March 2014 archive

Mar 06

Organism of the week #20 – Don’t point that thing at me

Diadema setosum [CC-BY-SA-3.0 Steve Cook]

It’s amazing how informative an anus can be. Take this sea urchin. The orange pucker in the middle of the spines is its “around-the-bum”, although zoologists would insist on writing that in Greek as “periproct“. The bright orange ring-piece is characteristic of this species, and marks it out as Diadema setosum, rather than any of …

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Mar 03

Nonlinear regression

Species-area relationship for Caribbean herps [CC-BY-SA-3.0 Steve Cook]

Nonlinear regression is used to see whether one continuous variable is correlated with another continuous variable, but in a nonlinear way, i.e. when a set of x vs. y data you plan to collect do not form a straight line, but do fall on a curve that can be modelled in some sensible way by …

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