Therefore, random mutations over time must have caused the red blood cells to sacrifice their life for the benefit of the organism. But hold on! This change in red blood cells is huge! Not small! Any organism that would have mutated to have living red blood cells turn into dead red blood cells would not have had the capacity to replenish these cells. The bones and the marrow would have had to change (mutate)to provide additional cells, because the red blood cells could no longer divide and multiply on their own. But they would only have about 120 days for those changes to evolve. Then the kidneys which filter the blood would have had to adapt to these new cells. The heart would have to adapt to these new cells. The blood pressure would change, because the capilaries would have to adapt. The fluid dynamics of the blood would have changed, and all the other organs would have to compensate. And not only would they have to compensate, but they would have to all coordinate together to compensate in avery short period of time.
This is the oldest and most ridiculous argument against evolution by natural selection. "It's too impossible!" "There's not enough time!" "The system is too complicated to handle change!" Every time an argument like this is made, it's shown to be utterly ridiculous. (E.g. the bacterial flagellum).
Anucleated erythrocytes are not an evolutionary problem. "Lower" vertebrates such as fish have nucleated RBCs, but they are still generated through erythropoiesis, similar to humans and other mammals. In fact they have similar signaling pathways:
In this issue of Blood, Paffett-Lugassy and colleagues take us back 450 million years, to the time when fish diverged from higher vertebrates in evolution, to show that the EPO-EPOR signal transduction axis is a highly conserved component of vertebrate erythroid
development.
Quote taken from
here
So, all that happens is that eventually, a mutation occurs that causes the RBCs to eject their nuclei after they've been generated. This is no real sacrifice as you argue because the only cells that truly reproduce, that put genetic information into the next generation, are the gametes. Or maybe it is sacrifice (but not in any divine sense), but in that case you must include ALL somatic cells because even ones that retain their nuclei and reproduce within the life of the organism still do not directly pass their genes to the next generation. Luckily for them, the gametes have (barring mutation) an identical genome and therefore in helping the gametic cells, the somatic cells are still increasing their own fitness, even RBCs.
But I digress. The point is, that no major change in the way erythropoiesis happens had to occur. As for the changing of the circulatory system, well, that's gone through way bigger changes than dealing with anucleated RBCs. E.g. fish have 2 chambered hearts, birds and mammals have 4 chambered hearts. And conveniently in between is the 3 chambered heart of the amphibians and reptiles. All of these changes can be easily explained by small step by step mutations over millions of years that never result in any catastrophic events that end life as we know it. (Obviously there could have been some "catastrophic" mutations along the way, but those organisms wouldn't have reproduced.) So, as for dealing with erythrocyte evolution, the size of the RBCs would have changed gradually, as would the change in capillary and vessel size, and there's no real problem.
"There are three kinds of lies: lies, damned lies, and statistics."
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