OEB 181: Systematics. Catalog Number: 5459

Transcription

1 OEB 181: Systematics Catalog Number: 5459 Tu & Th, 10-11:30 am, MCZ 202 Wednesdays, 2-4 pm, Science Center 418D Gonzalo Giribet (Biolabs 1119, Charles Marshall (MCZ 111A, ) Jessica Baker (Biolabs 1119,

2 Grades 4 class assignments (40%) First assignment on October 4th, 2weeks per assignment Class participation (10%) Final exam (December 16th; 50%)

3 Recommended books:

4 Recommended readings: Graur D, and Li WH (2000). "Fundamentals of Molecular Evolution." Sinauer Associates, Sunderland. Chapters 1 and 5. Kitching IJ, Forey PL, Humphries CJ, Williams DM (1998) Cladistics. Theory and Practice of Parsimony Analysis. The Systematics Association by Oxford University Press, Oxford. Page RDM, Holmes EC (1998) Molecular evolution. A phylogenetic approach. Blackwell Science, Boston. Schuh RT (2000) Biological systematics. Principles and applications. Cornell University Press, Ithaca. Swofford DL, Olsen GJ, Waddell PJ, and Hillis DM (1996). Phylogenetic inference. In: Hillis DM, Moritz C, Mable BK (eds) Molecular systematics. Sinauer Associates, Sunderland, Massachusetts, pp Felsenstein J (2004). Inferring Phylogenies. Sinauer Associates, Sunderland, Massachusetts.

5 Systematic journals/societies Society of Systematic Biologists: Willi Hennig Society:

6 Other systematic journals

7 Phylogenetic software

8 Systematics [ ] Discussion Group Fall 2006: Mondays, 1 Harvard University Herbaria

9 Motivation for systematics studies Systematics is the science of biological classification Biodiversity and its origins Relationships (pattern and shape) Conservation biology Medical applications Hillis, D. M. & Huelsenbeck J. P. (1994): Support for dental HIV transmission. Nature 369:

10 Biological Systematics Biological Systematics is the science that studies relationships among organisms (living and extant), establishing the patterns that relate those organisms among each other. Systematics was an intuitive science from its beginning, and it was not until the development of modern methodologies that it became a more strict numerical science. Empiricism was attempted first from a phenetic point of view, propounding a taxonomy which simply grouped based on the overall similarity (Sokal and Sneath, 1963). Simultaneously, phylogenetic systematics (= cladistics) originated as an approach that would directly reflect information concerning the results of the evolutionary process, where groupings are based strictly on special similarity, that is, similarity which arose from common ancestry (apomorphy) (Hennig, 1950, 1966). The application of the parsimony principle (minimizing requirements for ad hoc hypotheses of homoplasy: noise or convergence) to the cladistics methodology gave origin to modern quantitative cladistics. Probabilistic methods were later incorporated into systematic research.

11 Definitions: Systematics and taxonomy: methods and practices of describing, naming, and classifying biological diversity, at the species level and above. Classification: represents the codification of the results of systematic studies. Taxon (plural, taxa): basic units of systematics; group of organisms at any level in the systematic hierarchy. Characters: group of attributes. A unique combination of such attributes (or states of characters) define a species or any other supraspecific taxon.

12 The Linnaean Hierarchy: Systema Naturae (Linnaeus, 1758) Kingdom Class Order Genus Species Variety Current classification system Kingdom Phylum Class Subclass Order Suborder Superfamily Family Subfamily Tribe Genus Species

13 Current classification system Kingdom Animalia Phylum Arthropoda Subphylum Mandibulata Class Myriapoda Subclass Chilopoda Order Lithobiomorpha Family Henicopidae Subfamily Henicopinae Tribe Henicopini Genus Paralamyctes Subgenus Thingathinga Species Paralamyctes (Thingathinga) hornerae Paralamyctes (Thingathinga) hornerae Edgecombe, 2001 Paralamyctes trailli (Archey, 1917) Haasiella trailli: Archey, 1917

14 Pre-darwininan classifications William Macleay and Quinarianism

15 Schools of Classification: Evolutionary taxonomy: Methods and Principles of Systematic Zoology, by Ernst Mayr, Gorton Linsley, and Robert Usinger (1953). McGraw-Hill, New York. Phenetic: Principles of Numerical Taxonomy, by R.R. Sokal, and P.H.A. Sneath (1963). W. H. Freeman, San Francisco. Phylogenetic (Cladistic): Grundzüge einer Theorie der phylogenetischen Systematik, by Willi Hennig (1950); Phylogenetic Systematics (Hennig, 1966). University of Illinois Press, Urbana. (Reissued 1999)

16 Ernst Mayr MCZ Director

17 Schools of Classification: Phenetic Evolutionary taxonomy Cladistic Data type Grouping method Character data converted to a distance matrix Overall similarity Discrete characters Special similarity Discrete characters Special similarity Diagram type Phenogram Evolutionary tree Cladogram Hierarchical level determined by Amount of difference Amount of difference Sharing of unique attributes Sensitive to rate differences Yes Yes No

18 Musems: where systematics gets done

19 First MCZ director Louis Agassiz

20 Museums as sources of morphological and molecular data for systematics Traditional specimens Frozen tissues

21 Where to find more information: Schuh, R.T. (2000). Biological systematics. Principles and applications. Cornell University Press, Ithaca. Chapter 1 gives a general Introduction to Systematics