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Posts tagged ‘coding’

Weekly reading: Structural complexity in ancestral ontologies

Next week’s reading in our quickly ending series on coding characters and (most recently) dynamic homology.

Ramírez, M.J. & P. Michalik. 2014. Calculating structural complexity in phylogenies using ancestral ontologies. Cladistics (Early View). Available here.

Update: Wonderful paper! Love the innovative and somewhat irreverent use of ontologies specifically to address and answer a genuine systematic question complex, outside of the “Protégé paradigm” (and in fact without formal reasoning, period). Ramírez and co-authors are onto something novel and impactful.

Weekly reading: Missing values, inapplicable states and polymorphic taxa

The third and likely penultimate session in our “explore cladistic coding” series. A brief primer below; more during our discussions and practices.

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Weekly reading: Character types and coding methods

Second chapter in the “let’s get some practice” series. In this week’s reading practice we will explore the interaction of alternative coding schemes and tree/optimization outcomes, both “by hand” and with WinClada and NONA. In particular, we will apply and compare simple binary, non-additive multi-state, and complex additive character coding schemes. We will assess their effects on cladogram length and on the character state optimizations along the internal cladogram nodes. We will start by learning how to code complex character state hierarchies as additive binary as well as additive multi-state characters. Please do some reading of the handout beforehand.

Weekly reading: Introducing DELTA (DEscriptive Language for TAxonomy)

As part of the series on character coding and analysis, we will learn about the software DELTA during this week’s discussion (February 14, 2014). As stated on its website, “[t]he DELTA format (DEscription Language for TAxonomy) is a flexible and powerful method of recording taxonomic descriptions for computer processing”, and “[i]t was adopted as a standard for data exchange by Biodiversity Information Standards (TDWG).” Read more

Weekly reading: Cladistic matrices, Wagner trees, and optimizations “by hand”

This week our weekly lab discussion group shifts gears from the empiricism/realism debate to actual, and mostly still “manual” (as if hands could think), character matrix assembly, Wagner tree construction, and upward-/downward-pass parsimony-based character state optimization. Consistency and retention indices. And WinClada and NONA. Let’s see how far the first session will take us towards understanding the interaction between characters, parsimony, optimizations, and trees.

Weekly reading: Brady on the independence of systematics

Up next week, following Rieppel’s (2007) nuanced dissection of the limits of ‘direct reference’ (Kripke’s causal theory) and emerging lessons for comparative morphologists, we shall pivot to one of the more influential and sophisticated expositions of a pattern-centric view. Ronald Brady played a sometimes under-appreciated role in conversing and shaping views with cladists at the American Museum of Natural History starting in the late 1970s.

Brady, R.H. 1985. On the independence of systematics. Cladistics 1: 113-126. Availaible here.

Weekly reading: Rieppel on the performance of morphological characters

Last week we saw that coding inapplicables is tricky; essentially one must understand the limitations of the ‘square matrix’ and utilize reductive coding in such a way that logical and biological dependencies inherent in homology assessments are not distorted by the way in which global parsimony optimization occurs. We also saw a shift from a rather clear-cut stance about the boundaries between data and inference, to a more qualified position where inferences derived from an initial matrix and analysis should caution one to re-examine ‘the evidence’. Taking this dethroning of primary observations several steps further, next week we are reading:

Rieppel, O. 2007. The performance of morphological characters in broad-scale phylogenetic analyses. Biological Journal of the Linnean Society 92: 297–308. Available here. 

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Weekly reading: Coding inapplicables

For next week’s discussion in our budding coding cladistic characters series for this semester, we shall read a paper dealing with the ins and outs of coding “inapplicables”:

Strong, E.E. & D. Lipscomb. 1999. Character coding and inapplicable data. Cladistics 15: 363–371. Available here.