Yes. Observable. This is an example of the reaction upon the explanation of Darwininian evolution.
Of course it is a picture of a Darwininian.
Posted on 05/29/2002 8:32:25 AM PDT by cornelis
Agreed.
Yes. Observable. This is an example of the reaction upon the explanation of Darwininian evolution.
Of course it is a picture of a Darwininian.
Hmmmm. Let's have a look at a chunk of just the intro:
The Transitional Vertebrate Fossils FAQ.What is a transitional fossil?
The term "transitional fossil" is used at least two different ways on talk.origins, often leading to muddled and stalemated arguments. I call these two meanings the "general lineage" and the "species-to-species transition":
- "General lineage":
This is a sequence of similar genera or families, linking an older group to a very different younger group. Each step in the sequence consists of some fossils that represent a certain genus or family, and the whole sequence often covers a span of tens of millions of years. A lineage like this shows obvious morphological intermediates for every major structural change, and the fossils occur roughly (but often not exactly) in the expected order. Usually there are still gaps between each of the groups -- few or none of the speciation events are preserved. Sometimes the individual specimens are not thought to be directly ancestral to the next-youngest fossils (i.e., they may be "cousins" or "uncles" rather than "parents"). However, they are assumed to be closely related to the actual ancestor, since they have intermediate morphology compared to the next-oldest and next-youngest "links". The major point of these general lineages is that animals with intermediate morphology existed at the appropriate times, and thus that the transitions from the proposed ancestors are fully plausible. General lineages are known for almost all modern groups of vertebrates, and make up the bulk of this FAQ.
- "Species-to-species transition":
This is a set of numerous individual fossils that show a change between one species and another. It's a very fine-grained sequence documenting the actual speciation event, usually covering less than a million years. These species-to-species transitions are unmistakable when they are found. Throughout successive strata you see the population averages of teeth, feet, vertebrae, etc., changing from what is typical of the first species to what is typical of the next species. Sometimes, these sequences occur only in a limited geographic area (the place where the speciation actually occurred), with analyses from any other area showing an apparently "sudden" change. Other times, though, the transition can be seen over a very wide geological area. Many "species-to-species transitions" are known, mostly for marine invertebrates and recent mammals (both those groups tend to have good fossil records), though they are not as abundant as the general lineages (see below for why this is so). Part 2 lists numerous species-to-species transitions from the mammals.
- Transitions to New Higher Taxa
As you'll see throughout this FAQ, both types of transitions often result in a new "higher taxon" (a new genus, family, order, etc.) from a species belonging to a different, older taxon. There is nothing magical about this. The first members of the new group are not bizarre, chimeric animals; they are simply a new, slightly different species, barely different from the parent species. Eventually they give rise to a more different species, which in turn gives rise to a still more different species, and so on, until the descendents are radically different from the original parent stock. For example, the Order Perissodactyla (horses, etc.) and the Order Cetacea (whales) can both be traced back to early Eocene animals that looked only marginally different from each other, and didn't look at all like horses or whales. (They looked rather like small, dumb foxes with raccoon-like feet and simple teeth.) But over the following tens of millions of years, the descendents of those animals became more and more different, and now we call them two different orders.
There are now several known cases of species-to-species transitions that resulted in the first members of new higher taxa. See part 2 for details.
Why do gaps exist? (or seem to exist)
Ideally, of course, we would like to know each lineage right down to the species level, and have detailed species-to-species transitions linking every species in the lineage. But in practice, we get an uneven mix of the two, with only a few species-to-species transitions, and occasionally long time breaks in the lineage. Many laypeople even have the (incorrect) impression that the situation is even worse, and that there are no known transitions at all. Why are there still gaps? And why do many people think that there are even more gaps than there really are?
- Stratigraphic gaps
The first and most major reason for gaps is "stratigraphic discontinuities", meaning that fossil-bearing strata are not at all continuous. There are often large time breaks from one stratum to the next, and there are even some times for which no fossil strata have been found. For instance, the Aalenian (mid-Jurassic) has shown no known tetrapod fossils anywhere in the world, and other stratigraphic stages in the Carboniferous, Jurassic, and Cretaceous have produced only a few mangled tetrapods. Most other strata have produced at least one fossil from between 50% and 100% of the vertebrate families that we know had already arisen by then (Benton, 1989) -- so the vertebrate record at the family level is only about 75% complete, and much less complete at the genus or species level. (One study estimated that we may have fossils from as little as 3% of the species that existed in the Eocene!) This, obviously, is the major reason for a break in a general lineage. To further complicate the picture, certain types of animals tend not to get fossilized -- terrestrial animals, small animals, fragile animals, and forest-dwellers are worst. And finally, fossils from very early times just don't survive the passage of eons very well, what with all the folding, crushing, and melting that goes on. Due to these facts of life and death, there will always be some major breaks in the fossil record.
Species-to-species transitions are even harder to document. To demonstrate anything about how a species arose, whether it arose gradually or suddenly, you need exceptionally complete strata, with many dead animals buried under constant, rapid sedimentation. This is rare for terrestrial animals. Even the famous Clark's Fork (Wyoming) site, known for its fine Eocene mammal transitions, only has about one fossil per lineage about every 27,000 years. Luckily, this is enough to record most episodes of evolutionary change (provided that they occurred at Clark's Fork Basin and not somewhere else), though it misses the rapidest evolutionary bursts. In general, in order to document transitions between species, you specimens separated by only tens of thousands of years (e.g. every 20,000-80,000 years). If you have only one specimen for hundreds of thousands of years (e.g. every 500,000 years), you can usually determine the order of species, but not the transitions between species. If you have a specimen every million years, you can get the order of genera, but not which species were involved. And so on. These are rough estimates (from Gingerich, 1976, 1980) but should give an idea of the completeness required.
Note that fossils separated by more than about a hundred thousand years cannot show anything about how a species arose. Think about it: there could have been a smooth transition, or the species could have appeared suddenly, but either way, if there aren't enough fossils, we can't tell which way it happened.
- Discovery of the fossils
The second reason for gaps is that most fossils undoubtedly have not been found. Only two continents, Europe and North America, have been adequately surveyed for fossil-bearing strata. As the other continents are slowly surveyed, many formerly mysterious gaps are being filled (e.g., the long-missing rodent/lagomorph ancestors were recently found in Asia). Of course, even in known strata, the fossils may not be uncovered unless a roadcut or quarry is built (this is how we got most of our North American Devonian fish fossils), and may not be collected unless some truly dedicated researcher spends a long, nasty chunk of time out in the sun, and an even longer time in the lab sorting and analyzing the fossils. Here's one description of the work involved in finding early mammal fossils: "To be a successful sorter demands a rare combination of attributes: acute observation allied with the anatomical knowledge to recognise the mammalian teeth, even if they are broken or abraded, has to be combined with the enthusiasm and intellectual drive to keep at the boring and soul-destroying task of examining tens of thousands of unwanted fish teeth to eventually pick out the rare mammalian tooth. On an average one mammalian tooth is found per 200 kg of bone-bed." (Kermack, 1984.)
Documenting a species-to-species transition is particularly grueling, as it requires collection and analysis of hundreds of specimens. Typically we must wait for some paleontologist to take it on the job of studying a certain taxon in a certain site in detail. Almost nobody did this sort of work before the mid-1970's, and even now only a small subset of researchers do it. For example, Phillip Gingerich was one of the first scientists to study species-species transitions, and it took him ten years to produce the first detailed studies of just two lineages (see part 2, primates and condylarths). In a (later) 1980 paper he said: "the detailed species level evolutionary patterns discussed here represent only six genera in an early Wasatchian fauna containing approximately 50 or more mammalian genera, most of which remain to be analyzed." [emphasis mine]
- Getting the word out
There's a third, unexpected reason that transitions seem so little known. It's that even when they are found, they're not popularized. The only times a transitional fossil is noticed much is if it connects two noticably different groups (such as the "walking whale" fossil reported in 1993), or if illustrates something about the tempo and mode of evolution (such as Gingerich's work). Most transitional fossils are only mentioned in the primary literature, often buried in incredibly dense and tedious "skull & bones" papers utterly inaccessible to the general public. Later references to those papers usually collapse the known species-to-species sequences to the genus or family level. The two major college-level textbooks of vertebrate paleontology (Carroll 1988, and Colbert & Morales 1991) often don't even describe anything below the family level! And finally, many of the species-to-species transitions were described too recently to have made it into the books yet.
Why don't paleontologists bother to popularize the detailed lineages and species-to-species transitions? Because it is thought to be unnecessary detail. For instance, it takes an entire book to describe the horse fossils even partially (e.g. MacFadden's "Fossil Horses"), so most authors just collapse the horse sequence to a series of genera. Paleontologists clearly consider the occurrence of evolution to be a settled question, so obvious as to be beyond rational dispute, so, they think, why waste valuable textbook space on such tedious detail?
- Misunderstanding of quotes about punctuated equilibrium
What paleontologists do get excited about are topics like the average rate of evolution. When exceptionally complete fossil sites are studied, usually a mix of patterns are seen: some species still seem to appear suddenly, while others clearly appear gradually. Once they arise, some species stay mostly the same, while others continue to change gradually. Paleontologists usually attribute these differences to a mix of slow evolution and rapid evolution (or "punctuated equilibrium": sudden bursts of evolution followed by stasis), in combination with the immigration of new species from the as-yet-undiscovered places where they first arose.
There's been a heated debate about which of these modes of evolution is most common, and this debate has been largely misquoted by laypeople, particularly creationists. Virtually all of the quotes of paleontologists saying things like "the gaps in the fossil record are real" are taken out of context from this ongoing debate about punctuated equilibrium. Actually, no paleontologist that I know of doubts that evolution has occurred, and most agree that at least sometimes it occurs gradually. The fossil evidence that contributed to that consensus is summarized in the rest of this FAQ. What they're arguing about is how often it occurs gradually. You can make up your own mind about that. (As a starting point, check out Gingerich, 1980, who found 24 gradual speciations and 14 sudden appearances in early Eocene mammals; MacFadden, 1985, who found 5 cases of gradual anagenesis, 5 cases of probable cladogenesis, and 6 sudden appearances in fossil horses; and the numerous papers in Chaline, 1983. Most studies that I've read find between 1/4-2/3 of the speciations occurring fairly gradually.)
Predictions of creationism and of evolution
Before launching into the transitional fossils, I'd like to run through the two of the major models of life's origins, biblical creationism and modern evolutionary theory, and see what they predict about the fossil record.
- Most forms of creationism hold that all "kinds" were created separately, as described in Genesis. Unfortunately there is no biological definition of "kind"; it appears to be a vague term referring to our psychological perception of types of organisms such as "dog", "tree", or "ant". In previous centuries, creationists equated "kind" to species. With the discovery of more and more evidence for derivation of one species from another, creationists bumped "kind" further up to mean higher taxonomic levels, such as "genus", or "family", though this lumps a large variety of animals in the same "kind". Some creationists say that "kind" cannot be defined in biological terms.
Predictions of creationism: Creationists usually don't state the predictions of creationism, but I'll take a stab at it here. First, though there are several different sorts of creationism, all of them agree that there should be no transitional fossils at all between "kinds". For example, if "kind" means "species", creationism apparently predicts that there should be no species-to-species transitions whatsoever in the fossil record. If "kind" means "genus" or "family" or "order", there should be no species-to-species transitions that cross genus, family, or order lines. Furthermore, creationism apparently predicts that since life did not originate by descent from a common ancestor, fossils should not appear in a temporal progression, and it should not be possible to link modern taxa to much older, very different taxa through a "general lineage" of similar and progressively older fossils.
Other predictions vary with the model of creationism. For instance, an older model of creationism states that fossils were created during six metaphorical "days" that may each have taken millenia to pass. This form of creationism predicts that fossils should be found in the same order outlined in Genesis: seed-bearing trees first, then all aquatic animals and flying animals, then all terrestrial animals, then humans.
In contrast, many modern U.S. creationists believe the "Flood Theory" of the origin of fossils. The "Flood Theory" is derived from a strictly literal reading of the Bible, and states that all geological strata, and the fossils imbedded in them, were formed during the forty-day flood of Noah's time. Predictions of the Flood Theory apparently include the following:
- most rock should be sedimentary and indicative of cataclysmic flooding. There should be no rock formations that indicate the passing of millenia of gradual accumulation of undisturbed sediment, such as multi-layered riverbed formations. There should be no large lava flows layered on top of each other, and definitely not with successively older radiometric dates in the lower levels.
- terrestrial animal fossils should either not be sorted at all, or should be sorted by some "hydrodynamic" aspect such as body size, with, for instance, extinct elephants and large dinosaurs in the lowest layers, and small primitive dinosaurs in the upper layers. Terrestrial animal fossils should not be sorted by subtle anatomical details (such as, say, the number of cusps on the fourth premolar).
- marine animals are a puzzle, since it is unclear that a Flood would cause any extinctions of aquatic animals. If such extinctions did occur, aquatic fossils would perhaps be "sorted" by body size or ecological niche (bottom-feeder vs. surface swimmer). For instance, plesiosaurs, primitive whales, and placoderm fishes (relatively slow-swimming and quite large) should end up in the same layers. Ichthyosaurs and porpoises (smaller, faster swimmers with almost identical body shapes and similar diets) should also occur in the same layers.
- there should be no sorting of large rooted structures such as coral reefs and trees. There should likewise not be differential sorting of microscopic structures of the same size and shape, such as pollen grains.
- sorting, if it occurs at all, should be quite imperfect. With only 40 days for sorting, there should be occasional examples of individual fossils that ended up in the "wrong" layer -- the occasional mammal and human fossil in Paleozoic rocks, for instance, and the occasional trilobite and plesiosaur in Cenozoic rocks.
- sorting should not correlate with date of the surrounding rocks. If all fossils were created by Noah's flood, there is no conceivable reason that, for instance, lower layers of fossils should always end up sandwiched between lava rocks with old radiometric dates.
Finally, some creationists believe that fossils were created by miraculous processes not operating today. (Many of these creationists combine this idea with the Flood Theory, as follows: fossils were created during the Flood, but were "sorted" by a miraculous process not observable or understandable today.) Obviously, such a theory makes no testable predictions...except perhaps for the prediction that geological formations should not bear any obvious resemblance to processes occurring today.
- Modern evolutionary theory holds that the living vertebrates arose from a common ancestor that lived hundreds of millions of years ago (via "descent with modification"; variety is introduced by mutation, genetic drift, and recombination, and is acted on by natural selection). Various proposed mechanisms of evolution differ in the expected rate and tempo of evolutionary change.
Predictions of evolutionary theory: Evolutionary theory predicts that fossils should appear in a temporal progression, in a nested hierarchy of lineages, and that it should be possible to link modern animals to older, very different animals. In addition, the "punctuated equilibrium" model also predicts that new species should often appear "suddenly" (within 500,000 years or less) and then experience long periods of stasis. Where the record is exceptionally good, we should find a few local, rapid transitions between species. The "phyletic gradualism" model predicts that most species should change gradually throughout time, and that where the record is good, there should be many slow, smooth species-to-species transitions. These two models are not mutually exclusive -- in fact they are often viewed as two extremes of a continuum -- and both agree that at least some species-to-species transitions should be found.
Maybe it's just me, but I'm getting sentences, paragraphs, meaning above the individual word level here.
It is just you. Your language affliction is worsening. Maybe you should read and attempt to discern meaning before making yourself look like...
Post 453 mentions post 373. Post 373 has this in it---P.S. I recommend to read this article on talk.origins.
And if you can read simple things you'll see I quoted the article in blue, as I normally do. Guess what article contains ---cultures evolve but they don't evolve in the way that species evolve.?
My close relatives have many genes in common with me. If I act on their behalf so that they live and breed my genes will be passed on even if I don't reproduce myself. The second type is called mutual benefit altruism - I'll scratch your back if you scratch mine. Both kinds of "altruism" have obvious benefits and it is not hard to see why they are selected for.However there is a third kind which is rarer. Some animals (principally primates) live in social groups which act together and have complex social lives within the group. In these animals group cohesion is important and there is selection for actions which preserve the integrity of the group as a whole. . .
I still don't see where your criticism applies.
Is this supposed to be meaningless? Does it depend upon your definition of "meaningless?"
No surprise there.
The last statement of the article (which is what I cited)says it all.
I see we agree that the article was nothing. Thanks!
Because how we deal with Truth is important. One side of this debate spends all its time either frantically waving away the facts or waving away the logical, reasonable implications of the facts. Our side embraces the facts, and reason is our friend. Don't be afraid of facts and logic.
The design parameter for a species is reproductive fitness, an important part of which is survival. The design selection process in nature takes care of itself, though the rather loose selection parameters permit quite a bit of divergence. As for "instantiation", it was my way of saying that biological evolution would be an implementation of a general mathematical pattern (mathematical patterns having little or no context on their own).
How are we defining consciousness for the sake of this discussion?
And "truth" to you is evidently what you say it is.
The question isn't whether or not QM behavior is happening in the brain, it is whether or not meaningful coherent patterns in an information theoretic sense can be encoded in the QM substrate in an environment like the human brain. The argument is that even if QM effects are affecting the brain, it necessarily amounts to nothing more than noise due to environmental factors preventing any kind of persistent structure.
In a broader sense, the only thing we really know about the computational process of the human mind is that it is finite state machinery (this is something that can be measured and tested without knowing the mechanics of the machinery). This narrows the scope a lot, and even if there was QM machinery at work, then it must be a fairly simple finite state version of it. Note that this eliminates the necessity for QM behaviors as an explanation, as any FSM model that uses QM can necessarily be expressed as an ordinary boring FSM by definition. This is a much classier and more rigorous argument, but I don't bring it out much because it requires a little deeper understanding of the relevant points. In a nutshell, any QM behaviors that affect cognition must be FSM in nature based on measurable properties of the mind, which means that the human mind (in all its glory), must be expressable on any universal Turing machine (like ordinary silicon processors). Therefore, the QM argument is probably a moot point in any case, and at best would only affect the computational complexity of certain types of computations in implementation. It would not prevent the implementation of equivalent systems in ordinary silicon.
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