Card Set Information
Vertebrae Zoology 224
Terms n' stuff
What periods were in the Phanerozoic Era?
Cenozoic, Mesozoic, and Paleozoic
What was a notable point about the Cenozoic period?
Had the most diversification within Vertebrets
What was a notable point about the Paleozoic period?
Vertebrets originated around this time
How are Linnean Ranks based?
On morphological structures
Rules for making classifications
How are taxa defined and organisms classified?
Based on their evolutionary relationships
Evolutionary relationships of members within a taxon
What are phylogenies made of?
System of dichotomous branches developed from shared traits
Are cladograms concrete?
How are clades formed?
Through homologous traits
Trait shared due to common ancestry
Principle of Parsimony
Take the simplest explanation (least character state changes) to explain shared traits.
Group containing common ancestor and all decendents
Group that excludes some decedents due to divergent evolution
Taxa or group acquiring derived characteristics separating it from it's initial group into a new species.
Groups with similar traits that could have evolved independently (Bats and birds are polyphyletic)
Two species or groups that evolved independently but developed similar traits
Shared derived traits
that define the taxon you're looking at (4 walking legs are synapomorphic for tetrapods)
Derived trait present in only one taxon (hair only on heads for humans)
Traits of the ancestors of the common ancestor (vertebrae and hinged jaws are plesiomorphic to tetrapods)
A shared ancestral trait by 2+ taxa
Reference group that is closest related to the ones you're studying. Contain all ancestral but no derived traits.
Group most closely related to taxon under analysis (closest outgroup, look on other end of prong)
Extinct species with
derived traits of the crown group (closer related than sister group and all are paraphyletic)
Living (and some extinct) species with all derived traits.