Organ

Organs were introduced in Creatures 2.

They, like in real creatures, work together to ensure the creatures survival. Certain organs, like the heart, lungs, brain, and various support organs, are essential for life in the default genome. If any of these organs stop functioning it can cause death!

Organs all have certain chemical reactions that occur within them, for example, 1 water + 1 nothing = 1 hotness decrease + 1 nothing. This is the reaction for sweating and takes place in the skin organ. If the skin organ were to stop functioning the temperature of the creature would rise.

Organs have life forces and clock rates. The clock rate is how fast the reactions are taking place in that organ while the lifeforce is the health of the organ. Organ lifeforce naturally decays over time as the creature ages, but certain chemicals (Antigens, Lactate, heavy metals) can cause the lifeforce of certain organs to deteriorate faster. Another major lifeforce killer is ATP deficiency, causing all organs to deteriorate very quickly. As of C2, each organ comes with a certain ATP cost, and if an organ does not have enough ATP it loses lifeforce until its needs are met.source

The brain decreases to low lifeforce in seconds.

Organs naturally become less functional over the lifespan of the creature - this is controlled by a setting called 'organ vulnerability'.source