3 ms·

Bone is a composite material, made of calcium phosphate interwoven with collagen fibers. It's not clear to me that structural bits of iron would integrate well

• pvaldes 9y ago
  Blood cells contain iron. This is the reason to blood being red instead the cyan or transparent blood found in hundred of extant animals. Having a transparent blood could have pros and cons, like hiding the level of injuries to the other antagonist in a fight, but you need copper for that. On the other hand, if you could replace a bone by a hollowed tube of metal, you could bassically smuggle anything that you want at plain sight. Even radioactive substances. Such procedure would be quickly forbidden.
• falsedan 9y ago
  It's not clear to me what your point is. Are you saying that my suggestion that the article should have addressed a different (similar) hypothetical is at odds with your imagination and the physical structure of bone?
  • comicjk 9y ago
    It's an answer to your question "why haven't organisms evolved which use iron in their skeletons". The physical structure of bone would not be improved by incorporating more iron, so there's no reason for evolution to move in that direction.
    • falsedan 9y ago
      That's not my question… that's the question I would have preferred the article addressed. I already gave an answer to the question in my original comment. Also, the 'explanation' begs the question, why wouldn't we see a bone replacement evolve that's suited for iron reinforcement? Your clarificiation is a small step down the 'whys', but saying "because bones have evolved to use calcium" is tautological.