# Autonomous Biological Units, especially for Reproduction **URL:** \ **Category:** Cafe Society\ **Created:** [January 25, 2018, 2:59pm UTC](https://boards.straightdope.com/t/autonomous-biological-units-especially-for-reproduction/807449 "2018-01-25T14:59:51Z")\ **Posts on this page:** 3\ **Page:** 2
**Author:** ![JR\_Brown](https://avatars.discourse-cdn.com/v4/letter/j/d6d6ee/32.png) [@JR\_Brown](https://boards.straightdope.com/u/JR_Brown)\ **Post date:** [January 26, 2018, 10:21pm UTC](https://boards.straightdope.com/t/autonomous-biological-units-especially-for-reproduction/807449/21 "2018-01-26T22:21:22Z")
> [@CalMeacham](#): > > What I’m thinking about is an Autonomous Living Item that is created to establish one desired goal, then dies. It’s not really a creature in its own right, since is always created by the parent unit, doesn’t feed or reproduce on its own, and has a circumscribed period of existence. It can’t really exist on its own, or without the parent. As far as I know, there’s nothing like this in the real world – any examples I come up with end up requiring special pleading. Viruses? The viral capsid is basically just a delivery device; the payload is the RNA or DNA inside (and in most species some protein machinery to handle, e.g., integration). An empty capsid is worthless, but the RNA/DNA can make new capsids once it’s in a host cell. Sperm, as mentioned, are in a similar category; the exterior bits are the delivery system, the only part that makes it into the embryo is the DNA and its associated protein scaffold. For something multicellular, there’s a [large variety of jellyfish](http://blog.seattleaquarium.org/marine-animals/facts-jellyfish-life/attachment/jellyfish-lifecycle/) where sexual reproduction results in a completely different-looking, non-reproductive larva that eventually settles down and buds off clonal baby jellyfish that grow up to become sexually reproductive adults. Kind of like your facehugger example? The larval form eventually dies after budding a certain number of times, although in [some species](http://www.amnh.org/explore/news-blogs/on-exhibit-posts/the-immortal-jellyfish/) the adult jellyfish can convert back to the larval form and repeat the cycle indefinitely without going through a sexual reproduction step. ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [January 27, 2018, 3:11am UTC](https://boards.straightdope.com/t/autonomous-biological-units-especially-for-reproduction/807449/22 "2018-01-27T03:11:38Z")
It doesn’r pre-date \*It Conquered the World, but Cronenberg’s [_The Brood_](https://en.wikipedia.org/wiki/The_Brood) has an interesting variant on the premise. ---
**Author:** ![Miller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/miller/32/481_2.png) [@Miller](https://boards.straightdope.com/u/Miller)\ **Post date:** [January 27, 2018, 3:35am UTC](https://boards.straightdope.com/t/autonomous-biological-units-especially-for-reproduction/807449/23 "2018-01-27T03:35:53Z")
The cow at the _Restaurant at the End of the Universe_ seems to qualify: a genetically engineered creature with one purpose: to be delicious, and to want to be eaten. Which I guess is technically two purposes. [Previous page](https://boards.straightdope.com/t/autonomous-biological-units-especially-for-reproduction/807449.md?page=1)