Organelles such as flagellum are used for moving to find more resources. A large benefit of cell membranes is to provide a safe place for resources. I'd argue

Organelles such as flagellum are used for moving to find more resources. A large benefit of cell membranes is to provide a safe place for resources. I'd argue the entire lifecycle of parasites is to find (scout) suitable resource rich environments and to consume them all (gather), often in a way that wrestles territory control from it's host. Here are some articles describing bacteria doing the exact behaviors (search for resource, gather them, and territory control). * A good summary of group compeitive behavior of bacteria, including several territory control strategies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879262/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879262/ * "Distinct foraging strategies generated by single-action behavioural flexibility" https://www.biorxiv.org/content/10.1101/2021.03.09.434602v2.full.pdf https://www.biorxiv.org/content/10.1101/2021.03.09.434602v2.... * Marine bacteria changing behavior around resource rich locations to improve resource gathering. https://www.sciencedaily.com/releases/2020/09/200925113346.htm https://www.sciencedaily.com/releases/2020/09/200925113346.h... * Description of bacteria predators, and complex hunting behavior (scout and gather) https://www.llnl.gov/news/predatory-bacteria-bite-their-own https://www.llnl.gov/news/predatory-bacteria-bite-their-own * Description of properties of bacteria colonies and territory expansion https://nbi.ku.dk/english/news/news20/bacteria-colonies-of-billions-invade-new-territories-without-traffic-jams--we-now-know-how/ https://nbi.ku.dk/english/news/news20/bacteria-colonies-of-b... EDIT: I wanted to respond to the point "Importing resources from other planets or other extraterrestrial bodies can and would better be done by robots than humans." I'm sure robotic mining will occur first. However, we have a limit on the amount of resources we can bring to Earth. An estimated 10% of the mass of the astroid belt is water (on Ceres). Saturn's rings contains about half of Earth's glacier's mass as water. There's likely a dozen more large water deposits in our solar system, although we know less about their total mass. Titan, Ganymede, Callisto, twenty more likely candidates. Imagine tripling the amount of water on Earth. Where would sea level be? This is just gathering all "nearby" water, our most basic resource. We also have to consider the demand for metals like gold, platinum and lithium. Our demand for nitrogen to fertilize soil. Our demand for fuel sources such as hydrogen/oxygen, helium-3, or uranium. There's simply more stuff in our solar system than we can possibly fit on Earth or LEO.