Australopithecus africanus — The word “Australopithecus” means “southern ape. Raymond Dart, professor of anatomy at Witwatersrand University in Johannesburg, was the first to study these fossils. In at Taung in South Africa, Dart discovered a fossil skull consisting of a full face, teeth and jaws, and an endocranial cast of the brain. The brain size was cc. Its age is currently felt to be around two to three million years old. Dart was convinced that some teeth were man-like and thus concluded a transition between apes and man.
AMINO ACID RACEMIZATION DATING
Herbchronology Dating methods in archaeology[ edit ] Same as geologists or paleontologists , archaeologists are also brought to determine the age of ancient materials, but in their case, the areas of their studies are restricted to the history of both ancient and recent humans. Thus, to be considered as archaeological, the remains, objects or artifacts to be dated must be related to human activity.
It is commonly assumed that if the remains or elements to be dated are older than the human species, the disciplines which study them are sciences such geology or paleontology, among some others.
What this basically means is that amino acid dating is not based on any sort of understanding about how racemization takes place, but is strictly a function of correlation with other dating techniques, such as the radiocarbon technique.
Amino Acid Racemization Motion around a chiral center takes us from deep blue sea to deep dark space. Racemization is the process in which one enantiomer of a compound, such as an L-amino acid, converts to the other enantiomer. An older convention, commonly used by biochemists to describe amino acids and sugars, uses the letters D and L to designate absolute configuration Figure 1. In a laboratory setting, scientists are able to measure the degree of racemization using polarimetry, liquid chromatography, capillary electrophoresis, and mass spectrometry.
With these measurements, scientists can estimate the rate at which one enantiomer is converted to the other. Currently, these techniques are used to estimate the age of fossils, determine the life span of bowhead whales, and detect evidence of extraterrestrial life. Hand It to Nature. While both left- and right-handed enantiomers L and D, respectively are available to nature, life is biased toward the use of L-amino acids and D-sugars.
Chemical Whale Tales Since , whale hunters in Alaska have found at least six harpoon heads in bowhead whales that they have killed in the Beaufort Sea, southwest of the Arctic Ocean. The harpoon heads were made of stone or ivory. Anthropologists at the Smithsonian Institution Washington, DC estimate that they are between and years old and were probably used by Inupiat hunters in the late s.
This circumstantial evidence led Craig George and fellow researchers at the Department of Wildlife Management North Slope Borough, Barrow, AK to believe that bowhead whales, named for their exaggerated jaw curve, could have a life span of more than years. To hear a radio interview with George, visit www.
AMINO ACID DATING
Herbchronology Dating methods in archaeology[ edit ] Same as geologists or paleontologists , archaeologists are also brought to determine the age of ancient materials, but in their case, the areas of their studies are restricted to the history of both ancient and recent humans. Thus, to be considered as archaeological, the remains, objects or artifacts to be dated must be related to human activity. It is commonly assumed that if the remains or elements to be dated are older than the human species, the disciplines which study them are sciences such geology or paleontology, among some others.
Nevertheless, the range of time within archaeological dating can be enormous compared to the average lifespan of a singular human being. As an example Pinnacle Point ‘s caves, in the southern coast of South Africa , provided evidence that marine resources shellfish have been regularly exploited by humans as of , years ago.
In other studies, Bada and co-workers have applied this method to the dating of fossil bones, and have even applied amino acid racemization rates to the determination of past temperatures by measuring the extent of racemization in several radiocarbon-dated bones. 11 Kvenvolden, Peterson and Brown 12 have measured the rates of amino acid racemization in marine sediments.
A number of varieties of Homo are grouped into the broad category of archaic humans in the period beginning , years ago or ka. It typically includes Homo neanderthalensis 40ka— ka ,  Homo rhodesiensis ka ka , Homo heidelbergensis ka ka , and may also include Homo antecessor ka ka. Modern humans are theorized to have evolved from archaic humans, who in turn evolved from Homo erectus. Varieties of archaic humans are sometimes included under the binomial name “Homo sapiens” Latin: Archaic humans had a brain size averaging to cubic centimeters, which overlaps with the range of modern humans.
Archaics are distinguished from anatomically modern humans by having a thick skull, prominent supraorbital ridges brow ridges and the lack of a prominent chin. Non-modern varieties of Homo are certain to have survived until after 30, years ago, and perhaps until as recent as 10, years ago. Which of these, if any, are included under the term “archaic human” is a matter of definition and varies among authors.
Nonetheless, according to recent genetic studies , modern humans may have bred with “at least two groups” of ancient humans:
Temperature and humidity histories of microenvironments are being produced at ever increasing rates as technologies advance and technologists accumulate data. These are important for amino acid dating because racemization occurs much faster in warm, wet conditions compared to cold, dry conditions. Temperate to cold region studies are much more common than tropical studies, and the steady cold of the ocean floor or the dry interior of bones and shells have contributed most to the accumulation of racemization dating data.
Generally, they are not assumed to have a great impact in the natural environment, though tephrochronological data may shed new light on this variable. The enclosing matrix is probably the most difficult variable in amino acid dating. This includes racemization rate variation among species and organs, and is affected by the depth of decomposition, porosity, and catalytic effects of local metals and minerals.
Jul 01, · Amino acid racemization (AAR) dating of shell middens has a long history. As early as , the Del Mar midden site (California) was targeted for AAR dating on Chione shells (Masters and Bada, ; Wehmiller, ).
It introduces the men whose efforts ultimately helped STURP obtain permission to perform the scientific examination of the Shroud. Dorothy was the Publisher and Editor of Shroud Spectrum International, the first peer reviewed journal in the United States dedicated exclusively to the study of the Shroud Sindonology. This presentation was originally delivered at the Esopus Conference. English with a preface in Italian language.
Finding the Shroud in the 21st Century by M. Sue Benford and Joseph G. Marino This is the earliest paper by Benford and Marino December proposing their theory of a rewoven and anomalous sample site used for the radiocarbon dating of the Shroud Fire and the Portrait, The by Jack Markwardt – Czech Translation by professional translator Daniela Milton – Now available in the Ukrainian Language [10 October ] This paper proposes to resolve, and to reconcile, two of the Shroud’s most tantalizing mysteries:
Ten Reasons Evolution is Wrong
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. For most of the last century, a prevailing theory within the field of nutrition was that by eating acid-forming foods such as meat , we were, in essence, at risk of peeing our bones down the toilet. Experiments dating back to showed over and over that if you add meat to the diet, you get a big spike in the amount of calcium being lost in the urine.
And so, this made total sense; we had known since that meat was acid-forming within the body.
In Dr. Raul Esperante teamed up with Dr. Leonard Brand and others to investigate fossil whales within the Pisco Formation of Peru’s Atacama Desert.
What about the fact that the “simple” organisms are buried in the lower levels and the more “complicated” ones are buried in the higher levels? Doesn’t this fact support the notion that simple organisms evolved into more and more complex organisms over time, with the more complex organisms buried and fossilized above the earlier and simpler life forms?
Certainly this seems like a very logical assumption. But, things just aren’t that easy. There are a number of potential problems with this interpretation of the fossil record. For example, it is interesting to note that some general kinds of fossilized creatures are very generally found in the same relative vertical orientation, with respect to each other in the fossil record, that they would have naturally been found in during life. Single celled organisms make their first appearance in the lowest layers followed by multicelled ocean bottom-dwelling creatures like sponges and worms etc.
Higher up come creatures like bony fishes, then land plants and animals, then birds and larger land animals. Of course, this is a very general pattern and does not explain why certain creatures that lived on the bottoms of oceans, like trilobites, make their first appearance in the Cambrian Ma while other creatures that live on ocean bottoms, like crabs and lobsters, don’t appear until the beginning of the Cretaceous Ma.
If the geologic column truly represents a series of closely spaced catastrophic burial events instead of long ages of time, how can this feature be explained? Certainly this seems like a difficult and rather mysterious problem for those, like myself, who might think to question the long age notion of the fossil record.
Scientific Papers and Articles
The various dating techniques available to archaeologists by Michael G. Furthermore, when you consider that many archaeological sites will contain numerous types of artifacts that permit the use of multiple dating methodologies, a modern archaeologist can often employ cross-dating methodologies which can allow for extremely accurate dating as far back as 10, years in some regions. Natural Dating Techniques A modern archaeologist has almost half a dozen natural dating techniques that she can apply in the field that she can use to quickly determine an approximate date range, which, in the cases of varve analysis and dendrochronology, can often be used to decrease the date range estimate to a matter of just a few years.
One of the oldest natural dating techniques is geochronology, which is based on the principle of superposition — an object, or layer, on top must have been placed there at a later point in time. Once a geologist has determined the absolute age of a geological formation, the archaeologist can assign an indirect date to objects found in the formation.
Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established usually requires what is commonly known as a “dating method”. Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using.
At the time that Darwin’s On the Origin of Species was published, the earth was “scientifically” determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3. Finally in , it was discovered that the earth is “really” 4. In these early studies the order of sedimentary rocks and structures were used to date geologic time periods and events in a relative way. At first, the use of “key” diagnostic fossils was used to compare different areas of the geologic column.
Although there were attempts to make relative age estimates, no direct dating method was available until the twentieth century. However, before this time some very popular indirect methods were available. For example, Lord Kelvin had estimated the ages of both the Earth and the Sun based on cooling rates. The answer of 25 million years deduced by Kelvin was not received favorably by geologists. Both the physical geologists and paleontologists could point to evidence that much more time was needed to produce what they saw in the stratigraphic and fossil records.
As one answer to his critics, Kelvin produced a completely independent estimate — this time for the age of the Sun. His result was in close agreement with his estimate of the age of the earth. The solar estimate was based on the idea that the energy supply for the solar radioactive flux is gravitational contraction.