Classification and Evolution Lab 15. Taxonomy Taxonomy is the field devoted to the classification...
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Transcript of Classification and Evolution Lab 15. Taxonomy Taxonomy is the field devoted to the classification...
Classification and Evolution
Lab 15
Taxonomy
Taxonomy is the field devoted to the classification of living things. First devised by Carolus Linnaeus. Hierarchical – nested categories.
Modern Taxonomic System
Kingdom Phylum Class Order Family Genus Species
Modern Taxonomic System
The genus and species together make up the scientific name. Genus is capitalized, species is not. Both are italicized. Homo sapiens
Modern Taxonomic System
Our modern taxonomic system reflects evolutionary history.
Modern Taxonomic System
Organisms that are closely related to each other share a more recent common ancestor than those that are more distantly related.
Modern Taxonomic System
Some traits are more useful than others when determining relatedness. Homologous traits evolved from a trait
present in a common ancestor. Useful for determining relatedness.
Analogous traits evolved from different traits in unrelated groups, but look similar due to convergent evolution.
Not useful for determining relatedness.
Modern Taxonomic System
Homologous traits that are shared very far back (primitive traits) do not help us define smaller, more recent groups. Multicellularity or backbones do not help to
define mammals. Derived traits that are shared just be
the group we are defining are the most useful. Hair and mammary glands do define
mammals.
Two ways to classify terrestrial vertebrates
ReptiliaClass
Mammalia
Mammals
Early reptilesTraditional phylogeny and taxonomic classification Cladogram and cladistic classification
Class Reptilia Mammalia
ArchosaursClass Aves
Turtles Crocodilians Birds
Dinosaurs
Lizards andsnakes Mammals Turtles Crocodilians Birds Dinosaurs
Lizards andsnakes
Reading a Cladogram