animals: lobsters

codedredalert  asked:

loving the age/de-aging thread, thanks for taking the time to educate! why would lobsters ever molt too big if it kills them? is it just bc they don't know? so sentient lobsters aware of mortality would live forever?

So basically, this is a case where a gene(s) that gives you a reproductive advantage (just! keep! growing! GET AS BIG AS POSSIBLE!) also has a longterm disadvantage associated with it (you die of growing to death), but since you’ve already had lots of kids and passed on those genes by that point, there’s no way for selection pressures to fine tune that little glitch at the end.

selection doesn’t care if you die eventually, as long as you pass on more of your genes than the other guy.

since the “just keep growing” appears to be built in, sentient lobsters probably couldn’t short circuit that portion of the process.  if they don’t molt, they eventually outgrow their own exoskeleton, and if they nutrient-restrict enough to stop growing they probably muck up other physiological processes.

questbedhead replied to your post “dreadlord-mr-son replied to your post “Friendly reminder that…”

so does that mean a theoretical lobsteresque alien society with good medical care and/or a lot of energy drinks COULD achieve quasi-immortality, or at least create a ruling class of studly, geriatric giants?

In my opinion they could definitely extend their lives, probably a lot, with appropriate nutrition and advanced lobster medical care.  But they’d eventually start hitting other hurdles–for example, at some point their exoskeleton’s not going to be able to support their own body weight.  

Or, if they get big enough, they’d need to drastically up the oxygen content in their environment to counter the fact that they have an open circulatory system to deliver oxygen to their tissues. Their volume to surface area ratio would be slowly skewing, making that not a very effective plan anymore.  And oxygen is a pretty toxic chemical, so that’s going to start having its own problems.

codedredalert replied to your post “dreadlord-mr-son replied to your post “Friendly reminder that…”

is your labmate’s talk published anywhere i wanna read it

It’s not!  which is a shame, because he’s a really good speaker!

I’m going to bug him to see if I can get him to put together some kind of blog post or layman’s science version of it to put online, because even just all the background conceptual material was really, really neat.