Sunday, April 20, 2008

Placental genes

Cutting through the obligatory evolutionary ranting here, I think it's some pretty cool stuff. Basically, during the first stage in placental development, we activate primarily genes shared by other species. But in the second portion, we activate species-specific genes.

How cool is that?

The evolutionary error, of course, is to conclude from these facts that all the species are related. No go. Just because the Model T and the Highlander Hybrid both have tires doesn't mean they're related. But it's still really cool. I'm interested in what gene (or other biological structure) controls the activation of the genes within the two stages. How does the embryo "know" when different genes need to be activated?


William said...

Just because the Model T and the Highlander Hybrid both have tires doesn't mean they're related.

Whoa -- are you seriously claiming they're not related? Of course they are. And the fact they both have tires is an indicator of common descent.

Now, obviously we're not talking about sexual reproduction here. But what we are talking about is taking a basic design -- the early car -- and tweaking it, over time, to produce the modern one. Although both models were designed by humans, the new model was not designed from scratch; far from it. Numerous features of modern cars are the way they are only because older generations of cars had the same or similar features, and they've been carried over.

If you were, today, designing a personal transport from scratch, with modern technology, but with no reference at all to the technologies and infrastructures of the past, there's no reason to think that it would come out looking much like what we think of as a "car". The design of cars is suboptimal in many ways. That's because, in short, it evolved.

ungtss said...

Thank you for your comment.

IMO, you're conflating two uses of the terms "related" and "evolved."

In the evolutionary sense, "related" means "descended from a common ancestor," and "evolved," means "having differentiated from that common ancestor due to variation, natural selection, genetic drift, etc."

In the ID sense, "related" means "from a common designer, and based on a common design," and "evolved" means "reflecting changes in design initiated by a designer."

Yes, cars are "related" and "evolved" in the ID sense, but not in the evolutionary sense.

Similar characteristics imply either common descent or common designer. To use it as an argument for one or the other is therefore flawed.

The point I was making is that similarity in design does not imply descent from a common ancestor ancestor any more than it implies a common designer.