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  • Rising temperatures and seas,

  • massive droughts,

  • changing landscapes.

  • Successfully adapting to climate change is growing increasingly important.

  • For humans, this means using our technological advancement

  • to find solutions,

  • like smarter cities and better water management.

  • But for some plants and animals,

  • adapting to these global changes involves the most ancient solution of all:

  • evolution.

  • Evolutionary adaptation usually occurs along time scales of thousands

  • to hundreds of thousands of years.

  • But in cases where species are under especially strong selective conditions,

  • like those caused by rapidly changing climates,

  • adaptive evolution can happen more quickly.

  • In recent decades,

  • we've seen many plants,

  • animals,

  • and insects relocating themselves

  • and undergoing changes to their body sizes,

  • and the dates they flower or breed.

  • But many of these are plastic,

  • or nonheritable changes to an individual's physical traits.

  • And there are limits to how much an organism can change its own physiology

  • to meet environmental requirements.

  • That's why scientists are seeking examples of evolutionary changes

  • coded in species' DNA that are heritable,

  • long-lasting,

  • and may provide a key to their future.

  • Take the tawny owl.

  • If you were walking through a wintry forest in northern Europe 30 years ago,

  • chances are you'd have heard, rather than seen,

  • this elusive bird.

  • Against the snowy backdrop,

  • its plumage would have been near impossible to spot.

  • Today, the landscape is vastly different.

  • Since the 1980s,

  • climate change has led to significantly less snowfall,

  • but you'd still struggle to spot a tawny owl

  • because nowadays, they're brown.

  • The brown color variant is the genetically dominant form of plumage in this species,

  • but historically,

  • the recessive pale gray variant triumphed

  • because of its selective advantage in helping these predators blend in.

  • However, less snow cover reduces opportunities for camouflage,

  • so lately, this gray color variant

  • has been losing the battle against natural selection.

  • The offspring of the brown color morphs, on the other hand,

  • have an advantage in exposed forests,

  • so brown tawny owls are flourishing today.

  • Several other species have undergone

  • similar climate-change-adaptive genetic changes in recent decades.

  • Pitcher plant mosquitoes have rapidly evolved

  • to take advantage of the warmer temperatures,

  • entering dormancy later and later in the year.

  • Two spot ladybug populations,

  • once comprised of equal numbers of melanic and non-melanic morphs,

  • have now shifted almost entirely to the non-melanic color combination.

  • Scientists think that keeps them from overheating.

  • Meanwhile, pink salmon have adapted to warmer waters

  • by spawning earlier in the season to protect their sensitive eggs.

  • And wild thyme plants in Europe are producing more repellent oils

  • to protect themselves against the herbivores

  • that become more common when it's warm.

  • These plants and animals belong to a group of about 20 identified species

  • with evolutionary adaptations to rapid climate change,

  • including snapping turtles,

  • wood frogs,

  • knotweed,

  • and silver spotted skipper butterflies.

  • However, scientists hope to discover more species evolving

  • in response to climate change out of 8.7 million species on the planet.

  • For most of our planet's astounding and precious biodiversity,

  • evolution won't be the answer.

  • Instead, many of those species will have to rely on us

  • to help them survive a changing world

  • or face extinction.

  • The good news is we already have the tools.

  • Across the planet, we're making on-the-ground decisions

  • that will help entire ecosystems adapt.

  • Critical climate refuges are being identified and set aside,

  • and projects are underway to help mobile species

  • move to more suitable climates.

  • Existing parks and protected areas are also doing climate change check-ups

  • to help their wildlife cope.

  • Fortunately, it's still within our power

  • to preserve much of the wondrous biodiversity of this planet,

  • which, after all, sustains us in so many ways.

Rising temperatures and seas,

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TED-ED】野生動物は気候変動に適応できるのか?- エリン・イーストウッド (【TED-Ed】Can wildlife adapt to climate change? - Erin Eastwood)

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    黃于珍 に公開 2021 年 01 月 14 日
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