To indicate extinct organisms on a tree diagram, you can use various methods:
1. **With a shorter branch:** One way to show extinct organisms on a phylogenetic tree is to have a shorter branch leading to the extinct group. This shorter branch signifies that the lineage of the extinct organisms ended at a certain point in evolutionary history.
2. **With a different colored branch:** Another method is to use a different color for the branch that represents the extinct organisms. By using a distinct color, you can visually differentiate the extinct group from the extant (still existing) organisms on the tree.
3. **With a longer branch:** In some cases, a longer branch leading to the extinct group can also be used to indicate that the lineage persisted for a significant period before becoming extinct. This longer branch can highlight the evolutionary history of the extinct organisms compared to other groups on the tree.
By employing these visual cues such as branch length or color variations, you can effectively represent extinct organisms on a phylogenetic tree, aiding in the understanding of evolutionary relationships and the history of life on Earth.
