Life and change

[Fred56]

All life is changing, or evolving. This appears to be a teleological kind of process, in which all forms of life compete with each other and with other lifeforms, here on this planet.

 

The past 400 or 500 million years of our planet´s history is known by humans (us), with some detail. We know that the continents were all much closer together back then, and that they have split up and dispersed, spread around the globe by forces that act inexorably, but with great energy, and build new ocean floor constantly, as the continents are pulled and pushed around like a bunch of bumper cars, except very slowly moving ones. Also, during the Cretaceous, there were no masses of frozen water at either pole, and the newly-separating continents (mostly two large masses, a northern, and a southern continent) were flooded, or had shallow inland seas.

 

There was generally more tectonic and volcanic activity, because of all the plate movement and the new island chains, and hot spots -that are believed to be responsible for the welling up of heat beneath continental cratons, and then forming rift valleys that become new seas, and then oceans -this is how the Atlantic started. The climate was much warmer.

 

The Holocene era saw the dispersal of the continents reach an apogee, and the process should soon (within the next 15-20 million yrs) start to reverse and the oceans will start to close up again, and new rifts form (perhaps under Yellowstone´s hotspot, or Siberia). This process is cyclic, and has presumably seen several episodes of the breakup and re-aggregation of all the continental, less dense shields, or cratons (formed in the Permian era, and so referred to as Permian shields), that float on a plastic layer of basaltic rock, which subducts great swathes of the edge of an oceanic plate, or plates crash into and compress another plate, as in the case of India, which has raised a great table (the Tibetan Plateau) of mountains, and Africa itself, which continues to rotate anticlockwise and push north into Europe, so that the Mediterranean will eventually pinch off into a small inland sea, or series of inland saltwater bodies. These changes have seen big climatic change as well, and the planet is now locked, it seems into a cycle of freezing and thawing that has an interval, or a frequency, of hundreds (about 1.3 per glaciation) of thousands of years. The frequency correlates with subtle changes in the earth´s orbit and inclination: Milankovitch cycles.

 

Life also changes its environment necessarily, in order to itself change and keep changing. The first major global change that life made to the planet was arguably the growth of oxygen-producing organisms (cyanobacteria and blue-green algae), in the earth´s new oceans. These changed the atmosphere and altered the oxygen content to the extent that life could now learn to adapt (was obliged), to the new ´resource´ that oxygen, actually a very toxic substance, had to offer (because it readily accepts electrons it ´oxidises´ things -one of the first things that happened to it was the oxidation reaction with all the iron lying around, and in the oceans).

 

So change is ongoing and a necessary thing. And it is a balance, an ongoing cycle of exploitation, depletion, and learning -to find new resources or exploit existing ones with more efficiency.

 

Can an organism that changes its environment do so too efficiently, so that its own ability (to exploit and change the environment) places it in danger (from that change), so to speak?