Why did all dinosaurs, rather than just some of them, go extinct during the K-T extinction event? Birds are an exception, but being able to fly, they are also a very special kind of creature, and specalization doesn't usually help with resilience.

My understanding is that dinosaurs filled a very broad and diverse set of ecological niches. In view of this diversity, it is counterintuitive to me that all members of such a diverse set of species would disappear, rather than just a fraction of them.

Did they have (or lack) a common set of features that distinguished them from mammals and birds and made them particularly susceptible to whatever caused the extinction? Did their niches cease to exists temporarily? (It couldn't be the case for all of their niches, could it?) Did mammals already have superior potential which could finally be realized because something upset the global ecological balance?

To sum up, my question is why a large and diverse group disappeared completely rather than partially. There must be some ecological principles that could illuminate it.

Please excuse this naive question from an ignorant but interested layman.

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    $\begingroup$ They didn't. Birds exist today: biology.stackexchange.com/questions/17546/… $\endgroup$
    – kmm
    Jun 14, 2021 at 21:46
  • $\begingroup$ Most dinosaurs were bigger than most K-T survivors. A quick-and-dirty answer would be a sudden lack of sufficient foodstuffs induced by global cooling post-impact. That would off non-small herbivores, which in turn would cause most carnivores to starve $\endgroup$ Jun 14, 2021 at 22:13
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    $\begingroup$ Here's a good place to start your research: en.wikipedia.org/wiki/… It gives a good overview with references about different species groups and the extinction event and its aftermath. Remember that although it is thought to be a single impact, the size and location of the impact led to blast effects, thermal effects, steam/cloud effects, worldwide chemical changes to oceans and land, "impact winter" temperature and sunlight decreases, etc. $\endgroup$
    – Armand
    Jun 14, 2021 at 23:19
  • $\begingroup$ @Armand Summarize and make your comment an answer. $\endgroup$
    – kmm
    Jun 15, 2021 at 14:52


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