Embryo Evolution

A strange thing related to Embryos is that some organisms begin development looking like other species.

Examples

• Why do Mammals form their heads and faces from the very same embryonic structures that become the gills of fish?
• Why do vertebrate embryos go through such a contorted sequence of changes in the circulatory system

Answers

Each vertebrate undergoes development in a series of stages, and the sequence of those stages happens to follow the evolutionary sequence of its ancestors.

So, for example, a lizard begins development resembling an embryonic fish, then somewhat later an embryonic amphibian, and finally an embryonic reptile.

Mammals go through the same sequence, but add on the final stage of an embryonic mammal.

As one species evolves into another, the descendant inherits the developmental program of its ancestor: that is, all the genes that form ancestral structures. And development is a very conservative process.

META

Status:: #wiki/notes/mature
Plantations:: Evolution
References:: Why Evolution Is True