***Good post; you beat me to it. A genetic sequence written out on a piece of paper can't replicate, the biological one can. The medium is the message...
Good, now someone explain how to "create" DNA. Has it been done in a lab? And DNA is just one complicated part of the human body. How about blood clotting? How can blood clotting develop over time, step by step, without bleeding to death in the meantime? The whole system needs to be in place. Clot in lung, you die. Clot 30 minutes after a cut, you die. Clot throughout your whole body, you die. Clot that doesn't cover the whole cut, you die.
See below.
The whole system needs to be in place.
No it doesn't. There are animals that get along just fine with only a portion of the vertebrate clotting system. Nice try. Learn some science before you attempt to critique it.
Clot in lung, you die. Clot 30 minutes after a cut, you die. Clot throughout your whole body, you die. Clot that doesn't cover the whole cut, you die.
Modern vertebrates have come to critically depend upon the clotting system they've got now. However, when the current system was being evolved from simpler systems, the life forms which had those simpler systems didn't require anything as complex as our current system. A so-so clotting system is still better than none at all, especially for an organism that has other ways of dealing with vascular injury (or lower blood pressure compared to ours, or different blood composition which doesn't "leak out" as readily as ours, etc.) and doesn't put "all its eggs" in the one basket of blood clotting.
A huge amount of the evolutionary history of the modern blood clotting system has already been reconstructed, like which cascades were added in what lineages when, and based on what mutational changes -- most of what remains are just some of the finer details. Funny how the creationists sort of "forget" to mention that when they hand-wave about the "enormous complexity" of the blood clotting system, eh? Behe even goes so far as to falsely claim that nothing whatsoever is known on this subject -- he's either lying or is inexcusably incompetent, but neither option inspires confidence.
From a previous post of mine:
Now, also, you omitted all references to the blood clotting stuff.
...because Behe has already been hammered on that point thorougly enough that he has pretty much stopped using it as an "example". He has been concentrating on the flagellum mostly, thus the focus of my response.
For pete's sake, lets get comprehensive here! In detail, discuss why gradual evolution of blood clotting with 10 protein feedback loops all working at once is actually quite feasible evolutionarily speaking.
Well, okay, since you insist... Check out The Evolution of Vertebrate Blood Clotting, or The evolution of vertebrate blood coagulation as viewed from a comparison of puffer fish and sea squirt genomes. Excerpt from the latter paper:
It is thought that 50–100 million years separate the appearances of urochordates (which include the sea squirt) and vertebrates. During that time the machinery for thrombin-catalyzed fibrin formation had to be concocted by gene duplication and the shuffling about of key modular domains. The relative times of duplicative events can be estimated by various means, the most obvious being the presence or absence of a gene in earlier diverging organisms, although it must be kept in mind that lineages may lose genes. Another way to gauge events is from the relative positions of various gene products on phylogenetic trees, earlier branching implying earlier appearance. In this regard, (pro)thrombin invariably appears lower on the phylogenetic trees than do the other vitamin K-dependent factors (Fig. 2).Also, Evolution of enzyme cascades from embryonic development to blood coagulation:The order of events can also be inferred by considering the most parsimonious route to assembling the various clusters of peripheral domains. Nine of the proteases under discussion can be accounted for by six domain-swapping events (Fig. 5). Indeed, the presence of a multiple-kringle protease in the sea squirt genome provides a reasonable model for a step-by-step parallel evolution of the clotting and lysis systems. It should be noted that a serine protease with only one kringle has been found in the ascidian Herdmania momus (36). Although numerous scenarios have been offered in the past about how modular exchange was involved in generating these schemes (refs. 4, 12, and 37–41, inter alia), the new genomic data now provide a realistic set of starting materials.
Recent delineation of the serine protease cascade controlling dorsal-ventral patterning during Drosophila embryogenesis allows this cascade to be compared with those controlling clotting and complement in vertebrates and invertebrates. The identification of discrete markers of serine protease evolution has made it possible to reconstruct the probable chronology of enzyme evolution and to gain new insights into functional linkages among the cascades. Here, it is proposed that a single ancestral developmental/immunity cascade gave rise to the protostome and deuterostome developmental, clotting and complement cascades. Extensive similarities suggest that these cascades were built by adding enzymes from the bottom of the cascade up and from similar macromolecular building blocks.That was the abstract. An excerpt from the text:The downstream protease of the vertebrate clotting cascade (Fig. 1d), thrombin, belongs to the same lineage as complement factors C1r and C1s. The upstream and middle proteases of the clotting cascade (factors VII, IX and X) belong to the most modern lineage, that of horseshoe crab clotting factor C. Therefore, the lineage of thrombin is parental to that of the upstream and middle proteases of the clotting cascade (Table 1) and distinguishes it from the other vitamin-K-dependent clotting proteases (factors VII, IX and X, and protein C). This conclusion agrees with sequence and species comparisons implying that thrombin was the ancestral blood-clotting protein [11]. It also suggests that vertebrate blood clotting emerged as a by-product of innate immunity, because the entire functional core of vertebrate clotting shares ancestry with complement proteases.And if that's not enough, you could check these out:Banyai, L., Varadi, A. and Patthy, L. (1983). “Common evolutionary origin of the fibrin-binding structures of fibronectin and tissue-type plasminogen activator.” FEBS Letters, 163(1): 37-41.And so on...
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The 2.0-Å crystal structure of tachylectin 5A provides evidence for the common origin of the innate immunity and the blood coagulation systems
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