Macroevolutionary ratchet:
The team found some other evolutionary surprises as well. First, saber-toothed species seemed to show faster changes to skull and jaw shapes earlier in their evolutionary history than species with shorter canines — essentially a “recipe” for evolving into saber-toothed feline-like predators, Chatar said in a statement.
The research group also hypothesizes that the “over-specialization” of saber teeth more rapidly led groups with that feature to extinction.
This theory is called a macroevolutionary ratchet. “This phenomenon has been proposed as a potential driver of decline, wherein evolution favors the loss of early generalized forms, leading to the emergence of more specialized, yet more vulnerable, forms later in the history of the lineage,” Chatar says. [“Saber Teeth are as Mysterious Evolutionarily as They are Iconic Visually,” Paul Smaglik, Discover (paywall)]
I wonder if cheetahs are an example of this phenomenon; humans are rather the opposite.
