Fossils are autobiographical. They shamelessly reveal much about their lives without saying a word. But they have help.
If you want to find a fossil, you go where fossils are found. They are not ubiquitous, and there’s a reason for their distribution over the planet. They lie in rock where or near where the organisms lived, and they exist only in so far as preservation has occurred. Some places are not conducive to fossil preservation. It’s tough to become a fossil. Many variables disrupt the process. Let’s hypothesize.
You live in a humid climate with many other organisms. You expire, fall into the humus, and lie there exposed to consumers and scavengers: Crows, mice, fungi, and bacteria see you as a source of energy. Pretty soon, you’re bones. Then a dog or wolf takes a bone or two. Rain falls. Land floods. Scattering occurs. You are not going to become a unified fossil though your hard parts might be isolated remnants of what you once were, but only so if they are removed from further disintegration and consumption, say by burial. New waters bring sediments. Your parts get covered. The process repeats. Deep burial occurs. Your bones are replaced by precipitating dissolved minerals; okay, now you’ve been fossilized.
There are many rock units that bear no fossils. The lithified sediments of fast-flowing streams, for example, indicate an environment of high energy, where light bones might have been destroyed by collisions with rocks in white water and then washed away. Lava flows are also usually devoid of fossils because temperatures in excess of 1,000 degrees Celsius destroy life’s products. So, low energy, cool environments are a bit more conducive to fossil preservation, especially when they have an influx of burying sediments and a low oxygen content to prevent oxidation. Swamps are great places for fossilization as coal deposits attest. Muddy areas where fine particle clays settle out are also great preservers, and, as the Burgess Shale in Canada indicates, rapid burial by an underwater turbidity flow also works.
It’s tough to become a fossil, but should you become one because your surviving parts made it through the gauntlet of destruction, then a future conscious being, bent on understanding the past, might dig you up or find you exposed in an eroding landscape. And then, the autobiography your parts tell reveals itself not only in those preserved remnants, but also in the environment of their discovery.
In other words, someone learns about you by your associations. Find lots of fossils together? Two possibilities stand out: Either many organisms got washed into a collecting basin or many organisms lived together in an environment that provided sufficient food and shelter for their lives. Bunch of similar fossils? Colonial animals, right? Or animals or plants that thrived under similar environmental conditions. Rare specimen? Probably a solitary critter or maybe one that just happened by luck to be preserved out of a sparse population. Possibly too, an instinctive choice to isolate.
Now here’s the question: When the future paleontologist or archaeologist finds your fossilized parts, what will he or she discern about the way you lived? The environment of preservation will be as much a clue to your lifestyle as the remnants of your body.
Look around at your environment. What does it say about you? Place itself might become your biographer. In fact, it’s writing your tale as you read this.
If you want to find a fossil, you go where fossils are found. They are not ubiquitous, and there’s a reason for their distribution over the planet. They lie in rock where or near where the organisms lived, and they exist only in so far as preservation has occurred. Some places are not conducive to fossil preservation. It’s tough to become a fossil. Many variables disrupt the process. Let’s hypothesize.
You live in a humid climate with many other organisms. You expire, fall into the humus, and lie there exposed to consumers and scavengers: Crows, mice, fungi, and bacteria see you as a source of energy. Pretty soon, you’re bones. Then a dog or wolf takes a bone or two. Rain falls. Land floods. Scattering occurs. You are not going to become a unified fossil though your hard parts might be isolated remnants of what you once were, but only so if they are removed from further disintegration and consumption, say by burial. New waters bring sediments. Your parts get covered. The process repeats. Deep burial occurs. Your bones are replaced by precipitating dissolved minerals; okay, now you’ve been fossilized.
There are many rock units that bear no fossils. The lithified sediments of fast-flowing streams, for example, indicate an environment of high energy, where light bones might have been destroyed by collisions with rocks in white water and then washed away. Lava flows are also usually devoid of fossils because temperatures in excess of 1,000 degrees Celsius destroy life’s products. So, low energy, cool environments are a bit more conducive to fossil preservation, especially when they have an influx of burying sediments and a low oxygen content to prevent oxidation. Swamps are great places for fossilization as coal deposits attest. Muddy areas where fine particle clays settle out are also great preservers, and, as the Burgess Shale in Canada indicates, rapid burial by an underwater turbidity flow also works.
It’s tough to become a fossil, but should you become one because your surviving parts made it through the gauntlet of destruction, then a future conscious being, bent on understanding the past, might dig you up or find you exposed in an eroding landscape. And then, the autobiography your parts tell reveals itself not only in those preserved remnants, but also in the environment of their discovery.
In other words, someone learns about you by your associations. Find lots of fossils together? Two possibilities stand out: Either many organisms got washed into a collecting basin or many organisms lived together in an environment that provided sufficient food and shelter for their lives. Bunch of similar fossils? Colonial animals, right? Or animals or plants that thrived under similar environmental conditions. Rare specimen? Probably a solitary critter or maybe one that just happened by luck to be preserved out of a sparse population. Possibly too, an instinctive choice to isolate.
Now here’s the question: When the future paleontologist or archaeologist finds your fossilized parts, what will he or she discern about the way you lived? The environment of preservation will be as much a clue to your lifestyle as the remnants of your body.
Look around at your environment. What does it say about you? Place itself might become your biographer. In fact, it’s writing your tale as you read this.
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