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Science

The Little Algae That Could 196

Posted by Hemos from the evolution-devolution dept.
A reader writes "This NewsFactor Network article says scientists have discovered a genetic "missing link" that helps to explain how primordial pond scum evolved into the land plants that now cover the Earth. Their conclusion: A type of green algae is the closest living relative of the first land plants."
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The Little Algae That Could More

The Little Algae That Could

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  • Spawn (Score:4, Funny)

    by NiftyNews ( 537829 ) on Thursday December 27, 2001 @06:52PM (#2756739) Homepage
    And the first thing to spawn from it?

    Lawyers.

  • Not all pond scum evolved (Score:3, Funny)

    by 13013dobbs ( 113910 ) on Thursday December 27, 2001 @06:53PM (#2756742) Homepage
    Some did not. That type of scum is called a 'sales person'.
  • Sure seems like there would be many more 'missing links' between algae and a land plant.

    • Re:Leaves a lot to be desired... (Score:1, Funny)

      by Anonymous Coward
      Then they wouldn't be missing links, would they?
    • Leaves a lot to be desired...

      Or,

      "Leaves, a lot to be desired."

    • > Sure seems like there would be many more 'missing links' between algae and a land plant.

      No problem: every time a 'missing link' is found, it generates two new 'missing links' -- one to either side of the one just found. There shouldn't be any problem generating enough to fill your gap.

    • Re:Leaves a lot to be desired... (Score:5, Insightful)

      by Angry Toad ( 314562 ) on Thursday December 27, 2001 @09:12PM (#2757081)

      Well... the news article misses the beat on a few things, including which journal it was published in (Science, not Nature). The term "missing link" is often bandied about in the news whenever the topic turns to ancestral organisms. That wasn't really what the paper was about. The real issue was that this algae appears to be the closest living relative of the land plants. For that reason, any characteristics it has in common with the land plants are most likely ones which were present in the common ancestor of all land plants. Being able to place the ancestor of the land plants between two "frames" this way (common characters of land plants AND characters of Charales algae) gives us a window onto what kind of organism the land plants are derived from. Here's a tiny quote from the original paper:

      Identification of the Charales as the sister taxon to land plants with the Coleochaetales as sister to the Charales/land plant clade suggests that the common ancestor of land plants was a branched, filamentous organism with a haplontic life cycle and oogamous reproduction... Although it is tempting to envision the origin of land plants as having been from amorphous pond scum, these data indicate that the common ancestor of land plants and their closest algal relatives was a relatively complex organism.

  • Non-watered down story (Score:5, Informative)

    by ChazeFroy ( 51595 ) on Thursday December 27, 2001 @06:56PM (#2756754) Homepage
    You can find the original, non-watered down story at Nature [nature.com]. Of course, you need a subscription :-)

    • You can get the abstract here [nih.gov] for free and demonstrate to yourself that the news article was wrong, and that it was actually in Science [sciencemag.org], not Nature. Thus endeth my Karma whoring for today. :)

    • For those of you who don't have a subscription to the Science [sciencemag.org] journal, here's the article, with references:

      The Closest Living Relatives of Land Plants

      Kenneth G. Karol,1* Richard M. McCourt,2 Matthew T. Cimino,1 Charles F. Delwiche1

      The embryophytes (land plants) have long been thought to be related to the green algal group Charophyta, though the nature of this relationship and the origin of the land plants have remained unresolved. A four-gene phylogenetic analysis was conducted to investigate these relationships. This analysis supports the hypothesis that the land plants are placed phylogenetically within the Charophyta, identifies the Charales (stoneworts) as the closest living relatives of plants, and shows the Coleochaetales as sister to this Charales/land plant assemblage. The results also support the unicellular flagellate Mesostigma as the earliest branch of the charophyte lineage. These findings provide insight into the nature of the ancestor of plants, and have broad implications for understanding the transition from aquatic green algae to terrestrial plants.

      1 Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
      2 Department of Botany, Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103, USA.
      * To whom correspondence should be addressed. E-mail: karol@umail.umd.edu

      The evolutionary origin of the embryophytes (or land plants) from their green algal ancestor was a pivotal event in the history of life. This monophyletic group has altered the biosphere and now dominates the terrestrial environment, but uncertainty as to the identity of their closest living relatives has persisted in the literature after more than a century of scrutiny (1-3). Morphological and molecular studies have identified two distinct lineages within the green plants sensu lato, termed Charophyta and Chlorophyta. The Charophyta comprise the land plants and at least five lineages (orders) of fresh water green algae, and are sister to the Chlorophyta, which consist of essentially all other green algae. Previous molecular analyses have verified monophyly of most of the charophyte orders (4-6), but branching patterns among these lineages have been only weakly supported, with results that were sensitive to taxon selection and method of phylogenetic reconstruction. Similarly, analyses of morphological and genome structural data have clarified some relationships (7-10), but have been limited by the number of characters available, uncertain homology assessment, and a lack of character independence.

      Identifying the closest living relatives of land plants has been difficult. Roughly 470 million years of evolution since the colonization of the land, coupled with rapid radiation and numerous extinction events (2, 3, 11), has resulted in an inherently difficult phylogenetic problem, with much information from the early, common history of evolution obscured by subsequent evolution in the now independent lineages (12).

      To investigate the evolutionary origin of land plants and identify the closest living relatives of this group, we analyzed DNA sequence data from four genes representing three plant genomes: atpB and rbcL (plastid), nad5 (mitochondrial), and the small subunit (SSU) rRNA gene (nuclear). The data set used for phylogenetic analyses excludes introns and unalignable regions for a total length of 5147 base pairs [Appendix 1 (13)] (14). We sampled 34 representative charophytes, including eight land plants, and six outgroup taxa [Appendix 2 (13)]. The data were analyzed with Bayesian inference (BI), maximum likelihood (ML), maximum parsimony (MP), and minimum evolution with two distance measures [LogDet (ME-ld) and maximum likelihood (GTR+I+ [Gamma ] ; ME-ml) distances] [Appendix 3 (13)]. Both BI and ML are probabilistic methods that utilize explicit models of sequence evolution to test phylogenetic hypotheses. Advantages of BI are that it is relatively fast and provides probabilistic measures of tree strength that are more directly comparable with traditional statistical measures than those more commonly used in phylogenetic analyses (15, 16). To measure phylogenetic stability, posterior probabilities (PP) as inferred by BI were calculated and bootstrapping was performed for the ML, MP, and ME analyses.

      Using BI and ML on the combined four-gene data set (Fig. 1), we found the order Charales sister to the land plants with strong statistical support (PP = 1.0, ML = 94) and a monophyletic Coleochaetales sister to the Charales/land plant clade (PP = 1.0, ML = 59). The MP and ME analyses [Appendix 4 (13)] also support the result that Charales have a closer relationship to land plants than do Coleochaetales (MP = 80, ME-ld = 97, ME-ml = 92). The overall structure of the best tree is consistent with previous work in that the classically recognized orders were also recovered (land plants, PP = 1.0, ML = 100, MP = 100, ME-ld = 100, ME-ml = 100; Charales, PP = 1.0, ML = 100, MP = 100, ME-ld = 100, ME-ml = 100; Coleochaetales, PP = 1.0, ML = 62, MP = Fig. 1. Phylogenetic relationships for Charophyta determined by Bayesian inference from the combined four-gene data set. The maximum likelihood tree (-ln = 64499.87863) was of identical topology. Posterior probabilities are noted above branches and maximum likelihood bootstrap values are below branches. The topology is drawn with Cyanophora rooting the tree. Branch lengths are mean values and are proportional to the number of substitutions per site (bar, 0.05 substitutions/site). Taxonomy is modified from (23). [View Larger Version of this Image (41K GIF file)]

      The phylogenetic placement of Mesostigma, a unicellular, scaly green flagellate has been controversial. Traditionally classified with like forms as a prasinophyte, it also has been allied with the Charophyta. The phylogenetic position of Mesostigma is critical to understanding the evolution of form and structure in the lineage that gave rise to land plants. Like the results presented here, analyses of actin sequences place Mesostigma at the base of the Charophyta (17), and analyses of SSU rRNA gene sequence data place it among them (albeit in close association with Chaetosphaeridium, a grouping not supported by other data) (5, 18). By contrast, maximum likelihood analyses of amino-acid data from both the plastid and mitochondrial genomes of Mesostigma find strong support for placement of this genus as sister to all green algae rather than as a basal charophyte lineage (19, 20). The latter analyses differ from those presented here in the number of taxa sampled (8 versus 40). When divergence times are large and internal branches short, limited taxon sampling can lead to inaccurate phylogenies (12). If taxon sampling explains this conflict, then one would predict convergence on the phylogeny presented here as additional organellar genomes become available.

      Both Charales and Coleochaetales have long been considered to be close relatives of the land plants (1, 21-23). Key morphological characters uniting these three lineages include branched filamentous growth, oogamous sexual reproduction, and phragmoplastic cell division, along with a suite of ultrastructural and biochemical features (2). In light of similar morphological traits (i.e., parenchyma-like tissue, placental transfer cell wall ingrowths, and zygote retention), the genus Coleochaete and, in some instances, a single species, C. orbicularis, has been discussed as a possible sister taxon to land plants (8, 24). Our results indicate that the Coleochaetales are monophyletic and less closely related to the land plants than the Charales. Both Bayesian inference and bootstrap analyses permit evaluation of alternative hypotheses; we were unable to identify any alternative hypothesis with nontrivial support (25).

      The Charales also share numerous characteristics with land plants, some of which are not found in the Coleochaetales. These include gross sperm morphology and ultrastructure (26), numerous discoidal chloroplasts per cell, protonemal filaments, complete absence of zoospores (sperm are the only flagellate cells), and encasement of the egg by sterile jacket cells (cortication) prior to fertilization (10, 21). Our data suggest that many of the similarities between Charales and land plants reflect homology rather than convergent evolution. Cortication of the zygote reminiscent of that in Charales is found in some species of Coleochaete, but occurs only after fertilization of the egg, and zygote cortication is not thought to occur in Chaetosphaeridium (10). In addition, primary plasmodesmata have been confirmed in the Charales, a character shared with land plants (27). Although plasmodesmata have been described in Coleochaete, it is unknown whether their development is primary or secondary in nature.

      Identification of the Charales as the sister taxon to land plants with the Coleochaetales as sister to the Charales/land plant clade suggests that the common ancestor of land plants was a branched, filamentous organism with a haplontic life cycle and oogamous reproduction. The early stages of development in the Charales involve formation of protonemal filaments reminiscent of those found in some mosses and other land plants, which suggests that a similar heteromorphic development might have occurred in the common ancestor. Other characteristics of this ancestor, including both developmental and biochemical features, may explain not only how their descendants came to survive on land, but also how they ultimately came to dominate terrestrial ecosystems. Moreover, the charophytes have important applications in a wide range of disciplines (Charales in cell biology, Coleochaetales in ultrastructure, and Zygnematales in physiology) (10). Consequently, a robust phylogeny relating these taxa to land plants can place this work in an evolutionary context and lead to the identification and development of appropriate model systems for future studies.

      Although it is tempting to envision the origin of land plants as having been from amorphous pond scum, these data indicate that the common ancestor of land plants and their closest algal relatives was a relatively complex organism. The extant Charales are the remnants of a once diverse, but now largely extinct, group which includes some of the oldest known plant fossils [roughly 420 million years ago (Ma) from the late Ordovician] (11, 28). While the fossil record for the other charophyte orders is fragmentary at best (29), the molecular phylogenetic data presented here (Fig. 1) suggest that these lineages diversified more than 470 Ma. While not species-rich, these algae hold a key position in the tree of life and, consequently, represent an important part of eukaryotic diversity.
      REFERENCES AND NOTES
      1. F. O. Bower, The Origin of Land Flora. A Theory Based upon the Facts of Alternation (Macmillan, London, 1908).
      2. L. E. Graham, The Origin of Land Plants (Wiley, New York, 1993).
      3. P. Kenrick, P. R. Crane, The Origin and Early Diversification of Land Plants, Smithsonian Series in Comparative Evolutionary Biology (Smithsonian Institution Press, Washington, DC, 1997).
      4. R. L. Chapman et al., in Systematics of Plants II, D. E. Soltis, P. S. Soltis, J. J. Doyle, Eds. (Kluwer Academic, Norwell, MA, 1998), pp. 508-540.
      5. B. Marin and M. Melkonian, Protist 150, 399 (1999) [ISI][Medline].
      6. R. M. McCourt, et al., J. Phycol. 36, 747 (2000) [Abstract/Full Text].
      7. H. J. Sluiman, Plant Syst. Evol. 149, 217 (1985) [ISI].
      8. L. E. Graham, C. F. Delwiche, B. D. Mishler, Adv. Bryol. 4, 213 (1991) .
      9. B. D. Mishler and S. P. Churchill, Brittonia 36, 406 (1984) [ISI].
      10. L. E. Graham, L. W. Wilcox, Algae (Prentice-Hall, Upper Saddle River, NJ, 2000).
      11. M. Feist, N. Grambast-Fessard, in Calcareous Algae and Stromatolites, R. Riding, Ed. (Springer-Verlag, Berlin, 1991), pp. 189-203.
      12. J. Felsenstein, Syst. Zool. 27, 401 (1978) [ISI] .
      13. Supplementary material is available on Science Online at www.sciencemag.org/cgi/content/full/294/5550/2351/ DC1.
      14. Polymerase chain reaction (PCR) and sequencing: Total cellular DNA was isolated by the CTAB method [ J. J. Doyle and J. L. Doyle, Phytochem. Bull. 19, 11 (1987) ], UNSET method (a high-urea, SDS extraction buffer) or using the Nucleon Phytopure Plant DNA extraction kit (Amersham Pharmacia Biotech) following the manufacturer's protocol from fresh thalli growing in uni-algal condition. The genes were amplified by PCR with gene specific primers (atpB upstream: 5'-TGTTACTTGTGAAGTTCAACA-3'; atpB downstream: 5'-CTAAATAAAATGCTTGTTCAGG-3'; rbcL upstream: 5'-ATGTCACCACAAACAGAAACTAAAGC-3'; rbcL downstream: 5'-AATTCAAATTTAATTTCTTTCC-3'; nad5 upstream: 5'-GTAGGTGATTTTGGATTAGC-3': nad5 downstream: 5'-GTACCTAAACCAATCATCATATC-3'; SSU upstream: 5'-GTAGTCATATGCTTGTCTC-3': SSU downstream: 5'-CTTGTTACGACTTCTCCT-3') and sequenced using either an ABI-PRISM 377 or 3100 DNA sequencer (PE Applied Biosystems) according to the manufacturer's protocols. The resulting sequence chromatograms were edited and compiled into a single alignment using Sequencher 3.1.1 (Gene Codes Corp.) and exported in NEXUS format for phylogenetic analyses. Many published SSU rRNA gene sequences were difficult to align to published secondary structure models. Small subunit sequences that could not be matched to such structure models were resequenced for this study (13). A single intron was found in the Coleochaete orbicularis nad5 sequence and the distribution of introns in nad5 was examined in the taxa within our study. No introns were found in any other species of Coleochaete or other algal charophyte nad5 sequence sampled. Introns with the same insertion point as that of C. orbicularis were only found in Sphagnum (a moss) and Marchantia (a liverwort) which share a sequence identity of 69.39%, compared with only 37.82% and 37.81% to C. orbicularis, respectively. Anthoceros (a hornwort) has an apparently unrelated intron inserted 128 base pairs downstream with 37.35% identity with that of Sphagnum, 35.99% identity to Marchantia, and 39.46% to C. orbicularis. For comparison, pairs of random sequences with similar base composition and length as the natural sequences had an average of 37.78% sequence identity. These data suggest that the C. orbicularis nad5 intron was acquired independently from that shared by Sphagnum and Marchantia.
      15. J. P. Huelsenbeck, J. P. Bollback, in Handbook of Statistical Genetics, M. Bishop, Ed. (Wiley, London, 2001).
      16. J. P. Huelsenbeck, F. Ronquist, R. Nielsen, J. P. Bollback, Science 294, 2310 (2001) [Abstract/Full Text] .
      17. D. Bhattacharya, K. Weber, S. S. An, W. Berning-Koch, J. Mol. Evol. 47, 544 (1998) [ISI][Medline] .
      18. H. J. Sluiman and C. Guihal, J. Phycol. 35, 395 (1999) [Abstract].
      19. C. Lemieux, C. Otis, M. Turmel, Nature 403, 649 (2000) [CrossRef][ISI][Medline] .
      20. C. Lemieux, C. Otis, M. Turmel, in press.
      21. F. E. Fritsch, The Structure and the Reproduction of the Algae (Cambridge Univ. Press, London, 1935), vol. I.
      22. J. D. Pickett-Heaps and H. J. Marchant, Cytobios 6, 255 (1972) [ISI] .
      23. K. R. Mattox, K. D. Stewart, in The Systematics of the Green Algae, D. E. G. Irvine, D. M. John, Eds. (Academic Press, London, 1984), pp. 29-72.
      24. B. D. Mishler and S. P. Churchill, Cladistics 1, 305 (1985) .
      25. Alternative hypotheses that were explored include: Coleochaete orbicularis sister to land plants, PP = 0.0, ML = 0.0%; Coleochaete sister to land plants, PP = 0.0, ML = 0.0%; Coleochaetales sister to land plants, PP = 0.0, ML = 0.0%; Coleochaetales sister to Charales, PP = 0.0, ML = 0.4%.
      26. T. M. Duncan, K. S. Renzaglia, D. J. Garbary, Pl. Syst. Evol. 204, 125 (1997) .
      27. M. E. Cook, L. E. Graham, C. E. J. Botha, C. A. Lavin, Am. J. Bot. 84, 1169 (1997) [Abstract] .
      28. M. Feist and R. Feist, Nature 385, 401 (1997) [ISI][Medline] .
      29. H. Tappan, The Paleobiology of Plant Protists (Freeman, New York, 1980).
      30. We thank T. Bachvaroff, T. Cooke, G. French, M. Hibbs, J. Lewandowski, T. Marushak, and E. Zimmer for critical comments; C. Drummond, S. Snyder, and A. Zeccardi for technical assistance; J. Bollback and J. Huelsenbeck for important discussions and assistance with Bayesian analyses; M. Casanova, M. Feist, and V. Proctor for material; F. Lang et al., C. Lemieux, C. Otis, and M. Turmel for unpublished sequence data; and S. Fritz, A. Kaspar, R. Sudman, K. Sytsma, and the GPPRGC ("Deep Green"; USDA) for help with development of this project. This work was supported by NSF grant DEB-9978117 and is dedicated to the memory of C. C. Delwiche.
      7 August 2001; accepted 9 November 2001
      10.1126/science.1065156
      Include this information when citing this paper.

    • If you attend a major university, you may be able access Science magazine electronically free of charge (minus tuition of course) from any computer with an IP address on your university's network. Try going to Science's homepage [sciencemag.org]. If under the advertisments at the top of the page, there is some text that says "Institution: University of foo", then you have electronic access to all the articles that have appeared in print (Sadly institutional subscriptions don't include access to papers on ScienceExpress that have been published electronically but not yet on paper)

      --Phillip
  • From an angry writer to Wired on the technique used in this research: http://www.wired.com/news/commentarySection/0,1292 ,49350,00.html
    • Heh. I wonder if he's related to Dwayne Gish. His fallacy, of course, is in claiming that researchers use similar genomes to prove evolution. They don't; evolution has already been shown to occur in many other studies. Evolution really *is* the only game in town that makes any sense. :)

      -Legion

      • I think I need some clarification.

        If you mean evolution in terms of adaptation based on traits that make the species more hearty, that is scientific and observable.

        Extension of that pattern to explain origin of species is not scientific in nature. It is merely conjecture. When you speak of origin of all species, you move past the scientific method. Since it's not a theory that can be tested, it can't be called science.

        Evolutionists and creationists have the same data, we just have different explanations of the cause of that data.

        Your belief that it is explainable by survival of the fittest, time and chance may be the "only game in town that makes sense" to you, but having a creator who intelligently designed the basic species and allowed them to adapt from there seems to me to fit the evidence more accurately.

        Respectfully,
        Anomaly

        PS - God loves you and longs for relationship with you. If you want to know more about this, please contact me at tom_cooper@bigfoot.com
        • You admit 'adaptation based on traits that make the species more hearty, that is scientific and observable.' That's excellent. However, there's no bright line between this kind of change and 'origin of species'. Occam's razor demands that one not create one. It's 'the only game in town' in the sense that it is the only explanation that fits the facts and does not introduce invisible superheros into the equation. If we are allowed to introduce superheros, we can come up with an infinity of possible explanations.
          • If you are a materialist - which I presume based on your "invisible superheroes" comment - you have the challenge of explaining the material universe not having turned all of the kinetic energy into heat an eternity ago.

            I think that the "invisible superhero" makes a bit of sense given that you may need to bend the known rules of physics to allow for eternally existent matter.

            Respectfully,
            Anomaly
            • ---you have the challenge of explaining the material universe not having turned all of the kinetic energy into heat an eternity ago.---

              Eh? Why exactly- what reason do you have to think that this is what SHOULD have happened? The reality is that the material universe exists: one needs to explain how it works, not try to prove that it exists...

              ---I think that the "invisible superhero" makes a bit of sense given that you may need to bend the known rules of physics to allow for eternally existent matter.---

              First of all: what evidence is there that matter is "eternally existent"? And second of all, you don't have to bend the rules of physics at all: as victor Sternger has pointed out, it is perfectly acceptable to the laws of physics for the universe to litterally come out of nothing, the way that quantum particle/anti-particle pairs do ALL THE TIME everywhere.

              However, the more important point here, that you missed, is that "invisible superhero" explanations are unacceptable as explainations because a) they violate the very bounds of reasoned dicussion (because once this becomes an acceptable "explanation" we've destroyed the very need to explain anything at all: the "explanation" can work for ANYTHING) and b) they do not actually "explain" ANYTHING (i.e. that "something of unknown characteristics did it in an unknown way" is just a fancy way of saying "I don't know").
        • Evolutionists and creationists have the same data, we just have different explanations of the cause of that data.


          But unlike the creationist view, evolution is based on research and analysis. Creationism is based on a nifty book written by people long ago who didn't even write it down for several generations. For example, a classic game of "telephone" probably led to the Bible's editions of the past several hundred years or so. And before 1611 it was mostly in Latin and Greek. [pair.com]

          Somehow I feel I can trust evolution a bit more as a viable theory for how life came to be.

        • Re:an amusing comment (Score:3, Informative)

          by (void*) ( 113680 )

          Extension of that pattern to explain origin of species is not scientific in nature. It is merely conjecture.

          This is wrong on the factual level as well as on the philsophical level.


          On the factual level, we have observed speciation in the wild and in the laboratory. For example, the ring species of birds, where one species breeds with another as you move east, until they wrap back on each other. Change of species features has been observed!


          On the philosophical level, you can't do science without speculation! That's the only way to advance. Caring only to make "correct" statements, one will never invent and devise experiments to test if one is wrong. And not experiments means no progress. By being wrong (experimentally), scietists cause progress and advancement. These errors are beneficient, think about that!

          • I thinkg we agree more than we disagree.

            It's one thing to say that there are variations within a kind, but there are substantive issues with suggesting that the same process can explain the existance of the great diversity of species.

            I don't argue that species features are observed to change. That is objectively measureable.

            Of course scientists speculate, but there's a difference between speculations that can be tested and those that cannot.

            Those that can be tested are called hypothesis - after testing they are called theories.

            Those that cannot be tested are appropriately called speculation, or beliefs. They are not science, and shold not be called that.

            Respectfully,
            Anomaly
            • First of all, science no longer plays Platonic games like "kind" as if their were some higher-plane types the variation of which is tricky bussiness.

              But secondly, the theory of evolution is most certainly scientific. This is a moot point: claiming that it is not is simply in contradiction to virtually all accounts of what science is. You're going to have a _very_ hard time finding a preponderance of accredited theorists of science who would be willing to agree with your view.
              And indeed, it quite regularly makes testable predictions about what sorts of things we should expect to find if the theory is true, and these predictions have proved incredibly accurate. We have also been able to build models from evidence, and test these models in the real world. Just because something is historical does not mean that science is toothless in the face of it. Certainly, one cannot prove that _history_ happened in a certain way, but one can certainly amass all the evidence one can about the functioning of the world, records left by this functioning, and make and test hypothesises.

            • It's one thing to say that there are variations within a kind, but there are substantive issues with suggesting that the same process can explain the existance of the great diversity of species.

              Sorry, but you are basically repeating the same old argument from incredulity again. On what BASIS do you think you are coming out with this objection?


              Is this objection that variation within a species cannot ever produce a variation that makes news species. That's the factual problem right? So if one exception were ever to be raised, your "rule" or "law" would deserve to be revised, right? There is plenty of evidence out there that species change from one to the other. Many very direct! Many observed in the wild! (Try reading "The Beak of the Finch")


              Now what are you really objecting to? That there is a difference between a fact and a theory? That evolution is a theory, and so cannot be as good as a fact? BUT EVOLUTION is both FACT AND THEORY. There is a theory of evolution supported by facts of evolution. And this theory of evolution proposes new research directions, and lends coherncy to these facts of evolution. That is what a scientific theory is!


              Perhaps you think evolution has aspects that are speculative. But so what? There are speculative aspects to all theories. Do you object to Quantum Mechanics implying that there are many worlds? Do you object to GR predicting that time-travel is possible? Do you think you can "pick-and-choose" which part to believe and which part not to, arbitrarily and on whim, using your own gut level intuition as a guide? When the findings of science has shown consistently that our gut level intuitions are wrong in many points, subtle or otherwise?


              To rephrase: go ahead and object to the speculative parts of evolution. But please come out with a scientific argument for that objection. The onus is on the contratrian to supply the arguments, since the (overwhelming) weight of the evidence points to evolution.

        • > If you mean evolution in terms of adaptation based on traits that make the species more hearty, that is scientific and observable.

          > Extension of that pattern to explain origin of species is not scientific in nature. It is merely conjecture.

          All science is 'conjecture'. The difference between science and other types of conjecture is that scientists think out the implications of their conjectures and then look at the world again to see whether it conforms to those implications. That is the essence of the scientific method.

          > When you speak of origin of all species, you move past the scientific method.

          Not at all. Please re-read my previous paragraph.

          > Since it's not a theory that can be tested, it can't be called science.

          Ah, but it can be tested. Indeed, you can reasonably think of all of modern genetics as a big test of the theory of creation, which was originally a 'conjecture' based on the fossil record, but which had very strong implications for what we should see when we started realizing how genetics worked on the level of biochemistry. Alas for creationism, modern genetics bears those implications out quite well.

          If you understand the scientific method and then add just a tiny amount of knowlege about biology, biochemistry, and paleontolgy, it becomes immediately obvious why the 'conjecture' represented by the theory of evolution continues to be accepted as 'scientific'.

          > Evolutionists and creationists have the same data, we just have different explanations of the cause of that data.

          Yes: scientists have a dense network of interrelated and mutually supporting, falsifiable theories spanning several fields of study, whereas creationists have "I think goddidit."

          > Your belief that it is explainable by survival of the fittest, time and chance may be the "only game in town that makes sense" to you, but having a creator who intelligently designed the basic species and allowed them to adapt from there seems to me to fit the evidence more accurately.

          Anything can be made to 'fit' the evidence if you are willing to invoke enough miracles. And that's exactly what creationists do when they're pressed to actually explain something: lurk talk.origins for a while if you doubt me.

          Also notice that divine intervention has no explanatory value whatsoever: any observation is compatible with it. Unlike scientific explanations such as the theory of evolution, creationism is beyond falsification.

        • How does one explain the appendix???

          PS - Science loves you and longs for relationship with you. Dont be afraid to question your peers, and the world around you!
        • There are myraid other religions out there. I would be interested to see what other views of creation have arisen from them, and how christian creationists would respond to the creationist views of other religions.

          If you thump your bibles at them, they'll do the same right back at you. THEN who's right? heh? heh?

          --R
          • Judaism and Islam basically parallel Christianity in origins, except Talmudic Judaism is really off in the weeds compared with traditional Judaism, and there's extra rubbish about the world spinning on a bull's horn tacked on by some variants of Islam. Christianity as a social organisation is a pretty diverse conglomerate and you'll get philosophical hits in every part of the spectrum if you look hard enough.

            There are plenty of other origins in various religions around the world, but non of them are ex nihilo, and the vast majority were essentially dispelled by TIROS I (the first weather satellite, which sent down bulk photos - incidentally, TIROS I was designed by a Christian Creationist named Dr Gary D Gordon), if not already killed soon after the invention of the telescope.

            Some of these odd little cultures, however, are absolute rippers! For example, search for ``sirius'' in this page [warp0.com].

            Hope that's answered your question. (-:

        • Several other people have beat me to the punch on this, so let me just wrap up with this: I don't argue with creationists; they argue from a foundation of belief and I argue from a foundation of science, and the two will never be reconciled. You'll never convince me (unless God himself steps in, smites me, and tells me I'm wrong, and even then I'll immediately start testing the hypothesis that I'm hallucinating) and I'll never convince you, which is how it should be.

          PS - God loves you and longs for relationship with you.

          Has he appeared to you and told you this personally, or are you guessing?

          -Legion

        • Wait a minute (Score:3, Interesting)

          by cje ( 33931 )
          .. having a creator who intelligently designed the basic species and allowed them to adapt from there seems to me to fit the evidence more accurately. .. PS - God loves you and longs for relationship with you ..

          I've never completely understood why some of the Christian creationist folks automatically assume that people who don't have any problems with modern biology's conception of evolution must be atheists, agnostics, pagans, etc. I would submit that the vast majority of Christians on this planet have no argument with the fact that the universe is a tad older than 6,000 years and that evolutionary common descent is a perfectly sensible way for God to create the kind of biodiversity that we see on Earth today.

          Personally, I'm an apathetic agnostic (I care so little about religion that I can't be bothered to call myself an atheist ;-)) but it seems to me that if there was a God that created all of the life on Earth, He would be akin to the "ultimate engineer." Evolution, from an engineering standpoint, makes a heck of a lot of sense. There's no reason to believe that a perfect God would design a single species "from scratch", as it were, and then wipe the drawing board completely clean and start over from nothing to design a species that is 95% similar to the one He just got done with.

          Really, the fact that we see so many similarities between different creatures on Earth is one of the strongest pieces of evidence in favor of evolutionary common descent. Now, granted, this fact is certainly not evidence against creation ex nihilo. But if God was creating everything ex nihilo He could have made a diverse array of creatures with completely different internal systems specifically engineered for optimal operation in the creature's native environment. Evolution, by and large, has done a pretty good job. Sure, it's not perfect; there are some flaws in the human body that I'd just as soon not be burdened with, but hey .. we play what we're dealt. :-)

          At any rate, I just don't understand how people who believe in an all-powerful God could possibly suggest that He could not, and did not, create the biodiversity on Earth via the simple and elegant processes of evolution. Biology is in the business of answering the "how" questions. It is not in the business of answering the "why" questions, and has never claimed to be. Those who claim otherwise are "putting words in science's mouth", so to speak.
  • The cowboynealae algae has been known to Slashdot for quite some time, now...
  • I'm not sure which is closest, the
    account in Genesis in a little unclear
    on which day pond scum was created.

    I mean on day 3, you get herbs, grass
    and fruit trees on dry land.

    On day 5 you get the living creatures
    that move in the ocean. Does pond scum
    move? does this count?
    • Even the wildly-extrapolating scientists are guessing that this particular pond scum was on it's way (and how did it know what its way was?) to becoming parsley, sage and rosemary in thyme.

  • I'm sure I saw some of this primitive pond scum working in Target recently. They were the ones being more helpful than the rest of the staff...
  • can be found here [asu.edu]. This dates from spring 2001 and describes the possible linkage between the algae and modern plants, based on fossil similarities.

    Guess the genetics are just confirming an older theory. Now if they could only find the missing link between men and geeks... ;-)

  • Finally! (Score:2)

    by jht ( 5006 )
    This is the first good explanation for Geraldo Rivera I've seen yet!

  • Charales and Primordial scum (Score:3, Funny)

    by axolotl_farmer ( 465996 ) on Thursday December 27, 2001 @07:11PM (#2756807)
    For a long time, Charales has been one of the prime suspects in being the sister group of the land plants [arizona.edu]

    This however has nothing to do with primordial scum! Charales [arizona.edu] are advanced green algae that looks something like a submerged moss. I need to read the article, but i suspect the reason Nature would publish this is that they used some new fancy algorith to calculate the phylogenetic trees.

    • some new fancy algorith to calculate the phylogenetic trees.

      Spot on. Bayesian estimation. The newest latest way to get the "right" answer. Althought that being said I really do like it myself - I need to work through the math some more, but it seems like a way of approaching parametric bootstrapping results without the gigantic computational overhead...

    • The phylogenetic algorithms may be of interest- though I haven't read the paper yet and I'm not very knowledgeable about molecular systematics anyhow, but any results on the origin of a major taxa (and land plants certainly qualify) are inherently interesting, even if as you noted, they aren't surprising or arrived at by novel techniques.

  • Nothing alive today is comparable (Score:3, Interesting)

    by catbutt ( 469582 ) on Thursday December 27, 2001 @07:12PM (#2756810)
    Because anything that can exist today must compete against everything else, which has had a couple billion years to evolve. In other words it needs an immune system, a system of acquiring or making food, etc....or it would be gobbled up or starve before you even noticed it was there.

    The first form of "life" (i.e., a self replicating chemical) would probably be a million times simpler than anything that could survive today.
    • In other words it needs an immune system, a system of acquiring or making food, etc...

      Even crystals have to have a way of acquiring food, and that's generally by existing in a strong solution of their ingredients. Can you postulate a viable solution of protolife?

      The first form of "life" (ie, a self replicating chemical) would probably be a million times simpler than anything that could survive today.

      No.

      In detail, a million times simpler is dead. Ten times simpler than prokaryotic is generally dead.

      In even more detail, a couple of billion years is nothing like enough. Given stupidly optimistic conditions (e.g. entire universe made of the correct amino acids, target critter many times simpler than anything known today), a trillion years is many, many, many zeroes too few.

      • I don't understand what you are saying. Crystals don't have food, at least not in the sense that organisms do, so talking about crystals acquiring food is meaningless.
        Secondly, there are ways of quantifying genetic and genomic "complexity", but comparing the "complexity" of something abiotic to something living is inherently nonsensical.
        Thirdly, an order of magnitude difference in genome size (measured in number if genes, one way of giving a number to "complexity") between prokarotes is possible. The prokaryote with the smallest genome has roughly 400 genes, though I don't know the size of the largest prokaryotic genome off hand, I know it is a few thousand genes. So ten times "simpler" than a prokaryote isn't dead.
        • Crystals don't have food, at least not in the sense that organisms do,

          There is no conceptual difference between a crystal assimilating structure from a surrounding solution, and a macrophage ingesting other organisms or organic particles, except that the macrophage's filtering is generally better.

          The prokaryote with the smallest genome has roughly 400 genes, [...] so ten times "simpler" than a prokaryote isn't dead.

          Excellent! Name any standalone self-reproducing unit - either observed or with reasonable indirect evidence - with circa 40 genes and I'll agree with you.

          BTW, contrast a crystal structure (repeating pattern of one to dozens of atoms) with 400 genes, each consisting of specific chromosomes, each consisting of specific proteins, each consisting of specific amino acids, each far more complex than the most complex crystal.

      • ---In detail, a million times simpler is dead. Ten times simpler than prokaryotic is generally dead.---

        At the levels we're talking about, saying that something is "alive" or "dead" is not particularly enlightening, and usually misleading. There is no hard and fast line between "alive" and "dead." Ten times simpler than prokaryotic may not be alive in the sense that a prokaryote is "alive," but that doesn't mean it's inorganic, or has no complexity, or even no self-reproducing complexity.
        • At the levels we're talking about, saying that something is "alive" or "dead" is not particularly enlightening, and usually misleading. There is no hard and fast line between "alive" and "dead."

          Then let's draw one. ``Unable to continue growing or reproducing,'' or more succinctly, ``Positive nett entropy.''

          Ten times simpler than prokaryotic may not be alive in the sense that a prokaryote is "alive," but that doesn't mean it's inorganic, or has no complexity, or even no self-reproducing complexity.

          Yes, it does. Anything ten times simpler than prokaryotic has insufficient cellular machinery to survive unaided. By ``unaided,'' I mean that anything that simple has to be a parasite, and a parasite implies a host, and a host must be around ten times more complicated, but we're starting with something (in the original) ``a million times simpler.'' And if you delete the cellular machinery, there's this enormous gap left between the organisational ability of a simple crystal, and that of a ``simple'' (many millions of atoms) cell which no developmental theory seriously begins to cover. And we haven't even got to the Cambrian Explosion yet,

          GAME OVER PLAYER <1>

    • Conversely, many "complex" species that thrive today would have a difficult or impossible existing at prior points in earth's history because they've adapted to be reproductively successful in the environment that they live in in the present day. If you transported them to a different time with a different climate, soil conditions, or competing or predatory species, they'd go extinct- "complexity" isn't always optimal.
  • I Made Love To An Algal Bloom

    Today, on Springer! Men reveal secret fetishes to their significant others, with slurpy results!

    Guest: "Jerry, I've been having a secret space affair with an algal bloom on the blue planet known as Earth, and I'm here today to tell the truth to my space lover. I want her or him or it, whatever you call an amorphous sillicon entity, not that I actually know but man, the things he, she, or it can do ... but anyway, I want him, her, or it to know how much he, she, or it means to me."

    Jerry: "Oh really? Well, space man, we've got a surprise for you! Turns out your dalliances on Earth created something you didn't quite expect ... so let's bring them in, right now! Sneaky space twinkie, say hello to the entire human race!"

    Guest: "Uh-oh."
  • the term "missing link" was a creationist term used during the Scopes trial. it was part of an argument that said that an incomplete fossil record entirely undermined the whole theory of evolution. it's funny how it's been adopted by scientists.
    • it's funny how it's been adopted by scientists.

      Why is it funny? It was a challenge, which is now being met.
      • Critically speaking, the challenge in not being met because they have shown nothing that a creationist can't use to prove that the life was designed. Nor do they show that evolution is viable or real, just that the facts seem to fit nicely with what we think evolution would look like, presuming it is the correct method.

        Just keeping us all honest. ;-)

        Just for curiosity sake, I don't think evolution is correct. Figure I should show my colors in a forum like this. :-)

  • How does this work? (Score:1, Insightful)

    by Anonymous Coward
    I read that we lose 6 species each day from the face of the earth. You all already know where I am going with this. Yes, this is flamebait. But if you have an earnest argument, please reply. We lose 6 a day, we don't see new species being created, we see statistical laws in action everywhere we look, with increaing entropy being of great interest. What makes evolution feasible?
    • New ones evolve. Do you have any numbers that indicate there are fewer species today than there were at another time in history?
    • We actually don't see the 6 species being lost a day either. It's a guess.

      Wanna guess how many new species are being made a day?

    • You seem to be trying to make some syllagism here but I don't follow it at all.

      I read that we lose 6 species each day from the face of the earth

      6 species a day may be the correct figure for animals or plants during the last few thousand years- you should be able to find a better estimate in an ecology textbook. I don't know is there is an estimate of species lost and creation in bacteria, archaebacteria, or protists, especially since the notion of species in bacteria is somewhat tricky because of the magnitude of lateral gene transfer.

      The rate of speciation and extinction varies over geological time though. Sometimes the net change will be (roughly) zero, sometimes there will be mass extinctions, and sometimes there will be rapid and speciation and creation of new taxa.

      we don't see new species being created

      Yes we do, its all over the fossil record. Bacteria and plants can undergo rapid speciation because of the flexibility of their genomes, animals generally less so, so the documentation of speciation is better for bacteria and plants. We'll understand speciation much better when we have a better understanding of how organisms develop- how the interactions between genes and environment bring about a complete organism which is less or more simaler to its ancestors.

      we see statistical laws in action everywhere we look, with increaing entropy being of great interest.

      I don't see what this has to do with the rest of your post. Events which are more probable than the alternatives will on average occur more than the alternatives. Entropy will increase over time in closed systems but entropy can be shifted or exported from closed systems

      What makes evolution feasible?

      heredity, mutation, and varying reproductive success between organisms.

    • Heh (Score:2)

      by cje ( 33931 )
      We lose 6 a day, we don't see new species being created, we see statistical laws in action everywhere we look, with increaing entropy being of great interest. What makes evolution feasible?

      Do you honestly believe that biological evolution, a slow and meticulous process that takes millions of years to produce real results, can possibly compete with the destructive power of mankind, which can wipe out a species in a few short years? I've heard some pretty weak arguments against evolution, but I have to admit that this is one of the more desparate attempts at straw-grabbing that I've come across.
  • I recall one SF story in which a a conservation talks place between a modern human and a very very long lived member of a race from space.

    One telling point of the conversion was the space aliens nostalgia for the microbial (or some such thing) civilization he remembered from one of his earlier visits to earth.

    Sadly I do not remember the title or the author. It feels like a bar conversation, but that may be wrong.

    • I remember the same story too, the author is Larry Niven, but I can't remember what the story was called.
    • Most likely it one of the tales from Draco's Tavern, by Larry Niven. Conversation was with a Chirpsithtra, perhaps?
      • Most likely it one of the tales from Draco's Tavern, by Larry Niven. Conversation was with a Chirpsithtra, perhaps?

        for some reason Callahan's Crosstime Saloon now comes to mind, but I could be wrong. It feels more like a subplot atmosperic thing than a main plot point.

        [shrug]

    • Larry Niven and "Cautionary Tale."
      It wasn't that the alien was long-lived, but that it was a ramscoop pilot, living thousands of years real-time at close to lightspeed, so subjective time was short. The alien lamented the anaerobic ecology of the old, pre-photosynthesis earth. Our predecessors saw us coming and accepted their gradual replacement. Hence the cautionary tale.
    • Larry Niven wrote a story, in a bar with the chirpr...s who remembered a civilization on Earth, before plants added free oxygen to the atmosphere, which was a poison to them (as with most creatures of that time.)
  • I was under the impression that Charophytes gave rise to modern day vascular and nonvascular plants...
  • You don't get all those horrid ads if you use the printer-friendly [newsfactor.com] version...

    Sure it's cheap, but I had to share my non-discovery with the world. And by world I mean Slashdot.

  • "Algae" is plural. The title should be "The Little Alga That Could".
    1. Assume that B evolved from something in set A.
    2. Find the element of A that shares the most similarities with B.
    3. Declare said element to be the link between A and B on the basis of evidence. (If anyone challenges this conclusion, challenge them in return to come up with a better link candidate.)

    The article left me a bit flat because I went in with false expectations: I thought they were going to talk about the enormous gulf between pre-biotic soup and algae, not algae and land plants.

  • Maybe we can clone it and then send it to Mars. Then Val Kilmer and Trinity could fight a rogue military robot.

    Or perhaps I'm just thinking of a crappy movie.

    • Then Val Kilmer and Trinity could fight a rogue military robot.

      Are you sure you're not thinking of Princess Fiona fighting the Merry Men?

  • remarkable (Score:2, Insightful)

    by jopet ( 538074 )
    for me as an european what is remarkable here is how many people feel the need to come up with creationism in this forum. what kind of religious fundamentalism is this? or is it just another incarnation of the kind of thought that makes people believe in UFOs or witchcraft? or is this just some kind of geek humor I dont get?

    • Re:remarkable (Score:4, Interesting)

      by dublin ( 31215 ) on Friday December 28, 2001 @03:28PM (#2760223) Homepage
      for me as an european what is remarkable here is how many people feel the need to come up with creationism in this forum. what kind of religious fundamentalism is this?

      I'm not sure what being a European might have to do with it - there are lots of Creationists there, too, but they seem less willing to speak freely, possibly for fear of reprisals.

      There happen to be quite a lot of us that are trained as scientists and/or engineers, have looked at the data, and come to the conclusion that Creation 1) requires orders of magnitude less faith in the unseen than does evolution, and 2) fits the available data considerably better, too.

      I don't want or intend to turn this into a flame fest, but if you're at all interested in why, I'd suggest looking in one of several places:

      Uber-hacker Do-While Jones' excellent site [scienceaga...lution.org] on why science is against evolution. Be sure not to miss the archives of the newsletter, Disclosure [scienceaga...lution.org] - reading through these will keep you up nights if evolution is important to your world view... (Check out the article on "Lucy" for an enlightening look at the art of passing off a total pipe dream as "science".)

      There's a pretty good book out called "In Six Days" [amazon.com] containing essays from 50 respected PhDs who explain why they find it considerably easier and more scientifically consistent to belive in Creation than evolution.

      Michael Behe's excellent book, Darwin's Black Box. [amazon.com] This outlines the irreducible complexity argument for Creation that is far better butressed by actual science than is evolution.

      or is it just another incarnation of the kind of thought that makes people believe in UFOs or witchcraft?

      Creationists aren't stupid, or ignorant. There are a few that are knee-jerk fundamentalists, but I find many more are thoughtful scholars. I find that many Creationists are better versed on the science and the data relating to origins than most all evolutionists. In short, the only thing science can say with certainty about origins is that we do not know. Do not be so quick to dismiss alternatives that may well be completely legitimate, even if their implications may be quite uncomfortable for you... Please read up as suggested above before flaming.
      • ... The [harpercoll...ous.com.au] God [yahoo.com] Factor [mindbodyspirit.com.au] (Amazon don't seem to have it but everyone else does), also by John F Ashton. Qualifications? You want qualifications? For the taking, by the truckload! Quoting from the intro to the first of the fifty authors:
        JOHN R DE LAETER

        Professor de Laeter is Emeritus Professor of Physics at Curtin University of Technology in Australia [about 15km from here], where he was previously Deputy Vice-Chancellor of Research and Development. He holds a BSc in physics and BEd in education, both with first class honours, a PhD in physics and a DSc in physics, all from the University of Western Australia. Professor de Laeter has served as chairman of the International Commission on Atomic Weights and Isotopic Abundances, and is presently the Australian Academy of Science's representative on that Commission. He has published approximately 200 research papers and was awarded the Kelvin Medal of the Royal Society of Western Australia in 1993. A minor planet is named after Professor de Laeter in recognition of his contributions to astrophysics. He is an Officer of the Order of Australia.


        He also has all but one unit of a BSc in Philosophy, which he abandoned because it wasn't answering his questions, and he wasn't exactly dying for extra letters after his name. (-:

        • I'm not surprised - "In Six Days" was available in Oz for well over a year before I could get a copy here. Apparently, this one is embargoed too...
          • Apparently, this one is embargoed too...

            I wonder if it's just being delayed, or if someone's buying time to think of answers? If so, they're largely wasting their time. The God Factor, although still chocker with factual content, relies much more on personal testimonies and less on dry factoids.

            You might like to try ordering direct from an Australian retailer [koorong.com.au].

  • The real question is - where did the muck come from?

    Easy - it evolved from creationists!

    =tkk ;)
  • Since a _single_ plant is being discussed, the word is not "algae", which is plural, but "alga".

    hyacinthus.
  • I just smoked some. And in direct comparison to real weed there is a lot of effects missing. I have to conclude that Marijuana probably came some other way.

    I love first-hand science.

  • de-evolution (Score:3, Insightful)

    by peter303 ( 12292 ) on Friday December 28, 2001 @10:02AM (#2758498)
    (Not a band name!) Gould claims in several books that evolution goes in both directions at the same time. Some organizms are getting more complex, while others are getting less complex. For example viruses and parasites may be remnants of more complicated organisms. We tend to notice only the more complex organisms in life's diversity.

    The implcation here is that this pond scum could have been a more developed organization that gave up complexity over the eons.

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