It’s time to go spanning the globe for anatomy news and notes!
Fish Gills & Outer Ears
Our human outer ears may have a direct evolutionary connection to prehistoric fish gills, according to a fascinating new report that was written up by LiveScience. In fact, our outer ears may have “evolutionary roots” in ancient marine invertebrates such as horseshoe carbs. The work was led in part by Gage Crump, a professor of stem cell biology and regenerative medicine at the University of Southern California.
The origins of the outer ear have been a mystery. The middle ear? Not so much. Scientists long ago discovered that our middle ears are the transformed and repurposed jawbones of ancient fish. Prior to this new work, however, Crump said the outer ears were an evolutionary “black box” of unknowns.
The key was tracing the elastic cartilage in humans’ outer ears to the ancient fish. Using protein stains, the scientists found that the gills of zebrafish, Atlantic salmon, and other species of fish also contained elastic cartilage. The original, much more detailed research was first published in Nature magazine.
Dinosaurs’ Early Stomping Grounds
Did dinosaurs evolve in a much hotter and drier part of the world than previously thought? To date, Argentina and Brazil have been considered the likely home for the earliest dinosaurs of some 230 million years ago. But Eoraptor and Herrerasaurus were already dinosaurs at that point in time, meaning they had even evolving for many years before. “Many” as in probably millions of years.
In fact, there’s one big problem and that is the “dinosaur tree” has very large gaps. Now scientists are turning their attention closer to the equator.
“When you consider the gaps in the fossil record and the evolutionary tree of dinosaurs, it could very likely be a centre point for where dinosaurs originated,” says Joel Heath at University College London in this article in New Scientist.
At the time, Earth’s land masses looked much different. There was the single supercontinent called Pangea and its middle straddled the equator. But Heath and others built computer models to work backwards in time. In case you’re wondering, we have no idea how to ask a computer to factor in gaps in the fossil record. Or to account for geographic barriers that would have limited the dinosaurs’ range. Or how to inform the computer model that there are uncertainties about how the dinosaurs are related to each other. We have no idea, but we’re glad they do. This is all critical in understanding how the pieces all fit together.
The result, however, is that scientists need to set aside their thinking that dinosaurs could not have originated near the equator in an area that would have been very hot and very dry at the time.
In fact, dinosaur digging has overlooked such areas and, recently, a team from University of Wisconsin-Madison may have found the oldest known dinosaur from the northern part of Pangea. In fact, they discovered a species, a sauropodomorph related to long-necked dinosaurs like Diplodocus that evolved later.
Where was the find? In today’s Wyoming.
We will follow this story with interest! And might take a drive to the Cowboy State.
Stop And Wonder
It never hurts to stop for a second and remind ourselves about the incredible features, talents and facts about human anatomy.
Here are five fun ones from a list made for kids (and we are still kids when it comes to pondering this kind of stuff):
Your mouth produces about one liter of saliva every day.
Laid end to end, an adult’s blood vessels could circle the Earth four times.
The word “muscle” comes from Latin for “little mouse” because Ancient Romans thought a flexed muscle looked like one.
Nerves carry information at 400 kilometers per hour (about 248 miles per hour).
Scientists estimate that your nose is capable of recognizing one trillion different scents.
Especially bacon.
(Just kidding.)
Anyway, it’s always fun to take a few minutes and stop to think about how we’re all put together.
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