Why did ALL non-avian dinosaurs go extint, but not all reptiles?

Quite famously dinosaurs were the dominant clade on Earth for over 150 million years, which for animal species is a very, very long time (for example hominids have "only" existed for about 6 million years, apes even less than that, humans even less). Also quite famously not only did all non-avian dinosaurs go extinct, but they all did so in a quite short period of time in a single mass extinction event. (And yes, they did indeed go extinct surprisingly quickly all at once. In mere years, perhaps even less. It was absolutely catastrophic and devastating.)

A curious mind could ask: How come all of the thousands and thousands non-avian dinosaur species that existed 65 million years ago went extinct, while many reptile species survived (alongside many mammal species, etc)? This completely regardless of dinosaur type, size, eating habits, etc.

Many people often throw the guess that it was because of their sheer size, but they forget that there were literally hundreds if not thousands of dinosaur species that were very small, the size of a dog, some even the size of a chicken. Why did all of them go extinct too, while much bigger reptiles (such as crocodiles) survived? Likewise they went extinct regardless of whether they were carnivorous, herbivorous or omnivorous. It was definitely not about their size nor their diet.

Many conspiracy theorists, some young-earth creationists, and many other wackos, use this apparent paradox to claim that dinosaurs didn't actually exist, or similar silly theories (rather than actually trying to find out the reason.)

But it is indeed curious: Why did all of them (except the avian ones) go extinct? Every single species of dinosaur, without fail. This, while at the same time, many species of reptiles survived. How come the extinction event was this thorough but selective?

As you might surmise, the answer lies in how dinosaurs were different from other reptiles (and eg. mammals). While they are cladistically classified as "reptiles" that doesn't mean that they were identical to other reptiles.

While the full set of reasons why they went extinct is quite large and varied, ie. it was a combination of many things, their physical characteristics, their physiology, was a very crucial one. The characteristics that made them different from other reptiles (especially those that survived).

You see, most reptiles are cold-blooded, while dinosaurs (all of them) were mesothermic. They also quite crucially had a much higher metabolism rate than most other reptiles. (And this is, in fact, why so many dinosaur species were so incredibly fast-running apex predators, especially many of the theropod species.)

This meant, among other things, that they needed significantly more food than their non-dinosaur reptile cousins (most of which could go literally weeks without eating anything). And this is one of the crucial key characteristics that made them different from most other reptiles.

In a way, dinosaurs were extremely adapted and specialized for the Mesozoic environment: They were big, they were fast, they were strong, they were apex predators, they were capable of defending themselves (even if herbivorous). They were the pinnacles of the Mesozoic era. The top tier.

The problem with this is that this strength was also their weakness: The Cretaceous–Paleogene extinction event suddenly, completely and radically changed the environment in a way that made it completely unsuitable for the highly-specialized dinosaurs. Suddenly their fast metabolism became a liability rather than an asset. Suddenly their need for a constant supply of food became a deadly defect rather than a strength.

Of course this isn't the only reason why they suddenly became incapable of surviving in the changed environment (another one is that regardless of their fast metabolism, their reproduction cycle was really slow, which was also a liability after the extinction event), but it was one of the most crucial ones.

This explains why they all died, while many other reptiles survived: Those other reptiles had slower metabolisms, were cold-blooded, and did not require such a constant supply of food to survive. They also usually reproduced much faster.

From the dinosaurs, only birds survived, but that's because they could compensate their now-weaknesses with their unique ability of flight (and small size, feathers, and a relatively fast reproductive cycle).

The question of why all non-avian dinosaurs went extinct all of a sudden is actually a very interesting one. Too bad that many conspiracy theorists don't care. 

The Shroud of Turin is ridiculously and obviously fake

I find it a bit curious how seriously so many people, even many atheists and skeptics, take the Shroud of Turin. Obviously most skeptics don't believe that it represents the body of Jesus himself and instead it originates from the Middle Ages (with carbon dating putting it somewhere in the 1300's, give or take), but they still don't seem to have much problem or skepticism in believing that it's likely a real impression of a real body (although, to be fair, there are also those who believe that it's just a hand-made painting and nothing more.)

It's actually a bit unbelievable how many people believe that it's the actual real impression of a real human body, given how obviously fake it is.

As a side note (and somewhat unrelated to how obviously fake it is), the vast, vast majority of people don't even know what the entire cloth looks like and how the impressions are placed on it. The entire original cloth looks like this:

If it was covering a body, it would mean that the body was laying on top of it on one half, and then it was folded over his head on top of him, like a blanket.

Most people think that the shroud was actually wrapping the body, but it's quite obvious that it wasn't. Even if it was covering a real body, it was just laying flat on a surface, like a sheet, with the body on top of it, and the upper half folded over to cover it, like a blanket. The shroud was not wrapping the body.

This is, rather obviously, not under dispute, as it's extremely obvious from the shroud. It's just curious how few people know and understand this, and instead assume that the cloth was wrapping the body tightly.

Likewise few people are wondering what exactly are the human-shaped stains made of. They rather obviously assume it's blood, but they don't stop to think how unrealistic that is. It would mean that the body would have been completely covered, from head to toe, all of it, in fresh blood, at least fresh enough to permanently stain the cloth.

Believers in the authenticity of the cloth, and Jesus himself, never stop to think how impossible that is. According to the scriptures Jesus was kept on the cross after his death for several hours at minimum. Blood coagulates quite quickly and doesn't stay fresh for that long.

Also, at which point was this cloth used? Most people assume that it was probably used to wrap Jesus's body in the tomb. They forget that according to the narrative his body was washed before putting it in the tomb. Thus, even if we were to entertain the idea that this was used to wrap the body of the real Jesus, at which point did this happen? It would have been several hours after his death, after he had been taken down and his body transported somewhere else.

Analysis of the stain appear to strongly suggest that, at a very minimum, the original stains were enhanced and expanded using a mixture of red ochre and a gelatin medium, which was a common paint in the Middle Ages. While some experts dispute this, I think that it's pretty much certain.

But none of this makes the shroud "ridiculously and obviously fake". Even if it's from the medieval period rather than two thousand years ago, it could still be genuine in the sense that it was used to cover the real body of someone.

Let's examine more closely why it's ridiculously and obviously fake. In particular, let's examine the face:

This is a picture of the stains on the original cloth, and a digitally enhanced version of its negative, which emphasizes the details in the original.

Am I seriously expected to believe that a cloth placed on top of someone's face, said face covered in something (supposedly blood), is going to leave that many intricate details on the cloth? Eyelids perfectly lined, the sides of the nose perfectly lined and shaded, lips, moustache perfectly delineated, eyebrows and forehead perfectly shaded, cheeks perfectly delineated and shaded, and somehow long hair (apparently also soaked in blood?) leaving just the perfect impression on the cloth, all the way from the top of the head to the tips near the neck, not spread out, apparently not affected by gravity, no gaps, nothing? Are you seriously telling me that even the eyelashes of the closed eyes left a distinct impression in the cloth? That the gap between the bottom of the eyelids and the cheeks got so perfectly impressed into the cloth?

Also note the differences in shading, in how dark the stains are. The digitally enhanced image emphasizes this, but if you examine the original closely, you can see the different shades of darker and lighter areas there as well. Am I seriously supposed to believe that a cloth placed on top of a face (apparently soaked in blood for some reason) is going to leave these differently-shaded stains on the cloth, with for example the cheeks gently fading from darker to lighter, as if the face had been illuminated from above? Am I seriously supposed to believe that the nose has just the perfect shading, as if it had been illuminated from above and slightly from the right? Am I seriously supposed to believe that the underside of the eyebrows are perfectly shaded as if the face had been illuminated from above?

This is so obviously painted by hand that it isn't even funny.

The rest of the body isn't much better, although the face is the epitome of how obviously fake this is, because of all the minute tiny details that would absolutely not be that detailed if it had just been a sheet of cloth placed on top of a face covered in blood. You can even see individual fingers, and parts of the body that would not have been touched by the cloth if it had just been placed on top of it.

There are many other problems that can be pointed out as well, such as for example the curious fact that even though the entire body was supposedly covered in blood, there are literally zero signs of this blood dripping to the back part of the cloth. Apparently all this fresh blood, so fresh that it could paint the cloth, did not flow and drip to the part of the cloth that was under the body.

Curiously and funnily, the fact that the shroud includes the part that was under the body is a clear testament that the body was quite clearly not soaked in blood, or any other substance that would flow and drip onto that section that was supposedly under the body.

It is very likely that someone deliberately created the cloth. It might have been a deliberate hoax, or it might have been for genuine purposes, like a so-called death mask (assuming it was created from a real body and not a statue). It's quite clear that whoever created it painted the body with some paint and then put the cloth on top of it and pressed it against it in order to create the impressions, and then extremely likely retouched the end result to enhance the details.

Either way, it should be extremely obvious that it was a deliberate painting, even if it was based on a real body, not just a cloth placed on top of a dead body that just somehow miraculously happened to get such a perfect impression of the body.

And, rather obviously, given that it is quite clearly either a "death mask" of sorts, or some kind of deliberate hoax, it cannot be from the body of Jesus (assuming he even existed in the first place.)