image Which came first, the blood, the heart, or the blood vessels? If the heart came first, why did it evolve when there was no blood? If the blood came first, why did it evolve, and how did it get around without blood vessels? And if blood vessels came first, why did they evolve when there was no blood?
9 comments
Still have that Ikea assembly view of evolution, i see, Ray.
We have blood before we have blood vessels. Or a 4-chambered heart. Every one of us formed this way. There’s a tube that kinda washes the forming organs in a blood tide, then sucks it all back out.
Irreducible Complexity is indeed a pseudoscientific creationist Chicken and Egg argument. In a long gradually evolved and complex enough system, an organism can obviously be harmed by attacking its system. Organ failure for instance, can kill the whole organism. It doesn't mean that they have not evolved, often together over millions of years. Evolution is also not about individual organs or organisms, it's populations that slowly evolve. Just like evolution was never the equivalent of another creationist straw man of mixing random things together in a bag, hoping that it suddenly becomes complex. Replicating life and descent with modification doesn't mean the destruction of species and restarting anew, and if it did there'd be no extant complex life. Just like a certain order can be seen in developing embryos. You cannot deny that it only begins with a few cells, or claim that it's random shaking that aggregates them... And there's plenty of evidence of some organs having formed more than once, sometimes in different ways. Like the eye, and oxygen transport systems...
For those interested, I found the following (Monahan-Earley R, Dvorak AM, Aird WC. Evolutionary origins of the blood vascular system and endothelium. J Thromb Haemost. 2013 Jun;11 Suppl 1(Suppl 1):46-66. doi: 10.1111/jth.12253. PMID: 23809110; PMCID: PMC5378490.).
Existing evidence suggests that the blood vascular system first appeared in an ancestor of the triploblasts over 600 million years ago, as a means to overcome the time-distance constraints of diffusion. The endothelium evolved in an ancestral vertebrate some 540–510 million years ago to optimize flow dynamics and barrier function, and/or to localize immune and coagulation functions.
Looks like blood came first, then the vascular system (because diffusion couldn’t work for bigger creatures) and finally the heart.
For more details about blood, wee here , albeit it’s a bit old (Cooper EL. Evolution of blood cells. Ann Immunol (Paris). 1976 Nov-Dec;127(6):817-25. PMID: 1008528.).
@JeanP #189974
Always nice when you come up with something which sounds plausible to you, and it turns out to agree with actual science.
Just from reading the bananaman's post I thought: well, early multicellular organisms probably had some sort of liquid-filled cavity inside, where stuff from cells next to it can diffuse in and out, instead of only cell to cell. Optimize that into a branching internal structure, and it can support bigger organs. It works even better if you have muscles and move around, because that will stir your new blood somewhat. Optimize that by dedicating some muscles to this stirring, and you have your first simple heart. Then, optimize it further as needed, depending on body size and activity.
Which came first: the Chicken or the Egg?
Well, not taking into account that Reptiles laid eggs before Archaeopteryx, the Egg has a smug expression whilst having a post-coital cigarette while said poultry’s blood is pounding through its head - with a ‘WTF?!’ expression - after the pounding it just received.
That reptile with feathers simply adapted to changes in it’s environment, thus not only did it continue with the reproductive process of it’s scaly ancestors but also went further than said Reptiles, by becoming Endo thermic. Ergo, Evolution.
You still haven’t evolved after having to admit that what you thought was a ‘Gotcha’ to we Atheists was as a result of human intervention and not via your ‘God’, eh Ray ‘Bananabrain’ Cumfart…?!
Confused?
So were we! You can find all of this, and more, on Fundies Say the Darndest Things!
To post a comment, you'll need to Sign in or Register . Making an account also allows you to claim credit for submitting quotes, and to vote on quotes and comments. You don't even need to give us your email address.
