Since most of Blake’s hair-splitting centers on the use of the word “fact,” perhaps we could get back on-topic by avoiding it completely. In that case, could we re-word Pochaco’s question to:
“Do you believe that body scientific observations does or does not support the existence of speciation?”
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Blake is making the same mistake that the Dover board of education made; he’s arguing philosophy, not science.
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This is one important part of it – I mentioned this in another thread, and I was reminded of it by hearing on the radio a pro-Id commentator talking about how the Big Bang theory was once derided as contrary to observable science:
That I know of, before Big Bang, or Continental Drift, or the K/T Impact (heck, Darwinism) became part of the mainstream, there was at no point any concerted effort to enforce by regulatory authority that students in the public schools HAD to be advised of the dissident theories as an equally valid alternative to the then-established wisdom. That’s where the Dover and Kansas school boards and the ID-advocacy groups overreach themselves.
The advocates of the dissident theories in science’s history simply had to plug on the hard way until they broke into the mainstream, often in the face of derision and “you’ll never work in this town again” attitudes. Not being included mandatorily in the curriculum did not prevent them from gaining support and eventually coming up with good enough science that the establishment had to respect. Supporters of “Intelligent Design” are welcome to do it the hard way, not rely on a regulatory policy decision to annoint their position or earn them a “bye”.
I think you are still understanding what macroevolution is. There is nothing to be “at work”, since it is not a separate set of processes. It is more a discontinuity of micro processes. IF changes in the environment were gradual, and lineages adatped to those changes gradually, then it could most certainly be said that the macro stuff is, indeed, nothing more than a whole lot of micro. However, there are cataclysmic or monumental events in the history of life that are not so easily explained by just adding up a whole lot of accumulated mutations. Entire lineages can be wiped out in an instant (whether geological or near-literal), and this has nothing to do with having bad genes and therefore being selected against. A small change in the timing of development can result in a very profound morphological shift, again in a very short time, and it, again, may have little to do with selective adaptation (beyond the fact that the change itself was nto detrimental). Rare, but conceivable, macromutations can occur which can fundamentally alter the evolutionary path of a lineage (see, for example, Jeffrey Schwartz’s book Sudden Origins; Fossils, Genes, and the Emergence of Species for an argument that such macromutations played a major role in evolution). Such events can create a discontinuity between the “slow and steady” operation of natural selection and the resulting tree of life.
If you want to get right down to it, almost the whole of evolutionary theory is story-telling. Historical sciences being what they are, we have to create scenarios to explain that which we could not witness. Nature may not tell stories, but we humans always have and will, because that’s how we arrive at meaning. A thought experiment is but a story, after all, as nothing in the thought experiment really happened. So, I don’t see this as a valid critique of the method, or the resulting theories.
Being an tiny fissure bacteria is not, in any sense, an adaptation.
Indeed that is the case - probabilities extend to all levels of a taxonomic hierarchy. But, again, that’s not the point here. At a populational level, a strong, virile individual getting knocked in the head by a falling tree limb can be chalked up to the probabilities inherent in natural selection; NS is, after all, not a guarantee of success for any individual. An entire species – or several such species – getting a collective head-knock by a chunk of falling space debris goes beyond any probabilities involved in natural selection, however. The slow-and-steady action of NS over an entire population, over long periods of time, has been interrupted. A discontinuity in the slow and steady action has been created, and the structure of the tree of life is now very different than it was. The demise of dinosaurs and such cannot be explained simply by pointing to natural selection and saying, “I guess they were all selected against”. Remember, NS states that on average, the race will go to the swiftest, the fight to the strongest.
Again, to summarize, left alone, NS acting on populations will create macrolevel results. However, it has not often had the chance to do so for long (geologically- speaking), and major events occur which create a discontinuity between the “expected” result of slow-and-steady evolution via NS and the actual diversity of life. It is this concept of the discontinuous action of “normal” evolution which leads us to the concept of macroevolution: evolutionary events which are grander in scope than NS (and other population-level mechanisms, such as genetic drift) alone can explain. The emergence of evolutionary novelties is but one aspect of macroevolution (and, in many cases, these are almost certainly continuous with NS, but, as always, there is debate in the field, thus the reason the term exists in the first place). Extinction, particularly mass extinction, is another.
A story in today’s (24 December)Los Angeles Times certainly appears to indicate that we know that the African and the Asian elephants were once one species. They are now two different species. This is speciation on a level far higher than microbes where “species” is a little hard to grasp.
The cite might require registration so here is the crucial part.
That sequence of splitting off, Mastadons splitting off from Asian elephants after they split off from African elepahnts means as surely as night follows day (although some claim that day follows night) that the Asian elephant line and the African elephant line were once joined and are now separate species.
Finch, I guess my problem is that I have a hard time seeing how we could work in ideas like “expected path” (even fi we are careful to put it in quotes) or somesuch into even a picture of evolution, micro or macro alike. It just seems like benefit of human excitement rather than the shifting, thoughtless probabilities of nature, which never gave us any sort of guarantee of stability or extent of their effects. A sudden and unexpected famine that rewrites the laws of success for finches can create discontinuity in the expected path of microevolution: or it can kill every finch, either inevitably or because of mere luck (the finches coulod have made it, but their population was slightly too small). Is the same natural event micro or macro depending on the particular variations available among finches? Microevolution is gradual in terms of teh process itself, put seen from the perspective of morphological change, it can be all over the map.
My point about bacteria is that, at least in some gross sense, it can. Being a huge heat-light demanding temperature sensitive creature depending on a complex and patricular ecosystem is okay for a time, but when it turns out that you live on a planet prone to massive meteor strikes, it turns out that it ain’t such a hot idea after all. Having a huge body and a squat beak when the nectar you need is growing farther down a planty tube. In both cases, the particular creatures trying to make it are being exposed to problems their genes never anticipated or prepared them for ever before. In both cases, they fail to pass on any genes. Especially from the perspective of the genes, in both cases there was a gamble that failed to play out. Sometimes the odds are long, sometimes they are short. The odds can be altered by other genes that rest right beside you, or genes that exist elsewhere, or by non-organic nature.
Why is this different from any number of such studies that showed X and Y species split after the X/Y and Z species split. For instance, we have the same info about chimps, humans, and gorillas, showing that the chimp/human line split off from the gorilla line about 2M years before the human and chimp lines split.
I was under the impression that these weren’t based on DNA. However, now that I recall the “mutation clock” idea, maybe I was mistaken in that idea.
Facts are fluid…In my day it was a fact that there were 9 planets…not 76or 10…When more planets are discovered our best evidence indicates there are blank no. of planets at this time. There still is no basis to teach that there are 2,999 planets are what have you based on the massive collection of observable evidence we have now.
You appear to be confusing the concepts of “there are x y” and “there are x known y.”
If by fact you mean “observed phenomena” then I would say no, it was never a fact that there were 9 planets.
It once was a fact that we observed our own planet, plus a few other blobby thingies in the sky.
Based on those observed phenonema (blobby things) we devised a theory: they are gods. When that didn’t pan out, we invented a new theory: they are planets.
Then some joker asks, “Well, what is a planet, precisely? What makes a planet different from a moon or a comet or a meteor?”
The new theory is that of the blobby things, some are definitely planets like the ones we know, others are planets but not like ours, and some are planet-shaped thingies we don’t know what.
The “fact” that we observed blobby things in the sky never really changed.
Exactly. I remember once seeing a very old biology text at a garage sale that spoke of ancient “land bridges” being the way species got distributed over the Earth. It wasn’t until the ocean-mapping voyages showed the sunken borders of continents that exactly fit together, as well as the mid-ocean ridges, that continental drift was accepted. No politics to it. All science.
Specially key to it were the mid-oceanic ridges, and hence plate tectonics, which provided the driving mechanism.