The weird evolutionary story of cranberries
This Thanksgiving, take your cranberry sauce with a dollop of irony. You're eating cranberries mostly because cranberries stopped trying to get mammals to eat them.
Although there are a few plants that migrate, the vast majority of them are stuck in one place. This saves on energy, but has many disadvantages. One of those disadvantages is the lack of any ability to stake out a territory for one's young. Seedlings that drop directly below the plant end up competing with their progenitor for survival. Having a family battle itself is not the way to perpetuate a genetic line, so more successful plants adapted a way to disperse their seeds. They buried them in tasty fruit; fruit that animals would both enjoy and derive nourishment from. When the animals snapped them up, the seeds were either scattered immediately, or carried in the intestinal tract, through the world until they, uh, dropped, far from their parent plant.
To discourage animals from eating the fruit before the seeds matured, much unripe fuit is loaded with tannin, a chemical that makes the fruit taste sharp and dry. As the fruit matures, out comes the sugar, and the fruit begins to smell and taste sweet to hungry mammals.
Cranberries developed quite another strategy. Although the berries are edible, and at one time would have relied on mammals to disperse their seeds, they jettisoned that idea. They stopped adding sugar to their berries, and started pouring on the tannin, discouraging animals from eating them. In order to spread their seeds and relied on the forces of nature. Cranberry bushes thrived by the edges of streams, and their berries developed little air pockets that allowed them to float. Once they were ready to set off into the world, the berries dropped into the water and floated until they could wash up on another shore.
So why do we eat them? Because they loaded up with tannin and float in water instead of being devoured by animals. The tannin made them useful through the ages. Tannins stop bleeding in cuts, cure leather, prevent infection, and dye clothing. And, throughout history, sour food is still better than no food. Now that there are new ways to do most of the above, the main reason cranberries are still eaten is they are easily farmed. They float, so instead of time-consuming days of picking berries from their stems, farmers can flood their fields, temporarily, and skim the cranberries off the surface of the water.
All the work the cranberries did to shrug off the necessity of being eaten results in them being more easily consumed.
Via Physorg, Wise Geek and herbs2000.
Send an email to Esther, the author of this post, at einglisarkell@gmail.com.
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Your version of Internet Explorer is not supported. Please upgrade to the most recent version in order to view comments.Although it didn't turn out like cranberries had planned, their genetic survival is ensured nonetheless.Oh the sweet and sour irony!
Also the main reason cranberries are still eaten is they are loaded with sugar before being consumed. Hehe. Reply
[quote]All the work the cranberries did to shrug off the necessity of being eaten results in them being more easily consumed.[/quote]On the bright side, it also led to them being commercially cultivated, and thus much more successful than they otherwise would have been.
-Kle. Reply
The story of cranberries reminds me of the story of spicy peppers. "Ha ha! My capsaicin will make me unpalatable! What? No! Stop grinding me into powder! I am not delicious!" But, alas, it was very delicious. Reply
Those photos are giving me a jones for my homemade cranberry-orange sauce. In fact, I'm going to go make some now. Mmmmm.(For those wondering: 1 package cranberries, cover with water, add 1/2 cup non-concentrate OJ, low boil and stir until berries are popped, add honey to taste, skim off foam, reduce to delicious, delicious sauce. Takes about an hour.) Reply
Next step, they'll inflate those air pockets with helium, for crazy cran-fun-time shenanigans. Unfortunately for them, they'll still be harvested for Thanksgiving, this time for the Macy's parade. Reply
I know this is all wink wink nudge nudge, but people tend to get the wrong idea about evolutionary development. The parlance easily tends toward teleology, even in completely un-directed processes like evolution.Saying that cranberries didn't want animals to eat them and did want to float to other shores is like saying a hurricane sought out warm water for energy and then pounced on coastal Alabama. Reply
Gotta wonder who the guy was that thought "Geez, picking these things friggin' sucks and I'm dying for a cran-tini. I'm gonna flood this place and skim me some fine, fine berries. Un-huh" Reply
The thing that bedevils me is that the evolutionary process often follows an identifiably narrative arc. This happened, then this then this etc. Reading the post, you'd almost think that cranberries display traits consistent with cognition. Bury your seed inside a tasty fruit. Can't compete here, so exploit this untapped resource there. smart f*ckin berries. Reply
Also, the cool little air-pocket inside lets the farmers just dump the berries down what's basically a staircase, and only the ripe ones (with the fully formed and still intact bubble) would be bouncy enough to make it to the bottom. It's a particularly simple and elegant sorting mechanism made possible by the berries' new transport system. Reply
An unintended side effect is the release of cranberry juice, combined with distilled potato or grains, allowing the modern cougar to propagate in the wild. Reply
Humans interfering with the natural order of things will only lead to the next, inevitable stage - Zombie Cranberries! Reply
Sunday, 21 November 2010
The weird evolutionary story of cranberries
via io9.com
