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Earth Science

Asteroid Impact Helped Create the Birds We Know Today (sciencemag.org) 67

sciencehabit writes: Every bird alive today can trace its ancestry to creatures that lived about 95 million years ago on a chunk of land that split off from the supercontinent Gondwana, a new study suggests. The new family tree, compiled using information from fossils and from genetic analyses of modern birds, also reveals that this lineage underwent a major burst of evolution after an asteroid slammed into Earth about 66 million years ago and killed off the rest of their dinosaurian kin.
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Asteroid Impact Helped Create the Birds We Know Today

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  • by VernonNemitz ( 581327 ) on Sunday December 13, 2015 @04:22PM (#51110747) Journal
    We know that the dinosaur group filled most of the world's ecological niches, and when the Chicxulub event happened, a vast number of niches had their occupants wiped out. All we need do is assume that for any species, there is a reasonably constant mutation rate, and most mutants won't survive when there are better-adapted competitors already in a given ecological niche. If the mutant can find a different niche, though, then its chance of survival goes up a lot. So, no need to assume a "burst of evolution" when the simpler explanation is a "burst of opened opportunities", thanks to all those wiped-out competitors.
    • with "burst of opportunities" being the cause, indeed, that doesn't necessarily mean that a "burst of evolution" ensues. I think that evolution accelerates when ther is NOT a plethora of opportunities, because species are forced to specialize in various niches.

      • by Anonymous Coward

        It does give a second chance through. Once a slot is filled by something that works a mutation that would lead into that niche cannot compete. It is unlikely that the first incarnation of a creature with short gliding hops could compete with a more optimized flier.

      • by KGIII ( 973947 )

        I imagine there's a bit more nuance to it. Life finds a way. Sure, you *may* get a "burst of evolution" when specialization is required because you may end up with more unique mutations being viable. How viable are those in the long-term? Then, at the other end of the spectrum, if there's a diverse group to seed the the now vacant positions then it's likely that you'll see a "burst of evolution" at those points as well. It might even be that those bursts are greater in population numbers but with less varia

        • (We did not even suspect that birds came from dinosaurs when I was a child but we did study evolution.)

          Wow, that would make you about 160, maybe even 180 (I forget when the Saurischian/ Ornithischian split within the dinosaurs was recognised, even though it's confusing to this question).

          Archaeopteryx lithographica, the first specimen, was found in 1860 and described in 1861. The first skeletal specimen was found a few weeks or months later (the exact date of discovery of the feather isn't quite clear) an

    • "So, no need to assume a "burst of evolution" when the simpler explanation is a "burst of opened opportunities""

      I think you are confusing terms. Evolution is change. A
      lot of new species did appear: that's a burst of evolution *even* if that doesn't mean an increased rate of mutations or any other biology-related change.

    • The process in this scenario is called Adaptive Radiation. It occurs after every mass extinction event. Many geologic time periods end with a mass extinction and begins with an adaptive radiation. This shows in the strata (layers of rock) as a sudden change in fossils, as one set of species dies off and another takes it place. Note that these can occur both globally or locally, depending on the niche.

      The research in this article is simply pointing out which events (out of many hundreds) precipitated and sup

    • by dywolf ( 2673597 )

      you're not disagreeing with the article. it even says what you said. youre not actually saying something different.

      but the point of the article is why the bird lineages we have today, and not the other lineages we also know about that died out.

  • by nospam007 ( 722110 ) * on Sunday December 13, 2015 @05:10PM (#51110871)

    So it's the fault of that asteroid that I have to listen to that damned mocking bird all night?

    • by Gavagai80 ( 1275204 ) on Sunday December 13, 2015 @06:38PM (#51111187) Homepage

      Better than staying awake listening for a t-rex all night.

    • Actually, pigeons are a far greater nuisance, and a threat to our American way of life. All because of the actions of Asteroids! I called up Foreskin Humps' campaign office, but they could neither deny nor confirm any plans to ban Asteroids from entering Earth outer space . . . space.

      • by KGIII ( 973947 )

        If you make enough noise about it, get enough people behind you, then one of the politicians will surely claim that they have a plan and will be enacting legislation to prevent this evil asteroid menace from happening - if only you elect them. All you have to do is make enough noise and get enough people to join in the clamor with you. One of the politicians will, almost certainly, claim that they have a solution.

        To the Twitter accounts!

      • The real threat to our way of life is encrypted pigeons.

    • Indeed!

      And it is probably just as much the fault of that asteroid that you exist in the first place (because with the extinction of the dinosaurs, the mammals of course also got a chance to evolve, with humans as one of the many results).

  • by Anonymous Coward
    I thought it was commonly referred to as roughly 65 million years ago. Have we finally reached the point where it rounds up to 66 million?
    • by Anonymous Coward

      I thought it was commonly referred to as roughly 65 million years ago. Have we finally reached the point where it rounds up to 66 million?

      That was a million years ago. You just sit and watch news day after day and suddenly the time passes without you noticing.

    • Yeah, it was last Thursday.

  • by Anonymous Coward on Sunday December 13, 2015 @05:14PM (#51110881)

    According to the article "future birds" populated western West Gondwana and didn't spread until the dinosaurs died out. In other words they would not have moved in 30 million years and then suddenly they spread wildly when the dinosaurs vanished. Looking at how animals spread today and in recent history, it looks like they spread unless there is something preventing them from spreading, such as oceans or mountains. There is no reason to think it was any different back then and either they could walk/fly around to spread or they couldn't. There could be plenty of reasons why no fossils is found in an area even though the animal existed in that area. One could be that they haven't been found, another could be that past events prevented them from being created/preserved. Lack of evidence of existence is not evidence of lack of existence.

    If "birds" existed in a greater area in low numbers and haven't been found, then the evolution explosion could be explained by multiple already existing birds growing rapidly in numbers and suddenly started to appear in the fossil records. They "cheated" and started their evolution earlier than we can detect, means the rapid appearing new diverse species was more of a growth in numbers than in species.

    Sure this is pure speculation, but I think the same goes for the version provided in the article. I never understood why it is assumed when something is found, it's the earliest or latest member of the species to have ever lived. Most likely neither would be the case, which mean the timeframe of species will have to be open ended, yet if you look up a species, you get a closed ended timeframe based on the age of found fossils. I don't think it can be any different (we have to write what we know, not what we assume), but we should always remember the disclaimer that no fossils is not proof of non existence, both in age and geographical location. If it was, then some species would die out and then suddenly revive themselves 2 million years later.

    • by gtall ( 79522 ) on Sunday December 13, 2015 @06:48PM (#51111225)

      Unless them precursor birds hadn't yet figured out how to use their feathers to fly. Many dinosaurs had feathers about the time they went extinct but couldn't get off the ground due to weight, no traffic control, really bad transponders, etc. It was hard work to fly back then.

    • by Sique ( 173459 ) on Sunday December 13, 2015 @07:34PM (#51111381) Homepage
      If you read the last paragraph of the article, you find a more detailed picture. There were already birds populating all other continents before the KT event, the Enantiornithes. But they died out together with the other dinosaurs. It was just the population of the western gondwana island, that survived, already split into the main groups of birds we know today, and from there those groups conquered the continents and radiated into all the different species of birds we know today.
      • by KGIII ( 973947 )

        No, no... Some random AC on Slashdot is right and the article is wrong. They might be experts in their field but, damn it, AC read the first three paragraphs in a Wikipedia article. They might have even edited an article once. Sure, it was about My Little Pony but they're officially a Wikipedia Editor and eminently more qualified than these so-called-experts could ever hope to be.

        In all fairness, there are a few topics where I'd trust *some* of the Slashdot posters more than I'd trust the journalists who we

    • According to the article "future birds" populated western West Gondwana and didn't spread until the dinosaurs died out. In other words they would not have moved in 30 million years and then suddenly they spread wildly when the dinosaurs vanished.

      Since birds are dinosaurs, then dinosaurs did not "vanish."

  • by jfdavis668 ( 1414919 ) on Sunday December 13, 2015 @05:38PM (#51110953)
    It is my understanding that everyone had heard...
  • Was there a giant obelisk involved?

  • If something has trouble to be explained - throw in an explosion.

Never tell people how to do things. Tell them WHAT to do and they will surprise you with their ingenuity. -- Gen. George S. Patton, Jr.