Prof. Dr. Hanna Kokko

Research Priorities: Theoretical biology, evolutionary biology, ecology, mathematical models for biological questions, research on ageing

Hanna Kokko is a Finnish biologist whose main focus is on theoretical questions of evolutionary biology and ecology. Her work is based on the idea that there is mathematical logic behind biological phenomena. She uses mathematical computer models to better understand the interplay of evolutionary and ecological processes and to test theories. Her work covers a broad range of topics, from the lifecycles of various species, and strategies for coexistence, to the evolution of sexual reproduction, ageing, and cancer. 

Hanna Kokko considers some evolutionary theories to be too simple, for example the “survival of the fittest” concept. According to this theory, the individuals that are best adapted to their respective environmental conditions have the best chance of surviving and reproducing. The reality, however, is that a huge range of lifeforms have evolved over millions of years, and they succeed using very different strategies. Hanna Kokko wants to understand how this diversity arises. 

The computer models she uses to decode the logic of evolution offer various approaches to doing so. Depending on their environment, members of a species have to cope with various conditions, which in turn require different adaptations. Additionally, even close neighbours are not necessarily under the same pressure to adapt. For example, in the case of males and females, evolution may require quite different characteristics. Instead of prioritising perfect adaptation to the environment, males may focus on luxury, which costs energy, attracts the attention of enemies, and may even shorten their lives. However, the risk is apparently worth it when it comes to passing on their genes to the next generation. 

However, in light of the effort and high costs involved, the question arises as to why organisms focus on sexual reproduction at all. After all, there are asexual forms of reproduction, which are far simpler and more efficient. Hanna Kokko has also examined the theoretical connections behind such processes. The key advantage of mating is clearly that it leads to greater genetic variety. The more genetically diverse offspring there are, the higher the chance that some of them will adapt to new environmental conditions or cope better with pathogens. Furthermore, harmful genetic changes multiply over time in each organism. As reproduction means the partners’ genomes mix, it slows this process and leads to a healthier population.

In addition to their reproduction, various species also organise aspects of their lives differently. For example, even among close relatives there are those that live considerably longer or prefer to live in a community than alone. Hanna Kokko has also investigated the pros and cons of such strategies. For example, she has provided theoretical evidence that in some species cooperative behaviour can increase the survival chances of the group members. 

In other words, organisms on earth have found the most various ways of adapting to life’s challenges. However, this is no simple task, especially not in a world that is rapidly changing due to human influence. She also wants to shed light on this change and its consequences.