Archimedes, Atoms and Archaeopteryx

Peter L. Larson, paleontologist and geologist, is a paleontologist and the president of Black Hills Institute of Geological Research in Hill City, South Dakota. Larson is on the research team investigating Archaeopteryx and other fossils at the SLAC National Accelerator Laboratory. Today he blogs about the fossil Archaeopteryx and how high powered X-rays helps us learn new things about this unique fossil.

  
Paleontologist. Pete Larson (left) at the SLAC National Accelerator Laboratory.

The discovery, sale and subsequent scientific examination of the sole surviving thousand year old palimpsest recording the work of Archimedes (who died in 212 B.C.) has made it possible to study fossils using high energy x-rays to map the distribution of elements across the surface of the rocks containing their remains. A group of scientists gathered at the Stanford Synchrotron Laboratory in Menlo Park California to study one of the iconic “missing links” of evolutionary biology, Archaeopteryx. This investigation was able to show that not only was there original material from the living Archaeopteryx preserved in the dino-bird skeleton, but that the “feather impressions” were not impressions of feathers, but the feathers themselves, preserved in the limestone matrix for more than 145 million years. This research has opened a door to a new dimension for the study of fossils. It gives us a new way to study soft tissue, the chemistry of preservation, and details that everyone thought were lost in time.

For details about the X-ray Fluorescence imaging of the Thermopolis specimen of Archaeopteryx, see the May 10, 2010 issue of the Proceedings of the National Academy of Sciences.

Take a tour of our current Archaeopteryx: Icon of Evolution exhibit with Pete in the video below, and don’t miss your opportunity to ask him questions during our upcoming online webinar session. Join us on June 17 at 10 a.m. as Larson answers questions about Archaeopteryx, the exhibition and his own research. Register here, or see instructions below.

Archaeopteryx: Tour the Exhibit with Pete Larson from HMNS on Vimeo.

To register for our online webinar with Pete Larson
1)      Click here.
2)      Click “Register.”
3)      On the registration form, enter your information and then click “Submit.”


How To Make a Perfect Fish – Two Views

Ed Note: Many fossils from the periods discussed and the Solnhofen locality are currently on display in Archaeopteryx: Icon of Evolution. Join a live online discussion about the latest research into the title fossil with paleontologist Pete Larson on June 17.

Intelligent Design – For Jurassic Fish

Louis Agassiz

Right now,  in the 21st Century, the “Intelligent Design” is the latest development in arguments about Creation versus Evolution. Bur it’s not a new idea. The Father of Fossil Fish Science, Louis Agassiz, used Intelligent Design to explain Solnhofen sharks and bony fish in the 1840’s and 1850’s.

Here’s how Agassiz laid out the argument:

Expert Engineering in Fins and Jaws
Fish today have bodies that fit their environment. Bottom-living sharks and rays have flat bodies. Fins and teeth are “designed” to crush clams and crustaceans these predators find hiding in the sea bottom. In the open sea water, fast-swimming mackerel have thin scales, plump, streamlined bodies, and tall, narrow tail fins that seem ‘designed’ to catch small fish in fast attacks.

Jurassic Fish Were Built For their World
Each and every slice of geological time had fish shaped just right to fit their ancient habitats. The Solnhofen Gyrodus had the deep body ideal for hovering in quiet water near a reef. It carried incredibly strong teeth, dental tools that let the fish bite off chunks of coral and snatch clams embedded in the reef.

In Every Period, Fish Habitats Were Balanced
Each extinct habitat was balanced by precisely the right sort of predators and prey. Gyrodus pruned the reef, eating away excess algae, crabs and coral growth. That way the reef stayed healthy and no species became over-abundant. The aggressive reef predator Aspidorhynchus hunted the Gyrodus and kept its numbers down to just the right levels – not too rare, not too common. The big, fast teleost predators, like Thrissops, did their job in keeping Aspidorhynchus numbers in check.”

According to Jurassic Intelligent Design, the entire Solnhofen reef ecosystem was crafted by an unseen Creative mind that planned every detail.

Serial Creation, Agassiz’s view of Creation was not static. The entire World Ecosystem was revolutionized by change every million years or so. At the end of the Jurassic, many fish species went extinct. New species appeared. More extinctions and more waves of new species appeared at the end of the Cretaceous. More and more extinction-replacements occurred all through the next  Period, the Tertiary.

These revolutions were necessary because the World Climate changed fundamentally. Jurassic seas were tropical and Jurassic lands were as steamy as hot-houses. But the climate got cooler in later Periods. The fish that were perfectly designed for the Jurassic were not optimized for the Tertiary Period. Each new wave of extinction and replacement was required to maintain the exquisite balance in reef and coral-biter, coral-biters and Apex Predators.

The Theory of Natural Selection

Charles Darwin

Darwin and the Perfect Fish
Charles Darwin too was worried about perfectly designed fish. He recognized the extraordinary adaptations in predators that let them catch prey and the delicate balance among species in most habitats. But Darwin argued that natural processes could make ecosystems perfect, or nearly so. His theory had only a few simple steps:

All jaws and fins and bodies vary in all species
When a naturalist studied hundreds of specimens of Gyrodus or a living species, jaws and teeth and fins varied within the the species. Studies of domestic animals – Darwin liked pigeons – proved that much of the variation was genetic. Breed a tall pigeon female with a tall male and the chicks were, on average, tall. Breed a bigger than average goldfish with another big goldfish, and their young will be bigger than average.

Variations Pop Up All the Time
In 1859, when he wrote “The Origin of Species”, Darwin didn’t know where variations came from. The understanding of genes wouldn’t come until after 1900. But Darwin did know that new genetic variations arose in every population.

Nature is Cruel and Most Individuals Die Young
A big reef fish might spawn a hundred youngsters each summer. Few would live beyond six months. Only 1% or less would survive to breed. That’s the basic calculus of ecosystems.

Nature “Selects” the Genetically Fortunate
If a fish or wild pigeon hatches out with just the right genes, it gets an advantage. It can live longer, grow faster, and reproduce earlier than its relatives. Generation after generation, the lucky genes accumulate. In a thousand generations, a fish or bird species can be transformed.

Natural Selection Works All the Time to Keep Systems Nearly Perfect
Nature keeps selecting the lucky genes and keeps most of the species ideally “designed” most of the time.  That’s how Jurassic predators were kept fine-tuned to their prey. When climate changed abruptly, old species died out and new ones evolved.

Flat-Footed Reptiles to High Stepping Chickens

Most scientists believe that birds evolved from small therapod dinosaurs. The key step was the development of feathers, turning animals that could walk or climb into animals that could fly. In today’s post, Dr. Bakker discusses the evolution of a key feature of Archaeopteryx, the first dinosaur to be discovered with preserved feathers.

Lizard Paws to Chicken Fingers

320 million years ago – the first reptiles evolve, the earliest vertebrates that can lay air-breathing eggs on land.  Legs are sprawling and flat-footed. The front paws have five fingers, all with claws.

250 million years ago – the first archosaurs evolve, the close kin of crocodiles and birds.  Legs are more upright but still flat-footed. The hands have only three claws. The outer two fingers are thin and claw-less.

225 million years ago – the first dinosaurs evolve. Legs are upright and the heel held high, off the ground. The outer two fingers are weak.

160 million years ago – the earliest raptor-like dinosaurs evolve. The outer fingers are gone. Hind-legs are used for running and ankles are tall and thin. The three clawed fingers are long. And there’s a swivel joint on the wrist to let the hand move quickly side-to-side.

150 million years agoArchaeopteryx evolves. Hind legs are like those of raptor-type dinosaurs. The hand is almost exactly like a raptor-dinosaur’s.

110 million years ago – the first modern-style birds evolve. Hind-legs have stiff ankle bones, all fused together. The wrist bones too are all fused together and no fingers have claws.

Want to know more about our current Archaeopteryx exhibit? Check out this article on PlanetEye Traveler.

Interested in learning more about paleontology? Check out our past blogs.

Whole-Hole Catalogue: The Horned Meat-eater Ceratosaurus

Here’s the skull and life portrait of the carnivorous dinosaur Ceratosaurus, from the Late Jurassic of Colorado, Wyoming and Utah.  It’s the only meat-eater with a tall, sharp-edged horn on its nose.

(And it’s my very favorite dino of all time – isn’t it just lovely?).

Check out the holes in the skull and the organs that fill the holes in life.

The nostril is no surprise, it’s the oval slit up front.

The eye is in the third big hole from the front.

The very big hole between nostril and eye is for the complex air chambers connected to the throat – birds have these chambers too.

The triangular hole behind the eye was filled with jaw muscle.

The eardrum was located far aft, behind the muscle hole, tucked under a little ledge made by the skull.

Who had a stronger bite, Ceratosaurus or Tyrannosaurus? Compare the size of the holes for jaw muscles……..

Interested in learning more about dinosaur skulls? Check out my previous blog.