Comments on: History restricts and guides the evolution of innovations http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/ Mon, 26 Nov 2012 12:00:51 +0000 hourly 1 http://wordpress.org/?v=3.4.2 By: Walter S. Andriuzzi http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-510 Walter S. Andriuzzi Thu, 17 Mar 2011 18:43:05 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-510 I love Lenski's monster experiment, and your cover of it is as always excellent. However I'm not sure whether such a result can really support Gould's view over Conway Morris' view. The fact that most of the evolutionary routes DID in the end achieve the same results could be actually seen as a confirmation of Morris's view! It depends on how much importance it's given to the exception This is after all a manipulative experiment on a single species in controlled conditions. It sure shows that evolution has the potential to go in wildly different ways, but I would expect that genetic potential to be constrained by ecological factors. What seems evident by looking at natural communities is that, if there is a resource to be used (intended in the widest sense, could be food, habitat, etc.), most often you can be sure there is someone able to use it, and organisms adapted to the same resources, niches, whatever, tend to be similar in one regard or another - convergent evolution baby. So it seems that the phenotipical variability species can have is somewhat constrained in certain regards Now a counter-argument could be that, since organisms themselves are a major cause of evolutionary change for other organisms, a small but important change in one lineage could have a sort of butterfly effect on others and lead to unpredictable scenarios... but still, we should agree on what we mean when we say "very different paths". I wouldn't suggest that, say, dinosaurs would have evolved 9 times out of 10 if evolution started back from scratch, BUT I would expect some taxon to evolve "dinosaur"-like characteristics and fill their ecological role. After all that's exactly what happened with mammals after non-avian dinosaurs went extinct. So the Gould vs Conway Morris debate seems to me futile as long as we don't give a meaningful definition of Gould's "different paths" and Morris' "minor details" (quoting your words, not sure what words they actually used). And anyway it seems to be an unresolvable issue as of now, because even Lenski's wonderful experiment is way too simple to represent evolution in the real world I love Lenski’s monster experiment, and your cover of it is as always excellent. However I’m not sure whether such a result can really support Gould’s view over Conway Morris’ view. The fact that most of the evolutionary routes DID in the end achieve the same results could be actually seen as a confirmation of Morris’s view! It depends on how much importance it’s given to the exception
This is after all a manipulative experiment on a single species in controlled conditions. It sure shows that evolution has the potential to go in wildly different ways, but I would expect that genetic potential to be constrained by ecological factors. What seems evident by looking at natural communities is that, if there is a resource to be used (intended in the widest sense, could be food, habitat, etc.), most often you can be sure there is someone able to use it, and organisms adapted to the same resources, niches, whatever, tend to be similar in one regard or another – convergent evolution baby. So it seems that the phenotipical variability species can have is somewhat constrained in certain regards
Now a counter-argument could be that, since organisms themselves are a major cause of evolutionary change for other organisms, a small but important change in one lineage could have a sort of butterfly effect on others and lead to unpredictable scenarios… but still, we should agree on what we mean when we say “very different paths”. I wouldn’t suggest that, say, dinosaurs would have evolved 9 times out of 10 if evolution started back from scratch, BUT I would expect some taxon to evolve “dinosaur”-like characteristics and fill their ecological role. After all that’s exactly what happened with mammals after non-avian dinosaurs went extinct. So the Gould vs Conway Morris debate seems to me futile as long as we don’t give a meaningful definition of Gould’s “different paths” and Morris’ “minor details” (quoting your words, not sure what words they actually used). And anyway it seems to be an unresolvable issue as of now, because even Lenski’s wonderful experiment is way too simple to represent evolution in the real world

]]> By: Luna_the_cat http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-509 Luna_the_cat Thu, 05 Jun 2008 16:53:17 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-509 FWIW, the question of speciation -- especially speciation events which involve the rearrangement of chromosomes or changes in chromosome structure -- has interested me for a long time. If I run across any other examples I would be delighted to pitch them in your direction. (Not literally, of course, unless you *like* having mice thrown at you. I mean, some of us do...ok, shutting up now.) FWIW, the question of speciation — especially speciation events which involve the rearrangement of chromosomes or changes in chromosome structure — has interested me for a long time. If I run across any other examples I would be delighted to pitch them in your direction. (Not literally, of course, unless you *like* having mice thrown at you. I mean, some of us do…ok, shutting up now.)

]]> By: Luna_the_cat http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-508 Luna_the_cat Thu, 05 Jun 2008 16:43:11 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-508 And the mice -- On Madeira, ordinary Mus musculus has either speciated six times in the last 500 years, or is on the verge of having done so: <a href="http://www.genomenewsnetwork.org/articles/04_00/island_mice.shtml" rel="nofollow">http://www.genomenewsnetwork.org/articles/04_00/island_mice.shtml</a> And on Gough Island, there are now Evil Giant Mice eating albatross chicks, which has happened within the last 150 years: <a href="http://www.guardian.co.uk/environment/2008/may/19/wildlife.endangeredspecies?gusrc=rss&feed=worldnews" rel="nofollow">http://www.guardian.co.uk/environment/2008/may/19/wildlife.endangeredspecies?gusrc=rss&feed=worldnews</a> And the mice –
On Madeira, ordinary Mus musculus has either speciated six times in the last 500 years, or is on the verge of having done so:
http://www.genomenewsnetwork.org/articles/04_00/island_mice.shtml
And on Gough Island, there are now Evil Giant Mice eating albatross chicks, which has happened within the last 150 years:
http://www.guardian.co.uk/environment/2008/may/19/wildlife.endangeredspecies?gusrc=rss&feed=worldnews

]]> By: Ed Yong http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-507 Ed Yong Thu, 05 Jun 2008 16:37:45 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-507 Thanks Luna, that's both interesting and useful. Thanks Luna, that’s both interesting and useful.

]]> By: Luna_the_cat http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-506 Luna_the_cat Thu, 05 Jun 2008 16:04:11 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-506 An update: I don't know if it really counts as full speciation or not, but the green alga <i>Chlorella vulgaris</i> made a leap from a unicellular form to a multicellular organism in the lab, as a response to sustained predation by the protist <i>Ochromonas vallescia</i>. The slight irony in this case was that the researcher was actually studying the <i>Ochromonas</i> -- the shift to multicellularity in the alga was noted only in passing, as a thing of little interest, in his original paper! A few years later he went back and did another paper about the algae, though. Boraas, M.E., Seale, D.B., Boxhorn, J.E. "Phagotrophy by flagellate selects for colonial prey: A possible origin of multicellularity" <i>Evolutionary Ecology</i> Vol. 12, Issue 2, 1998, Pages 153-164 (Online at <a href="http://tinyurl.com/465ekj" rel="nofollow">http://tinyurl.com/465ekj</a> ) Another resource that you might appreciate is the book "Frogs, Flies and Dandelions" by Menno Schilthuizen ( <a href="http://www.amazon.com/exec/obidos/ASIN/0198503938/" rel="nofollow">http://www.amazon.com/exec/obidos/ASIN/0198503938/</a> ) which has some excellent information on things which had been observed pre-2000, as well as some good background information on understanding speciation. An update:
I don’t know if it really counts as full speciation or not, but the green alga Chlorella vulgaris made a leap from a unicellular form to a multicellular organism in the lab, as a response to sustained predation by the protist Ochromonas vallescia. The slight irony in this case was that the researcher was actually studying the Ochromonas — the shift to multicellularity in the alga was noted only in passing, as a thing of little interest, in his original paper!
A few years later he went back and did another paper about the algae, though.
Boraas, M.E., Seale, D.B., Boxhorn, J.E. “Phagotrophy by flagellate selects for colonial prey: A possible origin of multicellularity” Evolutionary Ecology Vol. 12, Issue 2, 1998, Pages 153-164
(Online at http://tinyurl.com/465ekj )
Another resource that you might appreciate is the book “Frogs, Flies and Dandelions” by Menno Schilthuizen ( http://www.amazon.com/exec/obidos/ASIN/0198503938/ ) which has some excellent information on things which had been observed pre-2000, as well as some good background information on understanding speciation.

]]> By: Luna_the_cat http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-505 Luna_the_cat Wed, 04 Jun 2008 21:09:49 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-505 Re: 1) <i>Culex molestus</i> -- just so that you are in the clear, it is <i>Culex </i>so-called <i>molestus</i>, because it was discovered that a Southern Hemisphere species had already been granted the <i>molestus</i> name back in the 1860s. I don't think they have gotten a good taxonomic replacement name yet. (The two -- <i>molestus</i> and <i>molestus</i>wannabe -- are completely unrelated, aside from being in the same genus.) There is a classic of plant speciation which everyone seems to miss, though, even though it is actually very well documented. <i>Spartina anglica</i> (English cordgrass) is a classic hybrid+mutation speciation event -- a hybridization of two very different cordgrasses, one native English -- <i>S. maritima</i> -- and one American -- <i>S. alterniflora</i>. The first such hybrid was noticed in the 1840s, I think, around Hythe, presumably because <i>S. alterniflora</i> had been accidentally introduced there as a hitch-hiker in ships' ballast. However, the original hybrid was sterile, a fact well-documented by the area's botanists. Subsequent to that, around 1870, an example of the hybrid underwent a polyploid mutation, and the tetraploid mutant had full fertility, and has spread ever since. I think I know of another couple of similar examples of speciation, which do not involve hybridisation. Will go dig. Back tomorrow. Re: 1) Culex molestus — just so that you are in the clear, it is Culex so-called molestus, because it was discovered that a Southern Hemisphere species had already been granted the molestus name back in the 1860s. I don’t think they have gotten a good taxonomic replacement name yet. (The two — molestus and molestuswannabe — are completely unrelated, aside from being in the same genus.)
There is a classic of plant speciation which everyone seems to miss, though, even though it is actually very well documented. Spartina anglica (English cordgrass) is a classic hybrid+mutation speciation event — a hybridization of two very different cordgrasses, one native English — S. maritima — and one American — S. alterniflora. The first such hybrid was noticed in the 1840s, I think, around Hythe, presumably because S. alterniflora had been accidentally introduced there as a hitch-hiker in ships’ ballast. However, the original hybrid was sterile, a fact well-documented by the area’s botanists.
Subsequent to that, around 1870, an example of the hybrid underwent a polyploid mutation, and the tetraploid mutant had full fertility, and has spread ever since.
I think I know of another couple of similar examples of speciation, which do not involve hybridisation. Will go dig. Back tomorrow.

]]> By: Ed Yong http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-504 Ed Yong Wed, 04 Jun 2008 19:02:07 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-504 Ian, I don't know about experiments that have demonstrated new species, but my handy Counter-Creationism Handbook lists the following examples of new species having arisen during historical times: 1) A new mosquito species <i>Culex molestus</i>, isolated in London's Underground, has speciated from <i>Culex pipiens</i>. 2) <i>Helacyton gartleri </i>is the HeLa cell culture, which evolved from a human cervical cancer in 1951. The culture grows indefinitely and has become widespread. 3) Several new species of plants have arisen via polyploidy (when the chromosome count multiples by two or more) One example is <i>Primula kewensis</i>. The book also lists several examples where speciation seems imminent, where it's in the process of happening and where it can be clearly inferred to have happened because some species only exist in environments that did not exist a few hundreds or thousands of years ago. I don't have time to list them all, but I'd recommend getting the book. Ian, I don’t know about experiments that have demonstrated new species, but my handy Counter-Creationism Handbook lists the following examples of new species having arisen during historical times:

1) A new mosquito species Culex molestus, isolated in London’s Underground, has speciated from Culex pipiens.

2) Helacyton gartleri is the HeLa cell culture, which evolved from a human cervical cancer in 1951. The culture grows indefinitely and has become widespread.

3) Several new species of plants have arisen via polyploidy (when the chromosome count multiples by two or more) One example is Primula kewensis.

The book also lists several examples where speciation seems imminent, where it’s in the process of happening and where it can be clearly inferred to have happened because some species only exist in environments that did not exist a few hundreds or thousands of years ago. I don’t have time to list them all, but I’d recommend getting the book.

]]> By: caynazzo http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-503 caynazzo Wed, 04 Jun 2008 16:47:39 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-503 arensb: if that's the creationists complaint, that it's still a fruit fly, then their making a categorical error. Speciation isn't a subjective classification. Remember, one of the criteria is the inability to reproduce fertile offspring from interspecific mating. I was at a talk last week that demonstrated this very thing: cladogenesis in fruitfly species in the wild and lab. arensb: if that’s the creationists complaint, that it’s still a fruit fly, then their making a categorical error. Speciation isn’t a subjective classification. Remember, one of the criteria is the inability to reproduce fertile offspring from interspecific mating.
I was at a talk last week that demonstrated this very thing: cladogenesis in fruitfly species in the wild and lab.

]]> By: Ian http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-502 Ian Wed, 04 Jun 2008 11:41:21 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-502 arensb - Sorry - I meant that last reponse of mine to be addressed to you! arensb – Sorry – I meant that last reponse of mine to be addressed to you!

]]> By: Ian http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-501 Ian Wed, 04 Jun 2008 11:40:06 +0000 http://blogs.discovermagazine.com/notrocketscience/2008/06/02/history-restricts-and-guides-the-evolution-of-innovations/#comment-501 Ed - I know they'll never accept anything as an answer(!) but it would still be nice to have something like that in my collection of evidence to pull out of the hat! I just read on Carl Zimmer's blog a comment by Allan Kellog(spelling?) about Myxococcus xanthus having a kingdom of its own. It might be worth following up on that, methinks. Ed – I know they’ll never accept anything as an answer(!) but it would still be nice to have something like that in my collection of evidence to pull out of the hat!
I just read on Carl Zimmer’s blog a comment by Allan Kellog(spelling?) about Myxococcus xanthus having a kingdom of its own. It might be worth following up on that, methinks.

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