Difficulty: Easy | Games: Creatures 1, Creatures 2, and Creatures 3/Docking Station
Anna Log: The genetics team was locked away for quite some time! As we finally step back into the light for another genetics lesson, make sure to brush up on the concepts from our first and second lessons. One of the most extensive genes, and one that can sometimes be misunderstood, is the one which defines half-lives. Today, we examine the following question: What is a half-life, and how does this factor into Creatures? Continue on for the answer!
Part I: Understanding a Half-Life
The concept of a half-life is not exclusive to Creatures: It exists in many scientific and mathematical lessons. Generally speaking, a half-life describes the length of time required for a chemical to reach half of its original value. For example, if a chemical begins with a value of 100, its half-life would define the time needed for that chemical to fall to a value of 50. At that point, it would take approximately the same length of time for the chemical to decrease to a value of 25, and so on. In the world of Creatures, once a chemical enters a Norn’s system, that chemical should either be used up through chemical reactions, or begin to decay (defined by its half-life).
There is a very important distinction between C1/C2 and C3/DS when it comes to half-lives. In Creatures 1 and Creatures 2, half-lives are more akin to full-lives: The value defines how long it will take the chemical to reach a value of zero. In Creatures 3 and Docking Station, half-lives follow with their original definition, where the value defines the time needed for a chemical to reach half of its original value. Make sure to remember this major difference!
Part II: Locating the Half-Lives Gene
For those who have taken a moment to examine a genome with the Genetics Kit, the number of genes can seem rather intimidating! Some genes might appear to be written in another language, while the relationship between others remains unclear. When it comes to figuring out the half-life of each chemical, though, the location of these definitions resides in one sole gene. This makes some tasks a little more difficult, but if every half-life had its own gene, a genome would be enormous! Take a look at the following screenshots to locate the half-lives gene.
Creatures 1 Genetics Kit Screenshot: Gene #001
Creatures 2 Genetics Kit Screenshot: Gene #468
Creatures 3 Genetics Kit Screenshot: Gene #0026
Denny D. Rite: Make sure to sort the genes by the first column (#) if you are having difficulty locating the gene. The Genetics Kit allows genes to be sorted by different methods, but when you’re trying to find one gene, it can be like searching for a needle in a haystack! Similar genes are typically not listed in numerical order in a genome. Chemicals within the half-lives gene are listed in order, based on their chemical numbers. No alphabetical option, unfortunately!
Part III: Half-Life Values and Times
When the half-lives gene is opened up with the Genetics Kit, every individual chemical has a value associated with it. The slider at the bottom helps to distinguish how values range from extremely slow (left-side) to instantly (right-side). However, this does not state the length of time associated with each half-life. Those familiar with the Genetics Kit may know that choosing a new value will bring up information at the bottom of the main Genetics Kit window. This can still be time-consuming, as one must constantly change the value in order to reach the desired time. For this reason, a handy chart is presented below to compare the half-life values and times between C1/C2 and C3/DS. These values are the only valid options in the C1 and C2 Genetics Kits. Other values are possible via mutations, but opening a genomes in the Genetics Kit will round a mutated value to the nearest valid value.
Please also note that in the Creatures 3 Genetics Kit, every integer may be chosen. To keep this chart from getting out of hand, only the valid values from Creatures 1 and Creatures 2 have been included. Also take note of the differences between the times, and the fact that the C1/C2 time represents the approximate total time needed for a chemical to completely dissipate from a Creature’s system. The C3/DS time represents the approximate time needed for a chemical to reach half of its initial concentration. Very important distinctions!
Part IV: The Role of a Half-Life
Now that we know the basic concept behind the half-lives gene and where to locate it in a genome, the more important question comes down to its purposes in Creatures. Perhaps the simplest example we can use is the aging (C1) or life (C2 and C3/DS) chemical. When a Norn, Grendel, or Ettin is born, he or she begins with an initial concentration of either the aging or life chemical. Generally speaking, there are no methods to increase this chemical: It can only decrease, or decay, over time.
In Creatures 1, the half-life of the aging chemical is set at 136. From the above chart, this translates into a time period of approximately 10 hours. Remember, though, that this is more like a full-life: The aging chemical should be at a value of zero after that time period. With the correct “die of old age” gene is in place, this half-life helps determine the life span of a Norn, Grendel, or Ettin. A similar example also exists in the other games. To understand half-lives better, though, other genes must be taken into consideration.
Chemical half-lives are most important when looking at chemical reactions. We will be taking a look at these genes separately in the future, but consider the following chemical reaction:
1*Water + 1*Air = 3*Oxygen
Imagine that this chemical reaction happens every 5 seconds. Without half-lives, the water and air stored in between the chemical reaction would immediately leave the Creature’s system and be unusable. Think about this in another way: When a Norn takes a deep breath, is all of the air instantaneously transformed into oxygen, or does some of it linger (even for a fraction of a second)? That’s the idea behind a half-life! The half-life defines how long it will take any unused chemical to reach a concentration of zero.
Emmi Ter: A Creature’s body and organs are constantly in motion on a chemical level, but that doesn’t mean chemical reactions happen at every single moment. Half-lives are essential to sustaining life!
Emmit Ter: Quite right! A Norn would end up perishing if certain chemicals could not linger in the body for at least a short period of time. Digestion, respiration, and even reproduction would be virtually impossible.
Part V: Extended Learning
Examine the half-lives of different chemicals and try to understand why some chemicals are short-lived, while others are long-lived. Some of the learning chemicals, like ConASH and DecASH1, are extremely short-lived. Why should chemicals associated with learning exit a Creature’s system almost immediately if they are not used up in a reaction? Also try to think of some other examples where half-lives would be useful. What would happen if long-term energy storage (glycogen) had a very short half-life? Dive into the Genetics Kit to get familiar with this idea: We will definitely be returning to it in the future, especially when we learn more about chemical reactions!