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Originally posted by thehumbleone
you still don't understand what I'm getting at do you?
When a mosquito changes into a bee, then I will call that proof.
When an ape changes into a human, then That will be considered proof.
Heck, I think an apple tree changing into an orange tree is far more likely.
And don't tell me "it takes millions of years" blah blah that's your problem, not mine, don't make up excuses for why you can't find the missing links, you're problem again.
Originally posted by kallikak
The concept of a 'species' is not solely defined by degree of reproductive isolation. There are multiple definitons of the word species, not all centered or based around reproductive isolation.
The other notion that seemingly functions in opposition to pretty much all available evidence, is the notion that major evolutionary innovation is the result of 'copying errors' and 'stochastic accidents.' Trying hard to sell an idea that not only doesn't make intuitive sense, and is further not supported by everything we know about genetics tends to alienate people.
Originally posted by melatonin
Do you think it would be worth my time outlining the subtle differences between the various conceptions of species (around 26 at the moment) for humbleone?
Mayr's rather simplified conception is sufficient here - reproductive isolation, common niche & gene pool.
Originally posted by kallikak
Not really. It's distinctly not what humble is referring to when he uses the word species. Perhaps he shouldn't be using the word species... perhaps Family would be better or even order... however, it's clear that when humble says no speciation has been observed, he's not referring to the change from one species of mosquito to another.. s/he is talking about the transition from one morphological type to another.
Originally posted by melatonin
But one quick point - Intuitive sense has nothing to do with science. It was intuitive that the sun orbits the earth, we know otherwise. Intuition and gut-feelings are great for quick and dirty decisions, and good currency in the realm of woo, not for objective science.
Originally posted by thehumbleone
you still don't understand what I'm getting at do you?
When a mosquito changes into a bee, then I will call that proof.
When an ape changes into a human, then That will be considered proof.
And don't tell me "it takes millions of years" blah blah that's your problem, not mine, don't make up excuses for why you can't find the missing links, you're problem again.
Originally posted by kallikak
The point about intuitive sense was only to highlight that which isn't observed about evolution, that is that evolution is the product of 'accidents,' and that the genome is some hapless victim, instead of an active participant in its own genetic future. Intuition is the stuff that hypotheses are made of however, and thus, intuition is an essential component of objective science. I bring up intuitive sense only as peripheral highlight, and not a direct objection. It's easier to sell a person on an idea that makes intuitive sense than one that is hard to grasp.
Originally posted by melatonin
And I did note that I thought he was conflating 'kind' with 'species'. As that is the normal issue in such discussions.
He stated that only 'evolution within species' has been observed - microevolution. However, new species have been observed, as have novel mutations and new functions.
I've discussed this on various boards and the same issues come up every time. Maybe I should have pinned him down for what he meant earlier (like I did with 'theory'). But, 'species' does tend to be viewed at a lower level than 'family'.
Otherwise, all hominidae are one species, and I don't think he would support that, no?
Originally posted by melatonin
I agree that common-sense ideas are easier to get over, but if it is hard to grasp do we just not bother?
Intuition may help guide hypotheses, but hypotheses are just unsupported assertions. Some will be based in observation and previous findings, others are just pure hot-air.
I'd honestly like to see some scientific evidence showing the genome actively drives it's own genetic future...
Originally posted by kallikak
Hence intuition is an essential part of the scientific process.
Surely you are aware of the vast multitude of DNA repair systems present in even the most 'primitive' cell types. Cells maintain a wide variety of such repair mechanisms, including mismatch repair, base-excision repair, photoreactivation, non-homologous end joining, to mention a few. Indeed, cells maintain a remarkable degree of genomic integrity.
Additionally, prokaryotic cells are known to be very promiscous, swapping genetic information with close relatives and completely unrelated genera. Prokaryotic cells actively maintain selectively beneficial genes when required, and dump them off when they don't. That is when genes aren't needed prokaryotes remove them. IOW, they control their genetic destiny by allowing certain genes to increase in frequency, and others to decrease.
The example of antibiotic resistance is a perfect example that stands in opposition Darwinian evolution. Antibiotic resistance isn't acquired gradually, often it's acquired in one single event. In fact, many antibiotic resistance genes can be acquired in a single conjugation event.
Indeed, the cell maintains many genes specifically for the restructuring of genomic information. This would appear to be the entire 'purpose' for the existence of transposable elements... the facilitation of genomic arrangement.
Indeed many of the examples often cited as being examples of evolution are related to recombination. The nylon degrading enzymes are re-arrangements of repeat sequences, for example.
Also... entire new classes of polymerases... mutator polymerases have been discovered. These polymerases are often expressed in response to stress, and may increase variation at certain loci inconjuction with transcription factors and other related proteins, as well as within epigenetic constraints.
The entire field of epigenetics, including methylation, chromatin remodeling, and chromatin condensations are testaments to the genomes regulation of it's own future.
What do you think they're evidence of?
Originally posted by melatonin
Aye, it can be, but to become science it needs to be backed by evidence, otherwise it is just speculation. In many instances the intuition is shown to be wrong at the first hurdle.
Yeah, I am. But mutations still happen. If the repair mechanisms were 100% perfect there would be no variation for selection. I probably possessed a hundred or so from birth. I hope most were pretty inocuous, haha.
Yep.
So genetic variation is produced by numerous processes including horizontal gene transfer. Natural selection acts on the produced variation.
Genes that are not essential are open to genetic change. Beneficial mutations are selected, detrimental mutations are removed by natural selection.
If beneficial genes are no longer beneficial, they are open to mutation. Whether genetic changes are beneficial is largely determined by environment.
Changes in frequency of alleles = evolution.
Yet, natural selection is essential and so is genetic variation. Darwinian evolution is one aspect of ToE and recombination, genetic drift, evo-devo etc also play a part. Changes in the rate of evolution have been noted and the idea of evolution as having periods of stasis and change are well-established - hence punk-eeq.
Not true. The presence of the nylonase genes provides no selective disadvantage. If the genes weren't required or useful, they were simply eliminated. The organism that adapted to degrade nylon isn't obligated to consume only nylon. It maintains standard biochemical pathways, which the nylonase enzymes supply with substrate. The nylonase genes aren't located on a chromosome, and are thus easily disposed of when there is no selective advantage to possessing them. The unlucky bug didn't suffer the downside of NS, it just rid itself of a useless plasmid.
And when this was performed in the past, the unlucky organism suffered the downside of natural selection. When it occured in the presence of nylon it became somewhat beneficial.
And as far as I know these act from environmental triggers and are another mechanism to drive adaptation. In fact, it may be viewed as a mechanism that enables 'memory' of environment.
Anyway, yeah, I just wanted to see where you were going with the 'genome as driver' idea, I have no issue with Dawkins' idea of selfish genes and have no problem with organisms having epigenetic mechanisms that support evolution. It's probably just as correct to suggest the environment drives evolution from natural selection to epigenetic effects.
Essentially, evolution has many mechanisms that allow adaptation to the environment. I also noted earlier evolution was more than RM & NS (drift etc).
Originally posted by madnessinmysoul
alright
how can you say that genetic mutation doesn't exist?
they've tested people in labs
we have observed children having genes that aren't found in either of its parents
[sarcasm]No Kidding? Well you learn something everyday[sarcasm]
that's a mutation
how else would you explain it?
Originally posted by kallikak
Not true. The presence of mutator polymerases, polymerases that purposely induce mutations within the genome would provide all the variation required. Furthermore, in a sexually reproducing organism, there are lots of other ways to generate genetic variation that don't involve mutation.
No. I am talking about something COMPLETELY different. I am talking about active removal of non-beneficial sequences wholesale, not inactive expression, repressed expression, or whatever. Straight up removal of the genes. I'm not sure how much molecular biology technique you're familiar with, but it's the reason that you have to harvest selective bacterial cultures within like 12 hours, and the reason you've got to keep genetically modified plants under selective pressure until transgenes are stably integrated. Bacteria routinely acquire and dispose of large chunks of DNA. This is completely different than what you've described above.
Your standard forum response isn't relevant here. I wasn't talking about mutation, I was talking about large scale genetic modification.... wholesale removal of genes that pose a conditional selective benefit. The question wasn't one of mutation, but large scale genetic modification.
This isn't relevant to your discussion with me. I don't deny evolution occurs, and I've not said anything about changing of allele frequencies. What I am talking about is different than simply changing an allele frequency.
Personally, I wouldn't call punctuated equilibrium 'well-established,' it's out there as a theory, but isn't the predominant theory with respect to evolution. Most scenarios are still centered around the notion of gradual change. What do changes in the rate of evolution have to do with this discussion? Furthermore, my comment didn't address recombination, genetic-drift, or development. It was simply a comment reiterating the fact that antibiotic resistance doesn't arise via anything resembling Darwinian evolution.
Evolution of drug resistance in experimental populations of Candida albicans.Cowen LE, Sanglard D, Calabrese D, Sirjusingh C, Anderson JB, Kohn LM.
J Bacteriol. 2000 Mar;182(6):1515-22.
Adaptation to inhibitory concentrations of the antifungal agent fluconazole was monitored in replicated experimental populations founded from a single, drug-sensitive cell of the yeast Candida albicans and reared over 330 generations. The concentration of fluconazole was maintained at twice the MIC in six populations; no fluconazole was added to another six populations. All six replicate populations grown with fluconazole adapted to the presence of drug as indicated by an increase in MIC; none of the six populations grown without fluconazole showed any change in MIC. In all populations evolved with drug, increased fluconazole resistance was accompanied by increased resistance to ketoconazole and itraconazole; these populations contained ergosterol in their cell membranes and were amphotericin sensitive. The increase in fluconazole MIC in the six populations evolved with drug followed different trajectories, and these populations achieved different levels of resistance, with distinct overexpression patterns of four genes involved in azole resistance: the ATP-binding cassette transporter genes, CDR1 and CDR2; the gene encoding the target enzyme of the azoles in the ergosterol biosynthetic pathway, ERG11; and the major facilitator gene, MDR1. Selective sweeps in these populations were accompanied by additional genomic changes with no known relationship to drug resistance: loss of heterozygosity in two of the five marker genes assayed and alterations in DNA fingerprints and electrophoretic karyotypes. These results show that chance, in the form of mutations that confer an adaptive advantage, is a determinant in the evolution of azole drug resistance in experimental populations of C. albicans.
Not true. The presence of the nylonase genes provides no selective disadvantage. If the genes weren't required or useful, they were simply eliminated. The organism that adapted to degrade nylon isn't obligated to consume only nylon. It maintains standard biochemical pathways, which the nylonase enzymes supply with substrate. The nylonase genes aren't located on a chromosome, and are thus easily disposed of when there is no selective advantage to possessing them. The unlucky bug didn't suffer the downside of NS, it just rid itself of a useless plasmid.
Allowing adaptation and changing in response to are disparate ideas in my mind. Personally, I think RM factors very insignificantly into evolution. I think most evolutionarily significant change is mediated via cellular biochemistry
Originally posted by melatonin
Originally posted by spiritconnections
I have said nothing in support of the likes of Sylvia Brown - why are you bringing her into this conversation? Would you like me to bring in a wacko fringe from the scientific community as representative of your stance?
The power behind all speciation is the Mind of the Spirit (in my opinion).
Mind of what spirit? Does this spirit cause mutations? So really rather than 'goddidit', you say 'themindofthespiritdidit'.
Mutations are the result of an imperfect copying method and other chemical and biological mechanisms. Does the 'mind of the spirit' underlie chemistry and physics? I always thought it was Nac-Mac Feegles behind intelligent falling.
Sylvia Brown is a psychic who 'channels' spirits like you claim to do. She makes a lot of dosh from her supposed abilities. She is well-known and no more whacko than most other people who 'commune' with spirits.
And, yeah, science makes no more contribution to people's lives than woo. When a person has a health condition, it's always better to see a spiritualist than a medical doctor who bases their treatment on effective science-based methods. When we want to figure out who commited a crime, Psychics provide as good an answer than that from forensic scientists; Building a bridge? Mission to Mars? Curing AIDS? New neurological therapies? Explaining Global Warming? IVF? Consult your local spiritualist.
[edit on 31-1-2007 by melatonin]
Originally posted by madnessinmysoul
alright
how can you say that genetic mutation doesn't exist?
they've tested people in labs
we have observed children having genes that aren't found in either of its parents
that's a mutation
how else would you explain it?
Originally posted by spiritconnections
Ok. I'm not going down the road of condescension you are traveling. I'll just answer your points to the best of my ability.
Originally posted by melatonin
Originally posted by spiritconnections
Ok. I'm not going down the road of condescension you are traveling. I'll just answer your points to the best of my ability.
That's cool and sorry for coming across as obtuse. I just think trying to show equivalence between a massively successful and productive form of gaining knowledge and improving the human condition (but not always), and subjective concepts such as spirituality is rather weak.
I understand some may want to do so, but they will do so whilst enjoying the benefits of all the people who work damned hard to produce tried and tested knowledge.