But who's to say what's up the tree and what's down?
That "mamms on a T. rex" thing you clammed up on: the point was that things don't move down the tree or from branch to branch.
That's the theory and that's one of the problems I have with it. It seems arbitrary. Consider the article. It notes how some say Old World and New World bats evolved independently. Or consider Gore3Ks point that we don't really know for certain if the some of the dinosaurs low on the tree didn't have teats. If survivability were the goal why would we have even gone beyond bacteria or algae?
That's why evolution says there are things that should not be found. Three ear bones in a salamander. Human bones down among the trilobites. Lots of things, but it's getting pretty late for them to turn up.
Palentology has been around for about 200 or so years. Consider some of the archaeological discoveries that have recently been made. It was long thought that Troy was a myth.
What's up your family tree and what's down? Can you inherit from your cousins? If you're modeling evolution, the tree is a real descent tree. If you're modeling anything else, it's just a coincidence the data fits evolution.
Yes. In the absence of data, you're left to wonder. There's no fossil record and the two kinds of bats are very different under the skin. It's going be hard to say until there's more to go on. But that's not the case all over, just with bats.
Or consider Gore3Ks point that we don't really know for certain if the some of the dinosaurs low on the tree didn't have teats.
Very telling that you still don't get it. Dinosaurs are just one line of reptiles, a group within the diapsids (two extra skull holes), which include birds and true lizards.
Here's the problem: The ancestors of mammals branched off the reptilian trunk way far back before the diapsids, much less the dinos, were a distinct branch. That's what I mean when I say you don't inherit from your cousins. By the time the ancestors of mammals were becoming mammals, the dinos were on a very different branch. How do the mammaries get across the tree?
If survivability were the goal why would we have even gone beyond bacteria or algae?
The only goal is survivability right now. What works, works, but just for right now. Multicellularity can work better for some species, some times. We still have examples of animals like slime molds, Volvox, and others which are only barely or only part-time multicellular.
More than one thing can work at the same time. Being a cyanobacterium has worked continuously for a long time, but perhaps not everywhere at once. Just always somewhere.