Saturday, May 26, 2012

You'd think Evolution would weed that out

I was driving home today when I saw one of these guys:

An arrogant Killdeer is standing here.


"By Thor's Beard!", I bellowed. I haven't seen one of these in ages. You see, when I was a minurature, we had these frolicking around on our property as I was growing up. They are peculiar creatures. They spend most of their time running around on the ground. They can fly, but they seem to prefer walking. They seem to collect into herds, and if you walk around after them, they'll just walk away from you. 

If, however, they have younglings, and you're walking towards them, they start to do this:

This Killdeer is behaving oddly

It's called the "broken wing act".  The parent will position itself between you and the children, strike this odd pose, and start squawking.  The Killdeer essentially tries to be a decoy - sacrificing itself (or potentially so) to save the young.

It's essentially a basic version of altruism.

Chipmunks

Derp Chipmunk
Look at this jerk
Before I continue about Killdeer, let me introduce you to a more common creature - the Chipmunk.

Many of these tetrapods live around my house and my general area. They appear to scatter into a fairly even distribution across the terrain. Chipmunks are fairly territorial, and unless they're young, or having hardcore chipmunk sex, they generally don't get along with one another.

There is one thing these bastions of fur do that is somewhat peculiar - they squeak. 

It's not just squeaking. If you try to walk up to one, it'll first attempt the "Deer in the headlights" maneuver, but if you get too close, the "Squeak alarmingly like an idiot and run away" protocol is engaged.

One would think that the best thing to do would be to silently slip away. Instead, they transform into boneheads and make a scene.

Shouldn't that behavior be weeded out by evolution? After all, the chipmunk in question has just alerted all predators within a 100 foot radius that it exists, and how to pinpoint it. Hypothetically, those chipmunks that do this would be more likely to be killed, and that behavioral trait would fade away from the gene pool.

Evolution of a Group

I am flipping through my rolodex of misconceptions of evolution. Ah, here it is!

Many people understand evolution does act on individuals, in terms of survival due to harmful or beneficial traits, but most don't appear to be aware that it also acts on a group as a whole.

While that chirping chipmunk may have reduced its own chances of survival, it does have a benefit to the fellow chipmunks who are nearby - as an alarm system. It's sort of like a neighborhood watch. While the alertee may be worse off, the other chipmunks are now aware a potential predator is nearby.

This behavior can evolve in a gene pool as a whole. Since they all share that gene pool, they all benefit mutally from it.  That same chipmunk who went off the deep end, at the sight of my walking towards it, has been aided by that instinct countless times.

They're not a social species, but it's a similar element to what makes a social species more likely to survive - having one member help another. Basic evolution works by selecting for those traits of a creature that have helped it survive to reproduction, and pass those genes along. If, however, those traits are mutually shared, it operates in the same fashion.

The First Mover of Traits

Chipmunk staring at me
I'm totally being checked out
The problem with shared group traits is that they need a "first mover" - something to start the behavior within the whole group.

Sometimes, I sit outside with a pile of seeds in front of me that I've placed repeatedly in the same spot previously. I want to lure the bastard in so I can take some close-up photos. What will happen for the first 10 to 20 minutes is that the chipmunk will sit at a safe distance from me and start chirping at me - over and over.

He's trying to provoke a response. If I respond and move, then I'm likely a dangerous predator. If not, and I hold still, especially after awhile, I may be safe to approach.

This approach of "testing the waters" can be a direct beneficial trait that evolution can select for, and not necessarily a group trait. It can then spread through the group as a beneficial trait, so they all start testing unknown objects before approaching.

This has the secondary effect for surrounding chipmunks of alerting them that there's potentially a problem. I've seen the reaction. When another chipmunk starts chirping in the distance, the one I'm observing will perk up and look around.

It's a transform of function, as it were. As an aside, this is how the hypothesis about "Irreducible Complexity" fails - it ignores the possibility of traits switching functional roles.

Back to the Killdeer

The "broken wing act" may or may not have had a similar starting point, but it's effect is the same - mutual benefit for the group. 

Not only would evolution not weed out this behavior - it would likely be enhanced. The existence of the behavior increases the chances of survival to reproduction by all the gene pool participants. If a local group of a species dies out, so does their specific traits. It's just to be expected that the surviving groups of a particular species today would have the traits that helped them, as a group, to survive.

On another note, one could even make an argument about the natural emergence of homosexuality within the human and animal populations - that it may play a role in the health of the group, for population control or other issues.

It's difficult enough to discuss evolution because there's so many misconceptions and misrepresentations about the topic. Educating these same people about the nuances of the theory can be even more frustrating, especially when they utilize their void of understanding as a basis for launching attacks.

Who knows, maybe they're just putting on a pathetic looking act to distract us from something else...

Soon.


No comments:

Post a Comment