tag:blogger.com,1999:blog-3164804243040726299.post4535878701232501361..comments2024-03-19T06:40:22.220-04:00Comments on The EEB & Flow: Why pattern-based hypotheses fail ecology: the rise and fall of ecological character displacementMarc Cadottehttp://www.blogger.com/profile/08335319636148357534noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-3164804243040726299.post-45837346481213419552013-05-02T15:41:03.241-04:002013-05-02T15:41:03.241-04:00Great article, I appreciate your point that multip...Great article, I appreciate your point that multiple processes can produce the same pattern but I agree with Devin that this is equally a problem for process-based and pattern-based studies. Anonymoushttps://www.blogger.com/profile/11498814298593814562noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-15030320146319055962013-05-02T14:17:39.564-04:002013-05-02T14:17:39.564-04:00"The only reason that we are able to sit arou...<br />"The only reason that we are able to sit around and talk about ECD (or any other ecological phenomenon) is that we have documented general patterns (e.g. divergent species in sympatry). Sometimes when we use pattern to infer process we discover we are wrong, the same can be said for process without pattern. "<br />->Probably! We are often wrong. Information is not wasted. Understanding systems is important. But we are never content with just describing and identifying patterns - we want to understand them, which requires process and then testing these processes deductively. <br /><br />"*quick footnote<br />My main beef is the death to pattern based hypothesis testing angle, but just a quick note about ECD. ECD may not be explain divergent species in sympatry, but that does not mean that competition is not the mechanism driving this pattern. Divergence may have occurred in allopatry and those individuals move back into sympatry after the matter, but it's likely competition that prevents co-occurence until after divergence."<br />->Yes! but this is the point of the paper, no? Just checking the boxes for look, I observed a pattern of divergence in sympatry presence isn't tell us that much about the dynamics in that system. It's possible, if you want, to understand more detailed molecular relationships between species, to experimentally test for competition or the absence thereof, and if we are content to stop at pattern we miss this much more useful approach to understand.Caroline Tuckerhttps://www.blogger.com/profile/09319215430054509345noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-21677128921652834792013-05-02T14:17:29.036-04:002013-05-02T14:17:29.036-04:00Hey Devin - too bad you aren't around to debat...Hey Devin - too bad you aren't around to debate with in person these days :) <br />I think we will ultimately disagree on some of these issues, but I think one issue is that I haven't defined my terms clearly enough that so we're speaking about the same thing. I'll try to clarify. I think a good starting point is that observational patterns have played a big role in ecology, so that's what I'm particularly referring to. *Also patterns are clearly a source of information, and we have needed them to develop hypotheses and inform us. What I object to is their use as "proof" on their own, without manipulation or understanding of the mechanisms at play, of the activity of a particular process.* So the latitudinal gradient exists, has informed many hypotheses, but on its own, its existence alone does not "prove" that speciation rates (for example) are higher in the tropics. You need to start with that hypothesis, understand its predictions (including context-dependent aspects), etc. Why? because multiple hypotheses could be supported by the existence of the latitudinal diversity gradient pattern. <br />So I'm hardly saying, ignore the patterns in nature that inform how we understand nature. I'm saying good science doesn't become caught up in looking for patterns, and suggesting they are evidence for a particular popular hypothesis (whether a latitudinal gradient, a productivity-diversity curve, etc). I think that community ecology in particular has been guilty of this.<br /><br />Let me see if I can respond to your points. (sorry I couldn't figure out a tidier way of quoting)<br /><br />"If a single process can produce multiple patterns, then process has no more power to predict than pattern. So while "we could predict what we expect give the context of the experiment", we would still have to test it empirically (using patterns). "<br />->Of course process has power, it makes predictions about expected (including context dependent) results. It's not unexpected that multiple possible outcomes could result from a given process. It's totally fine to experimentally test for the outcome (what you're calling patterns). If you are moving from mechanistic-hypothesis to predicted evidence and then you find that evidence, that's great. It's not "proof" in a strict framework, but it's support for your hypothesis. <br />A simple example from physics: you drop a ball from a tower. The speed at which it falls is dependent on multiple contexts (wind, ball materials, etc), so predicting the landing point depends on understanding the underlying process (gravity), and the contextual information. Varying context means there are different landing points or speed (multiple patterns), but this hardly makes the process "powerless". <br /><br />""So a pattern means very little without the appropriate context."<br />No, the pattern IS the context! Mechanism also means very little without the pattern! We can insert a different pattern (than ECD) and think about this. Lets use the latitudinal diversity gradient. There are MANY proposed processes for why there are more species in the tropics. If you found that net diversification (speciation minus extinction) was higher in the tropics, but had no idea that there were more species in the tropics, what would that information tell you? You would be left with a process that explains nothing. "<br />->I disagree. Latitudinal gradients obviously exist, and they allow us to generate hypotheses about process. BUT they can't really be used to inductively ascertain the processes at play. <br /><br />(cont'd below)Caroline Tuckerhttps://www.blogger.com/profile/09319215430054509345noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-87723305358918246662013-05-02T14:14:41.262-04:002013-05-02T14:14:41.262-04:00"The truth is that the same pattern may resul..."The truth is that the same pattern may result from multiple processes. Further, a single process can produce multiple patterns."<br />Absolutely! But you pose this as a criticism of pattern based inference when in fact it would be just as damning to mechanism driven work in the absence of patterns. If a single process can produce multiple patterns, then process has no more power to predict than pattern. So while "we could predict what we expect give the context of the experiment", we would still have to test it empirically (using patterns). <br /><br />"So a pattern means very little without the appropriate context."<br />No, the pattern IS the context! Mechanism also means very little without the pattern! We can insert a different pattern (than ECD) and think about this. Lets use the latitudinal diversity gradient. There are MANY proposed processes for why there are more species in the tropics. If you found that net diversification (speciation minus extinction) was higher in the tropics, but had no idea that there were more species in the tropics, what would that information tell you? You would be left with a process that explains nothing. Or, you might discover net diversification is higher in temperate regions that in the tropics, and infer that species diversity is higher in temperate regions that tropical regions. See the issue that you really raise, is that induction often fails, not that pattern based inference is somehow less robust than process based inference. <br /><br />The only reason that we are able to sit around and talk about ECD (or any other ecological phenomenon) is that we have documented general patterns (e.g. divergent species in sympatry). Sometimes when we use pattern to infer process we discover we are wrong, the same can be said for process without pattern. <br /><br /><br />*quick footnote<br />My main beef is the death to pattern based hypothesis testing angle, but just a quick note about ECD. ECD may not be explain divergent species in sympatry, but that does not mean that competition is not the mechanism driving this pattern. Divergence may have occurred in allopatry and those individuals move back into sympatry after the matter, but it's likely competition that prevents co-occurence until after divergence.<br />Devinhttps://www.blogger.com/profile/06596258809549513828noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-8749010655315285442013-05-02T13:43:30.655-04:002013-05-02T13:43:30.655-04:00This comment has been removed by the author.Devinhttps://www.blogger.com/profile/06596258809549513828noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-33109124683443490292013-05-02T13:41:39.946-04:002013-05-02T13:41:39.946-04:00This comment has been removed by the author.Devinhttps://www.blogger.com/profile/06596258809549513828noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-64088503957047763902013-05-02T12:58:13.294-04:002013-05-02T12:58:13.294-04:00Hi Hans - is this paper proof that ECD isn't ...Hi Hans - is this paper proof that ECD isn't important? No, not at all. I didn't go into detail, but they discuss the different possible reasons we aren't doing a good job of experimentally/observationally capturing ECD. Definitely worth reading. (i'll adjust the text to make this more clear). Likely ECD is important but more limited than its most optimistic supporters have suggested.<br />Although I yield your point that a meta-analysis is inappropriate in such a scenario as the one you describe, the point of the authors' meta-analysis was more to point out that the amount of support is less than often suggested. No one has considered the role of context, in the current or previous meta-analysis. This is obviously a fair critique of meta-analyses in general though.<br /> <br />I think that's separate from the overall point. If this was physics, we would have a strong mechanistic basis and we could predict what we expect given the context of the experiment (air/no air). Caroline Tuckerhttps://www.blogger.com/profile/09319215430054509345noreply@blogger.comtag:blogger.com,1999:blog-3164804243040726299.post-53100338892404028342013-05-02T12:41:54.558-04:002013-05-02T12:41:54.558-04:00A study shows that among 30 ecperiments, only 3 ha...A study shows that among 30 ecperiments, only 3 have shown that a feather falls with the same speed of a ball of iron (the 3 experiments are in void, whereas the other 27 are carried out in the atmosphere, as can be read in the supplementary material). This meta-analysis clearly shows that the claim of Galileo that speed of fall is independent of mass is practically not-existent on earth. Possibly there is some truth in the ideas of Galileo, but they are context-dependent (the presence of air or not) and therefore they prevent the progress of science. <br />Hans Castorphttps://www.blogger.com/profile/05016989070891441042noreply@blogger.com