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Why is taxonomy important?
Remember! Science changes all the time – nothing is
concrete!
• Unknown species are being discovered!
• New fossils are being uncovered!
How would these new
discoveries affect our
classification systems?
Cladograms/Phylogenetic Trees
• Diagrams showing evolutionary relationships
between species
– Like a family tree of species constructed using morphology
& DNA evidence
Cladograms
• Important features of cladograms are:
– Derived Characteristics: recently evolved characteristics
of organisms being compared
– Ancestral Characteristics: shared characteristics of all the
organisms being compared
Ancestral Characteristics:
vertebrae
Derived Characteristics:
hair, amniotic egg, etc.
According to this cladogram, who are rabbits
most closely related to?
A.
B.
C.
D.
Crocodiles
Amphibians
Primates
Birds
Which organisms are birds the least related to?
A.
B.
C.
D.
Crocodiles
Ray-finned Fish
Sharks
Primates
Sharks!