Why Are Traditional Grouping Such as Reptilia and Agnatha Not

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The Answer is Traditional groupings such as Reptilia and Agnatha are not recognized in cladistics because they are not monophyletic, meaning they do not include all descendants of a common ancestor. In cladistics, groups are defined based on shared derived characteristics, and if a group does not share a common ancestor and all of its descendants, it is not considered a valid clade.

For example, the traditional group Reptilia includes animals like snakes, lizards, and crocodiles, but it excludes birds, which are also descendants of the common ancestor of reptiles. Similarly, Agnatha includes jawless fish like lampreys and hagfish, but it excludes jawed fish, which are also descendants of the common ancestor of all fish.

From an evolutionary perspective, it makes sense not to recognize these traditional groupings in cladistics because they do not accurately represent the evolutionary relationships between organisms. By using cladistics to define groups based on shared derived characteristics, we can create more accurate and meaningful classifications that reflect the true evolutionary history of organisms. This allows for a better understanding of the relationships between different species and their shared ancestry.

Why Are Traditional Grouping Such as Reptilia and Agnatha Not

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