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Biology Articles » Protistology » Evolution of dispersal and life history strategies – Tetrahymena ciliates » Table 02
Table 02

List of variables used in statistical analyses 

Experiment 
Variable name 
Definition 
Estimation method and level 


Growth 
K 
Carrying capacity (see eqn 1) 
Logistic function fitted at the replicate level to successive densities (time > 0) estimated at the picture level (5 values per time step) 
r 
Growth rate (see eqn 1) 
Logistic function fitted at the replicate level to successive densities (time > 0) estimated at the picture level (5 values per time step) 

Final cell density (at K) 
Mean density of cells at the last time step (192 hours) 
Mean of 5 pictures per replicate 

Final cell size (at K) 
Mean size of cells at the last time step (192 hours) 
Mean of all cells of the 5 pictures per replicate 

Final cell shape (at K) 
Mean shape of cells at the last time step (192 hours) 
Mean of all cells of the 5 pictures per replicate 

Starvation 
Survival as a density sum over time 
Area between the density curve and the density at time = 0 line, starting at time = 8 h which was the mean peak density for all strains 
Curves defined by successive values through time of the mean of the 5 pictures per replicate 
Mean maximal cell elongation 
Difference between longest shape and start shape, expressed in percentages of start shape 
Estimated on means of all cells in the 5 pictures per replicate 

Variance in maximal cell elongation 
Difference between the 95th upper percentile and the mean of the shape distribution at the time when the maximal elongation is reached, expressed as percentage of the same difference at start 
Estimated on means of all cells in the 5 pictures per replicate 

Elongation persistence 
Sum of elongation over time, i.e. area between the shape curve and the shape at time = 0 line, starting at time = 8 h 
Curves defined by successive values through time of the mean of the 5 pictures per replicate 

Frequency of putative disperser morphs 
Frequency of disperser morphs observed at time = 8 h 
Mean of the 5 values per replicate (recorded on each sample just after picture was taken) 

Dispersal 
Initial cell shape 
Mean shape of cells in the initial tube 
Mean of all cells of the 10 pictures per block 
Dispersal rate 
Proportion of cells in the target tube at the end of the experiment 
Computed as a combination of parameter values at the replicate level 

Cell elongation 
Difference between mean cell shape in target tube and start tube, expressed as percentage of the shape in start tube ^{1} 
Computed as a combination of parameter values at the replicate level 

Colonization 
Colonization probability 
Proportion of tubes where a cell population developed from the single cell added to the tube 



^{1 }Estimating cell elongation relative to initial shape gave nearly identical results (results not shown). 
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