Variation and Sexual Dichromatism in Parrots


This worksheet explores a scientific research study in sexual dimorphism in parrots. Specifically, it looks at color differences between sexes of the same species, a phenomenon called “sexual dichromatism.”

The activity is based on a published study on parrots where the authors examine factors that could affect evolution. I only included a graph where body size (X axis) is correlated to coloration and also to male/female differences.

Excerpt from abstract:

” Plumage colour varies substantially between parrot species and sometimes also between males and females of the same species. Here, we use comparative analyses to evaluate what factors correlate with colour elaboration, colour diversity and sexual dichromatism.”

Students may find this topic challenging. There’s a lot going on in this graph! I also don’t provide much background information, so students really must rely on just details of the graph to figure out what is going on.

In order to be successful, students should have a basic understanding of evolutionary principles and natural selection. They do not necessarily need to know what sexual selection is. In fact, this could serve as good opening phenomenon for lessons on sexual selection and dimorphism. My students are already familiar with Darwin’s finches at this point, so parrots are a nice transition into more advanced evolution ideas.