Finding Your Inner Fish

Finding Your Inner Fish

• Summers are spent in the Arctic Circle searching for ancient fish bones.
• Ancient fish bones provide knowledge of the structure of our bodies.
• Skeletal remains from the past offer clues about the fundamental structure of bodies.
• Animals from the past are rarely preserved over time.
• Over 99% of all species that ever lived are now extinct.

Digging Fossils—Seeing Ourselves

• The "inner fish" was discovered while studying 375-million-year-old rocks on Ellesmere Island.
• The goal was to discover a key stage in the shift from fish to land-living animals.
• Paleontologists find fossils with surprising precision and predictability by designing expeditions to answer scientific questions.
• Field paleontology requires planning to get to promising fossil sites.
• Plans can be altered based on facts on the ground.
• Important fossils can be predicted to be found.
• Discoveries have been made regarding mammal origins, frog origins, and the origins of land-living animals.

Fossil Discoveries

• Field paleontologists can find new sites easier than ever before, due to increased geological knowledge and internet access to maps and aerial photos.
• Imaging and radiographic devices help visualize bones inside rocks.
• The hunt for important fossils still requires looking at rocks and removing fossils by hand.
• Fossil sites are rare.
• Maximizing success requires rocks of the right age and type that are exposed at the surface.
• Serendipity also plays a role.
• The invasion of land by fish is a great transition in the history of life.
• All life lived in water, until about 365 million years ago when creatures inhabited land.
• Life in water and on land requires different organs.

Fossil Order & Fossil Expeditions

• Fossils in rocks are not arranged at random, but in an ordered way.
• Rocks on the top are younger than rocks on the bottom.
• Earth's crust movements can cause faults that shift rock layers.
• Paleontologists can piece the original sequence of layers back together once faults are recognized.
• Fossils inside rock layers follow a progression: lower layers contain species different from higher layers.
• A single column of rock containing the entire history of life would show how life evolved
• Predictions can be made about what species in each layer might look like by comparing them with animals alive today.
• Fossil sequences in rocks can be predicted by comparing ourselves with animals at a zoo or aquarium.
• Living things can be organized like a set of Russian nesting dolls.

"Everythings"

• Every species has a head and two eyes, "Everythings."
• A subset of creatures with a head and two eyes has limbs, "Everythings with limbs."
• Headed and limbed creatures with a huge brain, that walk on two feet, and can speak are humans.
• This threefold division of "everythings" has predictive power.
• The fossils inside the rocks generally follow this order.
• The first member of the group "Everythings,” is found in the fossil record well before "Everything with limbs."
• First fish appears before the first amphibian.

Research Labs & Geological Time

• Labs analyze thousands of characteristics and species to show groups within groups.
• Hundreds of years of fossil collection have produced a catalog of the ages of the earth and life on it.
• Scientists can identify general time periods when major changes occurred.
• Early Mesozoic rocks date back 210 million years and are of interest to those studying the origin of mammals.
• Cretaceous period rocks date back 80 million years and are of interest to those studying the origin of primates.
• The order of fossils in rocks shows the connection of all life.

The Hunt for Relatives

• There is strong geological evidence of a period dating from 380 million to 365 million years ago.
• Younger rocks include diverse kinds of fossilized animals recognized as amphibians or reptiles from 365 million years ago.
• Jenny Clack uncovered amphibians from rocks in Greenland.
• Rocks that are about 385 million years old contain fish with fins, conical heads, scales, and no necks.
• Focus should be maintained on rocks about 375 million years old to find the transition between fish and land-living animals.
• The challenge is to find rocks that were formed under conditions capable of preserving fossils.
• Initial environmental settings leave distinct signatures on the rock layers.

Fossils & Sedimentary Rocks

• Volcanic and metamorphic rocks should be dismissed as good fossil sites.
• Sedimentary rocks are ideal to preserve fossils: limestones, sandstones, silt-stones, and shales.
• The gentler the flow of the stream or river, the better preserved the fossils.
• Each rock tells a story about what the world looked like when that particular rock formed through past climates and surroundings.
• The search can be limited to rocks that are roughly 375 million to 380 million years old that formed in oceans, lakes, or streams.
• The best places to look are where bones are "weathering out,” for fossil bones erode at a slower rate.
• Ideal fossil-hunting sites have little soil cover and little vegetation and have been subject to few human disturbances.

Hynerpeton

• Initial important discoveries happened along a roadside in central Pennsylvania.
• A local project doesn't require big research grants.
• The lure was the Catskill Formation of Pennsylvania, spanning the Late Devonian.
• These rocks were perfect to preserve early limbed animals and their closest relatives.
• The Devonian image is best thought of as the Amazon River delta with highlands and a large sea where Pittsburgh is today.
• Blasting by the Pennsylvania Department of Transportation (PennDOT) has exposed rock along roads
• Ted Daeschler arrived to study paleontology with a unique partnership.
• Hynerpeton, means "little creeping animal from Hyner."

Arctic Expeditions Begin

• After the discovery of Hynerpeton, there was a move to better-exposed rock.
• A "textbook" approach was taken, looking for well-exposed rocks of the right age and the right type in desert regions.
• Alaska and the Yukon were potential venues for a new expedition for relevant discoveries.
• Ancient freshwater streams were believed to be the best environment in which to begin the hunt.
• A diagram showed three areas with Devonian freshwater rocks, with river delta systems.
• The areas included east coast of Greenland, eastern North America, and the Canadian Arctic.
• The Arctic area perfectly fit all three of the criteria: age, type, and exposure, but it was unknown to vertebrate paleontologists.

Risk of Polar Bears

• Arctic expeditions face the risk of being eaten of polar bears, running out of food, or being marooned by bad weather.
• There had to be eight days planning for every day spent in the field, because the rocks were accessible only by air and the nearest supply base was 250 miles away.
• Limitations included a small time window to work in the Arctic and plane weight limits.
• Farish A. Jenkins, Jr. had led expeditions to Greenland and helped launch this venture.
• The team consisted of Ted, the former student; Farish, the graduate adviser; and the author to try to discover evidence of the shift from fish to land-living animals
• The first thought is of polar bears and scanning the landscape for white specks that move.
• One of the crew saw a moving white speck that looked like a polar bear until it turned out to be a hare
• Rocks exist over an area about 1,500 kilometers wide.
• It took four expeditions to Ellesmere Island over six years to find fossils.

Fossils & Scientific Analyses

• First sites were on Melville Island with rocks loaded with deep-water creatures.
• In 2000, Ashton Embry's geological analysis led to the expedition moving east to Ellesmere Island.
• In 2000, the real breakthrough came toward the end of the field season.
• Jason Downs, then a college undergraduate, found a carpet of fossil fish bones on the side of a hill between two river valleys.
• Finding the source of fragments was difficult due to Arctic temperatures that plummet in the winter and rise nearly 50 degrees in the brief summer.

Southern Ellesmere Island

• The base of work was in southern Ellesmere Island, in Nunavut Territory, Canada, 1,000 miles from the North Pole..
• All the fish found were well-known species from sites in Eastern Europe and were not related closely to land-living animals.
• The decision was made in 2004 to give the search one more try.
• In early July 2004, a patch of scales was discovered that had been a set of jaws connected to a flat head.
• Steve Gatesy revealed the snout of an animal with a flat head looking right out at him.
• Steve removed rock bit by bit in order to bring the entire skeleton back to the lab which led to the discovery of one of the finest fossils at the water–land transition.
• The rock as removed piece by piece with dental tools

Fish & Early Land Animals are Different

• What emerged in the fall of 2004 was an intermediate between fish and land-living animals.
• Fish have conical heads; early land-living animals have crocodile-like heads that are flat, with the eyes on top.
• Fish do not have necks, land animals do.
• Fish have scales all over their bodies; land-living animals do not.
• Fish have fins, land-living animals have limbs with fingers, toes, wrists, and ankles.
• The new creature has scales on its back and fins with fin webbing, it has a flat head and a neck.

Intermediate Forms

• Bones corresponded to the upper arm, the forearm, even parts of the wrist: a fish with shoulder, elbow, and wrist joints all inside a fin with webbing.
• Virtually all features with land-living creatures look primitive.
• The shape and various ridges on the fish's upper "arm” bone, the humerus, look part fish and part amphibian.

Tiktaalik Provenance

• The fossil confirmed the prediction of paleontology that a new fish was an intermediate found in the right time period and in the right ancient environment from 375-million-year-old rocks formed in ancient streams.
• The elders suggested Siksagiaq and Tiktaalik.
• Tiktaalik, it means "large freshwater fish” in Inuktitut
• Tiktaalik was the lead story in newspapers.
• Other children started to voice their dissent until they realized "Maybe it is both."
• neck of Tiktaalik has a set of bones that attach the skull to the shoulder.
• The head is completely free of the shoulder shared with amphibians, reptiles, birds, and mammals.
• It is traced to the loss of a few small bones in a fish like Tiktaalik.

Tracing Arm Bones

• Other parts of the skeleton can be traced such as the wrists, ribs, ears.
• This fossil is just as much a part of history as the African hominids, which lead to the prediction of the types of fossils around the world.
• The first member of “everything with head is found before" or predates “everything with limbs."
• More precisely, first fish predates amphibian.
• The rocks from the Early Mesozoic are rocks likely about 210 million years old
• Those interested in the origins of the mammalian go there.
• Rocks from the Cretaceous are rocks likely about 80 million years old
• Those interested in the origin of primates go there.
• If the earliest jellyfish in 600 million year old rocks was found to be found side by side next to the skeleton of a woodchuck, it would tell much of what we about the history of earth is wrong

Getting a Grip

• Dissection can become deeply and emotionally personal when the hand is uncovered.
• There are ten different muscles and at least six different bones in the hand that work in unison.

Human and Animal Structure

• The relationship between complexity and humanity within our hands has long fascinated scientists.
• Sir Charles Bell. wrote the classic book: The Hand, Its Mechanism and Vital Endowments as Evincing Design, with the structure of the hand being "perfect" with a divine origin.
• Sir Richard Owen was a scientific leader in the search for divine order within bodies who described the first gorilla and coined the name “dinosaur”.
• There is a pattern to the skeleton of a human arm: one bone in the upper arm, two bones in the forearm, a bunch of nine little bones at the wrists, then followed by a series of five rods that make the fingers.
• All creatures with limbs, whether wings, flippers, or hands, have a common design.
• This pattern underlies the architecture of all limbs with unique structure.
• There is a fundamental design in the skeleton of all animals: frogs, bats, humans, and lizards with variation on theme.

Darwin Vs. Owen

• Charles Darwin supplied an elegant explanation for it, based on the presence of a common ancestor.
• Darwin's theory allows us to make very precise predictions compared to Owen
• Owen's blueprint has a history that will be revealed in creatures with no limbs.
• The history of the limb pattern can be found in fish and their fin skeletons.
• In Owen and Darwin's day, the gulf between fins and limbs seemed impossibly wide.
• In mid-1800s, fish with lungs who have single bone at the base became significant.
• A trivial pattern in the fins fish had a profound impact on science.

Fish & Evolution

• Devonian rocks that are between 390 million and 360 million years old reveal the history of fins and limbs.
• A new research program was defined that sought the the origin of fingers and toes in the Devonian rocks.
• In the 1920s, Gunnar Save-Soderbergh, was given the opportunity to explore Greenland for fossils.
• His team discovered a major missing link between 1929 and 1934, which were described later on by his colleague Erik Jarvik.
• Ichthyostega is a remarkable intermediate with the fish having fish like heads and tails, with fully formed limbs (with fingers and toes), and vertebrae that were extraordinarily amphibian-like.
• Acanthostega had full limbs who was shape like the flipper of the seal and the earliest limb to walk
• In 1995, after driving through Pennsylvania, the PennDOT created a cliff from the roadside.
• Near Daisy there was the realization for bone inside boulder. Owen's pattern was found to be an important discovery.
• Need to find the right fins was a major key for fossil hunting.

Looking Forward

• For that find, almost ten years of searching.
• Fred Mullison and Bob Masek are used dental tools, and Bob had pulled Cube bone in big fin.
• A week later a find would that a Fred uncovered led to the discovery that this was an ancient find of wrist that attached to bone that led "had that bone”
• Over the next months there was part that contained that limb but the side the version that lead of Owen’s structure.
• It was later discovered that Tiktaalik was the first to have push up
• Tiktaalik's body was capable of all of this, with "palm" that also laid flat.
• Crest the attached themselves to bone that had been found in "that place and structure”
• The fossil had a fin in which which was shoulder, elbow, with a wrist that was type of push with it
• Tiktaalik was built that what ever way you want, there was even bank that the mud of rock
• Fin was very necessary and a key to move in every situation.
• Most of the time is found was preditation was very in fact was in a very bad position because it was sixteen fleet tall!!

Evolution of Features

• Most important things to get out of it or go and be more in the armor
• Joint that made it "earlier" has become and structure
• From Tiktaalik to be amphibians all what do they do? (Not to be like "creator or not and all that")
• Is it that had bone to be the legs and the wrist bones of it can be the reptile.
• Is it all the bone structure that makes it use our hands
• The structure of ball and socket is the same
• When Tiktaalik bends we can see there that a part radius is there and it also can mean and or to the same meaning “pronate that”.
• When we face our limbs with opposite ends, we share this is what other mammals.
• A difference in the situation is eustrenoptery
• With the growth , the elbow rotates just what the humans show in todays era.
• the structure of the hip has came to for the bones.
• Deep origins have led to the development ancient fish.
• There is is also a very "deep connected in between the human wrist or to had"