What do phylogenetic trees show?
The phylogenetic tree is a diagram that shows us the diversification of animals on Earth. The branches show us at what specific point in time two members of the same species became different enough to no longer be considered in the same species.
The phylogenetic tree is also useful for showing common ancestors of certain species as well as species that are closely related to one another. Its important to realize that a true phylogenetic tree would be a tree that branches from the very first life form, all the way to the present time (including all extinct species as well).
The phylogenetic tree is also known as the evolutionary tree. In the phylogenetic tree evolutionary history of the species or groups are depicted in line diagram. The evolutionary tree and its branches show the evolutionary relationships among other various biological species or othergroups. The phylogeny based on similarities and differences in their physical or genetic characteristics.
Dr B K Mishra, India.
A phylogenetic tree represents the evolutionary relationships of a group of organisms
Groups of organisms for example the category 'big cats' or the great apes are thought to have evolved from a common ancestor- they are 'related by descent' and a phylogenetic tree tries to show this relationship.
In a phylogenetic tree, the species that have a closer relationship are shown as 'branches' that are nearer together, and with fewer forks separating them, while species that diverged in evolutionary terms, that is are less closely related will have more forks separating them.
Time is represented vertically with the present at the top, and the past below; organisms that are more closely related are grouped together horizontally.