









First 'Rule' Of Evolution Suggests That Life Is Destined To Become More Complex2. Comment #145980 by Steve Zara on March 18, 2008 at 12:47 pm
3. Comment #145997 by Geoff on March 18, 2008 at 1:10 pm
4. Comment #145999 by Vincevl on March 18, 2008 at 1:11 pm
Each individual creature ever is potentially the start of a branch in the Tree of Life. Your Dad is the transitional form between your granddad and you.5. Comment #146003 by Steve Zara on March 18, 2008 at 1:15 pm
I think it's fair to address phenotypic complexity separately though, Steve.
6. Comment #146007 by Epinephrine on March 18, 2008 at 1:21 pm
7. Comment #146026 by chuckgoecke on March 18, 2008 at 1:47 pm
8. Comment #146030 by EnlightenedBlasphemy on March 18, 2008 at 1:49 pm
9. Comment #146032 by Steve Zara on March 18, 2008 at 1:51 pm
Changes in body plan are interesting though - I had read once upon a time that we are going to see continual reductions in the variety of bodyplans, but I'm not sure whether I agree - certainly some groups are more resistant to change than others - tetrapods are all still recognisably tetrapods, and are unlikely to become hexapods, but the arthropods can apparently lose and gain segments much more easily than we can. Is (are) mount(s) improbable truly unidirectional?
10. Comment #146034 by EnlightenedBlasphemy on March 18, 2008 at 1:52 pm
11. Comment #146043 by Tyler Durden on March 18, 2008 at 2:07 pm
12. Comment #146064 by Enlightenme.. on March 18, 2008 at 2:54 pm
If there was some mass extinction that took us back to invertebrates, who knows what the results might be?
13. Comment #146071 by Vadjong on March 18, 2008 at 3:11 pm
14. Comment #146087 by SmartLX on March 18, 2008 at 3:41 pm
Seems to me you only need one exception to bring this First Rule crashing down, and PZ Myers might have found it: the dicyemid mesozoa.15. Comment #146097 by Epinephrine on March 18, 2008 at 3:50 pm
16. Comment #146101 by SmartLX on March 18, 2008 at 3:53 pm
Ah, and the dicyemid mesozoa is a parasite. Whoops, went off half-cocked.17. Comment #146108 by Driver on March 18, 2008 at 4:04 pm
18. Comment #146143 by blu on March 18, 2008 at 5:08 pm
This is hardly surprising when considered in light of maintaining a equilibrium. The more complex something becomes, the more difficult it is to maintain and the more energy needed to for it to live. On the other hand, greater complexity allows for a greater number of survival strategies. So, as things evolve, they will tend to become more complex, eventually reaching a plateau where further complexity is counter productive. But less complexity will likewise need to provide a survival boost for it to be selected for. If the boast is provided simply for the greater simplicity and less energy use, then that suggests that the mutation that led to the greater complexity would not have been selected in the first place. Thus we can see that a wholesale string of changes that lead to more simplicity is unlikely. This is the logical results of the processes pointed out in "Climbing Mount Improbable", all change must be an improvement.19. Comment #146153 by the_ultimate_samurai on March 18, 2008 at 5:28 pm
changes result from either changing a gene, adding a gene, or subtracting a gene. Since in general you will only have added genes that were advantageous, removing them will not be as likely as adding others.
20. Comment #146189 by Opisthokont on March 18, 2008 at 6:09 pm
Evolution is far more than a change in genes. Regulation of genes is at least as important as the genes themselves, and changes in regulation are not as easy to trace as changes in genes. Genes are regulated both by elements on the chromosome and by environmental factors, and environmental factors include what other cells are nearby. Development of complexity is itself far more complex than simply the evolution of genes.21. Comment #146192 by Enlightenme.. on March 18, 2008 at 6:17 pm
22. Comment #146195 by chuckgoecke on March 18, 2008 at 6:27 pm
23. Comment #146212 by notsobad on March 18, 2008 at 7:19 pm
24. Comment #146218 by Mitchell Gilks on March 18, 2008 at 7:33 pm
25. Comment #146253 by dragonfirematrix on March 18, 2008 at 8:26 pm
26. Comment #146271 by Epinephrine on March 18, 2008 at 9:28 pm
27. Comment #146327 by Koreman on March 19, 2008 at 12:50 am
@ 8. Comment #146030 by EnlightenedBlasphemy28. Comment #146328 by Richard Morgan on March 19, 2008 at 12:51 am
29. Comment #146336 by Steve Zara on March 19, 2008 at 1:12 am
Above a certain minimal complement of genes, the size of the genome is irrelevant to complexity.
Genes are regulated both by elements on the chromosome and by environmental factors, and environmental factors include what other cells are nearby.
30. Comment #146442 by Geoff on March 19, 2008 at 5:00 am
Sea squirts hatch with a brain. When they find a rock to attach to, they digest their brain as it's no use to them any more. Is that more or less religious?
31. Comment #146464 by the_ultimate_samurai on March 19, 2008 at 5:45 am
oh i saw the part about it being a simplification and took it into account, i only quoted the other part because it was all i was concerned with.32. Comment #146486 by Shaden on March 19, 2008 at 6:12 am
It's become obvious to me now, in order to fend off extinction, we need to eliminate any species that is equal or greater complexity to ourselves.
33. Comment #146504 by j.mills on March 19, 2008 at 6:37 am
34. Comment #146525 by Luthien on March 19, 2008 at 7:00 am
35. Comment #147260 by Luis_Cayetano on March 20, 2008 at 4:51 am
I hardly think this qualifies as a "rule" of evolution. Building complex organisms is energetically expensive, so the question is really why selection would have favoured increased complexity in crustaceans. In other groups that have been studied, there was no overall increase towards complexity. I recommend Stephen Jay Gould's "Full House" for a view on this. Just because the crustaceans have undergone across-the-board complexification doesn't mean you can extrapolate to evolution in general and proclaim that you have uncovered a "first rule". I'm not saying that the researchers are wrong, just that until we've done a wider cataloguing and comparison of complexity throughout the biosphere, making these sorts of claims is going to give the impression of undue eagerness. Some parts of this article made me think, "so what? That's meant to be surprising?" Good on them for making this fascinating discovery, but I fear that they're attempting to draw conclusions that aren't warranted. That the Crustacea have become more complex overall is interesting enough. I'm sure some lessons can be drawn from this, but it seems somewhat wank-headed to think you can make sweeping generalisations from it.
1. Comment #145967 by VanYoungman on March 18, 2008 at 12:13 pm
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