Ectoderm

Real World Example

Imagine you're redecorating a room, starting with the walls which form the outermost part of the space. Similarly, in the development of most animals, the ectoderm is like the "wallpaper" of the embryo, forming the outer layer called the gastrula. Just as the wallpaper sets the tone for the room's design and is the first thing people notice, the ectoderm develops into the outermost structures of the body, like skin and the nervous system, providing the initial foundation for an organism's external appearance and protection.