Cladograms Honors Science Grade 8

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.

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.

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.

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

Practice Reading a Cladogram

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?

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

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

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

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