Subject: evolution data (extremely nasty post) Date: 9 Mar 91 23:20:26 GMT This post is ra

From: colby@bu-bio.bu.edu (Chris Colby) Newsgroups: sci.skeptic Subject: evolution data (extremely nasty post) Message-ID: <76557@bu.edu.bu.edu> Date: 9 Mar 91 23:20:26 GMT This post is rather long, but it contains a lot of info (as opposed to opinion) so I don't think it is a complete waste of bandwidth. This post also gets extremely nasty at the end. Wear asbestos if you read it 8-) In article <1991Mar8.222059.16311@bronze.ucs.indiana.edu> graham@venus.iucf.indiana.edu writes: >In article <76467@bu.edu.bu.edu>, colby@bu-bio.bu.edu (Chris Colby) writes... >> Evolution is an established fact. > >How so? Nothing would give me greater pleasure than to answer this. Actually there is one thing, but it can't be done via computer 8-) Evolution is now considered a fact due to a preponderance of data in favor of it and a complete lack of data refuting it. It is not possible to construct a capsule proof of evolution (either the fact that organisms all share a common ancestor or that the proposed mechanisms explain their descent.) I will here briefly outline some of the more compelling data supporting evolution. This is in no way meant to be an exhaustive list. Evolutionary biology is an active research field. Sevaral journals are devoted entirely to evolution (_Evolution_, _Molecular Biology and Evolution_ and the _Journal of Molecular Evolution_ to name but three.) In addition, the major general science journals routinely carry articles about evolution. On the board talk.origins I have summarized about 15 papers during the past year I culled from _Nature_ and _Science_). So, it would be literally impossible to present anything but a small portion of the relevent data concerning evolution. But, here goes. *All organisms share a common genetic material* All known living organisms (and viruses, which some biolo- gists do not classify as living) have a nucleic acid based genetic material. The vast majority of organisms have DNA as their genetic material. A few viruses have RNA. If organisms where individually created there is no reason why each should use the same type of macromolecule to serve as genetic material. Many different polymers could, theoretically, be used to store information. *All organisms share a common genetic code* In addition to using the same material, the same _code_ is shared all organisms. DNA (and RNA) can be thought of as a string of bases that is read in groups of three (called a codon). Each codon codes for a single amino acid. Why should all organisms share the same code if they were individually created? It should be noted that some organelles within a cell (and a few organisms) have been shown to contain divergent genetic codes. However, evidence is building that the code these organisms use is "corrected" back to the universal genetic code after the DNA has been transcribed into RNA (this has been termed "RNA editing"). It is also worth pointing out that four bases are all that are used in the genetic code, even though other bases could potentially serve (this has been confirmed by experimentation). Likewise, the number of amino acids (the building blocks of proteins) used by organisms is only subset of all naturally occuring amino acids. *Partitioning of genetic variation among species* DNA sequences from closely related species are much more similar than DNA sequences from more distantly related species. In fact DNA sequence data matches closely with phylogenies drawn up by morphologists. If organisms were not linked via descent, why should their DNA sequences so strongly suggest this? (trivia= homologous segments of DNA from humans and chimps have been sequenced. the similarity is ~99%.) *Developmental biology* The development of an individual (ontogeny) sheds light on it's ancestry (phylogeny). This relationship was first pro- posed by Ernst Haeckel. Unfortunately, he vastly overstated the connection; he claimed ontogeny recapitulated phylogeny. This has been shown to be false. But closely related organisms do exhibit closely parallel ontogenies. Why would this be true if they were not linked via a common ancestor? Wouldn't it make more sense for a whale to form more like a fish than a cow or a monkey? (trivia= data indicates humans evolved as "unfinished" chimps. young chimps look a lot more like humans than adult chimps. by arresting development early, the skull reamins soft so the brain can continue growing. note: humans did not evolve from chimps, we share a common ancestor with them. perhaps unfinished proto-chimps would be better terminology in the above trivia.) (trivia#2= humans develop gill slits in their development and kinda-sorta develop a tail) *Homologous traits* The traits and structures of morphologically diverse organisms can be shown to be modifications of basic "building blocks". For example, among mammals the different bones of what in humans is the arm, can be seen from bats to whales. The structures are the same (form from the same embryonic tissue, share distinquishing charactoristics, etc.) in type but different in dimension. This is interpreted by evolutionary biologists as evidence that extant (living) organisms share a common ancestor and each lineage has modified the structures of the ancestor. Evolution requires that there be no truly novel solutions to "problems" organisms face. A species can only modify the assets it has to overcome an obstacle. This leads to, in many cases, suboptimal design of many biological traits because the trait has evolved as a modification of an existing structure. It was not designed from scratch. (one example=the panda's thumb - it's not a thumb at all. it's an outgrowth of a wrist bone.) The creationist mumblings of organisms being perfect machines sure bites the dust in a big way when you learn even a little biology. Incidentally, this applies to behaviours as well as physical structures. Also note that most organisms have vestigal traits; traits that serve no use now, but were used back in the species history. Again, if a creator designed each creature from scratch, these are hard to explain away. *Fossils* Many people think the fossil record is real great evidence for evolution. I don't think so. It's nice, but the theory of evolution could do just fine without it. Creationists seem to think this is all there is to evolutionary theory. *Evolution and speciation demonstrated to occur* Most people are surprized to find out that evolution and speciation have both been documented to occur. Evolution has been documented in hundreds of cases. The example of the English moths is often cited. The species turned from predominantly speckled to predominantly dark over the span of a few decades. Speciation has been documented in the genus _Tragopogon_ (a plant species). Two closely related species (through a chromososomal "mishap") produced a new species (it could not cross with either of it's parent strains, only itself. Incipient speciation may be occuring in the apple maggot fly _Rhagoletis_ _pomenella_. I post cases a documented evolution in talk.origins all the time. *Mechanisms experimentally confirmed* The two mechanisms thought responsible for most evolution are natural selection and genetic drift. Both have been demonstrated in laboratories (selection has been (unintentionally) demonstrated by animal and plant breeders for hundres of years). This post is getting long; if you want some references on this, email me (that goes for refs backing up anything I said in this (or any other) post). >There is still (as far as I can tell) NO _direct_ evidence. Better learn something about the field before you criticize it then, jerk! Do you really think biologists would have been working on the theory for >150 years now and never tested some of it's basic claims? >Give me a choice between "literally interpreted biblical creationism" >and the theory of evolution, and I will choose the latter. Since you are completely ignorant of the theory, what differ- ence would it make? In either case you would just be accepting the theory on someone elses word. This is sci.skeptic not sci.uninformed- -opinion. >I'll bet though, that the real pins in the butt of hardline evolutionists >are the ones that claim that God is the dude behind evolution. :-) I'll bet not. I don't see how ad hoc, untestable face saving weaseling such as that would be a pin in anyones butt. Maybe Santa Claus is behind evolution. "Rudolph, go kill all the short necked giraffes you can find".-S. Claus. > ______________________________________________________________________ >| Internet: graham@venus.iucf.indiana.edu | Chris Colby email: colby@bu-bio.bu.edu ==================================================== From: lamoran@gpu.utcs.utoronto.ca (L.A. Moran) Newsgroups: sci.skeptic Subject: Creation "Science" Message-ID: <1991Mar10.230831.22723@gpu.utcs.utoronto.ca> Date: 10 Mar 91 23:08:31 GMT Recently I posted an explanation of the difference between evolution as a FACT and the THEORY of evolution. This is what I said, "We have been over this ground many times before in several different newsgroups. Evolution is a FACT. The evidence that modern organisms are descendants of organisms that lived in the past is overwhelming. Scientists have recognized this FACT for over 200 years. It is as solidly proven as most other FACTS of science. The MECHANISM of evolution is not understood. Darwin, and others, proposed that evolution could be accounted for by natural selection. His THEORY of the MECHANISM is widely accepted but there are competing THEORETICAL explanations of the MECHANISM of evolution. Creationists reject both the FACT of evolution and all THEORIES of the MECHANISM of evolution. Scientists accept the FACT of evolution and try to understand the mechanism. Chris Colby and Chris Stassen have made the same points although there are subtile differences between us. The crucial point here is that it is perverse to claim that the FACT of evolution is still in question as some posters to sci.skeptic have said. Stephan J. Gould has put this as well as anyone else, "In the American vernacular, "theory" often means "imperfect fact" - part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. Thus the power of the creationist argument: evolution is "only" a theory and intense debate now rages about many aspects of the theory. If evolution is worse than a fact, and scientists can't even make up their minds about the theory, then what confidence can we have in it? Indeed, President Reagan echoed this argument before an evangelical group in Dallas when he said (in what I devoutly hope was campaign rhetoric): 'Well, it is a theory. It is a scientific theory only, and it has in recent years been challenged in the world of science - that is, not believed in the scientific community to be as infallible as it once was.' Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered. Moreover, 'fact' doesn't mean 'absolute certainty'; there ain't no such animal in an exciting and complex world. The final proofs of logic and mathematics flow deductively from stated premises and achieve certainty only because they are NOT about the empirical world. Evolutionists make no claim for perpetual truth, though creationists often do (and then attack us falsely for a style of argument that they themselves favor). In science 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional consent'. I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms. Evolutionists have been very clear about this distinction of fact and theory from the very beginning, if only because we have always acknowledged how far we are from completely understanding the mechanisms (theory) by which evolution (fact) occurred. Darwin continually emphasized the difference between his two great and separate accomplishments: establishing the fact of evolution, and proposing a theory - natural selection - to explain the mechanism of evolution." Stephen J. Gould "Evolution as Fact and Theory"; Discover, May 1981 Whether or not you agree with Gould he is stating the prevailing view of the scientific community. In other words, the experts on evolution consider it to be a FACT. This concept is also explained in introductory biology books; for example, in one of the best such textbooks we find, "Today, nearly all biologists acknowledge that evolution is a fact. The term "theory" is no longer appropriate except in referring to the various models that attempt to explain "how" life evolves." Neil A. Campbell in BIOLOGY 2nd ed., Benjamin/Cummings p. 434 There are readers of sci.skeptic who reject evolution for religious reasons. These readers oppose both the FACT of evolution and THEORIES of mechanisms. What I find so bizarre is that there are some readers who are not creationists but still claim that evolution is "only" a theory. Just how much evidence does this group need? -Larry Moran Dept. of Biochemistry