PHYLOGENETIC TREE Question!

Question

In a phylogenetic tree how do you know which species are the MOST CLOSELY related to each other? If you could give an image as an example for me to see that would be great!

Answer 1

In a phylogenetic tree, species that are most closely related to each other share a more recent common ancestor. You can determine which species are closely related by examining how close they are to each other on the tree, particularly the branching points (called nodes). The closer two species are on the tree, the more recent their divergence from a common ancestor, indicating they are more closely related.

To identify closely related species:

Look for shared nodes: Species that branch from the same node or close nodes share a common ancestor.

Trace the branches: The shorter the branch between two species, the more recently they have evolved from their common ancestor, meaning they are closely related.

Let me generate an image of a simple phylogenetic tree for you to illustrate this.

Here is a simple example of a phylogenetic tree. In this tree, species A and B are closely related, as they share a more recent common ancestor (shown by the branch point closer to them). Species C and D are more distantly related, as they have a longer branch separating them from A and B, indicating a more distant common ancestor.

This visualization should help clarify how closely related species are determined in a phylogenetic tree.

Answer 2

Hello!

In a phylogenetic tree, the most closely related species are those that share the most recent common ancestor. To find the most recent common ancestor first find the species you are comparing, then trace back to their connecting point on the tree. This point indicates the most recent common ancestor. Next, compare the distance between the spaces with this in mind: the fewer branching points between two species, the more closely they are related, and, the closer the most recent common ancestor is to the species you are comparing, the more closely related the species are.

I am unable to attach a photo but here is a link to a khan academy video where they explain a phylogenetic tree!

https://www.khanacademy.org/science/ap-biology/natural-selection/phylogeny/v/understanding-and-building-phylogenetic-trees-or-cladograms

Hope this helps,

Collette