Co-evolution is the process by which two species simultaneous exert selective pressure on each other, termed “reciprocal evolutionary adaptations”. Flowers and bees are a good example of mutualism, wherein the shared selective pressure results in a tangible advantage for both species (the flowers get improved pollen dispersion, the bees get the raw ingredients for honey).

Co-evolution can be less synergistic—predators and prey co-evolve, too. When natural selection leads to a cheetah adding on a few more kilometers/hour, the antelope, with a different architecture, can’t keep pace, and so if it is to survive, selection may lead it in a different direction. Thus, the ability to stop and/or change direction on a dime.

Co-evolution also includes the interaction between a host and a parasite. Think of a virus which kills its host every time. In order for it to find another host to support its progeny, there is selective pressure for it to let its host survive. Over time, then, it is selected to become less virulent to its host, and a more stable host-parasite relationship ensues. Such a long-term relationship is analogous to that between the oak and the mistletoe, or that between Dilbert and the Pointy-Haired Boss (http://www.shatteredmoonlight.net/phb/). It is important for the host (oak, Dilbert) to survive so that the parasite (mistletoe, Pointy-Haired Boss) doesn’t perish looking for another victim.

The examples above focus on paired co-evolution. However, in some sense, all species are co-evolving, and so co-evolution can be extended to sets of three, four or more species, interacting and significantly affecting each other. When three or more species are considered together, the situation is termed "diffuse co-evolution".

Co-evolutionary terms can be applied to arenas outside of evolutionary biology. For example, the size of car seats (to accommodate the size of people’s hind quarters) has co-evolved with the size of drink cup holders in the same cars.

1. Mutual benefit to each species involved.

3. Collaborative (multiple species often providing complementary and/or redundant capabilities--this may even be applied to humans and dogs).

In brand protection, the complementary use of RFID and security printing can create a co-evolutionary situation. RFID should be used for shipping and tracking big items, and in other situations in which “line of sight” reading is not possible or tractable. Security printing should be used for smaller items, where “line of sight” reading is possible, and where RFID costs preclude their use. RFID and security printing, therefore, can complement each other for supply chain visibility, product tracking, security and authentication. They are mutually beneficial—RFID helping in workflows for which interrogating printed information is too costly, and security printing helping in workflows for which the item cost of RFID is too costly.

RFID and security printing are also free to adapt. For example, if RFID is someday efficiently and inexpensively printed, security printing may subsume the RFID process and the two will more closely combine. On the other hand, if next-generation printing technologies subsume more and more manufacturing processes—power, sensors, displays among them—a strong partnership between printing and manufacturing (as well as RFID) may create a new type of “diffuse co-evolution”. It will be exciting to see what the market selects for as technology moves inevitably forward.

-Steve