1. 1 Apply Concepts To an evolutionary taxonomist, what determines whether two species are in the same genius 2 Explain What is a derived character 3 Review How do taxonomist use the DNA sequences of species to determine how closely two species are related Relate Cause and Effect Explain why the classification of American vultures has changed

2. 18.2 Modern Evolutionary Classification
Ch 18 Classification
18.2 Modern Evolutionary Classification

3. Evolutionary Classification
Phylogenetic systematics
Group species into larger categories that reflect lines of evolutionary descent
Not overall similarities and differences
Phylogeny
Study of how living and extinct organisms are related to one another.

4. Clade Monophyletic group Cladogram
Group of species that includes a single common ancestor and all descendants of that ancestor
Monophyletic group
Must only include all species that are descended from a common ancestor
Cladogram
Links groups of organisms by showing how evolutionary lines, or lineages, branched off from common ancestors.

5. Building Cladograms Node
Represents the last point the new lineages shared a common ancestor
Speciation event.

6. Cladogram’s branching patterns indicate degrees of relatedness among organism.

7. Lineages 3 and 4 share a common ancestor more recently with each other than they do with lineage 2
Lineages 3 and 4 are more closely related to each other than they are with lineage 2.

8. This represents current hypotheses about evolutionary relationships among vertebrates.

9. Derived Character
Trait that arose in the most recent common ancestor and was passed along to its descendants.

10. Four limbs is a derived character for the clade tetrapoda
Hair is a derived character for the clade Mammalia.

11. Reading Cladograms
Simplified phylogeny of the cat family.

12. Lowest node represents the last common ancestor of all four-limbed animals.

13. Forks show the order in which various groups branched off over the course of evolution.

14. Trait of four limbs, for example, appeared before the trait of hair in the history of the cat’s lineage.

15. Some clades match up with traditional taxonomic groups
Mammalia
Some don’t
Reptilia.

17. Two clades do include the birds
Clade Aves and clade Reptilia
Birds are reptiles.

18. DNA in Classification
The more derived genetic characters two species share
More recently they shared a common ancestor
More closely they are related in evolutionary terms.