In: Biology
Apomophy and synapomorphy refers to the characters or traits that are derived from ancestral characters over the evolutionary time.
An apomorphy is a shared characteristic between two or more groups of organism but is different from the form found in ancestor, that sets the clade apart from other clades*. An apomorphy becomes a synapomorphy when it is shown that the trait also belonged to a common ancestor.
A synapomorphy is thus a shared, derived characted that is common between an ancestoe and its descendants.
When organisms become new species, they can develop new and unique characteristics. such novel trait is an autapomorphy whereas the clades often contain many synapomorphies because the animals are so closely related.
* A clade is a term used when describing phylogenetic relationships. A clade denotes that all the organisms within the clade are related to a single common ancestor.
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