Our Tree

Organisms Displayed

11. Coyote

12. Cat

13. Squirrel

14. Human

15. Downy Woodpecker

16. Igwan

17. Timber Rattlesnake

18. Sea Urchin

19. Uya'ga"da'

20. Methanothermobacter

How to Read a Phylogenetic Tree

What is a Phylogenetic Tree?

A phylogenetic tree is a diagram that shows the evolutionary relationships among various biological species based upon similarities and differences in their physical or genetic characteristics. These trees are essential for understanding how species evolve and relate to each other over time.

The Components of a Phylogenetic Tree:

Branches: Each branch of the tree represents evolutionary time and lineage. The length of the branch can tell how much time has passed since the last common ancestor between two species.
Nodes: The points where branches split, called nodes, represent common ancestors. The more recent the node, the closer the relationship between the species branching from it.
Terminal Nodes (Leaves): These are the endpoints of the branches that represent the species being studied, typically existing species or known extinct species.

Steps for Reading the Tree:

Start at the Root: Begin at the place where all branches converge. This point represents the last universal common ancestor (LUCA), from which all life has evolved.
Follow the Branches: Move along the branches from the root to the leaves. Each branch represents a lineage, and each node where branches split represents a point where species diverged due to evolutionary changes.
Assess Relationships: Closely related species will share recent common ancestors, which means their nodes will be closer to the leaves. Species that share a node closer to the root diverged earlier and thus are less closely related.
Ignore Physical Proximity on the Tree: The physical closeness of the terminal nodes on the tree doesn't necessarily indicate closeness in evolutionary terms. Focus on the order of branching and how recent the common ancestors are.

Installation Photo

Page updated

Google Sites

Report abuse