed, exactly?

    fmm speciation perhaps? Maybe the arrival of IC structures?

    Those sandpipers. Do you think any IC structures are involved in their speciation?

  17. Steve,

    Behe is right and microbes can’t beat vaccines.

    That’s why vaccines work for ever. Oh, wait …

    Shame God didn’t make us immune in the first place. At least you’re not an anti-vaxx-er.

  18. Rumraket is confused. He is conflating speciation with variation.

    There isn’t one single lineage of organisms living today that is splitting away from its ancestral lineage.

    There is not one single new type of organism in the making now.

    Macro evolution is dead, Rumraket. Guess you missed the news.

    Micro evolution is gene shuffling to keep things as they are. Nothing more.

    And that is exactly what Mendel found out. And that is exactly what the finches say. and the moths. and bacteria.

    Just ask them.

    Rumraket: Really? So speciation is due to double-mutations? Got any evidence for that claim? Clearly you’re just making shit up as you go along.

    This isn’t just false, it is nonsensical. Micro doesn’t “maintain” stasis, since stasis doesn’t refer to speciation, but to morphology.

    It is entirely possible that multiple speciation events could transpire but it’d look like “stasis” in the fossil record because it wasn’t accompanied by any appreciable anatomical changes one could infer from fossils alone.

  19. Nah, imperfect is just about right.

    Man is not ready for immortality. needs to kick the whining habit first.

    Besides, for God it is damned if you do and damned if you don’t.

    So He doesn’t.

    Until we do.

    Allan Miller:
    Steve,

    That’s why vaccines work for ever. Oh, wait …

    Shame God didn’t make us immune in the first place. At least you’re not an anti-vaxx-er.

    Allan Miller:
    Steve,

    That’s why vaccines work for ever. Oh, wait …

    Shame God didn’t make us immune in the first place. At least you’re not an anti-vaxx-er.

    Allan Miller:
    Steve,

    That’s why vaccines work for ever. Oh, wait …

    Shame God didn’t make us immune in the first place. At least you’re not an anti-vaxx-er.

  20. Allan Miller: That depends on its strength … !

    It’s weak except when it needs to be strong. Sounds more like an intelligent agent than a mechanism

    Allan Miller: Selection is not the only mechanism of evolutionary change.

    of course the “whatever” in the old RM plus NS plus whatever algorithm.

    The problem is not that we don’t have enough parts to the algorithm, It’s that there are some things that algorithms can’t accomplish no mater how complex they are.

    peace

  21. Rumraket: I know of no speciation event that required the evolution of a new protein fold. And I have this nagging suspicion that most of those who think it does don’t even know what a protein fold is. In fact as I documented extensively over on Larry Moran’s blog…

    Rumraket

    Would you be interested in putting up an OP along these lines? I’m sure it would be of interest to many here.

  22. fifthmonarchyman,

    Allan Miller: You may think you hold both positions simultaneously, but I put it to you that you cannot without misunderstanding one or the other.

    Fmm: That is quite a charge how about some specific evidence to back it up?

    How can I explain the same thing I have explained several times in words you will understand, when you clearly misunderstand? I can’t shove the argument in by force, you have to willingly evaluate it.

    Allan Miller: Try answering the ‘LUCA-giraffe’ question on archetypal intermediates. ‘Some’, ‘all’ or ‘none’? The answer is not in the Bible.

    Fmm: Do you think that all revelation is found in the Bible? There is such a thing as general revelation.

    Try answering the LUCA-giraffe question without dodging behind some irrelevant point about where the answer may or may not be found. It’s a very simple question. During an incremental succession of forms, is every intermediate an archetype, or only some? And why, either way? If every intermediate is an archetype, what’s archetypal about them? If only some are, what’s non-archetypal about the supposed ‘intermediates’?

  23. fifthmonarchyman: wow this natural selection thingy must be a pretty week mechanism.

    Why criticise a field of study you don’t actually know anything about? It’ll never make you look good. It does not matter how “strong” or “weak” natural selection is, it matters that it exists at all. And it’s just one of several mechanisms.

    fifthmonarchyman: speciation perhaps? Maybe the arrival of IC structures?

    So you don’t actually know? If you don’t know, how do you know it’s not already happening?

    Steve: There is not one single new type of organism in the making now.

    Don’t you mean “biblical kind”?

    Allan Miller: Those sandpipers. Do you think any IC structures are involved in their speciation?

    Well fmm? Does your inability to answer specific questions never give you pause that you don’t actually understand this stuff as well as you seem you think you do?
    Don’t all those questions you don’t even seem to understand, let alone acknowledge you can’t answer, ever give you pause that perhaps, just perhaps, you might not be in a position to criticise?

  24. fifthmonarchyman,

    It’s weak except when it needs to be strong. Sounds more like an intelligent agent than a mechanism

    Don’t embarrass yourself. Water is deep except when it’s shallow. Selection is the differential in offspring numbers between two types. Sometimes that differential is zero, or nearly so, sometimes it is stronger, by variable degrees. What in hell makes that an intelligent agent?

    Allan Miller: Selection is not the only mechanism of evolutionary change.

    fmm: of course the “whatever” in the old RM plus NS plus whatever algorithm.

    Your distortions are becoming tiresome. When selection is weak, the prime source of change is drift. It’s not ‘whatever’. It is the reason non-selected changes can accumulate in the population. A selection-only scenario has a hard time explaining patterns of polymorphism.

  25. Steve,

    There isn’t one single lineage of organisms living today that is splitting away from its ancestral lineage.

    There is not one single new type of organism in the making now.

    You’ve checked, then. No Black Swans anywhere.

  26. Allan Miller: During an incremental succession of forms, is every intermediate an archetype, or only some?

    in the transition between a circle and an oval is every intermediate a “form” in it’s own right?

    It depends on how many intermediates you have and and their characteristics.

    I would expect the same goes for giraffes. deciding whether two particular fossils represent separate species or just a variant example of a single species is sort of what taxonomy is all about.

    My approach would not eliminate the jobs of the taxonomists. It would only mean that their efforts were not in vain but that there is an actual reality behind it all that they were working toward.

    peace

  27. OMagain: Well fmm? Does your inability to answer specific questions never give you pause that you don’t actually understand this stuff as well as you seem you think you do?

    I answer specific questions when ever I notice them.

    I’ve said repeatedly that I’m terrible at detail and I often miss stuff when I’m chasing the bright and shinny object that is right in front of me at the time

    peace

  28. fifthmonarchyman,

    1) Species are bounded sets. The borders between species are clearly defined and it is easy to tell if an organism is inside or outside the set

    2) Species are fuzzy sets. There are no clear boundaries one species flows into the others. The organisms at the edges are especially difficult to categorize

    3) Species are centered sets. Organisms that exemplify the archetype belong to the set regardless of how far they are away from the center.

    You like number 2
    Apparently number one is the straw-man that you want to tear down,

    No, I’m happy to tear down 3 instead. 1) is actually more justified, in certain cases.

    Take a neat isolated population at a moment in time, one with no near relatives. It is a single set in all 3 senses. Issues arise when variation occurs. The conventional view is that, within that population, divergence is constantly in train, due to new variation (mutation and recombination, promotion and extinction of alleles). The population is kept mixed by mating (in the sexual world), which opposes this fragmentary tendency, though offers no particular ‘centre’ for the population to cluster around.

    Those changes, over the course of time, change the makeup of a ‘typical’ member of the population. It remains easy to see the species in terms of 1). There is no fuzziness at the boundary either, so 2) is not really the case. 3) however, requires something to pull the population to the ‘centre’. There is no apparent mechanism to do so, and the burden of proof is upon you to provide one.

    A population is not itself any more than the composite genotypes of its members. Sample the population at time t1 and you can construct a ‘typical’ member of that species from the commonest alleles. But at time t2, after a sufficient period during which new variation has been added and formerly common alleles lost, the population has moved on. There is a new mean. But you have decided that, no matter how far individuals move from the ‘centre’, they are the same as the starting archetype. Even if, at the limit, every single base has changed. Given that the original ‘reference’ population is gone, this seems a poor approach. There was an archetype but we are now totally different from it (but there’s still an archetype!).

    2) only comes in when gene flow is stemmed. The set composition depends on the species concept you apply. It can be a single set using some criteria, two sets on another, which is hardly unheard of in set theory. The boundaries of the superset remain clear; the fuzziness appears when trying to decide if there are two sets or one. If you use the BSC, the set is the set of all individuals which can form viable offspring with at least one other. As a population diverges, fewer and fewer intercompatible individuals remain. At the limit, there is just one pair of interfertile gametes. When they die off, the set splits with an imaginary ‘pop’.

  29. fifthmonarchyman: If I understand him

    The edge according to Behe is something like more than two unreinforced but necessary mutations present in the same organism and the same generation.

    Could you perhaps give an example of some actual organism that requires such “two unreinforced necessary mutations” to have been “present in the same organism and the same generation” – for it to have evolved?

  30. fifthmonarchyman,

    in the transition between a circle and an oval is every intermediate a “form” in it’s own right?

    Yes, of course.

    It depends on how many intermediates you have and and their characteristics.

    It doesn’t matter how many intermediates you have! Each is a ‘form’ in its own right if it differs from those before and after. There is not just one ‘oval’. There is a hypothetical infinity, though one would not wish to name them all.

    I would expect the same goes for giraffes. deciding whether two particular fossils represent separate species or just a variant example of a single species is sort of what taxonomy is all about.

    None of the succession is fossilised. It is simply a hypothetical succession with one DNA base changed per generation. A thought experiment, to illustrate the incompatibility of gradual change with essentialism.

  31. Steve:
    Rumraket is confused. He is conflating speciation with variation.

    No, I just know what the words mean. The sentence you wrote was nonsensical, which is why I commented on it.

    SteveThere isn’t one single lineage of organisms living today that is splitting away from its ancestral lineage.

    What does it mean to be “splitting away from” your ancestral lineage and how do you determine what any particular organism’s “ancestral lineage” is? How quickly should this suppsedly-not-happening-event happen, for it to demonstrably happen? How long do we have to wait?

    Steve: There is not one single new type of organism in the making now.

    Define: new type.

    Where is the cut-off? At what point does change go from “the same kind” to “new type”?

    There is not any “type of organism”, whether “new” or not, being instantaneously divinely created. Anywhere. At all.

    Forget macro-creation, the divine and instantaneous creation of a new species not before seen. Creationists can’t even show micro-creation, the divine appearance of a single member of an already existing species.

    Steve: Macro evolution is dead, Rumraket. Guess you missed the news.

    If “has not been directly observed” is the criterion for being dead, congratulations, all of ID-creationism is dead. Nobody has ever seen anyone or anything divinely and instantaneously create a fully functioning living organism, or a multi-component protein complex, or even a single base of DNA out of nothing. There are no examples of the designer magically poofing single DNA bases, a full flagellum, an entire bacterium or a colony of them, individual whales or anything biological into existence, anywhere, ever.

    In contrast, we have multiple observed cases of both micro and macro evolution. Which means that the evolutionary process producing actually measurable increasing biological diversity, both at the molecular and below and above the species level – is an observed fact.

    Steve: Micro evolution is gene shuffling to keep things as they are.Nothing more.

    If you wanted things to stay as they are, shuffling it’s genes seems counterproductive. Just a thought!

    Steve: And that is exactly what Mendel found out. And that is exactly what the finches say.and the moths.and bacteria.

    It seems to me all of them have changed a lot in a comparably short geological time. Where do we meet a million years from now?

    There’s an awful lot of different finches, moths and bacteria. Which ones in particular are you talking about? Bacteria, by the way, is a DOMAIN of life containing millions of different species. It is entirely possible that the bacteria in, for example, Lenski’s experiment have undergone bona fide prokaryotic speciation. That would be a laboratory demonstration of macroevolution.

  32. Alan Fox: Rumraket

    Would you be interested in putting up an OP along these lines? I’m sure it would be of interest to many here.

    Sure, I’ll throw it up later when I get home from work.

  33. Steve:
    Behe is right and microbes can’t beat vaccines.

    So only one flu-vaccine will do and you are perpetually immune to the influenza virus for eternity? Hmmm.

  34. Rumraket: So only one flu-vaccine will do and you are perpetually immune to the influenza virus for eternity? Hmmm.

    Creationism means antibiotics work forever.

  35. fifthmonarchyman: My approach would not eliminate the jobs of the taxonomists. It would only mean that their efforts were not in vain but that there is an actual reality behind it all that they were working toward.

    Then simply write a paper that explains how to use your approach and it might actually get used!

  36. fifthmonarchyman: I answer specific questions when ever I notice them.

    You missed this:

    Allan Miller: Spotted and Common Sandpipers, then. ‘True’ fmm-species or no? Why, either way? What weight is given to each distinguishing character?

    Your answer?

  37. FMM:

    What is the true platonic form of the Scotoplane genus? Which one of the three described species is closest to it, if any? Why?

  38. petrushka: Does Fifth actually believe his Platonic classification scheme has never been attempted?

    In times gone by the random musings of the uninformed would go no further then their local drinking hole. These days you can criticise things you don’t understand around the entire world.

    fmm, why don’t you give a potted history of humanities attempts to classify biology from start to present day? And then explain where we went wrong, and how it can be fixed (with examples)?

    Or does that sound like too much work for you?

  39. When I make a mistake online, I’m embarrassed, and I try to learn from it.

    I’m amazed at how cranks appear to be utterly immune to the feeling of embarrassment.

  40. You can’t learn if you can’t accept the possibility of being mistaken.

    You haven’t learned if you don’t know the history of the ideas you are criticizing.

    You are unlikely to learn if you accept the authority of dishonest people.

    The possibility that mainstream science is wrong about a fundamental concept diminishes with time, and with the number of challenges that have been investigated.

    Exceptions to this are rare, and usually involve concepts that haven’t been seriously challenged.

  41. Given all the above ffm, is it more likely that

    A) You have indeed spotted a flaw/improvement in classification that generations of scientists have all missed?

    B) You don’t know the history well enough to know why your idea is not very useful?

    If you had to bet, which option would you put your money on?

    Don’t get me wrong, A) is perfectly possible! Sometimes a lone wolf will change everything.

    But to do that, if you do consider yourself to be that lone wolf, you’ll have to put a bit more work in then a few posts on some obscure message board….

  42. Not knowing the history of a scientific concept is a giveaway.

    So-called lone wolves are seldom isolated from the scientific community.

    If you look at two of the most famous lone wolves — newton and Einstein — you see that they were addressing issues that “everybody” was working on.

    In English speaking countries, Newton invented calculus, but textbooks use the vocabulary of Leibniz.

  43. Allan Miller: Water is deep except when it’s shallow.

    you see Pharaoh it’s like this,

    The water was shallow and the Hebrews walked across the reed sea then it was deep and your army drowned. It’s just water, sometimes it’s deep and sometimes it’s shallow. No sign of intelligent agency at all

    peace

  44. Allan Miller: A population is not itself any more than the composite genotypes of its members.

    That is quite a view you have there. Are you honestly meaning to say humanity is nothing more than the composite genotypes of people?

    Allan Miller: Those changes, over the course of time, change the makeup of a ‘typical’ member of the population.

    You don’t find the ‘typical’ circle by averaging the dimensions of a population of circular objects. You find the ‘typical’ circle by drawing a shape who’s circumference is related to it’s diameter by the ratio that is exactly equal to pi.

    In the same way you don’t find the typical member of a species by averaging the measurements of the members.

    Allan Miller: But at time t2, after a sufficient period during which new variation has been added and formerly common alleles lost, the population has moved on.

    You are still thinking from a finite temporal perspective. This is directly contrary to the spirit of the definition I offered.

    Why do you insist on attacking a strawman?

    peace

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