Biological life as hard as iron?

[Kepler20f]

Would it be possible for biological life to evolve a part of itself to be as hard as iron?

I’m thinking of a tree analog. The wood or bark can replace metal for a low-tech society. The planet itself is deficient in metals because of its history, so I’m not thinking that the life form uses naturally-occurring iron as part of its makeup, even if that were deemed possible. Just a variation on bark/wood that is this hard. Or at least as hard as bronze, significantly stronger than wood on Earth. What do you think?

 

[Borek]

Iron is not that hard. Steel is harder, but still far from the really hard materials.

Do you really mean "hard"? Perhaps you mean "tough"?

Spider silk is extremely tough, so tough it was tested for use in bulletproof vests. But "tough" doesn't mean "hard".

 

[Enigman]

Chitin and sporopollenin are the only natural things I can think of (except teeth...). Kevlar is organic too and spider silk has greater tensile strength than steel but probably won't have the rigidity you need.
http://news.discovery.com/tech/gear-and-gadgets/body-armor-spider-silk-121015.htm
http://gertrude-old.case.edu/276/materials/21.htm
Edit- google search suggests- http://news.discovery.com/tech/print-body-armor.htm
beta-amyloid proteins tougher and lighter than stainless steel.

 

[Kepler20f]

Thanks guys. Hmm, semantics of tough, hard etc. I mean rigid and durable. Something that could be used instead of metal for weapons, armour, utensils and tools for a bronze/iron age equivalent civilisation. They wouldn't have the patience to wind spider silk into armour! Though I am considering something like silk. And I didn't know kevlar was organic, I'll look into that thanks. Thanks for the links Enigman, will check them out.

 

[Nimbian]

Doing some research I stumbled across this page

Basically good old wood can with the right treatment become harder then steel. the page describes the basic process.

 

[Kepler20f]

Thank you Nimbian, appreciate the help. Great article! Everything I've seen so far seems to show that my idea is feasible.

 

[Enigman]

If you are not pushing for realism then you could use biogenic Sillica ( http://en.wikipedia.org/wiki/Biogenic_silica ) in a crystalline form resembling that of diamond (http://en.wikipedia.org/wiki/Moissanite) ...
end result- You get cool shiny swords. oh and crystalline forests.

 

[Kepler20f]

Yeah that's good, thanks Enigman. I think my story will be a combination of realism and some more out there stuff, with the former hopefully helping to suspend disbelief in the latter... Cool shiny swords are probably too shiny for this story though, which is distinctly grubby in flavour. Could use the idea somewhere else maybe. Cheers!

 

[MartinV]

Use life form that builds carbon chains, effectively forming carbon nanotubes or something similar.

 

[Kepler20f]

Use life form that builds carbon chains, effectively forming carbon nanotubes or something similar.

Thanks Martin, interesting idea

 

[Borek]

Hardly a new one, carbon fibers were said to be enforcing skeletons of species living on Pandora (Avatar).

 

[Kepler20f]

Well in terms of decent, plausible sci-fi I'm not exactly going to hold that film up as a shining example! Never mind the flying islands, how about an earthlike world with a breathable atmosphere, a full biosphere and sentient humanoid life, in the very next star systetm to ours! That was a film for the Transformers fans...
Anyway I think people are reading too much into my question. There was a very specific reason that I asked for 'hard as iron' because that is EXACTLY as hard/tough etc as I wanted it. No harder. My story doesn't call for supermaterials. I can see I have to be very specific with my questions.
But thanks for the responses all the same.

 

[GTOM]

Could the mentioned things (biogenic silica, natural carbon fibers) justify bullet resistant life-forms? (I think about W40k orks.)

 

[James Holland]

probably not quite as strong as iron but sum tusks/horns from elephants and rhinos are pretty strong and also turtle shells
and the dinosaur that hed buts every thing