Posts Tagged ‘fossils’

REVIEWS FROM THE REV: The Page Museum and La Brea Tar Pits.

Sunday, February 17th, 2013
A Sabre Toothed Cat skull from The Page Museum.

A Sabre-toothed Cat skull from The Page Museum.

This is a remarkable museum.  For one, it’s a beautiful (and beautifully organized) building.  For another, it has the distinction of sitting on top of the very deposits that have yielded the countless fossils that occupy the displays.

As you approach the museum you pass by a water-filled pond that was once a tar quarry.  There are life-sized replicas of a Columbia Mammoth family — one of whom has been “caught” in the tar hidden beneath the water.  This tableau is artifice, of course, but the sulfurous gasses that continue to bubble up into this still-active “asphalt seep” are the real deal, and provide a quietly stunning reminder of a still very active Earth.

Inside the circular museum, one walks past display after display of the mounted fossils that make up a rich catalog of extinct fauna that once roamed the Los Angeles area.  The tar pits (in their time) captured every kind of organism, from the truly stupendous Columbian Mammoth to delicate dragon flies.  All of the La Brea fossils show the distinctive chocolate patina of their time in the tar.  There are sloths, mastodons, condors, ancient buffalo, horses, sabre-toothed cats and dire wolves.  Lots and lots of dire wolves.

Did I mention there are lots of dire wolves?  One of the more stunning displays is a lighted wall made up of row after row of dire wolf skulls.  There could easily be a hundred of them, filling an entire wall, floor to ceiling.  (Watch the informational videos in the two museum theaters, and you’ll learn that these skulls are only a hint of the bounty of fossils that continue to come from ongoing excavations on the site).

There are not dinosaurs, of course.  The tar pits began their life-capturing career only forty-thousand years ago (which turns out to be an important time-span in the story of the extinction of much of North America’s megafauna).  And though there is likely a connection between the arrival of humans on the continent and the subsequent extinction of these large animals, there has only been one human fossil recovered from the pits: a woman from about ten thousand years ago.

I can’t say enough nice things about this museum.  It is a fine blend of location, collection and architecture.  Everything one could want in a museum experience.

The Page Museum is located in central Los Angeles, right next to the Los Angeles County Museum of Art (hint: if you’re planning to visit both, do The Page Museum first — LACMA is a vast and overwhelming campus of buildings and collections).

t.n.s.r. bob

The rev gives it four Dimetrodons out of four!

The rev gives it four Dimetrodons out of four!

SERMON: “Trimming the Family Tree” by the not-so-reverend bob

Sunday, May 6th, 2012

Although it’s easy (and correct) to critique religious views that place humanity at the logical end of a creation timeline (whether that creation occurred in the Biblical Garden of Eden or through hundreds of millions of years of evolution), it is worth taking a step back to consider that this teleological bias infests just about every human head, be they believer or scientist.

When (as a boy) I first learned about Neandertals, they were seen (along with every other early hominid) as our direct ancestors.  At that time, all different shapes and sizes of early primates and humans were just sort of crammed into a single family tree, with explanations abounding about how one evolved into the other and, eventually, to us.

Of course, it’s fair to be kind to these ideas (that are now clearly wrong), as we haven’t had all that many ancient human fossils to examine, and the technology to truly examine them scientifically has been developing rapidly over the last forty years.

As my geo-chemist friend pointed out with regards to studying the tectonic actions of Earth “We only have one data point”.  Meaning that we’ve only found one planet (so far) that has the qualities of Earth to study.  When it comes to our early human ancestors, we have a few more “data points” than that but, still, we don’t have all that many.

When a new fossil discovery hits the press, there is always a bold proclamation about how “everything we thought we knew” is thrown out the window, or an equally confident claim of where the fossil fits in our family tree.

But it is a testament to the steady work of science that all such announcements are eventually put through the wringer, and out the other end comes a more sober evaluation of what the new discovery can reliably tell us.

And so the sequencing of Neandertal DNA (quite a story of technology and tenacity in itself) has opened up new swaths of data from bones that we thought had already told us all that they could.

The story of the story we tell of the Neandertals is enlightening.  At first thought to be our classic “caveman” ancestor, brutish and dumb, they have had a sort of re-birth as noble, red-haired, cultured savages who may have been our equals (in their time).  Both of those descriptions are turning out to be a bit overdrawn, and it seems like we are settling down to an understanding that — though necessarily based on frustratingly few pieces of evidence — seems much more likely to be accurate.

In my short monologue "Forbidden Love of the Pleistocene" I tell the story of a doomed love affair between a Cro-Magnon man and a Neandertal Babe. Hey -- it could have happened!

For the Neanderthals now appear to be cousin to our Ice-Age “modern” human ancestors.  It also appears that (though highly evolved in their own right) they may have lacked a handful of key social and cognitive traits that many think made the difference when it came down to a question of “them or us”.

More importantly, it seems to me, we are coming to appreciate them for who and what they were, without the need to either demean or ennoble them out of our own emotional needs to feel guilt or superiority (after all, there is a chance that we played an active role in killing them off about 40,000 years ago).

So what about this “cousin” relationship?  Darwin predicted that it was Africa that was the nursery for modern humans, and he guessed this without a single ancient human fossil to go by.  Subsequent fossil finds (and modern DNA sequencing) have so far proven him right.  There are still some who hold a view that many populations of humans evolved in multiple regions on the planet, but the mainstream view now is one that we did, in fact, evolve in Africa before spreading out into the rest of the Earth.

But here’s where things have gotten interesting.  As always seems to be the case, when scientists first decided that we had, in fact, all “come out of Africa”, they looked for a single migration event that led directly to us.  It seems we can’t help but think that way.  But the science now supports a more nuanced view that, frankly, fits much better with how nature actually works.

Our current view, then, is that there have been lots of lines of humans through the millennium, most of them evolving in Africa, and occasionally migrating out of there where some groups found long-term success (the Neanderthals in the Middle East and Europe, Homo Erectus in China before we “modern” humans arrived).  There are signs in our DNA of a lot of cross-pollination between ancient humans in Africa, which makes sense when we look at other animal populations.  (The fact is that we can’t tell from fossils alone whether our ancestors had spectated to a point where they could no longer exchange genes.  It looks like they hadn’t, despite some surely dramatic morphological and cultural differences.  And, knowing humans as we do, there can’t be much doubt that we would find a way to have sex with just about anything that looked remotely like us).

The DNA evidence also seems to confirm that there was mixing of genes between the Neanderthals and the modern humans that first migrated into their areas (there is no sign of this mixing in modern African populations, nor of modern human DNA in Neanderthals), as well as some mixing going on between modern humans and Homo Erectus in Asia.

What we begin to see is the natural ebb and flow of reproduction among related species in a way that fits with what we observe in other animals.  And here is the key: it has taken us a while to really see ourselves as being “just like” the other animals.  (Even in science, we held on to an idea of our specialness, even when it kept us from properly interpreting the data of our origins).

But having at long last made that intellectual leap, we can now begin to appreciate what we think we know about our evolution.  The picture is complex and rather sobering.  For it turns out that there have, indeed, been countless groups of human varieties since we split off from our last common ancestor with modern apes (but even then, there was much cross-breeding for a very long time!).  If this is true, what happened to all of the other groups of “humans” that did not lead directly to us?  The answer is that they went extinct, in groups large and small.

But not too large, for it appears that the most critical factor in the evolutionary leap that we refer to as the Neolithic Revolution may have had almost everything to do with population size.

Modern studies of hunter-gatherer populations give us a picture of what happens to groups of humans when their numbers drop below a certain threshold: we revert to more primitive means, losing the gains in culture and technology that we achieve when we have more of our fellow humans to exchange ideas (and genes) with.  This, combined with our extended period of childhood (compared to other primates and, it is assumed, other early humans) may be what gave us the advantage over all of the other groups of our “cousins” that managed to hang on to their basic, set ways, for thousands of years but, in the end, could not adapt well (or rapidly) enough to avoid oblivion.

The nice (if we can call it that) thing about this conclusion is that it does make us feel a bit special for being, well, the ones that “won”.  On the other hand, there rests beneath this understanding the uneasy realization that we were incredibly lucky.  For the evidence also suggests that our lineage was down to just a few thousand individuals at times in our history (for more on this look up our “Mitochondrial Eve”).  It also tells us that perhaps Homo Erectus or even the Neanderthal’s might have done equally well had they ever had the right “breaks” that allowed their numbers to expand.

The other stunning part of our story is how we went from being a fairly dispersed species of low population density for pretty much all of our history to numbering in the many billions in an astonishingly short time.  That, somehow, once we got a foothold on our “modern” state of mind (and had developed the social structures and technology to support our increasing numbers) we went from one more smallish troop of naked apes to the dominant life form on the planet.

The “true” story of we modern humans is one of heartbreaking drama, and deeply humbling knowledge.  Entire species of our fellow humans went extinct at different times (the Neanderthals as recently as 38,000 years ago, Homo Florensis — the “Hobbit” — perhaps only 8,000!).  We lost our cousins (or drove them to the brink of extinction) the same as any other modern animal that stands as one of the survivors.

But we couldn’t even come to this picture of the many branches of our human family until we let go of the idea of a single-file, heroic march through time.  Only then could we see the evidence for what it could actually tell us.

This capacity: the courage to see ourselves as we really are, is a huge achievement for us as a species, and perhaps we must give most of the credit to the objectivity of science, and the scientists themselves who have had to fight the same self-centered tendency that is shared by their entire species.

As time goes on, we will continue to discover more fossils.  New technologies (and new knowledge) will wrest more information from those discoveries.  It may well be (it must be, in fact, highly likely) that there will be even more dramatic twists and turns to our human story.  But at least we are now, it seems, ready to hear the truth.

t.n.s.r. bob

REVIEWS FROM THE REV: “A Fossil Tour of Las Cruces”

Sunday, March 6th, 2011

Something Permian this way comes...leaving tracks.

I find a certain comfort and satisfaction in looking at fossils of past life.  I think this comes from a bit of wonder at their mere existence, realizing that fossilization could only occur in certain types of environments and conditions.  And then there is the age of the things themselves, which can easily boggle the mind.  But mostly what I feel is a connection with the extinct life forms they represent.  They once lived: I live today.  Each bit of fossilized bone is a remnant of a single individual animal that lived for a set length of time before dying.  I, of course, will follow this same arc of life.  Chances are, however, that I will not fossilize, but will take the route of decay back into the elements and atoms that formed my body and be dispersed and re-utilized by some other life form down the road.

So, just in case any of you in the Las Cruces area share my idea of a good time, let me point out some of the nifty bits of natural history that are scattered about in the area.

Of course there is the Las Cruces Natural History Museum (located near Penneys in the Mesilla Valley Mall, southwest corner of Telshor and Lohman), that contains a few slabs of the renowned “Permian Trackways”.  (If you happen to be visiting the Thomas Branigan Memorial Library in Downtown Las Cruces, they also have a footprint on display in the southeast corner of the main floor, in a display case above the video department).

I love this Minke Whale. Check out those hip bones!

Moving on to the New Mexico State University Campus, the place is littered with some impressive (and beautiful) bits from the Zuhl Collection.

Starting with a huge fossilized tree trunk resting on the corner of Jordan and Stewart Streets (across from the swimming pool), you can stop into the lobby of the Zuhl Library lobby, and find a cast of the T-Rex “Stan”, and a dinosaur leg bone as well as a display of polished petrified wood, and some neat fossils of smaller fauna (though there is a nice display in the lobby, pieces are scattered throughout the floors of the library).

Take a walk down the “International Mall”, walking West, and just past Branson Library, you’ll find the entrance to Foster Hall.  Step into the lobby and look up to see a mounted skeleton (not a fossil) of a Minke Whale.  I love this whale.  Mostly for its two small vestigial hip bones left over from the critter’s evolution from four-toed ungulate to sea-dwelling mammal!

Brachiosaur Humerus in Gardiner Hall at NMSU.

Head north from Foster Hall, across the “Horseshoe” to Gardiner Hall, the new home of the Geology Department.  Walk in the front and take a right, and you’ll find yourself in a hallway packed with fossils and minerals on display down the length of an entire hallway.  A complete humerus of a Brachisaur, mammoth bits, and fossilized fish.  They are still organizing the displays, so many items are not yet marked, but plenty are.
If you head further west down College Drive, look to your right before you hit El Paseo for the home of the Zuhl Collection’s main display building (just east of the NMSU Police/Parking department).  A large mounted petrified log marks the spot.  This is a compact, but very impressive collection of fossils, petrified wood and minerals.

We may not be a Chicago Field Museum, but with a little bit of looking you can, literally, get your hands on some really ancient history in your own backyard.

Click her for NMSU Maps.

t.n.s.r. bob

REVIEWS FROM THE REV: “The Zuhl Collection”

Sunday, September 19th, 2010

Oviraptor egg nest at The Zuhl Museum

There is a little gem of a museum tucked away on the campus of New Mexico State University in Las Cruces, New Mexico.  Only a short distance from the corner of Union Avenue and College Drive (right next to the NMSU Police and Parking Departments) is The Zuhl Museum, which houses a stunning collection of minerals, petrified wood and fossils.  Though you can also find some dramatic pieces on display in the Zuhl Library on the main campus, the Museum is easy to reach at any time of the day (and parking is not a problem!).

I get the sense that the University built the Museum as a condition of the large donation from the Zuhls that resulted in the re-naming of the Library, but that doesn’t detract from the sheer quality of the pieces on display there.  It’s a modestly-sized space, but it is well-lit and arranged, and densely packed.  Definitely worth a visit.

As a side-note, there are also a few fossils on display in the hallways of Breland Hall, and a complete skeleton of a Minke Whale hangs from the ceiling of the entry atrium of the Biology Building on campus (where you can see the vestigial bones of what used to be the whale’s hips when it was still a land-dwelling quadruped).

Minke Whale skeleton in the NMSU Biology Building

(From the NMSU website) The Zuhl Museum is housed at the NMSU Alumni and Visitors Center, 775 College Drive, near the northwest campus entrance. Hours: 8:00 a.m. to 5:00p.m. Monday through Friday excluding holidays. For more information please call 575-646-3616 or 575-646-4714.

t.n.s.r. bob