So I’m sittin’ there lookin’ at the Pears that came with breakfast this morning and got to thinkin’ about the odd shape. Is it caused or aided by gravity/ Would a lack of gravity make a ball-shaped pear?
I’m a soldier. I have lots of time to ponder such things. You should see my Tetris score 
I think they’d still look like pears.
There’s an article here:
http://spaceresearch.nasa.gov/common/docs/highlights/seed_to_seed_2000.pdf
that indicates that micro-gravity isn’t that big a challenge to a plant’s morphological development.
(That’s a PDF file, by the way, so you may have to install the Acrobat reader if you have not already done so.)
Well, the first soybean plants grown in space look pretty much like soybeans. The starch content of spacegrown soybeans was reduced relative to seeds harvested on earth, but what this means in terms of the shape of pears is anybodies guess. Someone will have to grow a pear tree up there to find out.
Maybe a more relevant question is, “Why aren’t pears round?”
Because God made them in the shape of the earth!
Source it! (The belief that the earth is pear-shaped, not that god made pears in the shape of the earth ;))
Which prompts the question, “How would a partridge perch in such a pear tree?”
It is worth mentioning that, of the numerous species in the pear family (Genus Pyrus), by no means all of them have pear-shaped fruits; some do have spherical fruits, others are almost perfectly conical, yet others more nearly cyclindrical. I don’t think gravity plays a huge role; the fruits just grow that shape.
First of all, many, many fruits are naturally round. Oranges and all that. Secondly, pears are pear shaped very early on in formation, while they are still quite small and even hanging off the branches in all directions. Gravity doesn’t play a significant role here. It’s genetics. (Which Mangetout makes a good point about even in the pear family.)