Category Archives: Science

The Role of Marshes in Ancient City Sustainability: Recent Findings & Modern Applications

Until current research brought the prevailing opinions of leading archaeologists into question, it was widely believed that ancient cities in Mesopotamia sprang up alongside rivers. The theory was that river proximity allowed ancient city inhabitants to irrigate the surrounding desert, thus making the land arable. It was thought that cities such as Ur, which is believed to have originated near the mouth of the Euphrates River sometime in the 25th century B.C., were able to sustain themselves because of their ability to irrigate the surrounding areas with river water.

New Ideas

Interestingly, Dr. Jennifer Pournelle of the University of South Carolina has been pursuing a different explanation for the connection between water and ancient cities. She posits that early urban areas in Iraq were sustainable because of their location in marshes, not beside rivers.

Marsh Arabs in a mashoofThis might seem like a technicality, but it’s an insightful observation that’s changing the way archaeologists perceive the origins of ancient urban areas. If Iraq’s ancient cities thrived in lowland marshes fed by rivers, their inhabitants used resources in different ways than they would have if they had relied on irrigation to provide them with a way to grow food from the land. Pournelle and her research team have reason to believe that Iraq’s ancient southern cities were successful because of their location in marshes that easily sustained rice crops.

Digging Deeper

Together with an archaeologist from Pennsylvania and a geologist from Missouri, the South Carolinian research assistant combined excavation records, archaeological site maps, and aerial and satellite images to recreate an accurate representation of the ancient environment in southern Iraq. Pournelle’s work differs from previous efforts to study the ancient urban characteristics of this area in several ways. First, her efforts are the most recent after a short burst of interest from 1900 to 1950. Additionally, her work includes a comprehensive study of flora and fauna where previous archaeologists focused mainly on objects and architecture. And with recent developments in technology, she’s been able to combine research strategies to reveal a more holistic view of the ancient cities that thrived in the marshes of southern Iraq.

According to Pournelle’s work, marsh resources, wildlife, and environmental conditions were vital to the process of sustaining cities. These same conditions are also integral to our understanding of these civilizations and how they were able to function. In an interview published in a physorg.com article, Pournelle confidently states that the key to these cities’ long-term survival, as compared with cities in other environments, was the wetlands. Marsh areas have their own distinct ecology, different from riverside environments, and those unique characteristics were vitally important to some of the oldest cities in the world.

Iraq and South Carolina

Connecting past and present, Pournelle points out some of the commonalities between ancient (and modern) Iraq and the current problems being faced in South Carolina. She thinks that the two  regions, which have  similar environmental characteristics, can inform us about important modern-day issues. Both Iraq and South Carolina are working to overcome problems with water resource management, pollution control, coastal and port development, and environmental management.

Pournelle plans to continue her research in Iraq, hoping to uncover ancient sustainability strategies that might have parallel applications in her own century and state.

Author

Maria Rainier is a freelance writer and blog junkie. She is currently a resident blogger at First in Education where she writes about education, online degrees, and what it takes to succeed as a student taking a bachelors degree program remotely from home. In her spare time, she enjoys square-foot gardening, swimming, and avoiding her laptop.

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Mammoth protein designed to be cool

Researchers were recently able to isolate and study woolly mammoth hemoglobin and compare it to the modern African and Asian elephants. They isolated the genes from DNA that code for the creation of hemoglobin, the protein that carries oxygen in our blood. This was done for both the modern elephant species, as well as from DNA from mammoth bone from Siberia. They observed some minor differences between all the species, so the researchers wondered if the difference in the mammoth’s blood might have helped it survive in cold climates.

Hemoglobin supplies our body with oxygen by carrying it around in our blood stream and then releasing it to our tissues. When our tissues need more oxygen, like for muscles that are working hard, hemoglobin more easily releases oxygen because of the higher temperatures created by the heat generated by the muscle. However, in colder temperatures, hemoglobin does not give up oxygen as easily. This is potentially a real problem in colder climates. To keep the hemoglobin to working effectively an animal might need to expend valuable energy to maintain a higher body temperature.

The researchers (Campbell et al. 2010) wondered if the slight differences in woolly mammoth hemoglobin might have been an adaptation for living in colder temperatures. They inserted the Asian elephant genes that make hemoglobin into the common bacteria, Escherichia coli, and allowed the bacteria to act on the genes, thereby making Asian elephant hemoglobin. This process is not new as it is commonly used to have bacteria produce proteins that are identical to human-made proteins, like insulin.

To get the bacteria to make mammoth hemoglobin, they needed to modify the Asian elephant genes the same way they observed, then let the bacteria make the hemoglobin of a mammoth—thousands of years after the mammoths last did it themselves. Researchers could then compare the protein of the two species directly. The result was that mammoth hemoglobin released oxygen much more effectively at lower temperatures.

Woolly mammoths from Alan Turner (2004), National Geographic Prehistoric Mammals.

Woolly mammoths from Alan Turner (2004), National Geographic Prehistoric Mammals.

Woolly mammoths were adapted to colder climates in a number of ways, such as compact bodies, small ears, short tails, and long woolly hair. This result strongly suggests that their bodies were also changed at the molecular level for life in cold, high latitude climates during the Ice Age. It would be very interesting to see if other mammoth species, such as the Columbian mammoth, for example, shared this adaptation. But I suppose that will have to wait until we can get good DNA from that species. All in good time.

Campbell, K. L. et al. 2010. Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance. Nature Genetics 42:536-540.

Related posts:
Science in dinosaur movies: Jurassic Park then and now

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I am a paleontologist

I love the science of paleontology for many reasons. The science combines so many other areas of study into one bundle, such as geology, biology, functional morphology, evolution, stratigraphy, and systematics.

Not only that, dinosaurs and other prehistoric animals are just fun! And being fun, paleontology is a great way to introduce people to science in an engaging way. How many young people start their interest in science by learning about dinosaurs, and say they want to be a paleontologist when they grow up–a bunch!

Well, someone shared this video with me and I love sharing it with you. Enjoy! (you may need to scroll down).

Related Posts: check them out.

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Why dinosaurs are not extinct

In the twenty plus years I have been involved in paleontology I have been witness to a revolution within science. The revolution has been quiet, not noticed by most of the public. Like any good revolution, the battles of this revolution took place between two camps, the “traditionalists” and the “radicals” who were out to change things. And this shift is illustrative of how science as a whole moves from one way of understanding to a brand new way of looking at the world. It is, in fact, a paradigm shift that has profoundly changed biology and paleontology forever.

At issue is how we explore and classify the relationships of all living things. The traditional view, the one that I was taught as a young student, was the classification of living things into the taxonomy originally begun by Carl Linnaeus. This system started with a group, and then sought to put things into the group. For example, one can make the observation that animals that look like “dogs” could be grouped together, so you would start with the idea of a dog-group and look for animals that should be included.

You might put foxes, wolves, domestic dogs into the group, and call it the dog family. You might also note that “cats” could likewise be grouped, and do the same thing, creating a cat family. In this view, the families were equal in rank—and there could be no overlap. An animal would be included in only one of the equal-ranked families. Any animal was included in only one class, for example Amphibia, Reptilia, Aves, or Mammalia.

The equal-ranked heirarchy of classifications worked well enough when we mainly were concerned with modern animals. Clearly, birds look different than mammals and reptiles, so it seemed evident they belonged in their own class. But this classification scheme, however well it served us as a place to start, is myopic about how evolution actually operates—how organisms actually evolve. This is understandable since it was started 100 years before evolution as a theory was established.

In trying to shoehorn life into the system, we repeatedly ran into problems as we expanded our knowledge of the diversity of living things and our understanding that the history of life is a complex branching bush. We knew that early tetrapods (organisms with four limbs) gave rise to the early amphibians that crawled out on land, and that they in turn evolved into reptiles, mammals and birds. But despite this branching within tetrapods, the class ranks were forced to be exclusive, so somewhere in evolutionary history was an “amphibian” that had to become a “reptile,” and a “reptile” that had to become a “bird.”

The many transitional forms in the fossil record increasing became impossible to classify. These intermediate animals had to be forced into one class or another. Increasingly, it became evident that many times the criteria used to put an organism into one class were the whims of an individual scientist, and another equally qualified expert with different opinions might place the same animal in a different class with equal validity.

The origin of birds was for a long time a great mystery to paleontologists. Birds are a pretty unique and specialized group, and while we knew that they originated from reptiles somehow, exactly how and when was unclear. One early paleontologist noted that dinosaurs had many features in common with birds, but the early concepts of what dinosaurs were like distracted most scientists from comparing them too closely. After all, the common conception of dinosaurs was as big, lumbering, dim-witted, swamp-dwelling beasts. The bird ancestor must have been light, fast moving, and energetic.

However, dinosaur research over the last thirty years has completely changed our view of them. Evidence from many lines, including things like footprints and the cellular structure of the bones, all point to dinosaurs as being very dynamic creatures. With this new view, the notion that birds were linked to dinosaurs became clear too. Now, we have dinosaur fossils with feathers, and birds with teeth and dinosaur tails to attest to their close relationships. In fact, birds are most closely related to the meat-eating raptor-like dinosaurs of Jurassic Park fame.

To go along with the revolution in our view of dinosaurs was that revolution in science that I mentioned above–the emergence of a new way to understand the interrelationships of life on Earth. This new model accommodated the myriad branching events that life actually experienced in order to produce the great variety of living things. So, instead of starting with a conception of the group and looking for members, this new concept looked at the branching patterns evident in life, and then sought to apply names.

Below is an illustration of the branching pattern of selected tetrapods, those vertebrates with four well developed limbs. As the first tetrapods gave rise to new and different groups, the branches split off. An early tetrapod gave rise to amphibians and the other animals above it on the chart (mammals, turtles, etc.). A later tetrapod developed traits related to the production of eggs and young that we recognize as the Amniota. Some of those early amniotes went off on an evolutionary trajectory that we can recognize as being the early mammals, and all the diversity that resulted from them. And so it goes up along the branches.

Branching pattern of the tetrapods, mostly the land vertebrates

Branching pattern of the tetrapods, mostly the land vertebrates

We now explore the branches and can apply names to the groups that we find to be meaningful. For example, in the illustration below we can call everything in the box a reptile. Note that it includes things that used to be called reptiles, turtles, lizards, snakes, crocodiles, and dinosaurs, but now also includes birds.

Group that includes all the reptiles

Group that includes all the reptiles

Likewise, if we draw a line around the dinosaurs, they also include the birds. This view of life tells a more complete evolutionary history and retains the branches, letting the animals “fall where they will.” We do not pull birds out of their relationships and give them special consideration. Instead of birds being equal in rank with reptiles, they are included among them. This upsets the tradition that being a bird is somehow equally important to being a reptile, but better reflects the reality of descent, without forcing nature into earlier human conventions of naming and grouping. Of course, birds are a group within their own right, and we could zoom in to explore their branching pattern, but it does not change the group to which they belong.

Group of dinosaurs

Group of dinosaurs

This leads to another startling statement. Below I have highlighted the groups that are extant (still around today).

Groups of tetrapods that are alive today (extant)

Groups of tetrapods that are alive today (extant)

Because of our grouping scheme, birds are included in the dinosaur group, so dinosaurs are not really extinct! They live among us today flitting about, singing their mating songs in the trees. It is funny how things can change in science. Twenty years ago scientists would have told you the dinosaurs were all extinct, and today we say the opposite. I love scientific progress–it can be so startling.

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3D Scanners In Archaeology

3d scanners are relatively new technology. Only the advent of the laser and computers has allowed for the transfer of all details about an object into a computer, and possibly the manipulation of these items with computer aided drawing (CAD) software or similar software. 3d scanners have a huge variety of uses, but perhaps the best use is for reverse engineering and cultural purposes.

Such devices have been used by archaeologists since the invention of the technology. This application is excellent for the purpose of finding hidden details in an artifact or piece of artwork that are too small for the eye to detect it. Also, as the technology typically uses lasers or sound waves for the purposes of scanning the object, it is minimally invasive. For example, a scientist or historian may want to know more about the content of an oil painting and the chemical properties of the paint. He or she could take a small chip of paint out of the painting, but if the painting is historic enough, that likely would not be allowed. However, oil paint is very well known for accumulating in large bumps, with a lot of texture. A 3d scan of the painting could likely give enough information about the structure of the painting to figure out the contents of the paint.

There are a number of famous examples of the use of 3d scanners in archaeology. Perhaps the earliest is two different groups of researchers who were able to scan Michelangelo’s famous statue David in 1999. Both of these groups used scans at a resolution of .25 mm, which accumulated a huge amount of data, detailed enough to see the chisel marks. These data were able to tell the researchers a large amount about how the statue was made, what tools Michelangelo had to work with, and other important archaeological information. Today, most famous works of art have been subject to the same treatment. And best of all, it is completely noninvasive.

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