The Biological Spin - Multicellular Organisms
It's dry stuff until you start putting a biological spin on it. This dry stuff essentially is the means by which organisms have coped with their physical environment. Now of course you know that many plants and many animals are multi-cellular. The question then is, can we create a hypothetical universe for multi-cellular plants. You might also ask yourself why plants become multi-cellular? Unicellular organisms do quite well. In fact in an aquatic environment, it pays to be small and unicellular in many physiological respects. But, there are advantages to getting larger. One is that you can specialize. If you're unicellular and you go through sexual reproduction, every time two cells meet and fuse and have a good time and then go through meiosis, you get four cells back but you have to put two cells in. That means you only gain two cells in one sexual cycle.
But, imagine now if you become multi-cellular, you can have some cells that change into sperm and egg but, you leave behind an individual. Every time you go through sexual reproduction, you create four new individuals by every meiotic cell division. But, you've also left behind your two original parents. If you plot this process against the number of generations, the number of individuals in a population for a unicellular population versus a simple multi-cellular, you see over a succession of generations that there are more multi-cellular organisms produced every cycle compared to unicellular organisms.
There are advantages to being multi-cellular for other reasons. But certainly, sexual reproduction allows you to specialize cells that are dedicated to sperm and egg production and cells that remain behind to leave the individual. So, is there a universe of hypothetical multi-cellular organisms that we can create? Yes! We simply have to take the previously created universe for cells and combine it with the universe of how we put cells into tissues and then combine that with the universe of how we put tissues inside of a larger external shape.