Modern oceans, for comparison, max out at trophic level five or six, represented by apex predators like orcas, sperm whales, ...

The earliest known reptile, Hylonomus, was lizard-like and lived about 315 million years ago in what is now Canada. These early reptiles often shared characteristics in the morphology of their ...

There is little room for expansion under the solid dermal shield. This limited the size of the muscle. Very early in reptile history, changes to ancestral condition occurred in the nature of muscle ...

The earliest known reptile, Hylonomus, was lizard-like and lived about 315 million years ago in what is now Canada. These early reptiles often shared characteristics in the morphology of their ...

The earliest known reptile, Hylonomus, was lizard-like and lived about 315 million years ago in what is now Canada. These early reptiles often shared characteristics in the morphology of their ...

As these early reptiles adapted to new lifestyles, their legs became increasingly unnecessary. In environments like burrows, where movement was limited by tight spaces, legs were not as useful.