According to wikipedia: However many scientists see "Neo-Darwinism" as outdated and incomplete. Evolution is clearly much more complex than we thought it was. There are far more evolutionary mechanisms than the ones listed above. Gert Korthof who owns the website http://www.wasdarwinwrong.com/ believes that "the ingredients of the Third Evolutionary Synthesis are gradually becoming visible". Indeed many new mechanisms have been discovered such as: http://en.wikipedia.org/wiki/Niche_construction http://en.wikipedia.org/wiki/Molecular_drive http://www.doaj.org/doaj?func=abstract&id=327895 (internal selection) http://www.everythingology.com/lynn-margulis-symbiosis-is-the-driver-of-evolution/ (symbiosis) I created this thread to discuss some of these mechanisms and perhaps so I can learn of any others. Thanks.
Genetic mutations could and do at times create variations amongst things. Environment is another variable that can make changes happen over time.
I think the answer you are looking for is propagation. If a species makes a evolutionary change that makes it die out the species will not propagate or even survive to make additional random evolutionary changes. If a zebra became a bright red color instead of its camouflaged stripes perhaps they would be more readily spotted by Lions and other predators, and dies out. Yet the same Zebra in North America where lions do not exist could evolve into normal horse colors without harm to the species. If mankind did not exist and Lions were introduced to North America then striped animals might escape more readily than solid color animals due to camouflage. Eventually Striped Horses would breed with additional striped horses and we'd get another form of zebra at some point. Maybe there were some nice smelling skunks at some point, but they have long since been easy prey.
There is also the impact of an entropic force that can be generated by water. Anyone who grows plants knows more sun means more flowers, fruit and even branching, regardless of the DNA. This aspect of the entropic force is connected to photosynthesis generating solute in water (sugar) which creates an enhanced osmotic pressure, more or less, in proportion to the solar energy collected. The solute appears from gas into liquid. More sun means more sugar more osmotic pressure and more flowers. The entropic force is left out of all analysis for evolution. If you leave out the entropic force models of evolution are short of truth and become long on humanistic and statistical fudge. If you wish to know more about the entropic force I started a thread in the physics section called osmosis and liquid state physics. I have sensed this force for years. Now that I have proven at simple case, evolution is just a cute approximation for reality.
wellwisher Everything in your post has nothing to do with evolution, they are involved only with how well the plant does with the DNA evolution evolved for them. Just another Lamarkian misconception of what evolution is. Evolution is not occurring in organisms that are already alive, it is changes in their genome in the gametes that affect their offspring's ability to survive that is evolution. GrumpyPlease Register or Log in to view the hidden image!
All those appear to be newly discovered mechanisms of generating variation or selecting variants. How is Darwinian Evolution made obsolete by new mechanisms for generating or selecting genetic variation? Darwinian evolution has always allowed - even enforced - sequences and results of great complexity. That was one of the characteristics that first recommended it as a theory of biological phenomena, which are very often very complex.
Maybe, but symbiosis is much more than that. Describe what "Darwinian evolution" is? That is outdated by over 120 years, even the terms "neo-Darwinism" are outdated. Evolution is very complex and has moved way past most of Darwins ideas. Theres probably 40-60 mechanisms involved with evolution maybe even more, read the website was darwin wrong and you will see many news ideas and mechanisms which have been presented in the last 20 years.
I think you run the risk of oversimplifying the scientific method by posing this as some fundamental controversy. At this high a level I think we can safely say that the factors that influence evolution are universal maxims. Where the controversy may lie is in new ways that scientists learn to address problem analysis, obviously as tools themselves evolve, but also because they figure out how to see problems from a new angle. The controversy then, is getting fellow scientists to set aside certain assumptions that may grossly oversimplify the way nature works at some deeper level. Not at the higher level. That's not controverted. Also, when you turn to source material to try to examine fundamentals of a working theory, be sure to bounce it against good authoritative sources. It's hard to do without getting exceeding technically bogged down. You may have to pick some specific controversy. Let me give you an example from National Academy of Sciences. Here's a biologist explaining how and why she decided to insert herself into the the genetic study of taxa that were only then diverging, not yet evolved. You will notice she never argues against these higher level principles. What she has discovered is that she can watch specific markers on a chromosome that select for habitat during the migration between habitats that enable gene flow to occur. She explains why simplifying the actual process of speciation (in this case, assuming that all traits flow back and forth, and the divergent groups homogenize) produces a flawed conclusion because this is simply not how nature works. It's all about mutation and selection. It's lengthy, but very rich in science: http://sackler.nasmediaonline.org/2009/darwin/mobile/sara_via/sara_via.m4v If you manage to wade though it, I think you will come out of the experience with a completely different view than you have stated in the OP. You will notice that selection for habitat-specific markers is entirely fundamental to gene flow, in other words, that's just how nature works.
How so? Looks like standard Darwinian evolution to me - suppose you explain how it isn't. The mechanisms of variation and selection you posted were from there, right? I would need some kind of explanation of how mechanisms of variation and selection invalidate Darwinian evolutionary theory. And no, I don't care in the least whether Darwin himself made a mistake or two.
Darwin is just as valid today as he was 150 years ago. The two things Dawin showed was that Evolution occurred and the second thing he did is suggest the basic mechanism, the cause, Natural Selection, that is responsible. Neither have been shown to be false, we just understand much more of the details today. Details that in no way invalidate the overarching power of Darwin's insight. Whether it is Gradualism or Punctuated Equilibrium or some combination of both it is driven by Natural Selection within variations. Whether it is mutation or gene transfer or expression, it is still put to the test of survival to reproduce(which is the Selection criteria). GrumpyPlease Register or Log in to view the hidden image!
Scientists are currently saying neo-Darwinism is incomplete, there is nothing controversial about this, its a well known fact. Ask any biologist. Scientists are not disputing evolution, just there is a lively debate about which mechanisms are involved. You need to research the mechanisms, you seem to think evolution has not gone beyond Darwin? None of the modern scientists are saying the older mechanisms of variation and selection are wrong, they are just saying they are incomplete and that there are other mechanisms etc. One reason for this is that the fossil record does not show pure gradualism, clearly some evolutionary mechanisms are not gradualistic like Darwin thought they were. Symbiosis contradicts standard Darwinian evolution. Symbiosis is organisms that live together in a close relationship often which are mutualistic. Darwin was ignorant of cooperation in nature. Evolutionary biologist Frank Ryan has gone as far to say that symbiosis and cooperation was Darwins blind spot (Ryan wrote a fascinating book on this topic). The late biologist Lynn Margulis also believed that symbiosis was the main driving force for evolution and downplayed the role of natural selection. This is in opposition to "standard Darwinian evolution".
darryl, If you could provide some cites I could engage you on the specifics. First of all Neo-Darwinism is not an end, but a continuation of Darwin's work, with refinements where new information became available. The central theme, evolution by natural selection, has not changed. No one is saying that natural selection is the only ruling principle, only that it is the most significant. Besides adaption, there are also cases of maladaptation, for example. But these are not found to overturn Darwin, only to supplement him. The current teaching provides the following explanations: 1. Natural Selection 2. Genetic Drift (Founder Effect, Bottleneck Effect) 3. Mutation 4. Gene Flow 5. Nonrandom Mating Symbiosis is much different than Lynn Margulis' endosymbiosis, which involves genetic absorption of the parasite. Normally symbiosis involves co-evolution. There are thousands of details, they just don't cancel natural selection. In many cases they are just exceptions to the rule. Here's a pretty good link to more discussion on this, relating genetic drift: http://www.academicearth.org/lectures/neutral-evolution-genetic-drift As you see, nature is always a little more complicated than we think. We all have a tendency to oversimplify.
So let's see them. Examples, please - the stuff you have listed above all variation and selection of one kind or another. So? Nothing in standard Darwinian evolution prevents fairly rapid evolutionary change, bursts of change, self-reinforcing arms races or niche creation, and the like. If Darwin thought differently, he was wrong. No problem, we all make mistakes - even about the consequences of our own theories. No, it doesn't. 2, some of 4, and 5 are selection mechanisms - subcategories of 1. 3 and some of 4 are mechanisms of variation. Variation and selection among reproductive entities. Boilerplate Darwin.
I think perhaps there is some confusion here caused by different meanings for the word "cause". The mechanisms which have been proposed for how evolution works are not causes except in a superficial sort of way. Why should natural selection, or any of the other mechanism, result in a change of gene frequency? To my mind, climatic changes are probably the primary "cause" of evolutionary changes, as they cause the major, global changes in the environments in which plants and animals live. Evolution, specifically natural selection, works on a particular population in a particular environment - the articulation of the population with its environment is called "fitness". Rich
