Typically, animal skin appendages including hair, feathers, and scales are controlled by specific genes when an embryo is developing. There are some exceptions to this rule–including in crocodile ...

How can we explain the morphological diversity of living organisms? Although genetics is the answer that typically springs to mind, it is not the only explanation. By combining observations of ...

What do the earliest stages of a pregnancy look like? Embryonic development has been extensively studied, but most of our knowledge of the earliest stages of a growing baby come from stationary ...

The earliest days after fertilization, once a sperm cell meets an egg, are shrouded in scientific mystery. The process of how a humble single cell becomes an organism fascinates scientists across ...

Descriptions of the embryo go back at least to the time of Aristotle, but it has only been since the late 19 th century and early 20 th century that advances in experimental approaches allowed ...