The intricate features of his long, smooth shell, or carapace, identify him as K.cushmani. His carapace hid and protected his delicate body – like a shrimp stuffed inside a clam shell – as he propelled himself with scrabbling legs toward the bacteria he fed on. Around him swam hundreds of other ostracods, just like him, though the females were slightly fatter. Unbeknownst to our K. cushmani, this gender difference in body shape – known as sexual dimorphism – marked him and his kind for failure.The usual Tedx logic. Evolution is random mutation selected by energy cost.
It turns out that sexual dimorphism correlates extremely well with increased extinction rate, with more than 99 percent of models correlating the two. But it’s not sexual dimorphism itself that’s the problem – it’s the type of sexual dimorphism. Only where males were larger or more elongate than females was the extinction rate higher. In living ostracods, larger or more elongate male carapaces are used to house larger sex organs. So by analogy, for the fossil species, males that invested more resources in reproduction did so at significant evolutionary cost.
The current icon shows Polistra using a Personal Equation Machine.