How a Hobbit is Reshaping Our Idea of Human

Man has repeatedly tried to define what makes man different from Animals. Physical/Biological Anthropology have latched on to any number of ideas, from tool making to society building in order to define what it means to be human. But Tool-making has since been observed in any number of species, ranging from birds to Octopus- making tool making not only non-exclusive to man, but non-exclusive to mammals. And Society building is actually not uncommon among primates.

Observational Learning isn't restricted to man, either- in the wild, there is a species of monkeys that lived in two separate areas and had different preference in the type of food eaten. When one was relocated, at first he declined to eat the preferred fruit of his new population, to the point where there was worry that he might grow ill- that is, until he observed this population wash and then eat the new fruit. Afterwards, he mimicked the behavior he had observed, washing the fruit and then consuming it. Same goes with learning to Season food.

And so throughout the history of Anthropology, we have defined and redefined our idea of what makes man man, and our Ideas of how we came to be. Many details about early human history and Prehistory- as well as our pre-human ancestors- are still unknown.

In 2004, some scientists were studying a cave in Flores, Indonesia when they came across some skeletal remains. After studying them, several things stood out. First, that though the skull was the size of a small child, the teeth were those of an Adult. Second, that this individual would have stood at a mere 3 feet tall, but his feet, at about 8 inches, a 70% ratio to his thigh bone. (For comparison, the average adult human's foot-to-thigh ratio is about 55%.) Third, that the cranial cavity (space in the skull where your brain sits) was only about the size of an orange, but the tools found with the body were relatively advanced.

In part because of the tools found with the Skeleton, some Anthropologists dismissed the Hobbit of Flores as a pathological oddity of either Homo Erectus or modern human origin. They were skeptical that species before H. Erectus would have had advanced enough cognitive abilities to create the tools, and the traditional models of migration seemed to back up that this had to be from H. Erectus or later. Therefore some thought that the Hobbit of Flores may have been from a group of individuals with a genetic predisposition towards a smaller stature or for a number of conditions that cause Dwarfism. Alternatively, that a process of devolution had resulted from H. Erectus, resulting the much smaller stature found in Flores.

However, further study of the bones brought several things to light- first, that the structure of the feet lacked an arch. This is one of the primary indicators of the modern foot. Second, that the wrists of the Hobbit were not consistent with how the modern wrist bones are shaped. Third, and perhaps most strikingly, is the similarities with both Lucy (Australopithicus afarensis) and Homo Habilis.

Previously, the migration charts had placed H. erectus as the first Hominid to leave Africa (There's a chart showing range at the Hominid Fossil Sites link below). But these new developments regarding the Hobbit (known to scientists as H. floresiensis) suggest that H. habilis or their immediate descendants not only dispersed beyond Africa, but that they developed into a species of hominid that not only lived, but also thrived, in Indonesia until 17,000 years go. For perspective, the date usually used for the emergence of H. sapiens is 120,000 years ago, and the dispersal of H. erectus is about 1-2 Million years ago. The earliest finds related to H. floresiensis are 1.1 million years old, with evidence of tool making dating back to 2 million years, around Flores, suggesting that their ancestors could have left Africa even earlier than H. Erectus.

The Hobbit of Flores is completely reconfiguring our theories of Dispersal of Hominids. But he is also reshaping our ideas on early tool usage. While CTs of the skull found in Flores suggests that he had cognitive ability beyond that of an Ape, his brain was smaller than other species with similar tools to those found. Additionally, the structure and configuration of the wrists would have made the type of tool making used difficult and possibly more painful. The hows- and whys- of them fighting against the inherent physiological difficulties are intriguing, but also intriguing is what this could tell us about the development of cognitive ability as our studies of this species go on.

Resources
(Free/available online unless otherwise noted)

Tufted Capuchins and Macaques (Monkeys; Observational learning/Novel Foods/Deception):

• Acceptance of novel foods in capuchin monkeys: do specific social facilitation and visual stimulus enhancement play a role? (Note: this article must be purchased, but abstract available.)
• Do tufted capuchin monkeys ( Cebus apella ) spontaneously deceive opponents? A preliminary analysis of an experimental food-competition contest between monkeys (Note: this article must be purchased, but abstract available.)
• Do Japanese monkeys season their food?

Tool Use by Non-Humans

• Chimps Use "Spears" to Hunt Mammals, Study Says
• Crow Makes Wire Hook to Get Food
• Bait Fishing In Crows
• Elephantine Intelligence
• Cultural Transmission of Tool Use in Bottle-nosed Dolphins (Abstract, Full text available in PDF)
• Octopuses Use Coconuts as portable Shelters (includes video clip)

The Hobbit of Flores (and other early Hominids)

• Homo Floresiensis - Hobbit Feet Were Primitive But Not Pathological (So They Took It Slow)
• How a hobbit is rewriting the history of the human race
• "Hobbits" not good runners; proof of new human species? (National Geographic)
• "Homo floresiensis: A cladistic analysis"(Journal of Human Evolution; must be purchased)
• Further evidence for small-bodied hominins from the Late Pleistocene of Flores, Indonesia (must be purchased)
  
• 
  
• Flores Man (Nature's web focus on the issue; slightly out of date)

• Flores Man Special (News@nature special)
• Hobbit indeed a Separate Species (includes measurements of bones)
• 2009 Leaky Symposium on Human Evolution at Stonybrook
• Streams of the above symposium: part I | part II | part III | part IV
• ~~~~~~
• Australopithicus afarensis: The story of Lucy (unit from Washington State University)
• Homo Habilis (an introduction from archeologyinfo.com)
• Chart of time Spans for different hominids
• Early Hominid Biogeography (PDF)
• Hominid Fossil Sites
• How Man Began

Repost: Dating Methods in Archeology (10th grade)

*Note: this was written in 10th grade as a project for my science class. This was in 2004. I am adding it here because I was amused to find it earlier this evening.

I. An Introduction

The issue of an object’s placement in time is integral to processing an archaeological find. Without having a method by which to place a find in time, The find is useless in any manner other than knowing that the object has existed at some point. Chronology is a fundamental issue in archaeology, informing researchers not only of when an object was made, but also how long a civilization took to hit certain periods of development.
For example, If we know that civilization X started making iron tools around 1,000 BCE, and around 3,000 BCE they began to make bronze tools, then we know that civilization X ‘s Bronze Age lasted approximately 2,000 years, and can compare the development of a civilization to it’s contemporaries. Or if civilization Y appeared in location A around 2,000 BCE, but all traces of civilization Y are gone by 100 CE, then we know how long that particular civilization lasted in that location, and can also identify it’s contemporaries. The importance of chronology is obvious in the above example.

When considering this, one wonders what the methods of divining an objects age are and exactly how accurate these methods are. There are many different methods, each with their own accuracy adjustment. Some methods will give you an exact calendar date, while others will only tell you when it was used in comparison to the surrounding objects on site. Some methods will use the object itself, and others might use the things associated with the object. Until fairly recently, most objects were dated according to guesses, relative location, and other objects that were previously dated either at it’s making (a year on a coin, for example) or by another archaeologist.

Though an archaeologist uses dating methods to discover the date of an object or event, the dates that are found are used to create a framework in which is placed information found on the site or that is already known. This construction of a supposed time-line is a major foundation for archaeology.


II. The Basics of Archaeological Dating


As stated above, there are several different methods that provide different types of dates. Those methods that date in relation to other objects on site are commonly referred to as relative dating methods. Relative dating is exactly what it sounds like: the date of an object according to it’s relation to other objects on the site. Generally, the first step in processing a site is using relative dating to order the timeline of the site. This generally will not allow the researcher to give an object or event a calendar date without also using absolute dating methods.
Absolute dating methods give a calendar estimate as to the age of the object, which helps to determine the length of time between one object dated absolutely and another. Using the example of civilization X again, say that after excavating a site, we find some early iron weapons on the first level of the site that pertains to civilization X. After going through a few levels, we reach the bottom level of our excavations. Here we find an early bronze weapon. By using an absolute dating method, we learn that the early iron weapon dates to about 1,000 BCE and that the bronze weapon dates to about 3,000 BCE. Therefore, we can speculate that civilization X ‘s Bronze Age lasted about 2,000 years.

The relative and absolute dating describes the scale of measurement in dating. When an age is determined, it is determined by either direct or indirect means. When researchers determine the date of an object directly, they use a method, usually an absolute method, to date the object itself. When they use indirect dating, they have another object from the same or a contemporaneous event that they have used a direct dating method on to determine the age of the object you need the date for. Unfortunately, this sort of dating is both less reliable and more time consuming then direct dating because you must first show that they are from the same (or contemporaneous) event.

Following are several different methods of dating objects and speculated events from an archaeological site.


III. Stratigraphy and Seriation


Stratigraphy and seriation are two relative methods of dating. Stratigraphy is the oldest method of dating used by archaeologists and is relatively simple. Seriation is a bit more complex to jot down, and involves having the ability to interpret statistics gathered from a site into a graph. Both are the simplest and possibly the oldest of the methods still used by archaeologists.

The word stratigraphy has two meanings. It can mean the arrangement of strata in a geographic (or, in our case, archaeological) deposit. Most archaeologists, however, call this stratification. When they say stratigraphy, they generally mean the study of the stratification.
The principals of superposition are the basis for stratification. The principals of superposition are that the layer at the top was made the most recent, while the layer on the bottom was made the longest time ago. However, this relatively simple idea isn’t as simple as it first appears. In order to be sure that this particular method is accurate, the researcher must take into consideration several variables. Some of these variables is past human disruption of the layers, natural disaster eroding away layers, and occupation.

Seriation basically means ordering, and was first developed and used by archaeologist Sir William Flinders-Petrie around 1899. The concept behind it is based on an assumption that cultural characteristics change over time, which is particularly obvious in the case of fads, typically in a specific pattern usually containing an introduction, a peak, and a decline in popularity period. By graphing the results of the find, one can usually find the point in the sequence in which an object was more popular, therefore placing a culture’s development or even to get the exact date of an object by the frequency of occurrence in a particular location. By graphing the information with horizontal bars centered along a vertical axis, you can observe the rise, peak, and decline of a particular object, typically forming a battle-ship shape. The graph is founded on different sorts of information, such as stylistic (Changing styles of a sort of object) or frequency (the proportion of certain objects in a deposit).


IV. Other Relative Dating Methods


There are a couple of other forms of relative dating worth mentioning before we move on to absolute dating.

Cross-dating I mentioned previously. Cross-dating is basically indirectly dating an object. This was the only real method of dating an object in early archaeology. To use cross-dating, you must have two objects that you can prove are from the same event. One of these objects must already have a date given to it. If you then have a date for the one object, you can usually assume that the other object is from around the same date.

Pollen analysis uses the concept of relative abundance. Pollen of a certain plant will go through certain cycles of abundance. By calculating the abundance of each type of pollen found on an object, a researcher can calculate the date by placing the object at the date that the abundance of pollen on the object matches others with similar abundances.


V. Dendrochronology


Dendrochronology is an absolute dating method by which one observes the rings of a tree. This method is based on the idea that, in temperate climates, trees produce growth rings due to wood growth, the rings made by a layer of small cells paired with a layer of large cells. In years with more optimal growing conditions, the cells of each sort tend to be larger, and the cells tend to be smaller in poorer growing conditions. Trees of the same species in the same area generally will have the same pattern in rings.

By observing the growth rings of an area and matching them with progressively older pieces of wood, researchers can create a master chronology. By studying the results of this master chronology and comparing it to rings on a wooden object, they can determine the age of the object by placing it in the master chronology.

To get the sample of wood from the object, a small diameter core sample is typically extracted. On objects that are brittle from age, the wood is generally preserved first. Then the counting and measuring of rings is generally performed and then compared to the master growth ring.

For dendrochronology to be accurate, only tree species that show rings that are sensitive to the seasons can be used- most commonly pines, firs, oaks, and juniper. Also, the wood must be well enough preserved to still have the outer growth rings. And, as with all dating methods, the context of the object(s) is of vast importance- if the wood was taken from an older structure to build the one that is being studied, then the age will be inaccurate.


VI. Overview of Radiometric Dating


Radiometric dating is based on the concept of atrophy. Atrophy is a process of slow decay, usually at a fixed rate. Everything decays, but some elements decay at a more steady rate then others. The most commonly used elements are Carbon-14, Potassium-40, and Uranium-238. Most of the best elements to use in radiometric dating are those that are most commonly found in nature.

Though the exact decay of an element cannot be predicted, those elements with a stable average rate are ideal. The rate of decay in elements is put in the terms of half-lives, or “the amount of time it takes for half of the atoms in a sample of the radioactive isotope to decay to a stable form” (Anthropology Department, University of British Columbia). When you compare the amount of the original element to the amount of what is produced when it decays, then matching it to the element’s half-life, a reasonably accurate estimate of how long it has been decaying can be determined.

Some of the more common radiometric dating methods are radiocarbon, potassium-argon, fission track, and thermoluminescence. I will go more into each of these later. Each of these have a formula applied to them which results in an age for the object in question.

VII. Radiocarbon Dating

One of the more commonly used of the radiometric dating methods is radiocarbon dating, commonly referred to as “Carbon-14 Dating”. Radiocarbon dating was discovered in 1949 by a team of scientists at the University of Chicago. It is now the most commonly used and most publicized form of absolute dating. Radiocarbon dating was developed around the rate of decay of carbon-14, which is created in the upper atmosphere and is then oxidized into CO2 which is consumed by most living things through respiration. Carbon-14 is constantly decaying, converting into nitrogen-12, but in living organisms, is replenished until it stops performing respiration. Most living things (or things that were made from once living things, such as wood) can be dated using radiometric dating because of this.

As previously stated, radiometric (and hence, radiocarbon) dating methods use the half-life of an element to determine the age of an object. The half life of carbon-14 is 5730 years on average. By comparing the remaining and the current amounts of carbon-14, one can estimate how long ago the object stopped living. When reporting a radiocarbon measurement, the measurement is stated as x years B.P. (Before Present), present being 1950. As with all methods of dating, an error factor must be calculated into an equation before finally releasing a date to the public.

There are two common ways to go about dating an object using the radiocarbon dating method. The first and most conventional is done by first converting the material into a gas or liquid state and is then placed on a counter that measures radioactive activity to find the rate of decay. The formula for dating an object by this method is:

t=[In (Nf/No)/(-0.693)]x t1/2

In being the natural logarithm, Nf/No being the percent of carbon-14 in the object in comparison to the percentage in living tissue, and t1/2 being the half-life of carbon-14. The half life of carbon-14 is 5,700 years, so in a object with 10% carbon-14 compared to living tissue:


t=[In (0.10)/(-0.693)]x 5,700 years

t=[(0.10)/(-0.693)]x 5,700 years

t=[3.323]x 5,700 years

t=18,940 years old


The above example is taken directly from howstuffworks.com ‘s article on Carbon-14 dating, as is the formula (http://www.howstuffworks.com/carbon-14.htm/printable). Currently, the oldest date that can be accurately dated using this technique is 40,000-50,000 years.

The other technique of radiocarbon dating uses an accelerator mass spectrometry, also known as AMS, method to count radiocarbon amounts directly rather then measuring the decay rate. This allows for less of a sample to be taken from the object being dated, thus causing less damage to the object.


VIII. Other forms of Radiometric Dating


There are several other forms of radiometric dating that are worth mentioning before we get to other forms of absolute dating. These are potassium-argon, fission-track, and thermoluminescence.

Potassium-argon dating is based on the fact that potassium-40 decays into argon-40, and that in the case of a volcanic eruption, the only argon contained in the rock will have been produced since the rock cooled. By using samples that trapped all of the argon gas produced and measuring it then comparing it to the potassium in the sample, one can calculate an approximate age for an object. However, potassium-argon dating is one of the lest reliable of the radiometric dating methods.

Fission-track dating is based on spontaneous fission of uranium-238. Though most uranium decays into a stable lead, occasionally the atom splits in two at a high speed, damaging the surrounding structure. By observing an object under a microscope, one can see tracks left by this “spontaneous fission”. Uranium rarely goes through this process, but there is a fixed rate at which it does occur. At the time when uranium is made in an object, it has no fission decay, so by counting the fission tracks left behind, one can get an age for the object in question.

Thermoluminescence is a very new technique and is yet to become widely used in the field, though it has a lot of potential due to the fact that it can date heat-altered artifacts and has a larger effective range then the more commonly used methods. Instead of measuring the rate of radioactive decay, thermoluminescence looks at the “amount of radiation trapped within crystalline materials that have the property of storing this energy within the microscopic crystal lattice fabric” (Anthropology Department, University of British Columbia). This energy is released when the object is rapidly heated to about 500 degrees celsius, reaching a flash point at which all electrons are freed and the energy is emitted as a flash of light. The greater the light, the greater the age of the object.


IX. Other Absolute Dating Methods: Obsidian Hydration


Obsidian hydration is based on the fact that a fresh surface of obsidian will absorb water around it. The water seeps into the stone to form a hydration layer, containing 3.5% water, which increases the density of the layer to allow it to be observable under a polarized light microscope.

To get an estimate, the object in question is submitted to a lab where a small section of the object is removed and then ground to fit on a microscope slide, where the hydrogen band is measured. Though this method holds a lot of promise, obsidian hydration isn’t fully understood, making it slightly more unreliable and even a tad unscientific, as the factors cannot be fully controlled in a manner that is needed to make an accurate assumption.


X. Conclusion


As we have seen, there are many ways to date objects found on an archaeological site, some more accurate then others, but all with error margins. There are two different sorts of dating- absolute dating, where we can set a calendar date, and relative dating, where we can place an object in time relative to other objects found on site. There are two methods to go about dating objects: direct, where we find the date from the object itself, and indirect, where we find the date from other objects proven to be contemporary.

There were four types of relative dating covered in this paper: stratigraphy, seriation, cross-dating, and pollen analysis. Stratigraphy deals with where objects are relative to each other in the paper. Seriation deals with the rise, peak, and fall in the popularity of an object. Indirect dating and cross-dating are basically the same thing, both being a method of finding an object that is dated that is assumed contemporary. The last was pollen analysis, which compares the amount of pollen on an object to another object’s amount of pollen.

Six absolute methods were also mentioned: dendrochronology, radiocarbon dating, potassium-argon dating, fission track dating, thermoluminescence, and obsidian hydration. Four of these, fission track. radiocarbon, potassium-argon dating, and thermoluminescence, are radiometric dating methods, dealing with radioactive elements and their decay. For example, radiocarbon dating uses carbon-14, a very common radioactive element found in nearly all living things. On the other hand, dendrochronology deals with tree-rings and compares the rings in an object to a chart of growth rings for the area, thereby giving an approximate age. And last of all, obsidian hydration dating deals with the rate at which water (H2O) evaporates on the surface of obsidian.

Placement in time is a very important part of archaeology. With out it, we would not know what came first- Mesopotamian or Babylonian civilization (it’s Mesopotamian, in case the reader was wondering). And without methods by which we can place an object in time, the idea of archaeology would be futile, and development in understanding our pasts and ourselves would be useless.