1. Cladograms
Honors Science
Grade 8

2. Cladistics
Cladistics – a method of classifying animals and plants by the characteristics they have in common.
Clade - A group that includes a common ancestor and all the descendants (living and extinct) of that ancestor.

3. Cladogram A diagram that shows evolutionary relationships.
It is assumed that the more characteristics the two organisms share, the more recently they diverged from a common ancestor.

4. How to read a Cladogram
This diagram shows a relationship between 4 relatives.
These relatives share a common ancestor at the root of the tree.
Note that this diagram is also a timeline. The older organism is at the bottom of the tree.
Branches on the tree represent SPECIATION.
Speciation - the formation of a new species.
The four descendants at the top of the tree are DIFFERENT species.

5. How to read a Cladogram
Species A, B and C each have characteristics that are unique only to them.
But they also share some part of their history with species A.
This shared history is the common ancestor.
Unique history of A

6. Practice Reading a Cladogram

7. What trait separates amphibians from primates on this cladogram?
What separates rabbits and primates from crocodiles on this cladogram?
Which organism is most related to the bird on this cladogram?
What 5 traits do these two organisms share?

8. First, Identify Characteristics
Lamprey
Snapping Turtle
Tuna
Bullfrog
Nerve Cord X
Paired Legs
Paired appendages vertebrae column
Amniotic Sac
Total X’s

9. Paired appendages vertebrae column
Lamprey
Snapping Turtle
Tuna
Bullfrog
Nerve Cord X
Paired Legs
Paired appendages vertebrae column
Amniotic Sac
Total X’s 1 4 2 3

10. First, Identify Characteristics
Lynx
Chimpanzee
Lizard
Newt
Human
Bipedal X
Hair
No Tail
Amniotic Membrane
Lungs
Total X’s

11. Lynx
Chimpanzee
Lizard
Newt
Human
Bipedal X
Hair
No Tail
Amniotic Membrane
Lungs
Total X’s