Abstract Detail

Macroevolution

Beaulieu, Jeremy [1], O'Meara, Brian [2].

The impact of ascertainment bias in comparative biology.

In a recent paper, we expressed our concerns about the impact that ascertainment bias may have in understanding the history of a character. That is, perhaps by focusing on certain clades, those with variation in a trait of interest, we are often misled about general processes since we only look at peculiar subsets of life. The example we used was a simulation approach that tested the impact of analyzing many smaller, variable clades only. Here we revisit these results and demonstrate the various ways in which ascertainment bias is already accounted for in many comparative tests. We also highlight the many additional types of ascertainment biases unaccounted for in most comparative analyses, each capable of producing data sets that are not representative of the overall evolutionary process. For example, it is easier to communicate evolutionary patterns if the focal group has a name (either formal or informal). Clades are often chosen because they are tractable, neither too big nor too small, already have a fair bit known about them, and are often times geographically convenient. We also worry that this issue is compounded by the fact that only a portion of possible clades are examined closely, while others are ignored completely. We illustrate this point by conducting a detailed literature analysis, which clearly shows a strong phylogenetic signal in the clades that are chosen for study. We propose a few solutions, which includes, but is not limited to, examining larger, more comprehensive clades. They naturally include relatively obscure and unstudied groups often overlooked in favor of compelling, charismatic, and thus inherently biased, clades.

1 - University of Arkansas, Biological Sciences, 601 SCEN, Fayetteville, AR, 72701, USA
2 - University of Tennessee, Ecology and Evolutionary Biology, Knoxville, TN, 37996-1610 , USA

Keywords:
character estimation
ascertainment bias
clades.

Presentation Type: Oral Paper
Session: MACRO2, Macroevolution II
Location: Tucson B/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 2:00 PM
Number: MACRO2003
Abstract ID:1008
Candidate for Awards:None