1. Systematics Taxonomy, Phylogeny, and Classification

2. Diversity of Life

3. How do we organize it all? –MORPHOLOGY What the organisms look like (phenotype). –EVOLUTIONARY HISTORY Shared ancestry, relationships. CLUES: –Space – Biogeographic distributions of organisms –Time – Fossil record

4. Systematics Science of organizing the diversity of life. 1.Taxonomy – Identification & Naming 2.Phylogeny – Analyzing evolutionary relationships among groups. 3.Classification – Placing organisms into an organized categorization scheme.

5. Taxonomy Identification & Naming Taxon: a group of organisms (Taxa) “Species” – basic group, the only REAL taxon. –Group of interbreeding populations that are reproductively isolated from other such groups (and evolving independently of other such groups). Lineage – Taxa connected in time by genetic links.

6. Taxonomy “Species” are not always easy to detect! –Variation –Asexual reproduction –Morphology is not enough Need anatomy, physiology, ecology, behavior, biochemistry, evolutionary history, etc. Identified by experts in their respective fields.

7. Taxonomy New species published in peer-reviewed Journals.

8. Taxonomy A “Type Specimen” is denoted. –A single physical specimen that all others are later compared to. –The Latin description is based on this specimen. –Stored in a special place. ATCC: http://www.bioscience.org/urlli sts/atcc.htmhttp://www.bioscience.org/urlli sts/atcc.htm

9. Taxonomy New species each given a “Scientific Name” –Carolus Linnaeus –Binomial Nomenclature –2-word Latin name. Pinus strobus Dictyostelium discoideum Bubo virginianus “Common Names” also… –Can be misleading

10. Taxonomy Pinus strobus 1 st word = Genus –A generalized name 2 nd word = specific epithet –A descriptive name Always in italics or underlined. Genus is capitalized, epithet is lower case. Specific epithet never used alone!

11. Taxonomy “Variants” sometimes used –not different species, but “sub-species” –An additional descriptor is added to the end. Lampropeltis triangulum var. sinaloae Lampropeltis triangulum multistriata

12. Phylogeny Grouping new species/taxa with closely- related taxa from an evolutionary perspective. Phylogenetic Trees:

13. Phylogeny Easier said than done! 3 approaches: 1.Evolutionary Systematics Grouping based on similarities & differences Reliance on fossil evidence Subjective 2.Phenetics Grouping based on similarities only Convergence is a problem

14. Phylogeny 3.Phylogenetic Systematics (Cladistics) Based on similarities derived from a common ancestor – “Shared Derived Characters” (if only 1 in the group has the character, it’s no good) Plesiomorphic vs Apomorphic characters Want “Synapomorphies” Identifies Monophyletic Groups Look for homologous structures (not analagous ones).

15. Phylogeny Tree Polarity – –Need to know which character state is ancestral (plesiomorphic) and which is derived (apomorphic). –Fossil Evidence is good, but not always available! –Outgroup A closely related organism that is NOT part of the “ingroup” being studied. Acts as a means of comparison.

16. Phylogeny Outgroups:

17. Phylogeny Must REALLY know your organism Often, genes are used to INFER relationships between whole organisms.

18. Phylogeny Phylogenetic Trees –Represent CURRENTLY LIVING organisms. –DO NOT represent a This That NOW!

19. Phylogeny of Animals

20. Classification Categorizing organisms into a hierarchy of names (hopefully) according to their relatedness. Historically – based on convenience. Starting at Species (the most exclusive group), organisms are grouped into more and more broad & inclusive Taxa. “Species” is the only level that really exists as an true single entity.

21. Classification Kingdom Phylum/Division Class Order Family Genus Species Animalia Chordata Mammalia Primates Hominidae Homo Homo sapiens

22. Animalia Chordata Aves Mammalia Strigiformes Primates Tytonidae Hominidae Tyto Homo Classification Homo sapiens Tyto alba

23. Classification Meant to reflect phylogeny:

24. Classification Times are changing! Phylocode (http://www.ohiou.edu/phylocode/)http://www.ohiou.edu/phylocode/ Rankless Classification Clades are each given a name

25. Tree of Life

26. Systematics Tree of Life: http://tolweb.org/tree/phylogeny.html http://tolweb.org/tree/phylogeny.html