(Nosy) writes: > I am not a creationist. However, I would like to know what > predictive value the theory of evolution has shown. ****************************************************************************** An incredible amount. Here are a few that I wrote up rather quickly some months back. The person whom it was written for of course never replied. He's probably still muttering somewhere about how evolution makes no predictions, nyeah nyeah nyeah. (I do not recall if he was a dittohead.) If you read the scientific literature, you will find a deluge of Noachide proportions. Let me just mention that perhaps the most important, from a theological point of view, is the one regarding asymmetric DNA mutation and optimal rate (see below). It seems that not only is mutation and speciation a fact of life, but the method is optimal. One can try, sort of, to argue from design regarding eyes and all sorts of other body parts (and I say "sort of", since there are numerous suboptimalities that these design argument fans never know about), but how in the world can one argue that OPTIMAL MUTATION RATES was designed? ======================================================================== Evolution makes numerous predictions. For example, plate tectonics and radioactive dating make it very clear that the Hawaii chain of islands gets older as one heads northwest from the big island. So evolution makes a great big prediction here: the various species will be distributed over the islands in such a way that the ones on Honolulu will be more closely related to the mainland species while the ones on Hawaii will be more closely related to each other than to the ones on Honolulu. One can make this more precise over all the islands. Care to predict what investigating a hundred species of fruit flies has come up with? If you want numerical quantification, there are cladograms based on chromosome inversions, and dendrograms based on DNA sequencing. ------------------------------------------------------------------------ The first and most famous of all predictions of evolution is usually not thought of as such, but as a prediction it's solid gold, and one of the most astonishing in all of the history of science. Lord Kelvin, the premier physicist of his day, objected to the time frame Darwin was describing in his first edition, based on Kelvin's best comprehension of the earth cooling from a molten state. (Contrary to popular opinion, Kelvin did believe in evolution. He just believed it was directed by the hand of God, and so went much faster than Darwin allowed for.) Since Darwin wasn't too concerned with the physics and geology, he silently dropped the time estimates. But the hard-core evolution-rules attitude, please leave God out of the science, gave a rather basic prediction: End************************************************************************** Kelvin was wrong, and something was missing in his equations. It turned out to be radioactivity. I can't overstate this. Physics then (and today) was the pinnacle of the sciences. An argument from physics carried far more weight than any argument from biology. Yet it turned out that the _physics_ was flat-out embarrassingly wrong. ------------------------------------------------------------------------ Naked mole rats are another wonderful prediction. One of the most difficult problems with evolution, from Darwin on, is how to account for the social insects. How does one evolve sterility? Hamilton offered an explanation based on genetics in the sixties. It was based on the peculiar genetics of ants, bees and wasps: the males are an X, and the females an XX. Given this, a female is closer related to her sisters than her own daughters. But this explanation is unsatisfactory for termites, with normal genetics. In the mid seventies, Alexander offered an alternative ecological explanation for termite eusociality, based on their difficult choice of habitat. Because he took for granted that evolution is what made for termites, he could extrapolate what would happen to mammals in an analogous situation. He described in his lectures at the time what such an hypothetical mammal would have to be like: a hairless subterranean rodent living in east Africa, since only there would conditions be right for his version of termite evolution to carry through. And what do you know, after some time somebody recognized that animal he was describing, and so Alexander wrote a carefully worded letter to the world's leading (and only) authority on naked mole rats. All at once, the weird breeding habits of NMRs made sense, and people realized that NMRs were also eusocial. ------------------------------------------------------------------------ Evolution predicts thousands of transitional fossil forms would be found. Darwin staked his theory on this. They've been found in amazing quantity. See the FAQ. ------------------------------------------------------------------------ Of more recent vintage, the list is endless. One that caught my eye a few weeks ago, and which I posted here, was the question of asymmetric mutation rates in DNA strands. As is well-known, some programmers at some point realized that if the mechanisms of evolution often produce optimal or near optimal solutions to complicated problems, then this should be applicable as an optimization method. This basic prediction of evolution is now the field of "genetic algorithms". In fine-tuning the method, one asks, just how do mutations work? Standard implementa- tions assumed mutation was symmetric. The PNAS paper I recently desribed investigated asymmetric mutation rates for the leading and lagging DNA strands during replication. They discovered that a superior optimization algorithm existed for a bin packing problem if one used different rates. The implicit prediction--that nature beat us to it--was verified by an indepedent research group. From the point of view of this independent research group, who found asymmetric mutation rates in actual DNA of actual cells, the prediction went the other way: viz, GA algorithms would be superior if they used asymmetric mutation rates. This work is eminently "numerical". ------------------------------------------------------------------------ A classic problem has been the nature and evolution of sex. All sorts of predictions abound here. For example, life is difficult for parasites if the descendents' immune system is as different as possible from either of its parents. Hence, the incest taboo. Evolution predicts that an actual biological, not social, mechanism for enforcing this would exist in all parasite prone species. It turns out that the smell of MHC-II (the key immunological recognition molecule) is a heavy factor in mate selection in mice. Take an unrelated mouse, and paint it with odor of MHC-II of a close relative, and the opposite sex loses interest. (For what it's worth, people too can actually discriminate MHC-II smells.) Of course, some parasites are known to mutate at high rates. Why in the world would they do that? The origin of sex is a popular topic. It seems, at first blush, to be half as efficient. OK, so you buy the recombinatino argument--changing genes around deliberately is good for the species in the long run. Why two sexes? Why not six? Well, multiple sexes are known in some fungi, but overall, they are rare. The reason seems to be the following: evolutionarily speaking, multiple sexes are unstable. There is a hierarchy of mating types, and a mutation that cheats vis-a-vis where it is in the hierarchy will survive. The long range effect (if you believe in evolution) is to cancel the hierarchy into just two sexes. So, evolution makes a definite prediction regarding some of these fungi. What's your prediction? -- -Matthew P Wiener (weemba@sagi.wistar.upenn.edu) : > I am not a creationist. However, I would like to know what : > predictive value the theory of evolution has shown. : An incredible amount. Here are a few that I wrote up rather quickly : some months back. Just to add another that doesn't seem to have gotten a lot of press around here... Back in the 70's, Vincent Sarich predicted based upon studies of the iguanas indigenous to the different islands of the Galapagos chain that there was a missing island. That is he predicted that there was an island that used to peak (or is that peek, Jim?) above the ocean's surface but which does not do so today. I don't recall the details, but basically Sarich was claiming that there had to have been a place where iguanas intermediate between some of the current variants could form a population. About four years ago this island was discovered (under the ocean). The news was considered big enough that it was featured in an article in the science section of the New York Times. : -Matthew P Wiener (weemba@sagi.wistar.upenn.edu) -- Mickey Rowe (rowe@pender.ee.upenn.edu) }Just to add another that doesn't seem to have gotten a lot of press }around here... Back in the 70's, Vincent Sarich predicted based upon }studies of the iguanas indigenous to the different islands of the }Galapagos chain that there was a missing island. That is he predicted }that there was an island that used to peak (or is that peek, Jim?) }above the ocean's surface but which does not do so today. I don't }recall the details, but basically Sarich was claiming that there had }to have been a place where iguanas intermediate between some of the }current variants could form a population. About four years ago this }island was discovered (under the ocean). The news was considered big }enough that it was featured in an article in the science section of }the New York Times. Malcolm W. Browne, "Galapagos Mystery Solved: Fauna Evolved on Vanished Isles," _New York Times_ (Tuesday, January 21, 1992), page C1. The newspaper story mentions a 1983 article by Vincent M. Sarich and Jeffrey S. Wiles that was provocatively entitled "Are the Galapagos Iguanas Older Than the Galapagos?" It also refers to a paper in "the current issue of _Nature_," and I found D.M. Christie, et al., "Drowned Islands Downstream From the Galapagos Hotspot Imply Extended Speciation Times," _Nature_ 355:246-8 (16 January 1992). The references include J.S. Wiles & V.M. Sarich in _Patterns of Evolution in Galapagos Organisms_, (eds. R.I. Bowman & A.E. Leviton) 177-86 (American Association for the Advancement of Science, Washington, D.C. 1983). There's also a News and Views article. For folks whose libraries don't carry _Nature_ (mine almost dropped it during the last round of budget-cutting), there's Carl Zimmer, "Darwin's Atlantis," _Discover_ 14(1):59-60 (January 1993) and Jose H. Leal, "Iguanas as Island Hoppers," _Sea Frontiers_ 38(?):11-2 (June 1992). For a News & Comment article on Vincent Sarich that is totally unrelated to this topic, see Paul Selvin, "The Raging Bull of Berkeley," _Science_ 251:368-71 (25 January 1991). (I stumbled across it by accident and has a surplus of dimes for photocopying). -- Herb Huston -- huston@access.digex.net } I am not a creationist. } } However, I would like to know what predictive value the } theory of evolution has shown. By 1974, [Jennifer] Jarvis had joined the faculty at the University of Cape Town in South Africa. She returned to Kenya to collect naked mole-rats for physiological studies and attempted to establish breeding groups in the labora- tory at Cape Town. Because she was unable to collect en- tire colonies in the field, Jarvis combined individuals from several different wild-caught colonies. Initially there was considerable aggression, especially among females, in these mixed colonies. The conflicts gradually tapered off once a female began breeding; thereafter, breeding was usually restricted to one female in each colony. Whether or not the results from these mixed laboratory colonies re- flected the situation in nature was at that point unclear. In the mid-1970s, R.D. Alexander, a professor at the Univer- sity of Michigan, lectured on the evolution of eusociality at several universities in the western United States. In an effort to explain why vertebrates had apparently not evolved eusociality, he hypothesized a fictitious mammal that, if it existed, would be eusocial. This hypothetical creature had certain features that patterned its social evolution after that of termites (e.g., the potential for heroic acts that assisted collateral relatives, the existence of an ultrasafe but expansible nest, and an ample supply of food requiring minimal risk to obtain it). Alexander hypothesized that this mythical beast would probably be a completely subterranean rodent that fed on large tubers and lived in burrows inacces- sible to most but not all predators, in a xeric [i.e., dry] tropical region with heavy clay soil. When Alexander presented his lecture at Northern Arizona Uni- versity in May 1976, T.L. Vaughan was in the audience. After the lecture, Vaughan astonished Alexander by saying, "Your hypothetical eusocial mammal is a perfect description of the naked mole-rat of Africa." [From another source, I have it that Professor Alexander's reply was "What the hell is a naked mole-rat?" -- HH] Vaughan showed Alexander some preserved specimens of _H. glaber_, and provided him with Jarvis's address. Alexander wrote to Jarivs, posing a series of questions about naked mole-rats designed to test whether or not they were in- deed eusocial. Jarvis responded to Alexander's letter in de- tail, and all her answers tantalizingly seemed to be in the ap- propriate direction to suggest eusociality. Jarvis later com- mented to L. Gamlin of _New Scientist_ magazine (July 30, 1987, no. 1571, p. 41) "I realized eventually that there was always only one breeding female per colony, and I knew there was di- vision of labor--the penny was beginning to drop. But it was only when I received a letter from Dick Alexander in 1976 that the significance of it really became clear." -- "Preface," _The Biology of the Naked Mole-Rat_ (Paul W. Sherman, J.U.M. Jarvis, & Richard D. Alexander, editors), 1991, Princeton University Press, Princeton, pages vii-ix. The eusociality of naked mole-rats was eventually announced in J.U.M. Jarvis, "Eusociality in a Mammal: Cooperative Breeding in Naked Mole-Rat Colonies," _Science_ 212:571-3 (1981). -- Herb Huston -- huston@access.digex.net } However, I would like to know what predictive value the } theory of evolution has shown. My colleagues R.L. Trivers and H. Hare have recently [this was written during the 1970s] reported the following impor- tant discovery in _Science_ (January 23, 1976): they argue that queens and workers [they were studying ants] should prefer different sex ratios for fertile offspring. The queen favors a 1:1 ratio of males to females since she is equally related (by 1/2) to her sons and daughters. But the workers raise the offspring and can impose their pre- ferences upon the queen by selective nurturing of her eggs. Workers would rather raise fertile sisters (relationship 3/4) than brothers (relationship 1/4). But they must raise some brothers, lest their sisters fail to find mates. So they compromise by favoring sisters to the extent of their stronger relationship to them. Since they are three times more related to sisters than brothers, they should invest three times more energy in raising sisters. Workers invest energy by feeding; the extent of feeding is reflected in the adult weight of fertile offspring. Trivers and Hare therefore measured the ratio of female/male weight for all fertile offspring taken together in nests of 21 different ant species. The average weight ratio--or investment ratio-- is remarkably close to 3:1. This is impressive enough, but the clincher in the argument comes from studies of slave- making ants. Here, the workers are captured members of an- other species. They have no genetic relationship to the daughters of their imposed queen and should not favor them over the queen's sons. Sure enough, in these situations, the female/male weight ratio is 1:1--even though it is again 3:1 when workers of the enslaved species are not captured but work, instead, for their own queen. -- Stephen Jay Gould, "So Cleverly Kind an Animal," _Ever Since Darwin_. The full reference for the ant study is R.L. Trivers and H. Hare, "Haplodiploidy and the Evolution of the Social Insects," _Science_ 191:249-63 (23 January 1976). -- Herb Huston -- huston@access.digex.net === But even the fossil reefs pale compared to rocks that are composed of billions and billions of microfossils. For example, the chalk cliffs of Dover, England and Calais, France consist largely of coccoliths, the microscopic calcareous scales of a type of single-celled algae. The diatomite in localities like Lompac, California consist almost entirely of the siliceous skeletons of diatoms. This must be many cubic kilometres of solid "fossil". Most of the volume of the majority of limestones consists of fossils (there are some non-biogenic limestones, but they are less common by comparison). So if you see a limestone, often you *are* looking at a fossil, they are just tiny and/or fragmented. Take a fist-size chunk of chalk, and you are looking at thousands, if not millions of fossils.