Morphometrics: Introduction to the Analysis of Shape
7 days ago
- #paleontology
- #morphometrics
- #statistical analysis
- Morphometrics is the quantitative study of form, including size and shape, used to analyze distinctions, changes, and taphonomic effects.
- Principal Components Analysis and Principal Coordinates Analysis are key methods for summarizing multiple variables in morphometrics.
- Morphospaces graphically represent quantified shape; theoretical morphospaces use predetermined axes, while empirical ones derive from actual data analysis.
- Function of extinct forms is reconstructed via analogies, phylogenetic inferences, biomechanics, trace fossils, and correlations, though some features may be non-functional 'spandrels'.
- Landmarks are crucial points for comparing specimens, and traditional morphometrics involves measuring distances between these points.
- Phylogenetically independent contrasts correct for phylogenetic biases in statistical analyses, requiring a known phylogeny for meaningful correlations.
- PCA and related techniques reduce multiple variables for analysis, applicable beyond morphometrics to fields like ecology.
- Data acquisition methods include linear and outline methods like Fourier analysis, with adaptations for 3D morphometrics.
- Raup's morphospace exemplifies theoretical morphospaces; advantages include pre-set axes, but some areas may be unoccupied due to functional constraints or taphonomy.
- Empirical morphospaces use PCA-derived axes, better occupying the space but requiring reanalysis for new data.