manyblinkinglights:

curlicuecal:

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.

I wonder if they could have artificial plumbing installed, for a sort of dialysis-y system for their blood: an oxygenating backpack pulls blood from wherever makes the most sense, and returns it to points deep within the lobster, or perhaps feeding each of its organs. Maybe a separate oxygenation pack for each organ? A truly ancient leviathan would have a surface and body mostly dark and nearly anoxic, except for opalescent healthy patches shining near each of the assisted-respiration points.

Or maybe they’re good at bioengineering instead, and they figure out how to rip the gillfronds off of other species and seat them on themselves, so they wind up bristling with feathery extra external gills. It’d be a wealth/status/chieftan thing–out from beneath every armor plate and joint, a ruff of cultivated xenogills, extending the lives of the biggest and oldest and most influential lobster aliens.

If they stayed aquatic, they might not face as pressing of a structural-support problem with getting too big, right?… or maybe not one that artificial reinforcement to their armor wouldn’t solve (though they’d probs get too big to effectively move themselves).