Phylogenetic Trees
Trees show evolutionary relationships.
About this topic
A phylogenetic tree is a diagram showing evolutionary relationships. The branching points (nodes) represent common ancestors, and branch tips represent species. The more recent the shared ancestor, the more closely related two species are.
Trees are built from anatomy and especially DNA sequence data, which counts differences. Read them by following branches back to common nodes, not by tip positions: neighbouring tips aren't necessarily closest relatives. Cladograms use shared derived characteristics.
To read a tree, trace back from two species to where their lines meet; the closer that node, the more recent their common ancestor. Humans and chimpanzees meet more recently than either does with gorillas. Do not read tips as ranking species from primitive to advanced, because all living species have evolved for the same amount of time.
Trees are built from physical features and, increasingly, DNA and protein sequences; the fewer the differences, the closer the relationship. They are used to trace the spread of viruses such as SARS-CoV-2 and to guide conservation by finding unique lineages. A common mistake is to think the order of tips from left to right matters; branches can rotate around a node without changing the relationships.
Key ideas
- Branches are lineages
- Nodes are common ancestors
- Closer branches mean closer kin
Quick check
Use cases: where Phylogenetic Trees helps
- Homework: review the key idea behind Phylogenetic Trees before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Phylogenetic Trees without notes.
- Visual learning: play with the interactive lab to see how Phylogenetic Trees changes when you adjust its inputs.
- Teaching a friend: explain Phylogenetic Trees in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Phylogenetic Trees?
Trees show evolutionary relationships.
What will I learn in Phylogenetic Trees?
Branches are lineages. Nodes are common ancestors. Closer branches mean closer kin.
Is Phylogenetic Trees part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Phylogenetic Trees lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Phylogenetic Trees?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.