Why dont humans grow after some age?
Mammals have determinate growth. This means that they will reach a certain size and stop growing. Reptiles and many other vertebrates have indeterminate growth. Although growth slows down with age, it continues throughout their lives. The story of the evolution of determinate growth really takes place in the ancestors of all mammals. So the human story is really just a throwback to that. It’s possible that it may relate to the evolution of endothermy (warm-bloodedness) and related changes involving higher metabolism and fueling that metabolism. Mammals are a bit more precise a machine than reptiles in many ways. We have complex teeth that need to fit together properly if they are to work. The molars, premolars, canines, and incisors are quite a bit more advanced than the pointy teeth of reptiles. With a final set of permanent teeth (particularly molars and premolars), chewing happens efficiently only when things fit together properly. Evolution plays an important role in this, but it w
