Biology / Unit 8 Bio 1791 short lesson, about 20 seconds
Rooted and Unrooted Trees
Captions available
The idea
A rooted tree identifies a single ancestral lineage all included organisms trace to; an unrooted tree shows relationships without identifying that ancestor.
In practice
A rooted tree of life's three domains traces Bacteria, Archaea, and Eukarya to one shared origin point; an unrooted version omits that point.
Where people slip
An unrooted tree still conveys relationships shown — it lacks only the ancestor, not all information.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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