The Origins of Species
The Orange is a FREAK.
(Almost) all citrus species can interbreed, and the orange isn't even a species - it's just a hybrid between two other citrus varieties.
Even more so than sweet oranges as a whole, the Navel orange is a supreme freak of nature. Just think about it - NO SEEDS! How is this plant supposed to reproduce?
Truth is, it doesn't. Humans have been taking grafts off of trees and planting them, meaning that every orange you've ever eaten is almost 100% genetically identical to every other orange IN THE WORLD. Good thing they haven't pulled an Irish potato famine on us yet...
Since the dawn of agriculture, unusual plants have really been the norm. But, what makes Navels unusual is simple, unusual numbers of chromosomes.
Now in humans, having 3 (instead of the normal 2, one from mom - one from dad) copies of just ONE chromosome (c21) causes Down's Syndrome. Extra chromosomes aren't usually maladaptive to the vegetative aspect of the plant, but they common effect reproductive issues. If you've got a bunch of extra chromosomes lying around, they can't pair off and get equally divided into reproductive cells (i.e. sperm/eggs) and they generally give the royal screw to any gametes that form by randomly expressing way too much of certain cellular components. BTW, if you haven't read anything about meiosis yet--you should. You owe your life to the wonder of this event, and it's one of the most beautiful least understood biological phenomena around. It's biological ballet. And tragedy too--if it goes wrong, it usually kills itself.
Navel oranges = great at making fruits, bad at making babies.
Peeling an orange today, I wondered; WHY do oranges smell like that? Odor in flowers is to attract pollinators, but in fruit? Turns out that the d-limonene that's responsible for the citrus odor, otherwise known as citrus oil, is a natural insecticide. Which is probably the only part of the orange that still makes sense. Because that's pretty much ALL that plants do, attempt to manufacture toxic chemicals, spines, etc, to keep themselves from being eaten, & reproduce. I was thinking here we've got this fruit that's so extraordinarily obliging to my pleasure that it'll spray my hands with a pleasant scent as a by product of my EATING IT. But really, what we're looking at here is a tree that can't reproduce without the help of human-kind.
And that's not the only domesticated plant that is dependent on human cultivation to exist. Corn is a chance mutant that wouldn't live without someone with an opposable thumb peeling off the husk, and spilling a few kernels an inch or two deep into the soil. Corn would not exist without the people who cultivate it. And, I know that doesn't sound even remotely sinister, but gas and corn are pretty much the axis our society revolves around.
If you want to learn some unimaginably enlightening things about the entire American economy and food-chain, you owe it to yourself to pick up "The Omnivore's Dilemma" by Michael Pollan. Even if you just read pgs 15-115, you will be blown away.
(Almost) all citrus species can interbreed, and the orange isn't even a species - it's just a hybrid between two other citrus varieties.
Even more so than sweet oranges as a whole, the Navel orange is a supreme freak of nature. Just think about it - NO SEEDS! How is this plant supposed to reproduce?
Truth is, it doesn't. Humans have been taking grafts off of trees and planting them, meaning that every orange you've ever eaten is almost 100% genetically identical to every other orange IN THE WORLD. Good thing they haven't pulled an Irish potato famine on us yet...
Since the dawn of agriculture, unusual plants have really been the norm. But, what makes Navels unusual is simple, unusual numbers of chromosomes.
Now in humans, having 3 (instead of the normal 2, one from mom - one from dad) copies of just ONE chromosome (c21) causes Down's Syndrome. Extra chromosomes aren't usually maladaptive to the vegetative aspect of the plant, but they common effect reproductive issues. If you've got a bunch of extra chromosomes lying around, they can't pair off and get equally divided into reproductive cells (i.e. sperm/eggs) and they generally give the royal screw to any gametes that form by randomly expressing way too much of certain cellular components. BTW, if you haven't read anything about meiosis yet--you should. You owe your life to the wonder of this event, and it's one of the most beautiful least understood biological phenomena around. It's biological ballet. And tragedy too--if it goes wrong, it usually kills itself.
Navel oranges = great at making fruits, bad at making babies.
Peeling an orange today, I wondered; WHY do oranges smell like that? Odor in flowers is to attract pollinators, but in fruit? Turns out that the d-limonene that's responsible for the citrus odor, otherwise known as citrus oil, is a natural insecticide. Which is probably the only part of the orange that still makes sense. Because that's pretty much ALL that plants do, attempt to manufacture toxic chemicals, spines, etc, to keep themselves from being eaten, & reproduce. I was thinking here we've got this fruit that's so extraordinarily obliging to my pleasure that it'll spray my hands with a pleasant scent as a by product of my EATING IT. But really, what we're looking at here is a tree that can't reproduce without the help of human-kind.
And that's not the only domesticated plant that is dependent on human cultivation to exist. Corn is a chance mutant that wouldn't live without someone with an opposable thumb peeling off the husk, and spilling a few kernels an inch or two deep into the soil. Corn would not exist without the people who cultivate it. And, I know that doesn't sound even remotely sinister, but gas and corn are pretty much the axis our society revolves around.
If you want to learn some unimaginably enlightening things about the entire American economy and food-chain, you owe it to yourself to pick up "The Omnivore's Dilemma" by Michael Pollan. Even if you just read pgs 15-115, you will be blown away.