Hatchery

"The Hatchery is the heart of any Zerg colony. It spontaneously generates larva, which in turn are used to spawn your various warriors and minions."

- Daggoth

The Hatchery is the foundational building for every Zerg colony.

Overview
Hatcheries perform three vital functions that no colony can survive without: producing the Creep, which all Zerg structures require in order to be built, giving birth to Larvae that can mutate into the various Zerg breeds and digesting Minerals and Vespene gas to change into a nutrient form that Zerg can use to feed their mutations. In addition, the Hatchery, (except for the Extractor) is one of the only structures that can be built without pre-existing Creep and is therefore essential for any expansion attempt.

StarCraft
The Hatchery can mutate into a Lair, and later into a Hive.

Research
It can research the Burrow upgrade.

StarCraft II
The Zerg continue to use Hatcheries in StarCraft II. Two rally points are able to be set on a Hatchery; one for Drones and another for warrior units.

The Hatchery can evolve into a Lair.

Upgrades
It can research the Overseer's Slime ability.