Time: Human vs. Geological


Life on Earth is strange, and I don’t just mean physically. It’s odd how life goes on here.

In terms of time, we are so out of sync with our planet!

About 75% of the Earth’s outer crust, where we live, is composed of rock similar to this. (Image: James St. John, CC BY 2.0)


First, look at our natural surroundings — steady as a rock (most of the time, anyway).

And usually very, very old.

Then look at humans, or at cats — each born helpless; struggling to reach maturity; struggling more to survive and reproduce; and then aging and passing away.

It all happens quickly, too (at least to an outside observer: parts of our own lives seem to take forever).

In the wild, cats don’t live long, maybe five to ten years, or a little more if they’re tough and lucky.

More beautiful than any rock. (Image: SantiPhotoSS/Shutterstock)

Exceptionally elderly people might live for a hundred years, but even this is short compared to the social fabric that they are wrapped in. While often resembling a patchwork quilt, its history goes back many centuries.

The current British monarch, for example, is in her mid-90s. That isn’t very old, considering how long her royal house has been around, and it’s positively youthful compared to the age of her kingdom.

Still, what do centuries and millennia mean to a multimillion-year-old rock?

Nothing, of course. It’s inert, although there may be something living underneath it or even inside. The rock’s components — silica, oxygen, and various other elements — are just chemistry, facts for nerds to ponder.

Biology is where it’s at, and we’re at the top of the heap!

This delusion is so powerful that most of us need a strong reason to ask the really interesting question — what does that multimillion-year-old rock mean to us?

When asked, people usually say “very little,” unless they can make money off it or need to spend money to get the rock out of their way.

That’s all well and good, but it’s not the only possible answer.

Stromatolites worked it out a long time ago and have stayed with success ever since. (Image: Pat Scullion, CC BY-ND-NC 2.0)

Sometimes we get curious enough to poke around and discover part of the history of life on Earth, hidden in that rock.

With the right motivation, anyone can see it — even me.

Cats are from more than 20 million years ago, and let’s face it — that doesn’t mean a thing to most of us. It’s too much time to really feel.

So let’s turn our cat loose during a game again.



Set the long white field lines 1 mega-annum (Ma) apart instead of a yard.

This term “Ma” means one million years, so the playing field we are imagining is also a calendar of sorts.

We’re standing at the goal line today, and fossils do show that Proailurus, the Dawn Cat, popped into the game around the 27-Ma line. (Werdelin et al)

Just for reference, here are some other events you might have heard of:

  • Nonavian dinosaurs like T. rex, and several other players, left the game midway between the 70- and 60-Ma lines during the K/T extinction.

In brief:

  • This Earth is where cats come from.
  • The game is life, and cats are not the only players.
  • The field is a very restricted one, actually: the known fossil and geological records, which are only seen clearly in a few places on the planet. So there is a built-in bias to our play-by-play coverage, but we’re going to do it anyway: the whole story as we can see it.
  • Hey, the rules have a lot to cover! (Image:erebor mountain/Shutterstock)

  • The rules have always been in force, but the primary ones were first noticed by a monk in the 1800s and rediscovered in 1900, several decades after Western observers like Charles Darwin and Alfred Russel Wallace had begun describing some secondary rules. After some disagreements, some of the best minds on the planet collected those prior viewpoints and blended them into a modern “rulebook” between 1918 and 1931. Unfortunately, these brainiacs wrote mostly in math — while that’s certainly a universal language, we laypeople aren’t fluent in it. Luckily for us, former English major and paleontologist George Gaylord Simpson could understand math and also was able to express the game rules in simple terms, most famously in Tempo and Mode in Evolution, which was published in 1944 by friends and family while he was serving in World War II. (Fitch and Ayala; Simpson)

    Simpson’s book, although almost eighty years old now, still holds up in many ways today, per Fitch and Ayala.

    That’s probably because he addressed core points. Tempo and Mode really helped me understand what I was reading about cat evolution and evolution in general.

    I’m also going to use it because the boffins are back to writing in math again. Simpson was an English major, and it shows.

    The major developments since his time — molecular biology and cladistics — are well covered by other sources using the simple approach we take here.

Right. Let’s start off with the most basic question of all: what is life?

Read the whole thing.


Featured image: Juergen Wallstabe/Shutterstock


Sources:
Antón, M. 2014. 2013. Sabertooth. Bloomington: Indiana University Press.

Cope, E. D. 1880. On the Extinct Cats of America. American Naturalist. xiv (12):833-857.

Fitch, W. M., and Ayala, F. J. 1995. Preface. Tempo and Mode in Evolution: Genetics and Paleontology 50 Years After Simpson. Washington: National Academy Press.

Kitchener, A. C., Van Valkenburgh, B., and Yamaguchi, N. 2010. Felid form and function, in Biology and Conservation of Wild Felids, ed. D. W. Macdonald and A. J. Loveridge, 83-106. Oxford: Oxford University Press, Oxford.

Simpson, G. G. 1944. Tempo and Mode in Evolution. New York: Columbia University Press.

Turner, A., and M. Antón. 1997. The Big Cats and Their Fossil Relatives: An Illustrated Guide to Their Evolution and Natural History. New York: Columbia University Press.

Werdelin, L.; Yamaguchi, N.; Johnson, W. E.; and O’Brien, S. J.. 2010. Phylogeny and evolution of cats (Felidae), in Biology and Conservation of Wild Felids, eds. Macdonald, D. W., and Loveridge, A. J., 59-82. Oxford: Oxford University Press.



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