Haplo has a large number of parameters. Two of those describe how the population reproduces. There is one parameter, alpha, a which controls variablility of fertility, and another, beta, which controls rates of monogamy. One interesting concept in population genetics is that these two parameters can be fudged together with the real population size, into an effective population size. Here is an intuitive / visual example of why that works.
![](http://uor.beacons.discovery.org/wp-content/blogs.dir/28/files/sites/52/2018/09/effective-population.png)