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It goes without saying that many of our most precious resources are also the most limited.
Like, there’s only a certain amount of land that we can build on,
there’s only so much gold that we can mine... and there’s always the possibility of a bacon shortage.
And for some scientists, there’s another commodity that’s in increasingly short supply.
Over the last couple of centuries, we’ve found thousands of dinosaur bones. But only a limited number of species ever existed, right?
So some paleontologists have been wondering how many species of dinosaurs are actually left for us to discover
and how many fossils of them are out there?
Might sound like a funny thing for scientists to ponder, but it’s really an extension of a larger question that they’ve been wrestling with
which is: How many different kinds of dinosaurs were there in the first place?
Scientists who study living organisms deal with these questions all the time
like, how many different types of plants and animals are living in this forest glade? Or how many
Or how many microbes are in this petridish?
Since they can’t possibly count every single organism, they just count a small sample.
Then, they use statistics and probabilities to come up with a mathematical model of what that whole population might look like.
And in 2006, a team of biologists and statisticians used these methods to estimate Earth’s population of extinct dinosaurs.
Specifically, they wanted to figure out how many types of dinosaurs there once were,
as well as how long it would take us to find fossils of each.
Scientists usually count dinosaurs by genus
that’s the taxonomic rank just above “species” because nine times out of ten, there’s only one species of dinosaur per genus.
So the team started cataloging how many dinosaur genera had already been discovered.
Then they focused on how many of those genera were really common, and how many were really rare.
In many cases, for example, a dinosaur genus might consist of just one known specimen,
like the cute and creepy Segisaurus, which used to scamper around what is now Arizona.
But other genera were really common,
like, you can hardly swing a pick-axe in parts of America’s Northern Plains without hitting a fossil of Edmontosaurus.
So, based on the abundance, or scarcity, of known organisms, scientists estimate the diversity of unknown ones as well.
Or at least, they try to.
And the results so far suggest that while there are a lot of dinosaurs still out there for us to find,
we may have less than 200 years of good dinosaur hunting left.
As of 2006, the study concluded, we had discovered just 29 percent of the 1,850 dinosaur genera they think are out there, waiting to be found.
So, how soon until we find the very last known genus of dinosaur?
Well, because of better techniques being used in paleontology, we’re discovering new dinosaurs faster than ever before.
The very first dinosaur fossil was identified in 1824. For the next hundred and fifty years,
paleontologists only discovered an average of one new genus of dinosaur every year.
But now, we’re racking up an average of 15 new genera every year.
And as a result, according to scientists’ calculations, somewhere between the years 2037 and 2056,
we’ll have found 50% of the dinosaur genera that ever existed.
You might think of this as “peak dinosaur”. At that point, there would be more known dinosaurs than unknown ones.
After “peak dinosaur,” there will be fewer genera left to discover, and the remaining ones will probably be scarcer.
So the number of finds per year will start to decline.
But for a while, we’ll still be finding them often enough to keep dinosaur-hunters busy.
Between 2069 and 2102, according to these projections, we’ll have found 75% of the dinosaur genera.
By the mid-22nd century, 90%.
And by the year 2200, there will be only a few genera left, and they’ll be harder to find than ever.
At that point, even though there will probably still be some surprise discoveries of new dinosaurs every so often, those finds will be extremely rare.
Basically, the golden age of dinosaur discovery will be behind us.
However, these are just statistical estimates. It’s impossible to know when you’ve ever found the last of anything.
Plus, this timeline also only applies to dinosaurs, those reptilian land-dwelling diapsids
it doesn’t include all the other ancient forms of life: pterosaurs, mosasaurs, plesiosaurs,
fish, mammals, invertebrates, and plants!
So there will still be plenty of fossils for us to find, for a very long time.
And don’t forget, we’ll still have the dinosaurs’ relatives,birds, to keep us company.
Thanks for watching this episode of SciShow, especially to all of our Subbable subscribers.
If you want to support us, you can go to subbable.com/scishow to learn more.
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恐龍會永遠消失嗎? Will We Ever Run Out of Dinosaurs?

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Derek 發佈於 2015 年 5 月 23 日    Derek 翻譯    許允迪 審核
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