Mass extinctions do not explain skew in interspecific body size distributions
2013 (English)In: Journal of Zoological Systematics and Evolutionary Research, ISSN 0947-5745, E-ISSN 1439-0469, Vol. 51, no 1, 13-18 p.Article in journal (Other academic) Published
In several higher animal taxa, such as mammals and birds, the distribution of species’ body sizes is heavily skewed towards small size. Previous studies have suggested that small-bodied organisms are less prone to extinction than large-bodied species. If small body size is favorable during mass extinction events, a post mass extinction excess of small-bodied species may proliferate and maintain skewed body size distributions afterwards. Here, we modeled mass extinctions, and found that even unrealistically strong body mass selection has little effect on the skew of interspecific body size distributions. Counter intuitively, selection against large body size may skew size distributions towards large body size. Subsequent evolutionary diversification rapidly erases the rather small effects mass extinctions may have on size distributions. Next, we tested whether skewed body size distributions in mammals and birds can be due to mass extinctions at the transition from Cretaceous to Paleogene, approximately 65 million years ago. Body size distributions of clades that originated during the Cretaceous are on average more skewed than their subclades that originated during the Paleogene, but the difference is only minor in mammals, and in birds it can be explained by a positive relationship between species richness and skewness that is also present in clades that originated after the transition. Hence, we cannot infer from extant species whether the K-Pg mass extinctions were size-selective, but they are not the reason why most extant bird and mammal species are small-bodied.
Place, publisher, year, edition, pages
2013. Vol. 51, no 1, 13-18 p.
body-size skew, Cretaceous-Paleogene, extant species, macroevolution, phylogeny
IdentifiersURN: urn:nbn:se:umu:diva-49755DOI: 10.1111/jzs.12002ISI: 000313753400002OAI: oai:DiVA.org:umu-49755DiVA: diva2:457129