Monday, February 3, 2014

Soggy Egypt
or How Armored Amoebas Built the Pyramids
Sometimes you have to clean your apartment. And sometimes you want to turn on a show on Netflix about Ancient Egypt to help you get in the mood to Swiffer. But then your brain makes a sudden connection and you end up reading about about evolution, prehistoric seas, amoebas, and Greek historians well into the night...
Looking at the pyramids, it’s easy to feel a sense of awe and an appreciation for the vastness of human history. But just beneath the surface of those huge blocks of limestone--well actually right on the surface--is another story that is more ancient, more vast than the tale of human monument building that took place 4500 years ago.


This is the story of how modest, single celled organisms were the ones that actually built the pyramids.

Forget thousands of years, let’s talk about millions of years--sixty million years to be relatively precise. During that time Egypt (didn’t exist, but you catch my drift) was covered in a shallow tropical sea. While India was gearing up to ram into Eurasia and form a little something called the Himalayas, the Tethys Sea was sea-ing over most of north Africa, the Arabian peninsula, and a huge swath of Europe.
Earth as it was about 60 million years ago. 

Life loves nothing more than a not-too-hot, not-too-cold, not-too-deep, not-too-shallow expanse of water. Swimming among the evolutionary free for all that was the Tethys were creatures called Nummulites.
Nummies! Just in case you forgot: those are single-celled creatures.
They weren’t much to look at: single celled organisms wrapped in shells shaped like flat discs--what one biologist referred to as ‘amoebas with armor.’ 
Taking advantage of their resources, nummies grew to huge numbers and sizes. While remaining a single cell, some of them grew to be seven or eight inches across. By all accounts, the Tethys was swarming with these guys and gals.
Shortly after the heyday of nummies, the Tethys shrank considerably. Today's Mediterranean Sea is the last, watery vestige of the Tethys. After the virtual disappearance of the TS, Egypt (which still didn’t exist) dried out into the desert it is today. But the nummies were not to be so easily relegated to the dustbin of history. As nummies died, their bodies drifted to the bottom of the sea. Over millions of years, layer upon layer of sediment, other sea creatures, but most of all millions upon millions of nummies accumulated on the ocean floor and were compacted down.
Same planet, just a bit more recent. "Recent" here is a relative term meaning anywhere from 5 to 20 million years ago.
Layers of sediment that experience high heat and pressure become rock. Layers of sediment containing the remains of shelled sea critters that experience high heat and pressure become limestone.
Millions of years later, Egyptian workers quarried huge blocks of nummulistic limestone and shaped them into the engineering and artistic marvels that are the great pyramids. Limestone in general is great for fossils, and the limestone used to build the pyramids is no exception--nummie fossils are everywhere.
If you squint, you should be able to see all the nummie fossils embedded
in this pyramid stone. If you're unwilling to squint you are just going
to have to trust me. 
The Egyptians didn’t leave us a record of what they thought of all the little coin-shaped indentations in their pyramid stones. Regardless of whether they loved them (adds so much character!) or hated them (why can’t these stones just be smooth?!), they almost certainly noticed them. 

More than 2500 years after the last chisel left its mark on the pyramids, a Greek historian and intellectual called Strabo wandered by. He noticed the nummies and even posited an explanation for them:
One extraordinary thing which I saw at the pyramids must not be omitted. Heaps of stones from the quarries lie in front of the pyramids. Among these are found pieces which in shape and size resemble lentils. Some contain substances like grains half peeled. These, it is said, are the remnants of the workmen's food converted into stone...

To be honest, I have never wandered by the pyramids. I have several friends that have--though, admittedly, none were wielding chisels and very few were Greek intellectuals. Not one person has mentioned the nummies. If I had to posit a reason, I’d guess that it had less to do with a lack of perception and much more to do with being overwhelmed by the spectacle of the pyramids.
It’s easy to see them as ancient, unyielding blocks of stone that tell one specific human-centric narrative. What is much more difficult to grasp is that the pyramids can tell us about life not just thousands of years ago, but Life that existed long before you, I, and/or Greek intellectuals were even a glimmer on the surface of an ancient sea.