Fair enough. Since you have educated yourself on the matter, what are some of your problems with evolution?
So, since we cannot be reasonably sure about anything that has happened in the past, how do scientists create spacecraft like New Horizons that take past observations about planetary orbit and their gravitational forces, and use them to navigate the spacecraft billions of miles through space.
Another example: Forensics. Do you believe that, if one does not directly observe a murder, that forensic science cannot prove beyond the shadow of a doubt who the murderer was?
My base problem would be with the origins, but I have realized that this issue is preferred to be swept under the rug, so I am willing to move on. Presuming somehow the whole process got started by spontanious generation, I have never seen a mechanism reasonably proposed that allows mutations to create new and usable genetic information which can be passed down to the next generation of offspring through the pre-exsisting mode of reproduction that would allow one form/kind/species to become another. If anything natural selection and sexual reproduction reduces genetic information in a population.
You need to specify what part of creating a spacecraft relies on processes that cannot be observed.
Tell that to Al Gore and the other so called scientists that say the sky is falling cause man made climate change. If you have a hint of disagreement, you are labeled a crazy or working for big oil or something.
The same science that refutes them is ignored or mocked. Some of the most educated people can be the biggest idiots you will ever see.
Technically evolution is a fact, natural selection is a scientific theory.
Actually, its perfectly testable and repeatedly tested by the fossil record.
While there certainly are gaps in the fossil record and thus not fossils everywhere where we’d like them to be, at no place over more than 1 billion years of biological evolution is there a fossil found where is shouldn’t be given the tenets of macro-evolution (i.e., a bunny in the pre-Cambrian would be a problem)…
Macroevolution is well-supported by evidence from a number of different scientific disciplines. And macroevolution doesn’t mean that a dog evolved into a cat, no matter what Kent Hovind says.
One of the strongest lines of evidence for macroevolution is the genetic record. There are about 20 different amino acids (each of them coded by 3 base pairs of DNA), many of which are interchangeable (meaning that different 3-base-pair combinations can make the same amino acid), so there are many different arrangements of base-pairs of DNA that can combine to make a protein that serves the same purpose. So, tiny mutations in DNA can have no functional effect on the protein, meaning that the trait which is affected by the protein shows no real difference and different organisms with varying genetic code can exhibit the same features. With no functional difference, these mutations can accumulate over time because there’s no change to be selected against. As these genetic mutations accumulate, functional differences begin to appear (higher muscle/brain mass, greater visual acuity, etc.) which are beneficial to survival, and those with these accumulated mutations in their DNA become more likely to propagate their genes to a new generation. Likewise, those with mutations which result in changes that are not beneficial to survival would be less likely to survive long enough to pass on their genes.
So, back to the proteins. Evolutionary theory can predict, based on the distribution genetic information coded into proteins, that if species evolve from a common ancestor, the closer any two ancient species appear to be (based on their position in the fossil record, similarities in skeletal structure, etc.), the fewer differences (mutations) they will have in protein and genetic structure. An ape will have fewer genetic mutations (when compared to humans) than a rhinoceros will have.
So, when focusing on the genetic makeup of a specific protein found in the genes of a wide variety of species, you can get a picture of the ancestry of these species. And you get the same picture again and again, no matter which protein you choose. This is precisely what one would see if life evolved from a common ancestor.
Now, given this and the other mountains of other evidence for macroevolution, the only intellectually honest positions are:
Accept evolution as the best explanation for the abundance of species.
Come up with a better theory, and be prepared to have evidence to back it up.
I quite frankly dont agree with your opinion on that.
Fossil evidence is too lacking, disorganized, and open to other interpretation and conclusion for me to put any amount of weight into it as a hardened explaination other than we know for certain these creatures did live. Beyond that things can only be made evident, and that becomes a very slippery slope. The so called “cambrian explosion” by itsself as far as Im concerned implies just the opposite of a slow evolution from small and simple oganisms to larger and more complex ones. And I would also point out that fossils appear our of order of their supposed layers on a regular basis.
If anything natural selection and sexual reproduction reduces genetic information in a population.
Well…sexual reproduction certainly doesn’t. Have you encountered the Hardy-Weinberg law in your readings? Check it out. It says, basically, that in the absence of selection pressure, the frequencies of alleles and genotypes in a population will tend to remain constant–that is, to be in a state of equilibrium–from generation to generation. Selection pressure of any sort, whether natural or not (as Darwin observed, animal husbandry–the deliberate selection for specific traits in the breeding of animals–has the same effect as natural selection), will tend to push the system in a particular direction, i.e. toward a new equilibrium. These shifts in equilibrium can have quite dramatic effects, and can lead, over very long periods of time and along with the “background noise” of random genetic drift and mutation, to the “pooling” of differences in isolated populations that eventually won’t be able to breed with each other anymore.
As an example, try to envision a Great Dane breeding with a teacup Chihuahua. We can still make these breeds reproduce with each other–via artificial insemination–but the result would likely be disastrous both genotypically and phenotypically, particularly if the Chihuahua were the dam in the pairing (she probably wouldn’t survive to whelping). For all intents and purposes, these two breeds of dog can no longer mate with each other. And these are changes wrought over…how many hundreds of years? Now imagine this same kind of selection continuing over millions of years.
Evolution has never and will never claim to explain abiogenesis/the beginning of life. It explains the abundance of species. Someone who has educated himself/herself on evolution would surely know this. Nothing is being “swept under the rug”, your understanding of the basic principles of evolution is just lacking.
Again, something that evolution has never and will never claim.
Well, you’re in luck! I just posted a fairly detailed explanation of just one such mechanism.
How?
Agreed, a poor example, which is why I added the forensics example, which you conveniently left out.
You do know that the Cambrian Explosion wasn’t a single event, right? It was a period of rapid (by evolutionary standards) speciation that lasted roughly 80 million years. You don’t consider that to be slow?
Because of lack of good examples of benificial ones (especially in more complex forms), I just dont see mutations as being a reasonable explaination for allowing such changes to occure.
I will let you have but disagree with your opinions concerning intellectually honest positions. The theory is stuck with the burden of proof as far as Im concerned. Evolutionary theory has to prove its self true, I dont have to prove it untrue.
You are changing the subject, or in other words “moving the goalposts”. You asked for a mechanism by which new genetic information can be created. I gave you a rather well-defined example, supported by empirical data, and instead of addressing the evidence, you decided to change the focus of your argument.
I’ll be ready whenever you decide to address the evidence I’ve provided. Until then, I guess I can play your little game.
For a number of reasons it is not simple to give examples of favorable mutations. First of all, as we have seen, traits [6] may be favorable or unfavorable, depending upon the environment. Secondly it is not usually known to what extent a trait is genetically fixed and to what extent it reflects a reaction to the environment. Thirdly we don’t usually know what genes effect which traits. Moreover a mutation may be favorable in the sense that it permits survival in an unfavorable environment and yet be unfavorable in a better environment.
However there are a number of good examples:
[ol]
[li]Antibiotic resistance in bacteria - In modern times antibiotics, drugs that target specific features of bacteria, have become very popular. Bacteria evolve very quickly so it is not surprising that they have evolved resistance to antibiotics. As a general thing this involves changing the features that antibiotics target.[/li]> Commonly, but not always, these mutations decrease the fitness of the bacteria, i.e., in environments where there are not antibiotics present, they don’t reproduce as quickly as bacteria without the mutation. This is not always true; some of these mutations do not involve any loss of fitness. What is more, there are often secondary mutations that restore fitness.
Bacteria are easy to study. This is an advantage in evolutionary studies because we can see evolution happening in the laboratory. There is a standard experiment in which the experimenter begins with a single bacterium and lets it reproduce in a controlled environment. Since bacteria reproduce asexually all of its descendents are clones. Since reproduction is not perfect mutations happen. The experimenter can set the environment so that mutations for a particular attribute are selected. The experimenter knows both that the mutation was not present originally and, hence, when it occurred.
In the wild it is usually impossible to determine when a mutation occurred. Usually all we know (and often we do not even know that) is the current distribution of particular traits.
The situation with insects and pesticides is similar to that of bacteria and antibiotics. Pesticides are widely used to kill insects. In turn the insects quickly evolve in ways to become immune to the pesticides.
[li]Bacteria that eat nylon - Well, no, they don’t actually eat nylon; they eat short molecules (nylon oligomers) found in the waste waters of plants that produce nylon. They metabolize short nylon oligomers, breaking the nylon linkages with a couple of related enzymes. Since the bonds involved aren’t found in natural products, the enzymes must have arisen since the time nylon was invented (around the 1940s). It would appear this happened by new mutations in that time period.[/li]> These enzymes which break down the nylon oligomers appear to have arisen by frameshift mutation from some other gene which codes for a functionally unrelated enzyme. This adaptation has been experimentally duplicated. In the experiments, non-nylon-metabolizing strains of Pseudomonas were grown in media with nylon oligomers available as the primary food source. Within a relatively small number of generations, they developed these enzyme activities. This would appear to be an example of documented occurrence of beneficial mutations in the lab.
[li]Sickle cell resistance to malaria - The sickle cell allele causes the normally round blood cell to have a sickle shape. The effect of this allele depends on whether a person has one or two copies of the allele. It is generally fatal if a person has two copies. If they have one they have sickle shaped blood cells.[/li]> In general this is an undesirable mutation because the sickle cells are less efficient than normal cells. In areas where malaria is prevalent it turns out to be favorable because people with sickle shaped blood cells are less likely to get malaria from mosquitoes.
This is an example where a mutation decreases the normal efficiency of the body (its fitness in one sense) but none-the-less provides a relative advantage.
[li]Lactose tolerance - Lactose intolerance in adult mammals has a clear evolutionary explanation; the onset of lactose intolerance makes it easy to wean the young. Human beings, however, have taken up the habit of eating milk products. This is not universal; it is something that originated in cultures that kept cattle and goats. In these cultures lactose tolerance had a strong selective value. In the modern world there is a strong correlation between lactose tolerance and having ancestors who lived in cultures that exploited milk as a food.[/li]> It should be understood that it was a matter of chance that the lactose tolerance mutation appeared in a group where it was advantageous. It might have been established first by genetic drift within a group which then discovered that they could use milk. [9]
[li]Resistance to atherosclerosis - Atherosclerosis is principally a disease of the modern age, one produced by modern diets and modern life-styles. There is a community in Italy near Milan (see Appendices II and III for biological details) whose residents don’t get atherosclerosis because of a fortunate mutation in one of their forebearers. This mutation is particularly interesting because the person who had the original mutation has been identified.[/li]> Note that this is a mutation that is favorable in modern times because (a) people live longer and (b) people have diets and life-styles that are not like those of our ancestors. In prehistoric times this would not have been a favorable mutation. Even today we cannot be certain that this mutation is reproductively favorable, i.e., that people with this mutation will have more than the average number of descendents. It is clear, however, that the mutation is personally advantageous to the individuals having it.
[li]Immunity to HIV - HIV infects a number of cell types including T-lymphocytes, macrophages, dendritic cells and neurons. AIDS occurs when lymphocytes, particularly CD4+ T cells are killed off, leaving the patient unable to fight off opportunistic infections. The HIV virus has to attach to molecules that are expressed on the surface of the T-cells. One of these molecules is called CD4 (or CD4 receptor); another is C-C chemokine receptor 5, known variously as CCR5, CCCKR5 and CKR5. Some people carry a mutant allele of the CCR5 gene that results in lack of expression of this protein on the surface of T-cells. Homozygous individuals are resistant to HIV infection and AIDS. The frequency of the mutant allele is quite high in some populations that have never been exposed to AIDS so it seems likely that there was prior selection for this allele. (See Appendix IV)[/li]> [/ol]
Your mechanical expaination relied upon mutations as one of its main componants, I brought into question the abilities of the mutations. I dont see how this is changing the subject. At any rate, I have to go get some work done before the end of the day gets any closer - so its been fun guys. I appreciate all your efforts and explainations of what you believe.
The theory is stuck with the burden of proof as far as Im concerned. Evolutionary theory has to prove its self true, I dont have to prove it untrue.
Science doesn’t traffic in “proof,” not how you mean it anyway. It develops theories based in evidence, but nobody would ever declare something “proven” and above questionining. There is always the open end to a scientific theory, the possibility for revision or rejection in the face of new evidence. Hell, even the germ theory of disease…like the theory of natural selection, it’s “just a theory” supported by evidence. Do you have the same kinds of doubts about that?
Um, no. That’s not really how it works. Seems to me that evolution is indeed very provable. A walk through the Smithsonian’s natural history museum makes this pretty obvious to me.
I used to hold this very belief (I used to be an Evangelical Christian). I found it, ultimately, unsatisfying. “Macro-evolution” seems unobservable simply because of the time spans necessary to observe it in action, which we, as chronologically limited human beings, do not have. We are constantly in the midst of evolution. The process hasn’t stopped since it was set in motion. This, also, makes it apparently unobservable.
While we can observe this process occurring in real time, perhaps, we can reconstruct it by way of studying clues found in fossils as well as geology and the like.
Because of lack of good examples of benificial ones (especially in more complex forms), I just dont see mutations as being a reasonable explaination for allowing such changes to occure.
No offense, but an inability to understand the mechanisms for mutation in evolution doesn’t mean that it’s not a “reasonable explanation.”
I also don’t see (even having once believed this myself) why evolution is so threatening to a theistic world view, unless one is attempting a literal reading of the Genesis creation stories, which its authors (as Jewish tradition confirms) never intended.
(BTW, I realize I’m assuming a religious position in you, iGhost. If I am wrong in that assumption, I apologize.)
I will let you have but disagree with your opinions concerning intellectually honest positions. The theory is stuck with the burden of proof as far as Im concerned. Evolutionary theory has to prove its self true, I dont have to prove it untrue.
Well, you can’t prove a negative, after all…still, the same can (and should) be said for I.D. and creationism. Just sayin’.
Anyway, I think we’re now officially off topic in this thread…
