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  • Thanks to Brilliant for supporting this episode of SciShow.

  • Go to Brilliant.org/SciShow to learn more.

  • [ intro ]

  • Food, glorious food.

  • We need it to live, and stuff.

  • But for many people, it's more than that --

  • a hobby, a pastime, a passion.

  • Farms and businesses work hard to satisfy

  • the commercial and cultural needs of foodies the world over.

  • But not everything can be plunked down in the ground

  • and picked a few months later, or grown happily in a tank.

  • Some foodstuffs just aren't that cooperative.

  • No matter how much we want them,

  • the science of these plants, animals,

  • and fungi is at odds with the demand.

  • Take huckleberries for example.

  • They're kind of a big deal in the Pacific Northwest of the United States,

  • as flocks of people head out into the woods every summer

  • looking to fill their baskets with the sweet and juicy berries.

  • They are in such demand that huckleberry picking season is now

  • a regulated event in some areas to help make sure there's enough fruit to go around.

  • You see, these berries have a reputation

  • of being difficult to grow in a farm setting.

  • The soil conditions need to be just right.

  • If you're trying to grow them, .

  • Additionally, in the wild, huckleberry grows at high elevations.

  • This environment provides an insulating cover of snow to help protect the plant

  • during the sub-zero temperatures of winter.

  • Without this insulation phenomenon at lower elevations,

  • the plants simply freeze.

  • And it's hard to replicate these conditions in other climates.

  • Like, imagine carting in a bunch of fake snow,

  • then keeping it frozen.

  • Not to mention, they just grow painfully slow.

  • it can take up to 15 years after planting seeds or cuttings

  • to yield harvestable fruit.

  • But maybe we're approaching them all wrong.

  • After all, indigenous peoples have been cultivating huckleberry crops for centuries --

  • by managing the wild plants.

  • They were the ones who taught early European arrivals to North America

  • how to forage for the ripe berries.

  • And over time this practice of foraging, cooking, and preserving

  • evolved into the high-demand craze that we see every year.

  • At least here in Montana!

  • Researchers have been working on creating a domestic variant of the huckleberry

  • by cross-breeding it with certain strains of blueberries,

  • which are closely related to huckleberries.

  • These cultivars would be able to thrive in a variety of ecological settings,

  • making it more likely that the number of crops could rise to meet the demand.

  • But until that happens,

  • the huckleberry will remain a treat for dedicated berry-hunters.

  • And only at certain times of the year.

  • And that's not the only luxury food product in high demand.

  • According to sushi lovers, n

  • othing beats the flavor of bluefin tuna.

  • In 2019, a single large tuna in Japan sold for over three million dollars!

  • Since these fish are only found in the wild,

  • high demand has led to high prices and overfishing --

  • landing the bluefin on the endangered species list.

  • We can't grow these fish in hatcheries yet,

  • because bluefin tuna have a complex life cycle, making them very difficult to farm.

  • They are a really big fish.

  • Like, over three meters long and averaging two hundred fifty kilograms big.

  • They're fast-swimming, migratory fish,

  • meaning their natural habitat is much, much bigger than any tank.

  • They need to swim to develop properly.

  • Plus, they're predators at the top of the food chain,

  • so it also takes a lot of energy to produce the animals they like to snack on.

  • So the mature adults are difficult to care for, to say the least.

  • But even as tiny free-floating larvae,

  • they are difficult to maintain.

  • A study published in 1991, for example,

  • showed when larvae of one species of bluefin tuna are packed in tightly,

  • they grow more slowly, and fewer of them survive.

  • That study actually looked at conditions in the wild,

  • but with an eye toward what would happen in a tank --

  • though measures could also be taken to avoid such issues.

  • Also, larvae may be little, but their heads take up most of their size, so they're

  • a little top heavy.

  • So tank conditions need to be just right to prevent them from literally sinking

  • and actually getting hurt when they hit the bottom.

  • Because of their size,

  • it can take up to 8 years for them to reach sexual maturity and spawn more fish.

  • And fish in captivity often experience reproductive issues.

  • Researchers in the EU and the US are trying to overcome this issue

  • by manipulating the fish's own growth hormones to induce reproduction.

  • If we can't establish captive populations to keep up with demand,

  • overfishing is likely to continue -- which could be bad news for this fishy favorite.

  • Other high demand foods are at risk of becoming endangered, too.

  • The truffle is the poster child of expensive luxury foods.

  • Some varieties of truffle can sell for hundreds of dollars per ounce.

  • But this fungus could go the way of the dodo unless we figure out how to grow it ourselves.

  • See, truffles aren't like the mushrooms you're probably familiar with.

  • They grow underground in close proximity to the root systems of trees,

  • usually hardwoods.

  • They are mycorrhizal species,

  • which means they have a symbiotic relationship with the trees in which they exchange nutrients

  • and aid each other's growth.

  • But humans haven't been doing a good job of caring for this fungus.

  • Because deforestation and climate change

  • are major threats to the forests across southern Europe that truffles call home in the wild.

  • And they're costly and difficult to grow in a farm setting,

  • mostly because it takes time to grow a fungus with such a complex life history.

  • One researcher in the UK harvested his first truffle

  • almost 10 years after planting the holly oak tree that would develop a relationship with

  • the fungi.

  • However, there might be a small silver lining to the role that climate change has taken.

  • Even though the native habitats of truffle fungi are being destroyed,

  • areas in more northerly forests in Europe

  • may be growing more amenable to these species.

  • Given time, the ecosystem changes from climate change might just provide the opportunity

  • for truffles to move to brand new habitats.

  • Our demand for these foodstuffs outstrips the supply.

  • It seems unlikely that sushi fans or huckleberry lovers will let them go any time soon,

  • so we may need to apply some clever science in order to cultivate them.

  • In addition to farming, though,

  • this may be the incentive we need to preserve native habitats for the survival of all species

  • --

  • including the delicious ones.

  • Because after all, isn't biodiversity the spice of life?

  • Outro: We also think curiosity is an important part

  • of life,

  • which is why today's episode is brought to you by Brilliant.org.

  • Brilliant is a problem solving website and app

  • with a hands-on approach to science, engineering, computer science and math.

  • For example, you might enjoy their course on The Joy of Problem Solving,

  • which teaches you to see math not as a rote series of problems, but as a creative exercise.

  • Yes, math and creativity do go together, and this course will use hands-on exercises to

  • show you how.

  • Brilliant has over 50 courses that have storytelling, code-writing, interactive challenges,

  • and problems to solve.

  • This course, as well as the others, are available on mobile platforms like iOS and Android,

  • even offline --

  • so you don't have to worry about a spotty connection in order to keep learning.

  • The first 200 SciShow viewers to sign up at Brilliant.org/SciShow will get 20% off an

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  • So check it out and see if it's right for you

  • and thanks for your support.

  • [ outro ]

Thanks to Brilliant for supporting this episode of SciShow.

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為什麼我們還不能種植這些食物? (Why Can't We Farm These Foods Yet?)

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    林宜悉 發佈於 2021 年 01 月 14 日
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