Tsunami/Animals

[skeptigirl]

Well I found a very thorough and well written report.

Unusual Animal Behavior Before Earthquakes:
A Review of Possible Sensory Mechanisms
RUTH E. BUSKIRK[1], CLIFF FROHLICH, AND GARY V. LATHAM

The authors go through a wide variety of potential phenomena animals might sense and compare the phenomena to species' abilities to detect such events. This part I agree with everyone on and have no doubt, for example, an elephant senses ground vibrations too small for a human to sense without a mechanical device.

But what I am saying is also supported by these researchers.

Investigators familiar with the full range of behavior for a species will often recognize that reported 'abnormal' behavior is actually species-typical behavior which may be triggered by a variety of stimuli [Moore and Stuttard, 1979] not necessarily related to earthquakes.

Here's a more reader friendly article.
Can Animals Sense Earthquakes?
Maryann Mott
for National Geographic News
November 11, 2003

In the 1970s, a few studies on animal prediction were done by the USGS "but nothing concrete came out of it,"

There have also been examples where authorities have forecast successfully a major earthquake, based in part on the observation of the strange antics of animals. For example, in 1975 Chinese officials ordered the evacuation of Haicheng, a city with one million people, just days before a 7.3-magnitude quake. Only a small portion of the population was hurt or killed. If the city had not been evacuated, it is estimated that the number of fatalities and injuries could have exceeded 150,000.

The Haicheng incident is what gave people hope that earthquakes might be predictable, says Michael, and what prompted the animal behavior studies by the USGS.

It was later discovered, though, that a rare series of small tremors, called foreshocks, occurred before the large quake hit the city.

"It was the foreshock sequence that gave (Chinese officials) the solid prediction," Michael said.

And this is a reliable site I am familiar with, Biology-About.com

Other researchers are skeptical about using animals as earthquake and natural disaster detectors. They site the difficulty of developing a controlled study that can connect a specific animal behavior with an earthquake occurrence. The United States Geological Survey (USGS) officially states: *Changes in animal behavior cannot be used to predict earthquakes. Even though there have been documented cases of unusual animal behavior prior to earthquakes, a reproducible connection between a specific behavior and the occurrence of an earthquake has not been made. Because of their finely tuned senses, animals can often feel the earthquake at its earliest stages before the humans around it can. This feeds the myth that the animal knew the earthquake was coming. But animals also change their behavior for many reasons, and given that an earthquake can shake millions of people, it is likely that a few of their pets will, by chance, be acting strangely before an earthquake.

[Sarah90]

I guess I need now to understand exactly what's a 'meta-population' ?

I think I'm going to regret asking this !!!

[Yevaud]

Back from work, thank Ghu!

O.k...say you have pine trees.  Two groups of exactly the same type, seperated by a valley in which no trees grow.  Total distance between them = about 1 mile.  Each group of trees are a population.  Groups of multiple populations = a metapopulation.  Overall, the sequence of hierarchy in the natural world is (top to bottom):

Kingdom > Phylum > Class > Order > Family > Genus > Species.

A population is an isolated or semi-isolated group of the same species.  A Meta-population is groups of populations within a species that may (or not) include all of the species.

Using the pine trees as an example, even though they're only seperated by a mile, there can be wildly different environments between the populations.  Some of the environments can be lethal or near-lethal to a population.

But the way evolution works is based on random mutation - exactly the reason why, say, bacterias can become drug-resistant.  Since bacteria generally multiply every 20 minutes, over a very short time their numbers can grow into the billions, and random mutation can mean that some of them hit upon a mutation that makes them resistant to the drug.

So.  To equate this to the animal kingdom, small groups of animals (populations) of the same species experience the same thing, albeit at a slower rate.  And, quite by accident (through mutation) hit upon traits that are beneficial (or not) to them.

Now by definition, populations within the same species can successfully interbreed.  And those with the most useful mutations are the ones who breed more than the ones who don't have it.  E.g., over time, the successful and useful mutations cross over from a population into the meta-population.

Whew.

So, when I used the reference to a meta-population, I was stating "a group of population(s) [containing a large number, if not all, of the species] that had a useful or successful mutation."  In this case, say the ability to "hear" a low-frequency noise, and have the instinct to run away.  Since this helps the animals in a species to protect themselves from a tsunami or earthquake, I'd say it's a useful and beneficial mutation, wouldn't you?

And, the way the evolutionary pecking order is, those who didn't have the successful mutation would probably be decimated over time by repeated events, until they ceased to exist.  Where, for example, is Neanderthal man?  Simple answer: their traits couldn't compete successfully with Cro-Magnon, until there were no more Neanderthals.

Otherwise, we'd all have sloping brows, thick foreheads, and crouched, hairry bodies.

Hope that answers all.   

--Yev

Brain: "Now, Pinky, if by any chance you are captured during this mission, remember you are Gunther Heindriksen from Appenzell. You moved to Grindelwald to drive the cog train to Murren. Can you repeat that?"

Pinky: "Mmmm, no, Brain, don't think I can."

[skeptigirl]

I guess I need now to understand exactly what's a 'meta-population' ?

I think I'm going to regret asking this !!!

Yev's explanation is a bit obtuse.  Across different populations would have been my answer.

Research will often include meta-analyses. That's when someone takes all or a number of the research reports and evaluates them as a whole data set.

But my page search didn't find the reference to meta-population on any of the links. Where were you looking at it?

[Yevaud]

Yes, well.  Mea Culpa.

The reason I parsed it down so far is the question had been raised as to how a trait such as "knowing" how to run away from an earthquake or a tsunami.  It's kind of an unanswerable question in a way.  So, instead, I spoke about how a mutation could end up in a genotype, quite by accident, that would favor such a trait.

As to the term "meta-population," that was part of a biology lecture I attended recently on the randomness of mutations, and how they end up in the gene pool.  Since a PhD in Molecular Biology / Department chief utilized it appropriately, I assumed it was a legitimate term.

--Yev

[skeptigirl]

Randomness definitely ends up in the population. That's where it all begins, random mutations.

What is the advantage of perceiving an earthquake before it strikes? Is there some direction the animal runs? Do you think some animals have evolved to run away from falling objects?

There is no argument here that animals might sense a fore shock. They might sense other earthquake precursors. The question is have they evolved some mechanism that allows them to recognize that precursor is a forewarning of an earthquake?

For that, the sensation has to be meaningful to the animal. And for that, I don't think a random mutation fits the bill. By what mechanism would a random mutation produce an instinctual response to a very specific sensory input?

Let's break this down further. Animals have certain behaviors that are present without learning. My dogs were never taught to dig up a mole and catch it, but that's what they did at the age of 6 months. That was pretty skilled behavior so I have to say it was genetically hard wired in with their hunting skills.

But how long and under what conditions did that skill evolve? I believe they were specifically bred as "ratters" to chase rodents into small places. That breeding was a modification of hunting instincts that evolved over a much longer period of time.

Dogs in the wild would be hunting almost every day and would have evolved over thousands of years, thousands of generations, hunting every day.

For a random mutation to enable an animal to sense ground vibration, sure. A few more random mutations and the ground vibration sensing skill becomes very acute, that's plausible. But for that sensation, whether it's ground vibration or some other sensation, to then be connected in that animal's mind to an impending earthquake? No way. Now you are talking a ~0 to 3 or so quakes in a lifetime at most that had noticeable consequences for the animal. How is the animal supposed to connect the sensation to an impending quake? Even if in the most remote circumstance, (which I don't believe is possible, but say it is), in this remote circumstance a brain gene mutates and randomly gives the animal the 'instinct' the specific ground vibration foretells an earthquake, now what will the animal do with this knowledge? Nothing. It wouldn't offer a survival advantage. I can't see how it would lead to mate preference. There would be no 'selection pressure' on this genetic mutation.

With no selection pressure, random genetic mutations exist in populations, but are unlikely to become prevalent in the population and certainly aren't going to be common in meta-populations.

[Yevaud]

Good points.

In genetics most mutations are random.  In fact it's believed to be one of the principal factors in the evolution of species.  That's a well-accepted concept in Biology.  A mutation need not be a sensible one, and for that matter, according to any sort of evolutionary pressures.  Mutations in a genome are almost always random.  Just a statistical fact.  During cell division, and the various stages of transcription and translation, they always occur.

The only point I was making was that a trait in a population can creep into a genome for no apparent reason, but turn out to be useful.  And I'm not for a moment suggesting that an animal will connect a vibration in the ground with an earthquake.  That would be a sort of anthromorphism, and while I believe animals are intelligent to varying degrees, I don't believe that if a groundchuck senses a vibration and runs away, it thinks to itself, "oh my God, here comes an earthquake!"  Merely that the vibration frightens it and it leaves the vicinity in a hurry.  If doing so equates, in the long run, to the positive benefit of saving the animal's hide, all the better.

When did I develop the trait to know that the sound of an explosion is dangerous to me?  Intellectually, I know that since it's off in the distance, I am not threatened, but I still experience the flight-or-fight reflex.  Have my ancestors been using explosives for 500,000 years, until natural selection has made it an instinct in my species?

There are example, negative and positive, throughout all species.  In humans, is allopecia a useful trait?  Sickle-cell anemia?  Downs syndrome?  Probably not.  But they have happened, and all due to random mutation.

Of course on the flip side, perhaps there's a transcription error out there for telekinesis, or teleportation.  That would be pretty damned interesting, and I think anyone would be hard-pressed to state that evolutionary pressure was behind it manifesting itself.  But it might just be useful...

--Yev

Brain: "Are you thinking what I'm thinking, Pinky?"

Pinky: "Umm, yeah Brain, but how are we going to get the leather chaps on the chicken?"

[skeptigirl]

Sickle cells are less friendly to malaria parasites.