There are real drawbacks to living in an oxidizing atmosphere. You rust. That's aging in a nutshell - the stuff that makes you work bleaches in the sun. As soon as we committed to hemoglobin we committed to an expiration date and I'm unaware of any critter that's gotten around that. We'll live longer, presuming we maintain our standard of living. When the Soviet Union fell the life expectancy of adult males plummeted 23 years; it has yet to climb all the way back up. So much of our time is dependent on externalities. From my understanding, one of the main things that bites you in the ass is telomeres. Forgive me if I fuck this up, but they're basically "heat shielding" - they keep the important stuff from getting screwed up by absorbing the damage themselves. As a consequence, they shorten as you age. That's what fucked Dolly the Sheep - she was born with the same length telomeres as her adult donor, which means she was "born" adult. (Accelerated decrepitude!) Yeah, the patching will get better. But old people die of being old. Immune systems aren't as robust. Wounds heal more slowly. Organs function less efficiently. And I'm not seeing stem cell bits being perfect replacements ever. the NIH did a study a couple decades back where they eliminated all causes of death and did a regression to see what the average lifespan would be. I think it was like 114. That's a long-ass time when you consider it was barely 40 a hundred years ago but it's a far cry from Methuselah.
Maybe. But there's a lot of evidence that oxidation is not really the primary cause of aging, and that it's easily gotten around. No, the 'real' reason we age is because we've evolved to age. Take mice and humans, for example. Our basic biology is essentially identical, yet mice live 2 years if allowed to complete a full life cycles, while humans can live 40 or 50 times that. Energetically speaking (I know you're a thermo guy), it's actually much less costly for an organism to repair oxidative damage than it is to reproduce, which entails growing a whole new being, a being that is now also going to compete with you for resources. So, then why go to all the trouble of growing old and dying when there's no real biological reason it has to be that way? Because the very nature of biological evolution (descent with modification, in Darwin's very much more apt parlance) requires replacement. If we were perfectly suited to an environment, we could live forever. But even in that case, the environment will change eventually (or a new disease will crop up, or whatever other catastrophe), and the species will be wiped out in one generation. The species that have survived through the eons are the ones that have found ways to deal with small and even large changes in their niche. Therefore, the reason a mouse matures in 2 months and dies in two years, while a human or an elephant does not, is because that is the most stable state in which they can exist. It's an evolutionary strategy, so to speak (even though I hate to use terms that imply design; it's use is metaphorical). Whether it's oxidative stress, telomere shortening, or the several other specific mechanisms that contribute to decline, they don't answer the question of why we age, which is a way more interesting question. We age because it makes sense. In the end, the idea of living forever is not only stupid and pointless, it's downright harmful.There are real drawbacks to living in an oxidizing atmosphere. You rust. That's aging in a nutshell - the stuff that makes you work bleaches in the sun. As soon as we committed to hemoglobin we committed to an expiration date and I'm unaware of any critter that's gotten around that.
I...would like to see citations on that... Rust dissolves in certain liquids, and the same oxidation state, Fe3+, is released during heme degradation, which happens frequently enough to turn poop brown. Now I'm by no means an expert on inorganic chemistry in the human body, but this is definitely a claim that I have never heard before. Usually it's cancer or organ failure that kills everyone if they last long enough. Everything in us with a genome has telomerase, but the problem is that keeping it off is a nice safe-guard against tumors.There are real drawbacks to living in an oxidizing atmosphere. You rust. That's aging in a nutshell - the stuff that makes you work bleaches in the sun. As soon as we committed to hemoglobin we committed to an expiration date and I'm unaware of any critter that's gotten around that.
The former is uncontrolled cell division, most frequently due to genome mutations. The latter is a vague term that can be anything from cancer to gradual tissue necrosis / failure to replace the cells that regularly die. Cell failure generally results after loss of the nutrients / oxygen required to maintain protein levels and clear out cell poop. You also have cell suicide when it senses things are not as they should be and straight up bursting when too much liquid enters the cell. The list goes on and on, but I'm not sure what point you want me to get at / how it's related to iron oxidation...
I didn't much like biology. However, my father got his undergrad in it and my mother taught microbiology at the college level for 20 years. Both of them emphasized that most of the breakdown processes associated with replication and division were driven by oxidation. I'm asking, not telling.
Ah! I misinterpreted your original comment! Things definitely oxidize, it's just the carbon chains, not the iron atoms, that play the biggest role in maintaining the energy stores / structural integrity of cells. At their peak energy, they are stored in long -CH2- chains -- at rock bottom, CO2. The same goes for all the lipids, proteins, and sugars that hold a cell together, just at different degrees above rock bottom and with nitrogen, sulfur, phosphorus, and other trace elements mixed in. Now, cells are perfectly capable of reduction, too, when fed. It's not to say that an end to aging isn't possible, but really, human bodies were never designed to live past a hundred years. They accumulate problems that tortoise and elf genetics already figured out how to deal with.I didn't much like biology. However, my father got his undergrad in it and my mother taught microbiology at the college level for 20 years. Both of them emphasized that most of the breakdown processes associated with replication and division were driven by oxidation. I'm asking, not telling.
I'm unaware of any critter that's gotten around that
Barring "accidents", lobsters live forever. Presumably the same goes for other crustaceans. I have no idea whether they have hemoglobin, so your point may still stand.