biology azoology blog organs teeth growth allometry

Give a Little – and Take a Little

Increases of some structures appear to parallel decreases in others

It seems odd, but no animal with horns or antlers, whether fossil or recent, has all the teeth required to give it the complete and full dentition characteristics of mammals. No species of spider is known to possess the ability to sting, but all have a poisonous bite (although, luckily only a few possess poisons potent enough to harm humans). The most colourful birds like tropical parrots and Papua New Guinea birds-of-paradise leave a lot to be desired when it comes to their ability to sing and the increase in swim speeds of fish like the tuna apparently went hand in hand with the loss of the buoyancy organ, the swim bladder. There are lots more of such examples, but what am I trying to demonstrate with these examples? I’m trying to show that the development in one area frequently has consequences in another and that a “push” in one evolutionary direction can see a reversal in another. —>—>