It's really the "rule the Earth" idea that is problematic here; I guess most folks sort of connects "apex predator in the animal kingdom" to "aristocracy in human kingdoms"... or maybe some out-dated notion of "a great chain of being" is at play. I hesitate to even call it unscientific, since it is just too vague.
I think the trope owes a lot to the days when a museum had only a few prize fossils to show, and a simple and neat succession seemed like a good idea to present the exhibits and enthuse visitors, who still had to be convinced (as remains true today) that evolution actually happened.
Here is a restricted sense of "ruling" that is biologically meaningful: when ecological niches become available, we can see an adaptive radiation occurring within a fairly small clade. That clade... rules, man! So it's the Age of the Finches on the Galapagos islands, and the Age of the Fruitfly in the Hawaii archipelago. Other examples abound.
The connection with the great paleontological epochs is that they are separated by mass extinctions, which of course are the very reason we say e.g. the Permian ends here etc. Now, mass extinctions are typically followed by a slew of adaptive radiations. A nice example is the crocodilians, which attained a huge variety of body sizes, shapes, and ecological roles, with some looking a lot like dinosaurs. Only... the dinosaurs came later, after these early crocodilian species had been eliminated by a mass extinction. But that does not make present-day crocodiles losers, or lone throwbacks hanging on for scraps.
It's really the "rule the Earth" idea that is problematic here; I guess most folks sort of connects "apex predator in the animal kingdom" to "aristocracy in human kingdoms"... or maybe some out-dated notion of "a great chain of being" is at play. I hesitate to even call it unscientific, since it is just too vague.
I think the trope owes a lot to the days when a museum had only a few prize fossils to show, and a simple and neat succession seemed like a good idea to present the exhibits and enthuse visitors, who still had to be convinced (as remains true today) that evolution actually happened.
Here is a restricted sense of "ruling" that is biologically meaningful: when ecological niches become available, we can see an adaptive radiation occurring within a fairly small clade. That clade... rules, man! So it's the Age of the Finches on the Galapagos islands, and the Age of the Fruitfly in the Hawaii archipelago. Other examples abound.
The connection with the great paleontological epochs is that they are separated by mass extinctions, which of course are the very reason we say e.g. the Permian ends here etc. Now, mass extinctions are typically followed by a slew of adaptive radiations. A nice example is the crocodilians, which attained a huge variety of body sizes, shapes, and ecological roles, with some looking a lot like dinosaurs. Only... the dinosaurs came later, after these early crocodilian species had been eliminated by a mass extinction. But that does not make present-day crocodiles losers, or lone throwbacks hanging on for scraps.