It makes the argument, which I think is widely accepted, that dinosaurs went extinct in essentially one day, or a little longer if some survived the impact and immediate aftermath of the asteroid strike. Maybe it took a year to full extinctify all of them.
So boom. One day you've got a world full of dinosaurs munching on vegetation and each other, and then you go back a year later and you've got a barren wasteland full of corpses. The article says "the available fossil record shows that about 75 percent of known species completely disappeared, and things probably weren’t rosy for the survivors. “It’s is reasonable to suppose that the 25 percent of surviving species had near-total mortality...”. In other words, 75 percent of species were wiped out immediately, and the other 25 percent were almost wiped out.
Now, we generally have something like this happen about every 60 to 150 million years, because there have been five mass extinction events since life began forming on earth. Read more here if you're interested: https://www.nhm.ac.uk/discover/what-...sixth-one.html
For whatever reason, this is the cycle.
We had the first one, then 69 million years later we had the second.
Then we skipped a cycle and had the third one 124 million years after the second.
The fourth one was a bit ahead of schedule, happening 50 million years after the third one.
Then the fifth one (the dinosaur one) skipped a cycle and happened 135 million years after the fourth one.
Don't think about the fact that it's been 65 million years since the last one, by the way. Just put that out of your mind.
So the bottom line is that we get hammered on a cycle of about 65 million years, but sometimes we dodge the problem and get it on the next round at 130 million years.
So my question is, what would have happened if the asteroid that caused the last one 65 million years ago somehow missed us and the dinosaurs didn't get wiped out. Would we still have dinosaurs today? Or would cavemen have hunted them to extinction? Or would they have gone extinct naturally before humans came around, due to climate change or some such thing?
Disclaimer: if you believe the earth is less than 65 million years old, just move along and talk football. This thread has nothing for you. [Reply]
Originally Posted by suzzer99:
No way humans evolve if there are still dinosaurs. No mammal could get big enough, smart enough and walk the open plains.
Which could be yet another super rare variable to the Drake Equation on how likely there is to be intelligent life out there. If most planets develop giant but not super-bright apex predators, and no intelligent creatures can get a foothold to evolve, then maybe intelligent life needs an extinction-level event of just the right size at just the right time. Big enough to wipe out the dominant species, but not too huge so as to wipe out little mouse-like creatures that survive by hiding and getting by on their wits.
But one could argue that it doesn't require a T-Rex to kill a human. An average-sized sabertooth tiger could do it at 1/20th of the size. A T-Rex probably wouldn't even mess with a little Lucy creature running around. So I think we could co-exist with dinosaurs unless they had something smaller and more voracious than a giant feline that liked to snack on 60-pound proto-people. Maybe they did. I'm not up to date on dinosaurs these days.
The Drake thing is interesting. But I wonder how common the model is where smart creatures are preceded by big not-so-smart creatures. It seems like that would be one of many different possible models. [Reply]
Originally Posted by ThaVirus:
Human evolution is pretty interesting as well considering there have been a few different versions of 'humans', depending on how lax your definition of human is.
I think by most standards, you'd have to consider Neanderthals and Denisovans as human. Then you've got quite a few lesser known archaic humans as well.
The homo genus (is it genus?) has only been around for like 2 million years, which is nothing on the geological scale. At this point, every other homo group has gone extinct in just that short amount of time. Were just that unfit or are sapient just that fit to drive them all to extinction?
Good point. It also makes me wonder if there are a million dinosaur variations that we don't know about because we haven't found their bones. Maybe for every dinosaur we've labeled there are a hundred more that came and went like the dinosaur version of the Denisovans. It seems like people find dinosaur bones all the time, but at the same time it also seems like the total volume of dinosaur bones is not particularly huge. [Reply]
From what I’ve seen on Captain Caveman cartoons, he was a badass who would have single-handedly wiped out any remaining dinosaurs. Based upon that undeniable fact alone, I vote for man over Dino. [Reply]
Originally Posted by Peter Gibbons:
From what I’ve seen on Captain Caveman cartoons, he was a badass who would have single-handedly wiped out any remaining dinosaurs. Based upon that undeniable fact alone, I vote for man over Dino.
Don't sleep on the Shmoo, if they were at odds I think the Shmoo would take the cave man. [Reply]
Our species hoarded toilet paper to fight off the last mass extinction event, so I don’t feel too optimistic that cavemen would have survived a planet full of dinosaurs. [Reply]
I mean it's a little speculative because it's hard to know what could have wiped them out if not for an asteroid. There's all kinds of animals that have gone extinct since the last mass extinction like multi-toed horses.
Birds are the descendants of one branch of dinosaurs (theropods). Lots of human like primates went extinct but yeah the descendants of dinosaurs would be a lot more of the biodiversity on earth most likely.
I had a book in elementary school which speculated that maybe one branch of dinosaurs would have evolved intelligence and walking upright so instead of primate like humans we would be lizard or bird like [Reply]
Originally Posted by scho63:
The crazy thing about dinosaurs is if you believe in evolution, where did they evolve from and how did they get so ****ing big?
Dinosaurs evolved from earlier tetrapods most of whom where mostly wiped out several times
Why they got so big is a good question. Why aren't animals huge anymore? Big mammals died out millennia ago and it's not because humans hunted them to extinction. Some of it was climate related. Before the dinosaurs, insects ruled the planet and they got enormous because the oxygen concentration in air was much higher than today so their bodies could handle larger sizes [Reply]
The extinction of the dinosaurs gave an opportunity for small rodent like mammals to find their place in the world and that led to the rise of mammals. I don’t think dinosaurs and people would’ve ever co-existed. Without an asteroid, likely they would have gona extinct in an ive age, volcanic winter, etc. [Reply]