Comments on: New Study Casts Doubt on the Asteroid Strike Theory of Dino Extinction http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/ Mon, 22 Apr 2013 21:34:00 +0000 hourly 1 http://wordpress.org/?v=3.4.2 By: Skwish http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8065 Skwish Tue, 09 Jun 2009 14:42:00 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8065 I've always wondered if the impactor might have caused enough acid rain to kill off animals with open nests. This would have weakened the shells of animals like dinosaurs, but not turtles and birds, who cover the eggs one way or another. Not that I'm an expert or anything, just an idea I've had. I’ve always wondered if the impactor might have caused enough acid rain to kill off animals with open nests. This would have weakened the shells of animals like dinosaurs, but not turtles and birds, who cover the eggs one way or another. Not that I’m an expert or anything, just an idea I’ve had.

]]> By: Helen http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8064 Helen Mon, 11 May 2009 20:52:53 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8064 I have to agree with the first two comments: Keller's study leaves a lot of elbow room. The Chicxulub meteor event has never been definitively linked to the extinction of the dinosaurs. It's just the closest match we've found, in size and time-period, to what would have been needed to create a planet-wide scorch-mark in the geologic record. Even if Keller disproved Chicxulub's involvement in this event, she won't be able to entirely rule out a meteor impact. I have to agree with the first two comments: Keller’s study leaves a lot of elbow room. The Chicxulub meteor event has never been definitively linked to the extinction of the dinosaurs. It’s just the closest match we’ve found, in size and time-period, to what would have been needed to create a planet-wide scorch-mark in the geologic record. Even if Keller disproved Chicxulub’s involvement in this event, she won’t be able to entirely rule out a meteor impact.

]]> By: SamIAm http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8063 SamIAm Thu, 30 Apr 2009 17:24:20 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8063 The extinction of the dinosaurs and other species is related to the excessive volcanic activity that created the Deccan Traps / just as the Siberian Traps was created by fractures in the Earth's crust following the asteroid impact at the end of the Permian period that led to the Great Extinction. Until the scientific evidence is completely in and analyzed, all we can safely say is that both extinctions were the indirect & direct result of large asteroid impacts. The extinction of the dinosaurs and other species is related to the excessive volcanic activity that created the Deccan Traps / just as the Siberian Traps was created by fractures in the Earth’s crust following the asteroid impact at the end of the Permian period that led to the Great Extinction.

Until the scientific evidence is completely in and analyzed, all we can safely say is that both extinctions were the indirect & direct result of large asteroid impacts.

]]> By: Sundance http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8062 Sundance Thu, 30 Apr 2009 16:05:03 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8062 The beauty of the impact theory of extinction has always been that (aside from fitting the facts - an impact did occur) it explained why the large, probably warm-blooded creatures became extinct while the smaller things, like lizards, rodents, fungi, and plankton didn't. It seems to me that this study simply shows that the impact theory successfully explains what it was supposed to. The beauty of the impact theory of extinction has always been that (aside from fitting the facts – an impact did occur) it explained why the large, probably warm-blooded creatures became extinct while the smaller things, like lizards, rodents, fungi, and plankton didn’t. It seems to me that this study simply shows that the impact theory successfully explains what it was supposed to.

]]> By: amphiox http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8061 amphiox Thu, 30 Apr 2009 15:33:59 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8061 Macroscopic life is the unique habitat for probably a majority of the diversity of microscopic life, so in any major extinction of macroscopic life, a substantial portion of microscopic lifeforms would go out with their multicellular hosts, even if it would be hard to find direct evidence of this in the fossil record. In the case of the plankton, though, even if the impact decimated them to the point of just a couple bedraggled survivors, so long as the species aren't wiped out completely, in just a couple centuries populations numbers could easily recover all the way back to pre-impact baseline. Macroscopic life is the unique habitat for probably a majority of the diversity of microscopic life, so in any major extinction of macroscopic life, a substantial portion of microscopic lifeforms would go out with their multicellular hosts, even if it would be hard to find direct evidence of this in the fossil record.

In the case of the plankton, though, even if the impact decimated them to the point of just a couple bedraggled survivors, so long as the species aren’t wiped out completely, in just a couple centuries populations numbers could easily recover all the way back to pre-impact baseline.

]]> By: Jamie http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8060 Jamie Thu, 30 Apr 2009 14:46:18 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8060 I have to agree with the previous poster. There have been many extinction events; but from memory they're all famous for extinguishing macroscopic life, not microscopic. The fact that no plankton were rendered extinct is very unimpressive - they had an entire ocean's worth of population to draw on. Further, the fact that plankton are the ONLY lifeform they make reference to to support their theory makes it look even lamer. It really looks like they have a pet theory about the Deccan traps (An idea that's been around a long time) and are clutching at straws to discredit the asteroid theory. More research needed. Find evidence of impact on more significant species and then you've got something. I have to agree with the previous poster. There have been many extinction events; but from memory they’re all famous for extinguishing macroscopic life, not microscopic.

The fact that no plankton were rendered extinct is very unimpressive – they had an entire ocean’s worth of population to draw on.

Further, the fact that plankton are the ONLY lifeform they make reference to to support their theory makes it look even lamer. It really looks like they have a pet theory about the Deccan traps (An idea that’s been around a long time) and are clutching at straws to discredit the asteroid theory.

More research needed. Find evidence of impact on more significant species and then you’ve got something.

]]> By: Brian http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8059 Brian Thu, 30 Apr 2009 02:11:01 +0000 http://blogs.discovermagazine.com/80beats/2009/04/29/new-study-casts-doubt-on-the-asteroid-strike-theory-of-dino-extinction/#comment-8059 On the face of it, this study's reasoning is not impressive. Not at all. Let's see, the authors want to know whether the impact damaged populations of dinosaurs, so they study... plankton. Yeah, I know, prey species, base of the food chain, and all that. Still not impressive. #1. If I were a lifeform at the time, interested in the survival of my species, I'd WANT to be plankton. The oceans have a shot at shielding me from the worst effects of impact. I'm tiny and have trillions of friends. I can be wiped out locally and recolonize from waters far, far away. I have a short life and can evolve quickly under pressure. Being plankton is good under these conditions; #2. It's not just what, or whether plankton species went extinct. It's relevant what the relative proportions of extant species are. It's also relevant what the total biomass of plankton is before and after the event. #3. My understanding of large scale impacts are that the worst effects are often on land. Major fallout? Worse on land because all that matter has nowhere to go, whereas in the ocean it can at least sink to the bottom. Continental firestorms? Not a problem in the water. Atmospheric poisoning? If you breathe water you're not in immediate danger. #4. Look at large species known to have survived the event. Crocodilians. They live largely aquatic lives, they can binge feed then fast for long periods, and they can go dormant if necessary. #5. Do you want to be around, anywhere on Earth, during a Chicxulub scale event? Seriously, does this sound like a good place to be? This doesn't even pass the laugh test. On the face of it, this study’s reasoning is not impressive. Not at all.

Let’s see, the authors want to know whether the impact damaged populations of dinosaurs, so they study… plankton. Yeah, I know, prey species, base of the food chain, and all that. Still not impressive.

#1. If I were a lifeform at the time, interested in the survival of my species, I’d WANT to be plankton. The oceans have a shot at shielding me from the worst effects of impact. I’m tiny and have trillions of friends. I can be wiped out locally and recolonize from waters far, far away. I have a short life and can evolve quickly under pressure. Being plankton is good under these conditions;

#2. It’s not just what, or whether plankton species went extinct. It’s relevant what the relative proportions of extant species are. It’s also relevant what the total biomass of plankton is before and after the event.

#3. My understanding of large scale impacts are that the worst effects are often on land. Major fallout? Worse on land because all that matter has nowhere to go, whereas in the ocean it can at least sink to the bottom. Continental firestorms? Not a problem in the water. Atmospheric poisoning? If you breathe water you’re not in immediate danger.

#4. Look at large species known to have survived the event. Crocodilians. They live largely aquatic lives, they can binge feed then fast for long periods, and they can go dormant if necessary.

#5. Do you want to be around, anywhere on Earth, during a Chicxulub scale event? Seriously, does this sound like a good place to be? This doesn’t even pass the laugh test.

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