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  • Congratulations.

  • By being here,

  • listening, alive,

  • a member of a growing species,

  • you are one of history's greatest winners --

  • the culmination of a success story four billion years in the making.

  • You are life's one percent.

  • The losers,

  • the 99 percent of species who have ever lived,

  • are dead --

  • killed by fire, flood, asteroids,

  • predation, starvation, ice, heat

  • and the cold math of natural selection.

  • Your ancestors,

  • back to the earliest fishes,

  • overcame all these challenges.

  • You are here because of golden opportunities

  • made possible by mass extinction.

  • (Laughter)

  • It's true.

  • The same is true of your co-winners and relatives.

  • The 34,000 kinds of fishes.

  • How did we all get so lucky?

  • Will we continue to win?

  • I am a fish paleobiologist who uses big data --

  • the fossil record --

  • to study how some species win and others lose.

  • The living can't tell us;

  • they know nothing but winning.

  • So, we must speak with the dead.

  • How do we make dead fishes talk?

  • Museums contain multitudes of beautiful fish fossils,

  • but their real beauty emerges

  • when combined with the larger number of ugly, broken fossils,

  • and reduced to ones and zeros.

  • I can trawl a 500-million-year database for evolutionary patterns.

  • For example,

  • fish forms can be captured by coordinates

  • and transformed to reveal major pathways of change

  • and trends through time.

  • Here is the story of the winners and losers

  • of just one pivotal event I discovered using fossil data.

  • Let's travel back 360 million years --

  • six times as long ago as the last dinosaur --

  • to the Devonian period;

  • a strange world.

  • Armored predators with razor-edge jaws dominated

  • alongside huge fishes with arm bones in their fins.

  • Crab-like fishes scuttled across the sea floor.

  • The few ray-fin relatives of salmon and tuna

  • cowered at the bottom of the food chain.

  • The few early sharks lived offshore in fear.

  • Your few four-legged ancestors, the tetrapods,

  • struggled in tropical river plains.

  • Ecosystems were crowded.

  • There was no escape,

  • no opportunity in sight.

  • Then the world ended.

  • (Laughter)

  • No, it is a good thing.

  • 96 percent of all fish species died

  • during the Hangenberg event, 359 million years ago:

  • an interval of fire and ice.

  • A crowded world was disrupted and swept away.

  • Now, you might think that's the end of the story.

  • The mighty fell, the meek inherited the earth,

  • and here we are.

  • But winning is not that simple.

  • The handful of survivors came from many groups --

  • all greatly outnumbered by their own dead.

  • They ranged from top predator to bottom-feeder,

  • big to small,

  • marine to freshwater.

  • The extinction was a filter.

  • It merely leveled the playing field.

  • What really counted was what survivors did over the next several million years

  • in that devastated world.

  • The former overlords should have had an advantage.

  • They became even larger,

  • storing energy,

  • investing in their young,

  • spreading across the globe,

  • feasting on fishes,

  • keeping what had always worked, and biding their time.

  • Yet they merely persisted for a while,

  • declining without innovating,

  • becoming living fossils.

  • They were too stuck in their ways

  • and are now largely forgotten.

  • A few of the long-suffering ray-fins, sharks and four-legged tetrapods

  • went the opposite direction.

  • They became smaller --

  • living fast, dying young,

  • eating little and reproducing rapidly.

  • They tried new foods,

  • different homes,

  • strange heads and weird bodies.

  • (Laughter)

  • And they found opportunity, proliferated,

  • and won the future for their 60,000 living species,

  • including you.

  • That's why they look familiar.

  • You know their names.

  • Winning is not about random events

  • or an arms race.

  • Rather, survivors went down alternative, evolutionary pathways.

  • Some found incredible success,

  • while others became dead fish walking.

  • (Laughter)

  • A real scientific term.

  • (Laughter)

  • I am now investigating

  • how these pathways to victory and defeat repeat across time.

  • My lab has already compiled thousands upon thousands of dead fishes,

  • but many more remain.

  • However, it is already clear

  • that your ancestors' survival through mass extinction,

  • and their responses in the aftermath

  • made you who you are today.

  • What does this tell us for the future?

  • As long as a handful of species survive,

  • life will recover.

  • The versatile and the lucky will not just replace what was lost,

  • but win in new forms.

  • It just might take several million years.

  • Thank you.

  • (Applause)

Congratulations.

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【TED】Lauren Sallan: How to win at evolution and survive a mass extinction (How to win at evolution and survive a mass extinction | Lauren Sallan)

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    Zenn posted on 2017/11/21
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