Mass Extinction

If at first you don't succeed, try, try, try, try, try again

The Cretaceous Boundary is amazing. Dinosaurs below the line and then no more

The Gauntlet

Know thy reader is what my last post taught me about breakfast. Even though I think the polls are FUN, sometimes the readers are indifferent. What I learned from the last poll about what constitutes breakfast is DON’T MESS WITH COFFEE. Coffee won the poll in a landslide! I may just have to compare coffee to decaf to tea to Postum to drive engagement :)

Can You See the Line?

The line in the feature photo above is captured all over the planet and guides us to a difficult day (at least for the dinosaurs) about 66 million years ago. Everywhere we look, we find the same story. Something “big” happened and it affected the whole planet. Modern analysis based on finding the impact crater in the Yucatan Peninsula near Mexico tells us the asteroid impact was equivalent to perhaps 10 billion atomic bombs of Hiroshima size. It was a very bad day but at least no fallout. To read more, here is a link.

The Little Asteroid That Could

Sure, it is a drag to think about 10 billion atomic bombs. Another way to look at it is we are a little blue marble lying out in an open field. The asteroid that came to visit was about 10 km in diameter so about 6 miles across. That doesn’t SEEM that large. I guess the problem is it was going fast. The crater which has been carefully studied is closer to 150 km across. That is about the distance from New York to Philly. Without Philly, who would be the worst sports fans? I expect my Philly relatives to respond :).

What’s a Mass Extinction?

Definitions are always handy if only a rule of thumb. A mass extinction event is when species vanish much faster than they are replaced. This is usually defined as about 75% of the world's species being lost in a 'short' amount of geological time - less than 2.8 million years. to put that in perspective, we think there are about 9 million species on the planet or thereabouts.

There is a background rate of extinction that seems to have carried on for the last billion years or so until recently. The current age we are in has markedly increased the background rate which MIGHT BE ALARMING. The best available science indicates that four of the five mass extinctions were due to climate change as the major driver. The most recent one is the one we are talking about and just seems to be a bad break. I am not an expert on all of the creation stories. I wonder how a story like creation attempt #1, fallback, creation attempt #2, fallback, creation attempt #3, fallback, creation attempt #4, fallback, creation attempt #5, fallback, okay now it is time for some interesting primates. Let’s make one of them a sweater who walks on his hind legs. My guess is such would not be readily accepted and would be rejected as too far-fetched to be reasonable. It certainly lacks a poetic flow.

The fossil record of our planet is the gift that keeps on giving. Humans have not been that helpful until recently to figure out the history of our planet. The fossil record provides amazing indirect evidence of what’s going on over time but luckily nature left some great clues. So many of us have enjoyed the Jurassic Park films. Many are fascinated by this lost period in our planet’s history.

While I am sure the analysis and specialization are varied, the fossil record is fundamentally a pretty simple thing to understand. Stuff dies and piles up. In certain periods stuff gets buried. However, and quite logically, the deeper you go the older the stuff. So when you stop seeing particular creatures after a certain period it is safe to assume they died out. This is a pretty good way to organize your thoughts. When I reduce archeology to these basic principles, everything gets pretty cozy. One of the cool things about science is that most of the time the simple becomes elegant and it remains easy to explain and apply.

To me, despite lacking any background in archeology it does not seem that difficult to accept that dead stuff piles up, and by studying the layers you can piece together a story over time. A few years back in my history book club we read a book about the Great San Francisco Earthquake in 1906. If you are interested, the book title was “A Crack in the Edge of the World: America and the Great California Earthquake of 1906”. The book told a lot of personal stories as well as explained the shifting of the rocks. The coolest takeaway from the book was about the pretty new science of plate tectonics. It describes the world as a big bathtub and the pieces of the earth are always moving a bit like bars of soap floating around. An author who can help me understand it with such a great example is awesome!

The cool outcome of all of this was that WE KNOW the middle of the Pacific Ocean ended up raising the Rocky Mountains. The proof is the rock (basalt) in the Pacific basin is THE SAME rock that we all see today on the Western face of the Rocky Mountains. That is simple enough and elegant enough to convince me.

Humans, by comparison, didn’t get to witness very much of this story. We are pretty new to the planet and even now, just a blip in its history. Our wonderful ingenuity has been remarkable at deciphering the clues that nature left behind. Equally, however, humans are good at digging in and denying proof in front of their eyes. I think that is mostly our two-brain legacy, a primitive lizard in the back and a cerebral cortex in the front that explains why we (and dolphins) have such prominent foreheads. Our frontal cortex has led us to a Milky Way galaxy that is about 13.5 billion years old and the Earth came to be close to its current form around 4.6 billion years ago. An upright walking ape seems to have emerged around 2 million years ago and we finally got around to having an alphabet less than 4000 years ago. Until then, at best, we scratched some stuff in the walls of caves. Our primitive brain, instinct, and what we are instilled with early in our lives embrace different explanations sometimes concluding that the whole story is only 6000 years old. Doesn’t leave much room for compromise it seems.

While many amongst us would prefer to write our history based upon the emergence of the Veda, the Tripitaka, the Hebrew Bible, the Christian Bible, or the Koran, the fossil record provides more extensive clues to the story.

We are newcomers and we only began touting our achievements for posterity to recognize quite recently. The various sacred texts reduce our home planet story to less than 10,000 years! I believe that all significant history is recent so focusing on the past is a sensible way to simplify and understand our place in the world. While filling in the blanks may be challenging, it is worth wondering what was going on in the other 99.9999% of the time since the beginning of the Milky Way. Seems a fair and worthwhile question. I think it is always useful to put history in perspective. This written record of the Earth only begins 99.8% (~4000 years ago) of the way into just the human story (2 million years ago). A useful metaphor is that humans emerge about 99.95% (2 million) of the way into the Earth story (4.6 billion) and only start writing stuff down 99.9999% of the way into the Earth story. It is hard to argue how important the appearance of humans has been for the planet. Nevertheless, life has evolved MULTIPLE times on the planet. Each mass extinction resets the clock. It is only after the last mass extinction that human life emerged. We are pretty confident this is the first rodeo for a branch of mammals we call primates.

None of this, in any way, precludes divinity. It merely requires we throw off black and white rigidity in our thought. The world is gray and it is okay.

When I do a little reading for these stories I AM AMAZED by the ingenious paths to workable theories that scientists make. The cretaceous boundary has been PARTICULARLY well exposed and studied in South Dakota and Wyoming because of its unique geology. Information from the region points toward a period of about two years after the asteroid in which wildfires layered enough soot in the sky to shut down photosynthesis and lead to the elimination of at least 70% of all land species. That asteroid was a VERY BAD DAY!

Ah, finally we have come to today’s title! So what is a mass extinction? Scientists agree, mostly due to the fossil record that there have been at least five mass extinctions we can identify in Earth’s history. Science estimates that evolution leads to a natural thinning of the species. Here are some generalizations and statistics:

• About 10% of all species will disappear (become extinct) every one million years or so. This rule of thumb seems to align with the fossil record pretty consistently over a long period (all that stacked up dead stuff).

• Some die off completely while others “speciate” and become something a little bit different.

• That is a good description of what became of Neanderthals for example. Lots of us have some Neanderthal DNA in us so arguing is quite pointless. There are not any creatures around anymore that we would call Neanderthals yet we have the remnants. Argue if you wish but mind your blood pressure. According to 23AndMe, my DNA results say I have 35% more Neanderthal variants than an average 23AndMe customer. I do like eating with my hands, so there is that.

• The 10% rate is referred to as the background rate of extinction. Some creatures are PARTICULARLY well suited to survive like sharks.

• The 10% rate, if extended tells us that a species, on average, gets a ten million-year run. The variation from one to another is pretty large.

My mother labored long and hard to get me to use utensils instead of my hands. She was fighting nature as my 23AndMe results show.

The Poll & Music

Here’s a fun song from one of my favorite animated movies, Wall-E.

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What’s Next

I’ve decided to keep you subscribers on your toes. A steady diet of what scares me is not a perfect formula. I have a lifetime friend who recently passed away. Michael Badnarik was his own man and lived a bit of a renegade life with no regrets. He and I did not agree on a lot of things but that did not stop us from cultivating and nourishing a long-distance friendship for over thirty years. The world is a better place for making Mike part of it. RIP Michael. Mike would not have enjoyed my newfound eating proclivities but the science beyond some of it would have made him smile. Next time I am going to write about “Heme“. If you believe the missive you are what you eat, having a little more yeast can inflate your image of yourself.