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Why would any creature have hormones to accelerate aging as opposed to just letting the body wear out naturally with use?

Waterluvian 3y ago
Probably just a side effect of some other advantageous trait. Getting old or not is probably not relevant for reproduction.
loudmax 3y ago
This is pure speculation, but maybe it's beneficial in some circumstances to make way for the younger generation? Natural selection doesn't necessarily favor genes that optimize the health of a particular animal. Natural selection favors genes that optimize for more copies of themselves, at whatever cost to their current carriers. Perhaps under some scenarios of canine evolution, the fittest genes might have been ones that selected for higher turnover than would happen if bodies wore out naturally.
idopmstuff 3y ago
Bear in mind dogs are pretty unnatural creatures at this point - we've done so much breeding that you can't really assume any natural forces apply to their development at this point. After all, why would any creature develop a facial structure that makes it hard to breathe (like bulldogs, pugs, etc.)? The answer is because humans are selfish.
- Der_Einzige 3y ago
  I want tail docking to be banned so bad. Corgis have tails and they look like foxes when they're kept! So beautiful! like a friendly fox.
nonameiguess 3y ago
I don't know what the mechanism for accelerating aging is in this case and it doesn't say, but IGF-1 serves a lot of purposes and it is ubiquitous among at least all mammals and I'm sure other animals I'm not familiar with. It is necessary for growth and healing and is what causes infants to grow and mature into adults. As with just about any molecule synthesized by a body, when its effect on mortality has been studied in humans, being either too low or too high are both associated with greater mortality risk. I'm guessing it's probably the same with dogs. Having higher growth hormone levels makes the larger breeds larger but also shortens lifespan. Nonetheless, being larger can clearly be important for a predator, especially in very cold regions where most available prey like caribou and bison and what not are very large. Shorter life might even be evolutionarily advantaeous on its own in places with food scarcity that can't sustain large predator populations. The old die to make way for the young as they'd otherwise starve them out.
huytersd 3y ago
Because the dogs we made aren’t naturally selected. We heavily selectively bred for many superficial phenotypes so it’s not strange to see side effects like this.
graphe 3y ago
Wolves can live 15 years. Big dogs are just inbred small dogs with pituitary gland overgrowth.
I_Am_Nous 3y ago
Kind of seems like a mercy, especially depending on what part of your body would wear out first. Would be interesting to study since we know stress also seems to increase aging, so I wonder if a stressful event triggers the aging process as a way to reduce suffering in the aging individual. Similarly there are cases where long married spouses die pretty closely to one another and I could see the stressful loss of your partner increasing your aging factor in such a case.
apwell23 3y ago
> body wear out naturally with use Body doesn't `wear out` from use. Yes there are overuse injuries and overuse arthritis . Aging related `wear out` has nothing do with use. Infact, opposite is often true. Its unfortunate that doctors refer to age related joint issues as 'wear and tear' issues.
JumpCrisscross 3y ago
> Why would any creature have hormones to accelerate aging Octopuses trigger rapid aging after giving birth from their “optic gland,” which “undergoes dramatic changes to produce more pregnenolone and progesterone, maternal cholestanoids, and 7-DHC during the stages of decline” [1]. (”Some females in captivity even seem to intentionally speed along the death spiral, banging into the sides of the tank, tearing off pieces of skin or eating the tips of their own tentacles” [2].) When the optic gland was removed, the affected females “abandoned their eggs, resumed feeding, and some even mated again.” Leading theories include octopuses being “cannibals” having evolved “a biologically programmed death spiral may be a way to keep mothers from eating their young.” Alternatively, octopuses are close to biologically immortal, “so eliminating hungry adults keeps the octopus ecosystem from being dominated by a few massive” members. TL; DR Programmed death is biologically precedents. There is evidence it is at work in most animals, including humans. [1] https://news.uchicago.edu/story/what-causes-octopus-death-spiral-new-study-points-changes-cholesterol-production https://news.uchicago.edu/story/what-causes-octopus-death-sp... [2] https://www.sciencedaily.com/releases/2018/09/180925140402.htm https://www.sciencedaily.com/releases/2018/09/180925140402.h...

Waterluvian 3y ago

Probably just a side effect of some other advantageous trait. Getting old or not is probably not relevant for reproduction.

loudmax 3y ago

This is pure speculation, but maybe it's beneficial in some circumstances to make way for the younger generation? Natural selection doesn't necessarily favor genes that optimize the health of a particular animal. Natural selection favors genes that optimize for more copies of themselves, at whatever cost to their current carriers. Perhaps under some scenarios of canine evolution, the fittest genes might have been ones that selected for higher turnover than would happen if bodies wore out naturally.

idopmstuff 3y ago

Bear in mind dogs are pretty unnatural creatures at this point - we've done so much breeding that you can't really assume any natural forces apply to their development at this point. After all, why would any creature develop a facial structure that makes it hard to breathe (like bulldogs, pugs, etc.)? The answer is because humans are selfish.

Der_Einzige 3y ago
I want tail docking to be banned so bad. Corgis have tails and they look like foxes when they're kept! So beautiful! like a friendly fox.

nonameiguess 3y ago

I don't know what the mechanism for accelerating aging is in this case and it doesn't say, but IGF-1 serves a lot of purposes and it is ubiquitous among at least all mammals and I'm sure other animals I'm not familiar with. It is necessary for growth and healing and is what causes infants to grow and mature into adults. As with just about any molecule synthesized by a body, when its effect on mortality has been studied in humans, being either too low or too high are both associated with greater mortality risk. I'm guessing it's probably the same with dogs. Having higher growth hormone levels makes the larger breeds larger but also shortens lifespan. Nonetheless, being larger can clearly be important for a predator, especially in very cold regions where most available prey like caribou and bison and what not are very large. Shorter life might even be evolutionarily advantaeous on its own in places with food scarcity that can't sustain large predator populations. The old die to make way for the young as they'd otherwise starve them out.

huytersd 3y ago

Because the dogs we made aren’t naturally selected. We heavily selectively bred for many superficial phenotypes so it’s not strange to see side effects like this.

graphe 3y ago

Wolves can live 15 years. Big dogs are just inbred small dogs with pituitary gland overgrowth.

I_Am_Nous 3y ago

Kind of seems like a mercy, especially depending on what part of your body would wear out first. Would be interesting to study since we know stress also seems to increase aging, so I wonder if a stressful event triggers the aging process as a way to reduce suffering in the aging individual. Similarly there are cases where long married spouses die pretty closely to one another and I could see the stressful loss of your partner increasing your aging factor in such a case.

apwell23 3y ago

> body wear out naturally with use Body doesn't `wear out` from use. Yes there are overuse injuries and overuse arthritis . Aging related `wear out` has nothing do with use. Infact, opposite is often true. Its unfortunate that doctors refer to age related joint issues as 'wear and tear' issues.

JumpCrisscross 3y ago

> Why would any creature have hormones to accelerate aging Octopuses trigger rapid aging after giving birth from their “optic gland,” which “undergoes dramatic changes to produce more pregnenolone and progesterone, maternal cholestanoids, and 7-DHC during the stages of decline” [1]. (”Some females in captivity even seem to intentionally speed along the death spiral, banging into the sides of the tank, tearing off pieces of skin or eating the tips of their own tentacles” [2].) When the optic gland was removed, the affected females “abandoned their eggs, resumed feeding, and some even mated again.” Leading theories include octopuses being “cannibals” having evolved “a biologically programmed death spiral may be a way to keep mothers from eating their young.” Alternatively, octopuses are close to biologically immortal, “so eliminating hungry adults keeps the octopus ecosystem from being dominated by a few massive” members. TL; DR Programmed death is biologically precedents. There is evidence it is at work in most animals, including humans. [1] https://news.uchicago.edu/story/what-causes-octopus-death-spiral-new-study-points-changes-cholesterol-production https://news.uchicago.edu/story/what-causes-octopus-death-sp... [2] https://www.sciencedaily.com/releases/2018/09/180925140402.htm https://www.sciencedaily.com/releases/2018/09/180925140402.h...