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To determine much about its noncoding DNA is hardly ever possible, but even if a species were hypothetically unchanged in its physiology, it is to be expected from the very nature of the reproductive processes, that its non-functional genomic changes would continue at more or less standard rates.
It follows that a fossil lineage with apparently constant morphology need not imply equally constant physiology for example, and certainly neither implies any cessation of the basic evolutionary processes such as natural selection, nor reduction in the usual rate of change of the noncoding DNA.
The subject of very low evolutionary rates, however, has received much less attention in the recent literature than that of high rates Living fossils are not expected to exhibit exceptionally low rates of molecular evolution, and some studies have shown that they do not.
For example, on tadpole shrimp (Triops), one article notes, "Our work shows that organisms with conservative body plans are constantly radiating, and presumably, adapting to novel conditions....
Living fossils commonly are species-poor lineages, but they need not be.
The term living fossil is not formally defined, but in scientific literature the term usually connotes a bradytelic group.
The minimal superficial changes to living fossils are mistakenly declared the absence of evolution, but they are examples of stabilizing selection, which is an evolutionary process -- and perhaps the dominant process of morphological evolution.
As a rule, to be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade.See for example the uniquely and highly autapomorphic oxpeckers, which appear to be the only survivors of an ancient lineage related to starlings and mockingbirds.The term living fossil is usually reserved for species or larger clades that are exceptional for their lack of morphological diversity and their exceptional conservatism, and several hypotheses could explain morphological stasis on a geologically long time-scale.Living fossils exhibit stasis over geologically long time scales.In popular literature "living fossil" commonly embodies radical misunderstandings such as that the organism somehow has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological, but scientific investigations have repeatedly discredited any such claims about molecular evolution.