Trilobites were a diverse group of marine arthropods that lived throughout the p

Question

Trilobites were a diverse group of marine arthropods that lived throughout the paleozoic era before going extinct 250 million years ago. The photos show two fossil trilobites in the order Lichida found in the same rock formation. The right fossil is a species in the genus Actinurus, and the left is in the genus Acanthopyge. Imagine you found only Actinurus fossils in one layer of rock and then only Acanthopyge fossils in the next rock layer above the previous, making you wonder if Actinurus is the direct ancestor of Acanthopyge. In a well-constructed essay, discuss why it might be difficult to determine definitively that Actinurus is, in fact, the direct ancestor of Acanthopyge. Possible topics to include are fossil dating, biases and complications in the fossil record, gradualism vs punctuated equilibrium, and/or the origin of complex traits. You will be graded on content, writing style (grammar, word choice, sentence construction), and organization (logical flow, clear topic and concluding sentences). You can neatly hand-write in the space below or attach a typed answer to the end of this assignment.

Explanation / Answer

One of the method to determine age of fossil is fossil dating which is subdivided into relative dating, It is a method which determine the age on comparing to something for which an age is already known other method is absolute dating in which age of fossil is determined on the basis of radiometric dating methods. So, with both these method age of the fossil can be determined but it does'nt correlate with their parental relationship. Since both the genus belong to 250 million year ago thusthere is more chance that genus may have destroyed by geological accident. So you might expect a biasness in the context that more recent, younger fossils would be more numerous, in better shape, and more diverse than older fossils. According to literature species with a shorter evolution evolved mostly by punctuated equilibrium, and those with a longer evolution may discover by gradualism. It give the information related to duration of evolution period but it does'nt correlated with ancestoral relation among fossil. Complex trait extends to genetic correlations between related traits. it helps to infer changes in heritability over aging and development. In conclusion, there is usually no definate method to know exactly how close a transitional fossil is to the point of divergence. Therefore, it is not possible to determined that Actinurus fossils are direct ancestors of Acanthopyge.

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