Hacker News Reader

Comment by gattr | Hacker News Reader

I remember reading somewhere that the Tierra ecosystem/evolutionary simulation ([1]) readily produced such higher-order parasites of parasites.

[1] https://en.wikipedia.org/wiki/Tierra_(computer_simulation)

View on HN

Interesting. From what I remember, the parasites that evolved in Tierra resembled viruses. Tierra had a downward-pressure on organism size (the bigger you are, the longer it takes to make a copy of yourself), so organisms evolved that jettisoned their own replication mechanism and relied on pirating the mechanism of another. I wonder what the advantage of being a parasite of a parasite is in that environment.

The hyperparasites in Tierra are strictly speaking not parasites of parasites, rather they’re host "species" that evolved a resistance against some parasite types and, critically, a trick that causes the parasite to actually make a copy of its host when it tries to copy itself using the host’s replication code. So essentially the hyperparasite steals the parasite’s CPU time and still has its own timeslice left to replicate itself.

The whole thing relies on the fact that the Tierra "organisms" live in a flat memory space where you can jump anywhere, including into the middle of other individuals, and just merrily keep executing code from that point. I wonder if something like that was possible in the (hypothetical) RNA world, before cell membranes developed, but I don’t think cell-based life can have a precise equivalent of Tierra hyperparasites. The closest analogue is probably mutualistic relationships that have evolved from parasitic ones.

Reply on news.ycombinator.com