verlainne@cafeantinomie
morphology and morphospace for the CS bunny egirls who asked. what the heck is it?
morphology is the study of form (the shape of the thing) rigorously. what does it look like? how can we make that a number?
and morphospace is the space of all possible forms. you pick your measurable traits like limb ratios, curvature, angles, whatever is meaningful to your subject of study. then, you make axes out of them so every hypothetical form is now a point. now, you have a space! ... unfortunately
MOST OF IT IS EMPTY
why? well...because life occupies a tiny region. the rest is theoretical organisms that dont exist and (maybe) can’t. morphospace asks why THESE points dont exist? is it constraint? selection? developmental canalization? historical accident? vibes??
dear CS kitty, morphospace is similar to manifold learning style analysis. (but not identical keep that in mind ok..) when you run UMAP PCA, t-SNE on your embeddings you are doing something similar to morphospace analysis on a feature space. the questions are the same. where do things cluster? what regions are empty? what does distance mean? you have been doing this
geometric morphometrics is one formal version of this. procrustes alignment + PCA, align your shapes (remove translation, rotation, scale, pure shape remains), find principal components of variation, plot
you can model organisms that dont exist and ask why they dont? hmm? you can watch lineages move through the space. you can find convergence! (two clades arriving at the same region independently) which is one of the most interesting things in biology.
sometimes people mix up waddington’s epigenetic landscape. it is related but it is mostly a metaphor for developmental trajectories. there’s also the phylotypic stage/developmental hourglass idea where vertebrate embryos have a similar form despite having very different early stages and very different adult forms. waooow how does a cow human rabbit pig chick all pass through a similarish body plan bottleneck?
can early shape predict late outcome? how much of the space is accessible given our developmental architecture?
that’s it. no language wars with the morphospace octopuses and CS bunnies please