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Department of Evolutionary Anthropology

PD Dr. Karin Isler

Karin Isler, PD Dr.

  • Studienkoordinatorin Fachbereich Biologie

Studienkoordination Fachbereich Biologie UZH


BIO 207 Comparative Systematics and Evolution of Primates (lecture)

Information about teaching and courses in Anthropology

Completed Research Projects

Brain size evolution in mammals (2003 - 2017)

The human brain is about three times as large as that of our closest relatives, the chimpanzees. To understand how this remarkable characteristic of our species evolved, we studied brain size evolution in animals by comparing a broad array of mammal and birds species.
Having a large brain brings many obvious benefits, but it is also costly as brain tissue is energetically expensive. To evolve a larger brain than its ancestors, a species can either increase its total energy turnover, or allocate its energy budget differently. We found evidence for both pathways in mammals. However, rather than trading off brain size against the size of other expensive body organs such as the gut, there is a strong negative relationship between brain size and reproductive output. Although relatively large-brained species compensate their reduced annual fertility rate by a prolonged lifespan, their population growth rate under optimum conditions is still relatively low, resulting in an ultimate negative correlation between brain size and demographic viability of a species. Only if the mother receives help from conspecifics during breeding, the energy subsidies alleviate this constraint. We therefore concluded that the human lineage was only able to evolve an ever larger brain due to a change in lifestyle towards cooperative breeding.

Kinematics of locomotion in primates

In my PhD project, I studied 3D-kinematics of vertical climbing in hominoid primates (gorillas, bonobos, orang-utans, gibbons and atelines). Analyses revealed that differences in climbing kinematics between individuals of one species are mostly size related, whereas diferrences between species may reflect specific locomotor adaptations.