Embedded Files
A trait that is unique to a group and therefore defines that group. There are two kinds that we will use:
synapomorphy - a derived trait that is shared by two or more taxa and therefore defines that grouping of taxa.
autapomorphy - a derived trait that is unique to one taxon; a trait found in only one member of the group being studied.
In this diagram assume vertebrates are the group being studied and that stick insects are the outgroup.
The trait of vertebrate is a derived trait that defines all members of what we call vertebrates. Notice how all taxa except for the outgroup have this trait. It is a synapomorphy.
The trait of amniote is a derived trait that defines all members of what we call amniotes. Notice how all taxa except for the goldfish and the outgroup have this trait. It is also a synapomorphy.
The trait of hair is a derived trait that is unique to the dog in this trees. Notice no other taxa have this trait. It is a autapomorphy.
The trait of vertebrate is a derived trait that defines all members of what we call vertebrates. Notice how all taxa except for the outgroup have this trait. It is a synapomorphy.
The trait of amniote is a derived trait that defines all members of what we call amniotes. Notice how all taxa except for the goldfish and the outgroup have this trait. It is also a synapomorphy.
The trait of hair is a derived trait that is unique to the dog in this trees. Notice no other taxa have this trait. It is a autapomorphy.
Page updated
Report abuse