Is It Not Always A Good Idea? Essay

1776 Words8 Pages
1.Why is it not always a good idea to describe a population by its average size? In other words, how do any of the individual simulations differ from the average of all simulations, and why might this difference be important to realise?

It may not be a good idea to describe a population by its average (blue line on trajectory summery), as the model takes into account the standard deviation (indicated by upper and lower error bar thresholds). This standard deviation displays the equal probability that a population will reach these upper and lower abundances over the course of the population model. It is important to realise this difference as over the course of a population model (25 years), the standard deviation error thresholds may allow the population to become extinct or it may allow it to explode to excessive numbers which is a huge population range between upper and lower figures. Each time a model is simulated, the average abundances will be different but will remain within the standard deviation outliers.

Brook Trout Trajectory Summary

Exercise B
Using the criteria on page 38 for classifying a population as critical, endangered or vulnerable, should the spotted owl be considered critically endangered? Why or why not?
The northern spotted owl should be considered critically endangered based on Mace and Lande (1991) which categorise critically endangered as a species having a 50% or greater probability of extinction over five years. As the trajectory summary
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