Losos_Seeing - Harvard University
Losos_Seeing - Harvard University

... method (after Sessions and Larson, 1987) and the first, after the original, to use the Huey and Bennett squaredchange parsimony method. I point this out not only to demonstrate that there was a delay before these methods were widely adopted, but also to establish my bona fides as someone who has bee ...
Cladistic Parsimony, Historical Linguistics, and Cultural
Cladistic Parsimony, Historical Linguistics, and Cultural

... In addition to the theory of natural selection, the other great triumph of Darwin’s On the Origin of Species is the advancement and defense of the theory of common ancestry. This is the idea that any two organisms, including those that belong to different species, will have, if we look far back enou ...
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... Assume no convergent evolution; and no derived traits have been lost. Lampreys are the outgroup—any species or group outside the group of interest. The group of interest is the ingroup. Comparison with the outgroup shows which traits of the ingroup are derived and which are ancestral. ...
Taxonomy Five Kingdoms Three Domains Evolutionary Trees
Taxonomy Five Kingdoms Three Domains Evolutionary Trees

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... • But with the development of fast modern computers, parsimony and cladistics have been integrated into methods of maximum likelihood. These methods are used to evaluate which of many likely trees (given the data) seems to be the most probable. ...

Ancestral reconstruction

Ancestral Reconstruction (also known as Character Mapping or Character Optimization) is a method in evolutionary biology by which one can attempt to understand the phenotypic and genetic states of organisms that lived millions of years ago. This is desirable because it means that one can “fill in” gaps in phylogenetic trees, thus being able to more clearly see which organisms are closely related and evolved from one another and so forth. The idea is that modern genetic sequences are essentially a variation of ancient ones. Therefore, if one can gain access to ancient sequences, one may be able to find out which other variations could have arisen from that sequence, and thus, which organisms may also be descendant from that sequence. On a smaller scale, one can also attempt to track the changing of one character trait to another (example: fins turning to legs).Ancestral reconstruction is performed using statistical models for genetic variation. The idea was first proposed in 1963 by Zuckerkandl and Pauling. Overall, the consequence is that one can use the genetic information already obtained through methods such as phylogenetics to determine the route that evolution has taken and when evolutionary events occurred. One of the most prominent examples is tracing the evolution that took place from ape to man. More creatively it has been used to compare the catalytic properties of ancient versus modern proteins.