Discussion of everything related to the Theory of Evolution.
Hi AFJ -
I just want to address your point about habitat. When a species has an environment-specific (read niche) adaptation they are much more likely to remain within that environment because:
a)Their adaptation increases their competitive fitness within the specific environment
b) Their adaptation (often, not always) decreases their fitness outside of the specific environment.
So if the lungfish hadn't already instinctively stayed in low 02 water before developing lungs, their new adaptation would put selective pressure on the population to develop such an instinct.
What did the parasitic Candiru fish say when it finally found a host? - - "Urethra!!"
I will try to get to niche. Thank you. I understand the concept your talking about. I can see that because they had lungs they could live in water with low O2 more fitly than other fish could. I'm not sure they would be less fit in highly oxygenated waters. But having gills and lungs, they could have more habitat options than other fish.
I guess the actual question is "why does instinct arise?" I have not read on this subject much--it would rather seem self-evident to me. If one would stop and think how many instincts there are which cause organisms and eco-systems to work. One must ask "is not the cause of instinct somewhere within the actual organisms, and not in the past history of it's ancestors and their adaptation?" Just some examples are the mating of salmon, or migratory patterns in animals. Birds flying south for the winter. Or how do animals know what is poisonous to eat in nature?
The only other comment I have about evolution theory is that it tends to speak in broad principles, and not in the specific mechanics of how something would actually take place. Even some of the illustrations are so overly-simplified compared to the mechanics of what has to take place to achieve the illustrated hypothesis. It's hard for some people to "buy in" to systems of thought that do this.
That has to do with how a lungfish's circulatory system works. Internal flaps in the heart help to direct blood flowing out of the heart first to the lungs where it is oxygenated. Blood flowing out of the lungs then returns immediately to the heart, where those same internal flaps direct blood returning from the lungs to the gills where it can be further oxygenated before going to the body. This isn't quite the same as the multi-chambered heart found in tetrapods, but it's a similar concept and a clear evolutionary ancestor. The problem with this in well-oxygenated water is that it takes longer for blood to circulate through the body, since it must first pass through the lungs before going on to the gills and body. This means that fish without lungs have an advantage in well-oxygenated water since they can circulate their blood much more quickly.
This is an interesting question that, as far as I know, has never been satisfactorily answered. It depends to a large extent on what you consider instinct, and the answers are probably different for different organisms. Some behaviors, such as migratory patterns in birds and mammals, are probably learned from birth. Others may be genetically-programmed, such as an instinct to avoid brightly-colored insects that might be poisonous. As for salmon, I know they navigate by smell, returning to the stream of their birth by its unique scent. This could even be hormonal. Perhaps their reproductive hormones make them want to find that smell, sort of like how human women appreciate the smell of roses?
You may have a point here, and that's because we don't have all of the pieces to the puzzle. Considering how many different species there are, it's impossible to ever know for sure how each and every one evolved. Yet we do know from experiment and observation that evolution happens, and we know many of the general concepts that govern its progress. We also know a lot of details about how it's worked in each case, but far from all details. We'll probably never know everything.
Generally speaking, the more people talk about "being saved," the further away they actually are from true salvation.
#2 Total Post Count
...we already know how lungs evolved as an off-shoot of the intestine...In essence, your thinking is dependent on the organ already existing before it can be selected for;
First, you don't know because you weren't there to see it. And I have never seen an intelligent designer. All hypotheses must be testable and pass the test to become a theory and all theories must pass many tests without contradiction to become scientific law. The subject of origins is loaded with unprovable circumstantial evidence, questions, and speculation.
You said, "In essence, your thinking is dependent on the organ already existing before it can be selected for;"
No that is not my thinking at all. My thinking is that all change in species is genetically controlled and not dependent at all on an organ. It doesn't matter what the intestine became. The origin point is not the organ but the gene in control of the organ.
Secondly, what do you mean "before it can be selected for...." Again hard mechanics in natural selection and speciation has to do with reproduction, mating, and isolation of populations over time. The genetic material which is in the fittest organisms gets passed on and becomes a dominant trait within a species.
Of course there has to be something there to be passed on to the next generation--not the organ but the info in the DNA--in order for the organ to develop. In order to have another organ there has to be new info in the DNA. The uniformintarian philosophy of evolution says that it happened slowly--not me.
SO I suppose most evolutionists would say that genetic material was added gradually over much time to have the proper alleles for the lungs. Would that be your opinion Alex?
Chemistry only causes reactions and guidance between atoms, compounds (molecules) and mixtures. It has no mechanism of intelligence or puposeful guidance toward life--OTHERWISE WE WOULD SEE ABIOGENESIS EVERYDAY.
I'm not sure I follow your reasoning. Maybe I've misunderstood you, but you seem to be saying that organs are not important, only genes. Yet the construction of organs is controlled by genes, is it not? This is where the organs themselves become important. If an organ confers some selective advantage, then the same would be true for the genes that created that organ, and those genes would have a better chance of being passed on to the next generation. New organs can evolve when pre-existing structures find new purposes and are modified by genetic mutation and variation to better suit that purpose, such as in the development of lungs as separate organs from the intestines. Such organs that make an organism more likely to survive also make the genes that created that organ more likely to be passed on. That's where I'm having trouble following you. The two are basically two different faces of the same concept, yet you seem to be separating them as if they're unrelated. Are you suggesting that organs have nothing to do with genetics?
#2 Total Post Count
Hey I read your post on lungfish--yeah I understand what your saying--thanks.
Initial Mutation in genetic material of organism----> Positive result realized in organism----> Natural Selection ---> positive traits passed on into species----> speciation----> new species
Yes organs are important. Where I have a problem is initial information within the genome that produces the organ that does not come from NatSel or SPec but from an initial mutation. The whole nature of the idea that something in the genetic material that has never been there before and is suddenly there through unguided mutation, and along with it a POSITIVE RESULT realized in the organism. Bare with me please.
In context of the INITIAL MUTATION
1) the genetic material itself has no brain or consciousness to add information to itself.
2) So a mutation which added information to the genome would have been random i.e. a mutation by nature can know nothing--where it was going--it didn't know what lungs were and it had no blueprint or allele for lungs. Neither did the genes, they have no intrinsic knowledge, but are only information containers.
3) In other words, the new information that was produced was not guided by intelligence from the mutation itself, nor intelligence within the genetic material--because the info was not there before in the genes--it was the result of unguided, unintelligent mutation.
4) If there is no outside source (ID) of the information, and no inward source of the information (DNA)-- unguided mutation is the only deduction left for the newly added information.
The fact that evolution requires so many mutations-- and that they bring positive results, when the evidence shows that most mutations bring negative results makes me scratch my head.
5) Speciation and Nat sel can not come into play until the result of the mutation is realized in the organism (an allele which produces something to further evolve lungs) so it must be mutation in the genes first, then result of the mutation second (something to evolve lungs), then if the result of the mutation is realized and causes a positive trait spec and nat sel take place to pass the result into the species.
At this point one could ask when it comes to any new trait, organ, oganic material or system in the organism or population.
1)Since mutations are unguided why would there not be negative mutations with negative results (as most of them are today) that counteracted evolution or destroyed the organisms? Why would evolution even take place if the more part of mutations are negative?
It seems like saying we know lead used to float on water though it doesn't today.
2) Why is it assumed that unguided mutations would continuously act upon the same relative codons of the genetic material over time so as to evolve a new organ never before realized? That is mechanically required to achieve evolution of new organs which had never been realized before i.e. before lungs there were no lungs.
I understand that according to evol NatSel would come into play after an initial mutation to incorporate it into the species, but then there would have to be another mutation to further the process.
Intestines----> mutation A in genes--> new information in genes & positive result in organism----> NatSel ---> Mutation A now established trait for organ in species ---> Mutation B ---> N.I. in genes & Positive result in org. ----> NatSel ----> Mut B now est. trait for organ in species...Mutation BZ...---> of course times speciation= functional lungs in organism
3) Why did the mutations not correct themselves, as many non-evironmental genetic disorders are rare and are not passed onto the next generation, let alone an entire species? Otherwise we would all have cancer or down's syndrome, or be midgets.
4) Where did all that new information and come from? New information WITH positive results continuously. Answer from evolution: Unguided mutation which today wreaks havoc on the organism (cancer, down's syndrome, sickle cell anemia), and usually does not necessarily pass itself onto the next generation, let alone the species.
Natural selection prevents negative traits from being passed on. As for destroying organisms, the Earth's history shows that all species go extinct eventually.
Because some mutations are beneficial. Over a sufficiently long time period (remember, we're talking hundreds of millions of years here), simple statistics guarantees that beneficial mutations are going to happen at some point. If they didn't, bacteria and viruses would never evolve resistance to antibiotics.
See above point on statistics.
No, we wouldn't. There's a very important difference between a genetic mutation and genetic disorder. A mutation is a minor alteration to a single gene; a disorder is a serious malfunction involving entire chromosomes and thousands of genes.
The enzymes responsible for DNA replication usually catch and correct an errors or mutations, but not always. Different species are better at this than others, but all species have some rate of mutation in their DNA. In fact, one that didn't would become evolutotionarily stagnant and become incapable of adapting to changing conditions, a sure recipe for extinction.
Unguided mutation today has shown enormous ability to benefit an organism, such as my above-mentioned example of viruses and bacteria evolving resistance to antibiotics.
I would like to hear your response to my previous post concerning problems with ID. I'll post it again to make it easy for you to find:
#2 Total Post Count
Of course "negative" traits are "passed on." Disorder is phenotypic description of a phenomenon that may involve single or multiple gene function. Mutation is genotypic.
judging the creator as "incompetent" assumes you know the motivation of the actor. You don't and the concept is sophomoric. If there were an intelligent designer, it's unlikely little alex at biology-online would be so wise and insightful in a universe sense as to judge his motivation.
It's valid to question such a designer's reasoning when you consider the implications of ID "theory" and its failure as a scientific hypothesis, which is its failure to produce experimentally testable and falsifiable hypothesis. For example, one could look various imperfections if the morphology of organisms and at the progression of intermediate forms in the fossil record (which seem to clearly indicate an evolutionary process) and say that this is not evolution at all. The designer simply made it this way and it's only coincidental that it happens to resemble evolution. However, the failure of this as a scientific concept is that anything can thus be written off as simply the product of the designer's whim, and the critical scientific requirements of testability and falsifiability are destroyed. In conclusion, I was not so much trying to question the designer's motive as I was making a point about why ID is worthless as a scientific concept.
#2 Total Post Count
You're completely correct, although sadly many people do not seem to agree. The proponents of ID believe their "theory" has even stronger scientific standing than evolution, which it does not. Though I would never call ID science, I think it should still be a topic of discussion in the scientific community, if only to raise awareness of the problem and help stop the persistent efforts of certain conservative factions to force ID to be taught in schools as if it were genuine science.
#2 Total Post Count
Who is online
Users browsing this forum: No registered users and 1 guest