texified

When I reached the beach on my walk two Sundays ago, I saw a large black body out in the water, then a great fin protruding above the surface.  At first I was confused as to what I was seeing,  then everything clicked into place, and I realized that I was watching a pod of Orca or Killer Whales coursing north through the narrows of Puget Sound.  I immediately began shouting with excitement.  Not only was this the first time that I had ever seen these magnificent creatures, but they are rarely seen this far south in the sound.  They had just passed the park which I was in and were taking their time on their way north, their backs and fins protruding above the water.  I stood there watching them until they disappeared.  Then I realized that I had been the only one shouting, but I felt blessed and full of energy.

The Killer Whale got its name from the fact that it often was observed eating whales, but there are at least three different groups or Orcas which seem to have specialized in either fish and squid eating, and those which eat almost exclusively marine mammals.  I was tremendously excited after seeing the Orcas pass, and while musing on them I was curiously reminded of the end of the universe.

I was reminded of the death of the universe by the fact that Killer Whales occupy the top of their food chain, and thus their numbers and biomass are severely limited by the Second Law of Thermodynamics which basically says that energy tends to go from ordered states to disordered states, and during any transfer of energy some energy is lost to the system (converted to heat).  Thus every time a cow eats its supper (plants) roughly 90% of the energy in the plants is converted to heat and lost to the system (ecosystem in this case).  So consider the following marine food chain scenario:

phytoplankton (100%)—->zooplankton(10%)—->small fish(1%)—->larger fish(.1%)—->seals(.01%)—–>Killer Whales(.001%)

Suppose the phytoplankton by means of photosynthesis captures a certain amount of energy from the sun.  We’ll say this amount of energy is 100%.  This represents what we start out with in this food chain.  The zooplankton (small floating animals) eat the phytoplankton, but about 90% of the available energy is lost, so the zooplankton only ends up with 10% of what we started with.  Then the small fish eat the zooplankton and the same thing happens, 90% is lost and the small fish end up with 1% of the original amount.  And so on…until we end up with the Killer Whales which in this example will end up with only 1/100,000 of what we started with–all due primarily to the Second Law of Thermodynamics!   Not much energy is available to the top predators in food chains.

Or consider this alternate food chain:

phytoplankton (100%)—->zooplankton(10%)—->Great Blue Whales (1%)

The Great Blue Whales by eating much lower on the food chain (zooplankton: krill mostly), theoretically has 1% of the energy with which we started–a thousand times more potential energy than is available for the Killer Whales!  So theoretically the biomass of Great Blue Whales could be as much as the total biomass for the small fish in the first food chain…just concentrated in much bigger bodies, potentially much more biomass than in the Killer whales.  Two strategies exist in this case:  by eating at this level in this food chain, you can be small and extremely numerous or large and much less numerous–the biomass should be about the same.  I think there is a lesson here as the human population density soars above 6 billion people.  Can we continue to eat high on the food chain?

So why did all this make me ponder the end of the universe?  Because if energy continues to go from concentrated sources of energy to less concentrated sources (entropy), then eventually the universe will run down.  All the stars  and other energy systems will have dissipated their energy into heat, there will be no more people, spiders, planets, stars…nothing but a universe in which the energy is evenly distributed–the Heat Death of the Universe.