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I never understood why small dinosaurs wouldn't have had the same likelihood of survival as small mammals? Also why didn't dinosaurs living in the sea survive

I never understood why small dinosaurs wouldn't have had the same likelihood of survival as small mammals? Also why didn't dinosaurs living in the sea survive this? I've always had the suspicion there was something more going on to wipe out an entire animal kingdom at once.

tokenadult 14y ago
why small dinosaurs wouldn't have had the same likelihood of survival as small mammals? A good question. Of course one category of small theropod dinosaurs (clade Aves, commonly known as birds) did survive the extinction of the rest of the dinosaurs, as the article points out. It's a greater puzzler to figure out why the sea-going groups of clade Reptilia (NOT dinosaurs), like the mososaurs and plesiosaurs, became extinct. An extinction event that brings an end to life forms both on land and at sea is quite a major extinction event. http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_ex...
Nursie 14y ago
"I never understood why small dinosaurs wouldn't have had the same likelihood of survival as small mammals?" Maybe they did have the same likelihood, as in mathematicl probability, but the specific circumstances just worked out this way. A little like the anthropic principle - if it hadn't, we wouldn't be in the world we observe. Maybe some proto-rat-creature-mammal-things just lucked out.
- arbitrage 14y ago
  The anthropic principle, and this type of stochastic lottery argument, are terribly unsatisfying. They may be right, but then again, they may not. They're eminently unfalsifiable, and shouldn't be given any more credence than a typical appeal to divinity.
  - Nursie 14y ago
    I vehemently disagree with it being equivalent to an appeal to divinity. I haven't anywhere said 'this is what happened'. If you want to say it's equivalent to an answer of 'I don't know', then that's fine.
    - arbitrage 14y ago
      I'm sure you didn't, but either way the outcome is the same. You throw your hands up in the air and walk away, seemingly content to look no further. The anthropic principle and its ilk are a dead end for investigation, and ultimately useless to invoke.
      - Nursie 14y ago
        Who said I was content not to look further? Does "this is what I guess, as far as I know" imply I don't wish to know any more?
  - svachalek 14y ago
    The question is "why didn't some other outcome have the same likelihood?" and the answer was, perhaps it did. We don't know what the most likely outcome of the extinction was, only which one occurred.
jug6ernaut 14y ago
Mammals are more adept to adapting to climate change. Reptiles on the other hand have a very hard time dealing with even a few degrees of temperature change from there norm.
- Steuard 14y ago
  Sure, but dinosaurs were closer to birds (and thus also warm blooded, as I understand it).
  - jug6ernaut 14y ago
    Birds are not strictly "warm blooded" as mammals are, but yes they are not strictly cold blooded ether. They are able to generate their own body heat to some extent yes, but are still fare more susceptible to climate change then a mammal would be.
    - Amygaz 14y ago
      I don't know about birds during these "dark" times, but todays birds are pretty resilient to wide change in temperature even on a daily basis. They are capable of generating and circulating fair amount of body heat. Their average temperature is typically much higher than mammals. They are also well insulated, more than humans, apes, dogs, cats...
      - JanezStupar 14y ago
        Its also easier for birds to migrate than for land based creatures.
    - run4yourlives 14y ago
      Except that birds did quite well during the extinction event, all things considered; more so than mammals.
- tocomment 14y ago
  But plenty of reptiles survived just fine. It's as if there were something special about dinosaurs. Could there have been some major virus that wiped them out and left other species untouched?
nickgully 14y ago
They did, they're called birds. Small mammals just grew into more large animal locations.
edanm 14y ago
I know next to nothing about dinosaurs, so someone correct my ignorance: Don't we define Dinosaurs, in some sense, as "animals that were alive then and aren't alive now?". Obviously, some of the Dinosaur species were related, but aren't there lots of different families of Dinosaurs which aren't connected? Had the wolves died too, wouldn't they also be considered as just another family of Dinosaur? (Again, I don't really know if this is how Dinosaurs are defined or not. One argument against is that people talk about "birds" being descended from Dinosaurs).
- jcastro 14y ago
  No, dinosaurs are a distinct kind of animal; - http://en.wikipedia.org/wiki/Dinosaur http://en.wikipedia.org/wiki/Dinosaur - http://en.wikipedia.org/wiki/Archosaur http://en.wikipedia.org/wiki/Archosaur Animals species that used to be alive are classified "extinct", as opposed to being around today which is "extant". Wolves wouldn't have died off at this time, large mammals hadn't evolved yet.
- fhars 14y ago
  No, we define dinosaurs "as the group consisting of Triceratops, Neornithes [modern birds], their most recent common ancestor, and all descendants" (Benton, via http://en.wikipedia.org/wiki/Dinosaur http://en.wikipedia.org/wiki/Dinosaur). And to answer the GP: yes, many small dinosaurs did in fact survive until today. You can hear them singing in the big blue room behind your office window in spring and summer.
jcastro 14y ago
> Also why didn't dinosaurs living in the sea survive this? The entire ecosystem of the planet collapsed, lots of things went extinct (including some mammals), the classic "dinosaurs" are just the most famous ones.
- ufo 14y ago
  Precisely. So many things went extinct that is probably better to ask "why did this group survive?" instead of "why did this group go extinct?".

tokenadult 14y ago

why small dinosaurs wouldn't have had the same likelihood of survival as small mammals? A good question. Of course one category of small theropod dinosaurs (clade Aves, commonly known as birds) did survive the extinction of the rest of the dinosaurs, as the article points out. It's a greater puzzler to figure out why the sea-going groups of clade Reptilia (NOT dinosaurs), like the mososaurs and plesiosaurs, became extinct. An extinction event that brings an end to life forms both on land and at sea is quite a major extinction event. http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_ex...

Nursie 14y ago

"I never understood why small dinosaurs wouldn't have had the same likelihood of survival as small mammals?" Maybe they did have the same likelihood, as in mathematicl probability, but the specific circumstances just worked out this way. A little like the anthropic principle - if it hadn't, we wouldn't be in the world we observe. Maybe some proto-rat-creature-mammal-things just lucked out.

arbitrage 14y ago
The anthropic principle, and this type of stochastic lottery argument, are terribly unsatisfying. They may be right, but then again, they may not. They're eminently unfalsifiable, and shouldn't be given any more credence than a typical appeal to divinity.
- Nursie 14y ago
  I vehemently disagree with it being equivalent to an appeal to divinity. I haven't anywhere said 'this is what happened'. If you want to say it's equivalent to an answer of 'I don't know', then that's fine.
  - arbitrage 14y ago
    I'm sure you didn't, but either way the outcome is the same. You throw your hands up in the air and walk away, seemingly content to look no further. The anthropic principle and its ilk are a dead end for investigation, and ultimately useless to invoke.
    - Nursie 14y ago
      Who said I was content not to look further? Does "this is what I guess, as far as I know" imply I don't wish to know any more?
- svachalek 14y ago
  The question is "why didn't some other outcome have the same likelihood?" and the answer was, perhaps it did. We don't know what the most likely outcome of the extinction was, only which one occurred.

jug6ernaut 14y ago

Mammals are more adept to adapting to climate change. Reptiles on the other hand have a very hard time dealing with even a few degrees of temperature change from there norm.

Steuard 14y ago
Sure, but dinosaurs were closer to birds (and thus also warm blooded, as I understand it).
- jug6ernaut 14y ago
  Birds are not strictly "warm blooded" as mammals are, but yes they are not strictly cold blooded ether. They are able to generate their own body heat to some extent yes, but are still fare more susceptible to climate change then a mammal would be.
  - Amygaz 14y ago
    I don't know about birds during these "dark" times, but todays birds are pretty resilient to wide change in temperature even on a daily basis. They are capable of generating and circulating fair amount of body heat. Their average temperature is typically much higher than mammals. They are also well insulated, more than humans, apes, dogs, cats...
    - JanezStupar 14y ago
      Its also easier for birds to migrate than for land based creatures.
  - run4yourlives 14y ago
    Except that birds did quite well during the extinction event, all things considered; more so than mammals.
tocomment 14y ago
But plenty of reptiles survived just fine. It's as if there were something special about dinosaurs. Could there have been some major virus that wiped them out and left other species untouched?

nickgully 14y ago

They did, they're called birds. Small mammals just grew into more large animal locations.

edanm 14y ago

I know next to nothing about dinosaurs, so someone correct my ignorance: Don't we define Dinosaurs, in some sense, as "animals that were alive then and aren't alive now?". Obviously, some of the Dinosaur species were related, but aren't there lots of different families of Dinosaurs which aren't connected? Had the wolves died too, wouldn't they also be considered as just another family of Dinosaur? (Again, I don't really know if this is how Dinosaurs are defined or not. One argument against is that people talk about "birds" being descended from Dinosaurs).

jcastro 14y ago
No, dinosaurs are a distinct kind of animal; - http://en.wikipedia.org/wiki/Dinosaur http://en.wikipedia.org/wiki/Dinosaur - http://en.wikipedia.org/wiki/Archosaur http://en.wikipedia.org/wiki/Archosaur Animals species that used to be alive are classified "extinct", as opposed to being around today which is "extant". Wolves wouldn't have died off at this time, large mammals hadn't evolved yet.
fhars 14y ago
No, we define dinosaurs "as the group consisting of Triceratops, Neornithes [modern birds], their most recent common ancestor, and all descendants" (Benton, via http://en.wikipedia.org/wiki/Dinosaur http://en.wikipedia.org/wiki/Dinosaur). And to answer the GP: yes, many small dinosaurs did in fact survive until today. You can hear them singing in the big blue room behind your office window in spring and summer.

jcastro 14y ago

> Also why didn't dinosaurs living in the sea survive this? The entire ecosystem of the planet collapsed, lots of things went extinct (including some mammals), the classic "dinosaurs" are just the most famous ones.

ufo 14y ago
Precisely. So many things went extinct that is probably better to ask "why did this group survive?" instead of "why did this group go extinct?".