AP Biology / Unit 7: Natural Selection
7.9 Phylogeny
Notes
Phylogenetic trees and cladograms show evolutionary relationships.
- Nodes are common ancestors. Species sharing a more recent node are more closely related.
- Shared derived characters define groups. The outgroup is the least related.
Practice
On a cladogram, the closest relatives:
Most recent shared node.
The outgroup:
It anchors the comparison.
Trees built from DNA are often more reliable than ones from anatomy because:
Lots of independent evidence.
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