Posted on 09/24/2001 1:12:24 PM PDT by ThinkPlease
Tonight is the beginning of the Evolution Series on PBS. I thought I'd open up some threads of discussion here prior, during and after the telecast of the episodes.
Here's PBS's homepage for the telecast:
And Here's something from the Discovery Institute, who is evidently irritated about turning down free publicity on the telecast. (They were offered time on the final night of the telecast, and turned down PBS.)
What are you talking about? This kind or experimentation has already produced numerous freaks of the canine world. Behold the whippet, the weiner dog, the bichon frise(sp?)...
Forgive me for my own failure to adequately explain similarities of convergence vs similarities of lineage. Convergence produces life forms with similar superficial traits, such as a hydrodynamic body or a sprinting body and forward bifocal vision for predation. Different species who occupy similar ecological niches may adapt over time to have similar outward appearances due to biology's having come up with the same solutions for say, running down prey, hiding from predators, climbing, digging, etc. But the overall phisiology will tell a different story. The bones of a marsupial will be very different from the bones of a mammal despite their superficial similarites (in the case of smilodon and thylacosmilid). You must admit that while they look very similar, they clearly belong to to entirely different class let alone genus. The holes for blood vessels will be different, the number and arrangement of tarsals, number of vertibrate etc. The details will be vastly different in instances of convergence.
Now in divergence you have just the opposite. The details change slowly, (or perhaps quickly during environmental turmoil and only minutely during periods of relative environmental stability, if you're of the PunkEEK school of thought - which I accept as a valid evolutionary mechanism). So that over the distance of time, while the outward appearance of the progenitor species and it's perhaps many descendent species may differ quite dramatically, it is the details, that is, the alignment of fissures in the cranium, a peculiar occipital knob, serrated ridges on the back of a particular tooth which exist on no other animals except the progenitor and it's descendents, which are the hallmarks of common divergence and lineage.
What experiments would you perform to determine whether or not that is the case?
First understand this. I'm not trying to challenge your knowledge on this matter. I'm trying to learn from you. I've recieved a Master's degree in Science, but my studies focused on Nursing. Still, I've been exposed to evolutionary theory during my studies. I also graduated years ago, and I want to explore the veracity of new studies which have come to my attention. Please bear with me.
To answer your question, I suppose I would start with a lesser theory, perhaps that the universe is ordered rather than random. I would seek to prove this because I believe that a designed universe would follow a preconceived plan, and thus follow a centralized, logical, somewhat consitent, pattern. Testing this alone should keep us busy for awhile.
Following that I would need to narrow my scientific inquiry even more, perhaps to theorize that the probability of species remaining true to type would be greater than the probability of a species mutating outside of its species. A related inquiry would involve permanence of mutations over time.
I would perhaps start with something observable, which could reproduce generations quickly, such as bacteria. For example, I would observe whether changes in bacteria exposed to antimicrobial agents remain permanent generations after the antimicrobial agent has been removed. Right now, I'm hearing they revert back to their previous state, as did the Galapogos Island finches' thicker beaks once drought conditions subsided. I would begin by verifying if these claims (about the bacteria) are indeed correct, either by examining the method used to arrive at those conclusions, or by retesting the original evidence.
If mutations like these are impermanent, what causes reversion to the original condtion over time, especially if the mutations did not weaken the species? Is there some type of genetic "go back to start" message which directs organisms to shed new mutations when they are no longer needed? If so, why?
I'm not saying I know all these ideas are viable, but I think they are "scientific" questions. I'm concerned that questions like these are censored, and that the questioners are broadly portrayed like religious lunatics. I'm learning that many who question Darwin's theory are non-religious, or are Catholics, who believe the theory of evolution can coexist with their faith. I fear any scientific theory which disallows scrutiny.
If you have two populations of animals that live today you can easily determine whether they are part of the same species or not. But if you try to do that with a population along the time axis that's an arbitrary categorization. You cannot say that at a particular point in time that population changed from one species into an other. That's the same as saying that at this particular wavelength yellow changes into green and at an other particular wavelength green changes into blue - that would be as arbitrary as the categorization mentioned above.
You don't.
The female fish eggs and the male fish sperm just somehow "know" that "there's little opportunity or pressure for sea creatures to become land creatures" so they don't even bother producing fish with little legs.
No. What happens is that any mutation that has a tendency to try to come up on the land has to compete with the creatures already there, and will be unsuccessful, so it won't reproduce. In the past, this would have been a successful mutation. Presently, it would be a failed one.
I do understand that. My question was quite sincere--this is actually a subject in which I have a good deal of interest.
I believe that a designed universe would follow a preconceived plan, and thus follow a centralized, logical, somewhat consitent, pattern.
Not necessarily. Like DNA, it might be less of a plan (a blueprint, as it were), than a recipe (i.e., a set of rules for building animals, or universes).
Testing this alone should keep us busy for awhile.
How would one test that?
Following that I would need to narrow my scientific inquiry even more, perhaps to theorize that the probability of species remaining true to type would be greater than the probability of a species mutating outside of its species. A related inquiry would involve permanence of mutations over time.
I would perhaps start with something observable, which could reproduce generations quickly, such as bacteria. For example, I would observe whether changes in bacteria exposed to antimicrobial agents remain permanent generations after the antimicrobial agent has been removed. Right now, I'm hearing they revert back to their previous state, as did the Galapogos Island finches' thicker beaks once drought conditions subsided. I would begin by verifying if these claims (about the bacteria) are indeed correct, either by examining the method used to arrive at those conclusions, or by retesting the original evidence.
If mutations like these are impermanent, what causes reversion to the original condtion over time, especially if the mutations did not weaken the species? Is there some type of genetic "go back to start" message which directs organisms to shed new mutations when they are no longer needed? If so, why?
It sounds like you're proposing that there's a "backup" of the original DNA stored within the DNA. If that were the case, you would have to locate the part of the DNA that contained the information required to do that. The problem with the theory is that there would be no obvious way to prevent that part of the DNA from mutating as well (perhaps in some non-viable direction).
I'm not saying I know all these ideas are viable, but I think they are "scientific" questions. I'm concerned that questions like these are censored, and that the questioners are broadly portrayed like religious lunatics. I'm learning that many who question Darwin's theory are non-religious, or are Catholics, who believe the theory of evolution can coexist with their faith. I fear any scientific theory which disallows scrutiny.
Evolution allows, and undergoes, abundant scrutiny. If it didn't, we wouldn't have competing theories (e.g., punctuated equilibrium vs Darwinian gradualism) that provide fodder for creationists to (spuriously) claim that because the details of the matter aren't settled, that the basic concept of natural selection is not viable.
What it doesn't, and shouldn't, allow is claims that it's wrong simply because some divine revelation says so. When we do that, it takes it out of the realm of science, and into theology. As a believer in the scientific method, I don't claim evolution to be absolute truth--it's just the best explanation that science has to offer. If you wish to get your truth by methods other than science, I have no quarrel with that. The only objection that I have is when theology tries to masquerade as science.
There are an infinite number of theories to explain the workings of the universe, but only a finite number of them are scientific theories in the Popperian sense (e.g., falsifiable). I can put forth a theory that the entire universe was created ten minutes ago, complete with memories. It may even be correct (though I think it unlikely). The problem with it is that there's no way to prove it false--no experiment one can perform, etc. It is thus scientifically uninteresting.
I freely admit that my faith lies in science, with its unprovable axioms--that there is an objective reality, that we can learn about its nature by asking questions of it in the form of repeatable experiments, and that it is amenable to logic. As I said, I have no quarrel with people of different beliefs, as long as they don't pretend that they're science.
I'm wondering about these ladybugs. For some reason I don't see red ones anymore. They're all an orange color.
Ooooooooooooh, now I get it. By the way...how many of these mutations have you or anyone else observed trying to "come up on the land"??? I'm sure this has been documented many times since we all know that evolution is fact and not just an athiest's lame excuse for the obvious. ;-)
That's kind of a stupid question. We've already told you that it happened hundreds of millions of years ago, and took place over a long period of time. How would anyone have seen it?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.