Saturday, April 15, 2006

The Fragility of You and Me

Friday's issue of the journal Science had an article on worms that thrive on undersea hot-water vents. Researchers brought the worms into the lab and tested the temperature range that they could withstand. The worms survived for as long as seven hours at 122 degrees Fahrenheit (50 degrees Celsius). Water of 140 degrees Fahrenheit (60 degrees Celsius) killed them. For comparison, a hot tub ranges from 100 to 105 degrees Fahrenheit. It was an interesting article but raised several points: 1) did we really need to drag the poor creatures from their homes and cook them alive/why is it OK for us to experiment on other animals 2) Although these worms like it warmer than you or I, we're not all that different. We both need very stringent parameters for survival.

If you think about it, there are certain things that we all need - oxygen, temperature, water, food, protection from radiation. For each of these variables, only a very small parameter is compatible with life.

- oxygen/altitude/pressure
The percentage of oxygen in the air at two miles (3.2 km.) is the same as at sea level (21%). However, the air pressure is 30% lower at the higher altitude because the atmosphere is less dense (the air molecules are farther apart). Most of us living near sea level develop hypoxia at 1-2 miles altitude. Climbers have reached peaks that are over 5 miles high, but only by using tanks of oxygen to assist in breathing.

- temperature
Normal body temperature is 37° C (98.6F). Below 94F. (34.4 C.) hypothermia starts to set in, and above 105F (40.6C) we run into problems where the brain and other internal organs start cooking. That's a whopping range of 10 degrees. Those of us fortunate to have air conditioning and heating may think this is less important, but even industrialized continents run into trouble - record heat wave in Europe (August 2003) claimed 35,000 lives.

- water
The human body is made up of ~60 -70% water and biochemical and metabolic processes that take place in the body depend on water. We just cannot survive without clean, drinkable water.

- food - calories, protein, fatty acids, minerals, vitamins
The lack of adequate nutrition leads to an endless list of medical problems, some maiming and some life-threatening: scurvy, beri-beri, pellagra, marasmus, anemia, goiter, night-blindness, birth defects, rickets/osteomalacia, blood clotting problems...

- protection from high levels of radiation
Stratospheric ozone is a naturally-occurring gas that filters the sun's ultraviolet (UV) radiation. UVB causes skin cancer, premature aging, cataracts, impaired response to immunizations, increased sensitivity to sunlight, and reactions to certain medications. Increased UV can also lead to reduced crop yield and disruptions in the marine life.

We have all these requirements for survival, but due to technology and luck that we live in the developed world, there's often a false sense of invincibility. We live blissfully unaware in our sheltered bubble. We celebrate the feats of extreme athletes, patting ourselves on the back for the brave representatives of the human race who push the borders of what is possible - i.e. those who climb everest - but we easily forget that extreme is relative. Imagine a snail congratulating another snail for making it up and down a big rock pile - after all, mountains are just transient elevations in topography - it doesn't change the fact that either snail will shrivel in the presence of salt.

Let's live and let live and take care of our planet. For those who think that environmentalism is just for the crunchy granola types, think again. We're all interconnected, and if you really pare it down to the basics, to irreversibly alter the world hurts fragile you and me.

3 Comments:

Blogger Jeremy Cherfas said...

Nice post.

I hope that quip about the lethal parasite wasn't meant seriously, or that you know better now.

10:03 PM  
Anonymous Judith said...

Actually the temperature range you quoted is 10 fahrenheit degrees and less than six celcius degrees.

And don't forget we also need a way to avoid predators. In the real world, they'd be picking us off pretty easily!

All this explains why parasitism could be considered the most highly evolved lifestyle choice!

8:42 AM  
Blogger always learning said...

Hi Judith - Thanks for catching the error! :)

Jeremy - thanks for the link :)

- wv

9:34 PM  

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