Kristin Albert, 38 years old
A living fossil is an extant taxon that closely resembles organisms otherwise known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are species-poor lineages, but they need not be. Living fossils exhibit stasis over geologically long time scales. Popular literature may wrongly fossil relative dating activity that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims.
Between the late nineteenth century and the early twenty-first century, Archaeopteryx had been generally accepted by palaeontologists and popular reference books as the oldest known bird member of the group Avialae. Similar in size to a Eurasian magpiewith the largest individuals possibly attaining the size of a raven the largest species of Archaeopteryx could grow to about 0. Despite their small size, broad wings, and inferred ability to fly or glide, Archaeopteryx had more in common with other small Mesozoic dinosaurs than with modern birds. In particular, they shared the following features with the dromaeosaurids and troodontids: These features make Archaeopteryx a clear candidate for a transitional fossil between non-avian fossil relative dating activity and birds.
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Fossil relative dating activity
More about fossil relative dating activity:
Datingin geologydetermining a chronology or calendar of events in the history of Earthusing to a large degree the evidence of organic evolution in the sedimentary rocks accumulated through geologic time in marine and continental fossil relative dating activity. To date past events, processes, formations, and fossil organisms, geologists employ a variety of techniques. These include some that establish a relative chronology in which occurrences can be placed in the correct sequence relative to one another or to some known succession of events. Radiometric dating and certain other approaches are used to provide absolute chronologies in terms of years before the present. The two approaches are often complementary, as when a sequence of occurrences in one context can be correlated with an absolute chronlogy elsewhere. By mid-century the fossiliferous strata of Europe had been grouped into systems arrayed in chronological order. The stratigraphic column, a composite of these systems, was pieced together from exposures in different regions by application of the principles….
The standard approach to looking at fossils in the geological column is to assume that lower is older. Since the geologic column represents millions of years of Earth's history, then obviously the fossils in each of the layers must be the same age as the layer in which they are found. What is especially interesting is that the fossils do appear to show a progression from the most "simple" of organisms, fossil relative dating activity as single celled creatures like bacteria, to the most "complex" organisms, such as vertebrates, mammals, and of course humans. This evolutionary progression seems to be clearly demonstrated in that certain kinds of creatures in the upper layers are rarely if ever seen in lower layers. Many of the layers also show a certain specialization. Some layers contain mostly fish fossils while others contain land-dwelling creatures such as dinosaurs. Since each of these layers seems so specialized it is easy to conclude that one type of creature gave rise to the next type of creature over the course of whatever time it took to form the various layers between them. Radiometric dating and many other techniques are used to support the idea that this transformation process took tens and hundreds of millions of years.
It is not about the theory behind radiometric dating methods, it is about their applicationand it therefore assumes the reader has some familiarity with the technique already refer to "Other Sources" for more information. As an example of how they are used, radiometric dates from geologically simple, fossiliferous Cretaceous rocks in western North America are compared to the geological time scale. To get to that point, there is also a historical discussion and description of non-radiometric dating methods. A common form of criticism is to cite geologically complicated situations where the fossil relative dating activity of radiometric dating is very challenging.