Joel, you accessed the descriptive news article, but not the main paper.
joelazcr said:
Here's the interpretation of these facts:
It is assumed that the range of maternal and fetal tissues are in various stages of evolution.
That's not an assumption. It's a
conclusion. Remember the deductions from the theories of creationism and evolution. If creationism is correct, then there should be no intermediate stages in the formation of placentas: they are complex and had to have been made directly and in complete form. So, first the evidence falsifies creationism.
Second, evolution states that if it is true then there should be intermediate stages from egg formation to placentas. This is what is found in the fish. A series of intermediates in the formation of placentas among species that are otherwise very similar. As you said: the
fact is "variation from species that have no such specialized tissues to those with highly elaborate placentas, plus a range of species in between with less elaborate placentas."
Therefore, the
conclusion is that the intermediate placentas represent an evolutionary sequence.
They use further evolutionary assumptions to build phylogenetic trees
and estimate evolutionary timelines using molecular clocks and dated volcanic eruptions. They conclude that complex adaptations can evolve rapidly.
Now, once they concluded that there was evolution, then it is time to do additional hypotheses. In this case those are the lineage relationships and estimates of the time of the sequence by
independent dating methods.
Here are some interesting quotes from the article:
"Its one of the oldest riddles in evolutionary biology: How does natural selection gradually create an eye, or any complex organ for that matter? ... Now a team of researchers presents a model system for studying the evolution of complex organs-in this case, the placenta-that Darwin could only dream about.
Notice that we are dealing here with natural selection. Which
should leave intermediates. Direct creation or manufacture, the common denominator of all versions of creationism, should not have intermediates.
"Another Yale biologist cautions that Reznick has not proved that this little guppy placenta is a complex organ, and Reznick admits it. But at least these guppies might provide a glimpse of how it happened. "We cant ask how this kind of adaptation evolved with mammals because it only happened once over 100 million years ago," he says. Morell agrees: "But like the evolution of the eye, the evolution of the mammalian placenta is lost in history."
You misquoted! Did you think I wouldn't check! Shame on you to violate the 9th Commandment like that! Joel, this isn't the first time you've misquoted. Why do you want to destroy your credibility that way?
The
real quote:
"Other researchers, such as Günter Wagner, an evolutionary biologist who is also at Yale, caution that Reznick has yet to demonstrate convincingly that the poeciliids' placenta is a complex organ.
But even with this caveat, Wagner concedes that the poeciliid model offers evolutionary biologists a rare opportunity: "We should welcome any model, and especially one like this that has several related species with all the variations in the evolution of this trait."
"Reznick admits that the poeciliid placenta might not be as sophisticated as the mammalian placenta. But like the evolution of the eye, the evolution of the mammalian placenta is lost in history. "We can't ask how this kind of adaptation evolved with mammals because it only happened once over 100 million years ago," he says. The answer might come instead from small, guppylike fish. "
Very different.
The article ends with a directive for more genetic research.
"Experimentally accessible phenomena in Poeciliidae might include the progressive development of the genetic and morphological mechanisms associated with maternal provisioning or the escalating intergenomic conflict associated first with egg retention and then with the increasing commitment of maternal resources after fertilization."
It's not a directive. It's stating that the different species provide the opportunity for genetic research to compare genes.
If this genetic research is ever done, how will it be interpreted if
each Poeciliidae species contain the genes for the advanced follicular pseudoplacenta, just not fully expressed?
There are two "ifs" there. The first -- that the genes will be compared -- is almost certain to take place sometime. I suspect Reznick and company have already submitted the grant for funds to do so.
The second "if" is not at all certain. What I predict to happen is that the genes will be there, but won't code for advanced follicular development. Instead, they will be different DNA sequences between species and the correlation of sequence to function will then be determined.
What you are proposing is that all the genes are there, but that in the less advanced placental species, some genes are not being expressed. IOW, "advanced" placentas required more genes than less advanced ones, and that the extra genes are in the species with less advanced plancentas, but are "dormant".
Why would those extra genes even be there under creationism? If the species are directly made by a Creator, why install extra genes that would only be needed if the species "evolved" later?
If you are thinking the genes were put there so that the fish could "adapt" and gain advanced placentas later, then random mutations would inactivate them or distort them so badly they won't function.
This has already been shown with an alternative developmental pathway in Drosophila. The pathway is suppressed by the protein HSP90 (heat shock protein 90). When the flies are under heat stress, the HSP90 is used to combat the stress and is pulled from suppressing the developmental pathways. The resulting flies are very deformed from the mutations that accumulated in the pathways that were never removed by natural selection.
2. E Pennisi, Heat shock protein mutes genetic changes. Science282: 1796, Dec. 4, 1998. Describes Nature article on acceleratedevolution. HSP 90 suppresses some developmental pathways, allowing themto accumulate mutations. When HSP 90 is tied up protecting from heat stress,then these pathways become active, giving large morphological changes since thesmall mutations are in HOX genes.
3. SL Rutherford and S Lindquist, HSP90 as a capacitor for morphological evolution. Nature 396: 336-342, Nov.26, 1998. Primary paper for above. Look at pictures of large changes in the flies.
This data falsifies your hypothesis.