Presentation on theme: "Lecture 1 – Introduction and Importance of Systematics Mayr - “the theory and practice of classifying organisms”. -Taxonomy – includes species descriptions,"— Presentation transcript:
Lecture 1 – Introduction and Importance of Systematics Mayr - “the theory and practice of classifying organisms”. -Taxonomy – includes species descriptions, taxonomic keys, and diagnoses. -Taxonomy – includes identification of natural groups and biological classes. -Taxonomy – includes study of evolutionary processes and patterns. Biosystematics Society of Systematic Biologists “The study of organismal diversity, including both the pattern of that diversity and the processes that have generated it.”
II. Roles of Systematics. A. Provide -taxonomy. There may be ~5 million extant species on Earth (Costello et al. 2013), and we’ve only described 1.5 million (maybe around ~ 30 %) of them. 57% of the 150 most prescribed drugs contain active ingredients derived from natural compounds B. Provide specimen identification Indirectly, via keys. Directly, via expert examination.
II. Roles of Systematics. C. Maintain Collections Provide reference for identifications. Serve as permanent repository for important specimens. Type specimens Voucher specimens Physical evidence of range shifts
II. Roles of Systematics. D. Classification Provide a framework of names that is universal. This must reflect evolutionary history – monophyletic groups It also must be stable (we should resist change). Do we want taxonomic ranks to be equilibrated across groups?
II. Roles of Systematics. E. Phylogeny estimation. ISI Web of Science “phylogen*” >643,500 papers published since 2004 Understanding Adaptation Study of Evolutionary Patterns and Processes Co-speciation – for example between parasites and their hosts. Historical Biogeography – molecular phylogeography Hybridization Gene Duplication and Genome Structure Deep-time evolutionary Patterns extinction and speciation rates (e.g., lineages-through time) species selection and the study of evolutionary trends
II. Roles of Systematics. Molecular Epidemiology HIV transmission in Edinburgh Inferred a single donor infected the blood supply.
“The current outbreak is likely caused by a Zaire ebola virus lineage that has spread from Central Africa into Guinea and West Africa in recent decades, and does not represent the emergence of a divergent and endemic virus.” II. Roles of Systematics. Molecular Epidemiology – Ebola Virus: Spread from central Africa or new variant?
II. Roles of Systematics. Forensics http://www.genomenewsnetwork.org/articles/01_03/hiv.shtml Richard Schmidt, M.D. Janice Trahan Schmidt was accused of intentionally injecting Trahan with HIV he collected from his HIV + patients. Louisiana v. Richard J. Schmidt This allegation predicts that HIV collected from Trahan should be very closely related to HIV collected from one or more of his patients.
Why Study Phylogenies? Epidemiology & Forensics Trahan’s HIV This (along with other evidence) lead to Schmidt’s conviction.