Monday, May 2, 2016

Pictures At An Exhibition Part 2



Today I’m returning to my Pictures At An Exhibition. In case you haven’t read part 1, here’s the link http://davidsamateurpalaeo.blogspot.com/2015/03/pictures-at-exhibition-part-1.html

We continue the series of murals with one that has been restored to display after a 20-year hiatus. It’s the first one visitors see in Evolving Planet, right between the stromatolites, next to a display on banded iron, and a model of a eukaryotic cell. Those are pretty good hints, by the way, on the setting and content.

 

The time is stated to be 1.5 billion years ago, and titled “The Beginnings of Life”. The name shows the age of the painting, as that was the date estimated in the 1930s. Alexandr Oparin had brought back the theory of abiogenesis in 1924, placing the date between 1 and 2 billion years ago. Turns out life is older, but important evolutionary landmarks took place at that time none the less, and the painting’s depiction is still accurate, thanks to Knight making a calculated risk.

The painting shows geological and biological revolution. A series of plateaus and jagged rocks make up the background, a continuation of the barren mountains of the previous painting. In the center and foreground, however, there is a contrast-instead of the yellow-brown rock, there are bright green-blue pools in a steplike configuration. In the fore and left, there are a large group of red-brown graptolites next to the lowermost pool. This depicts Precambrian Earth-seemingly peaceful, but subtly revolutionary.

It was Oparin that invented the term “primordial soup” a simplistic but generally accurate term to refer to earth’s conditions promoting life-water with the proper chemical composition at the right temperature to stimulate the formation of amino acids and in turn proteins, and that is what Knight is depicting. In the pools are cyanobacteria, blue and green photosynthetic life that is turning the sky blue and adding oxygen into the atmosphere. 

It is also these cyanobacteria forming mats and colonies and producing the stromatolites. Knight was working on modern analogies, and this environment is not too dissimilar from living stromatolites forming in saline lagoons in Australia and Mexico.  At 1.5 million years ago, there is no doubt this environment would be common for life.

However, there was also other forms of life. Microbial fungi and eukaryotic bacteria have also left fossils dating back to this period in time, the first eukaryotic organisms that precede all of today’s macroscopic life. The blue pools of bacteria would have sustained these other forms of microbe, and both green and red algae shared the same pools. It would still be microscopic, soft, aquatic life, but those beautiful blue-green pools would be rich with tiny life.

 The painting shows life as it began-simple and small but numerous, successful, and beginning evolution. Evolution requires life, and life, uh, finds a way.

1 comment:

  1. This comment has been removed by a blog administrator.

    ReplyDelete