Yeerks: first host?

[Darth Zakryn]

Ok, how did the first Yeerks infest the Gedds on their home world, thereby discovering their ability to subjugate other minds? My theory is that one day, the Gedds went swimming in a pool and an ambitious Yeerk (perhaps seeking adventure) entered the Gedd's ear. Or something. I don't know, this theory seems kind of weak to me, and I created it. Does anyone else have any reasonable theories?

[cams]

Is it possible for nature to slowly (a few million years) give the Yeerks the ability for mind control through evolution while the Yeerks themselves didn't realize it?

[NateSean]

I think your theory is as good as any Zakryn.

Either the Gedds tripped and fell in the water, or they went for a swim and caught a parasite the way we sometimes get leeches if we go into swampwater. It's a chicken and the egg scenario.

[DinosaurNothlit]

Well, the way I see it, the Yeerks and the Gedds would have had to evolve together.  The Yeerks could not have evolved the ability to control minds without having minds to control during the process, and the Gedds could not have evolved to be the barely-conscious creatures that they were without something controlling them.

The way I see it, their relationship is actually advantageous for both species, at least from a purely evolutionary standpoint.  The Yeerks get large, mobile bodies to control, whereas the Gedds get the benefit of the Yeerk's intelligence without having to evolve brains of their own.

So maybe at first, the Yeerks have the ability to control only a few basic motor functions.  Maybe they start by latching onto the outside of the skull and just poke the Gedd in the direction the Yeerk wants it to go, more like steering a horse than mind-control.  Then, as Gedds and Yeerks both become more and more dependent upon one another, the Yeerks get better and better at "steering" the Gedds, eventually entering the brain itself.  And the rest is history.

[Myitt]

It's also mentioned in The Capture that the Yeerks had evolved to infest a number of other hosts before the Gedds, throughout their planet's evolutionary history...so it isn't such a big step to go from infesting one type of brain to another.  Perhaps deep in Yeerk evolutionary history, though, some of these types of things started to happen with the first Yeerk hosts; at that point probably only a few groups of Yeerks (they do appear to evolve in relatively isolated pools) had evolved the ability to attach their neurons to other creatures' neurons.  Maybe back then there were creatures that had their brains on the outside of their bodies, and the Yeerks provided an extra layer of protection as well as control?

[Chad32]

There are creatures that have the ability to control their hosts right here on Earth. I'm thinking the Yeerks probably had that ability with the Gedds before they developed sentience.

[Phoenix004]

I'm not normally a fan of "the Ellimist did it" as an explanation but perhaps Crayak was somehow involved in influencing Yeerk evolution? They were at least a part of his plans after all.

[TobiasMasonPark]

     There is an excellent mock-essay on the history of Yeerk-Gedd relationships. The second chapter is an Appendix focusing on the Vanarx. It's on Fanfiction.net.

     Also, I never considered Crayak as the sort who plans things out.

[Dogman15]

I know you guys are going to hate this, but what if the Yeerks were created with the ability to control minds? For a long time in their early history, they just stayed in the pool. One day a Gedd fell into the pool by accident and a Yeerk crawled inside. He grabbed a Yeerk in the pool and put it in another Gedd, and so on.

I'm almost certain that the "A Gedd fell in one day" story is mentioned as canon somewhere in the series. If that's not true, and I only read that idea in a fan fiction, then I must be going crazy.

[Terenia]

I think it was mentioned as a joke at one point.

I forgot about the part where Yeerks had evolved to infest other species prior to the Gedd. It makes sense, to me, that the Yeerks initially infested aquatic species. They wouldn't have to worry about leaving their pools and there would be some sort of mutual advantage. Then, as the life on the world evolved, amphibious creatures came into being and the voila - the Yeerks can visit land, eventually transferring to the Gedds. Perhaps eventually the other species they had infested died off, or maybe they still exist but are seen as unfit for hosts out of arrogance. Or maybe they are used as "trainer hosts" for young Yeerks.

[Morilore]

It's also mentioned in The Capture that the Yeerks had evolved to infest a number of other hosts before the Gedds, throughout their planet's evolutionary history...so it isn't such a big step to go from infesting one type of brain to another.  Perhaps deep in Yeerk evolutionary history, though, some of these types of things started to happen with the first Yeerk hosts; at that point probably only a few groups of Yeerks (they do appear to evolve in relatively isolated pools) had evolved the ability to attach their neurons to other creatures' neurons.  Maybe back then there were creatures that had their brains on the outside of their bodies, and the Yeerks provided an extra layer of protection as well as control?

I agree with this idea.  The Yeerks probably belong to a large clade of aquatic organisms that, through accident of history, have exposure to their brains on the surface of their bodies.  At some point some proto-yeerkoid mutation gave some of those creatures the ability to interact with each others' brains; this would prove advantageous if, say, the Yeerks had an aquatic predator that one of their relatives had the ability to fight off.  The more powerful a creature they were able to control, the better off their lineage would be.

Going from that to "physically squeeze themselves into a land-dweller's braincase" would seem quite a formidable development, but that was always the craziest part of the idea of the Yeerk organism. (How does the Yeerk not destroy the human cochlear nerve? There's no open hole between the ear canal and the brain!)  At some point one just has to suspend disbelief.

I'm almost certain the "Gedd fell into the pool" idea is from that Catholic missionary fanfic, and even there it is presented more like an origin story than an actual history.  If that were the canon explanation, it would be incredibly stupid: sophisticated evolutionary abilities like infestation would have to be are developed from more primitive abilities; if a Yeerk could infest a Gedd then its ancestors would have to be able to infest something similar to a Gedd.

[Myitt]

Well technically, maybe, a Yeerk could find its way along the auditory canal, following the auditory nerve to the brain...but still!  Quite a jump.  Thanks for the support, as a biologist I really favor the idea of having some kind of advantage to such an adaptation (whether Crayak created it or not!)

[Dogman15]

Morilore, you say "that Catholic missionary fanfic," but that gives me the idea that you're not that fond of that story. It's not like the author was trying to force his viewpoint down your throat. 

The way I see it, regardless of your religious beliefs (or lack of), that story is so believable within the Animorphs universe that anyone (that knows Animorphs) can enjoy it.

http://www.fanfiction.net/s/3464631/1/Sacred_Host
It was even recommended here:
http://tvtropes.org/pmwiki/pmwiki.php/FanficRecs/Animorphs

[Morilore]

<snip>

There's no need for defensiveness.  I chose that term because those were the first two words that came to mind.  I will say that you are right, I did not enjoy what I read, but I don't want to hijack the thread to argue about it and I don't think anyone's fanfic tastes should bother anyone else.

EDIT: Just to make it clear, I was not accusing the author of the story of being an idiot in my previous post.  From what I recall, the Gedd-fall-into-pool idea was presented as being legendary, which is all well and good.

[Darth Zakryn]

TobiasMasonPark: Link, please?

I agree with your theory, Terenia, but what aquatic organisms could also live in the Yeerk pools?