Cladogram — Science definition
A branching diagram that groups organisms by shared, derived traits to show their evolutionary relationships and common ancestry.
Where it is taught
- Classification & Biodiversity — Evolution, Ancestry & Biodiversity, Life Science: Biology, Grade 10
In use
To picture these relationships, biologists draw a cladogram — a branching diagram, read much like a family tree, in which each branch point represents a common ancestor.
Classification & Biodiversity
Questions using cladogram
Problem 1
Answer and explanation
A shared derived trait is a feature that first evolved in a common ancestor and was inherited by all of its descendants. On a cladogram, all the organisms that share that trait form a group (clade) branching from that ancestor, so shared derived traits let you identify which organisms are more closely related.
Problem 2
- Salamanders and turtles are more closely related to each other than either is to sharks
- Sharks are more closely related to turtles than salamanders are
- All three are equally related
- Branch points on a cladogram carry no information about relatedness
Answer and explanation
Salamanders and turtles are more closely related to each other than either is to sharks
A more recent shared branch point means a closer relationship, so salamanders and turtles are more closely related to each other than either is to sharks.