Decoding the secrets of evolution to tackle today’s greatest challenges

The study of evolution remains relevant today as it was when Charles Darwin first introduced it in 1859. Meet the NUS researchers – (from left) Asst Prof Lim Jun Ying, Asst Prof Nalini Puniamoorthy, and Asst Prof Chang Ying – who are uncovering the mysteries of evolution to illuminate the truths about our natural world.

Evolution Day is observed on 24 November each year, marking the anniversary of the publication of Charles Darwin’s groundbreaking work, On the Origin of Species, in 1859. This day commemorates not just a book but a seismic shift in our understanding of life — a theory that connects all living organisms in a vast, intricate web of shared ancestry.

This year, to commemorate Evolution Day, we shine the spotlight on researchers from the Department of Biological Sciences at the NUS Faculty of Science who are building on Darwin’s legacy, exploring the mechanisms of evolution and its impact on biodiversity in the region and beyond. Their work underscores the enduring relevance of evolutionary theory in addressing modern challenges, from conservation to climate change.

ReproLab members with Asst Prof Nalini (centre in purple) are investigating the evolutionary processes and patterns involved in reproduction to study insect biodiversity and to find solutions to tackle environmental challenges.

Learning from insects: Understanding biodiversity through reproductive evolution research

Evolution is often synonymous with the phrase ‘survival of the fittest,’ but in evolutionary biology, ‘fitness’ refers to an organism’s ability to survive, reproduce and pass on its genes to the next generation. Reproductive evolution, which focuses on how mating behaviours and reproductive strategies evolve across species, plays a crucial role in shaping population dynamics, speciation, and biodiversity.

Assistant Professor Nalini Puniamoorthy from the Department of Biological Sciences at the NUS Faculty of Science, together with her team at the Reproductive Evolution Lab (ReproLab), are exploring how sexual selection – a mechanism of natural selection – affects reproductive traits and influences population differentiation and speciation, the process by which new species emerge.

“Since reproductive processes directly influence a species’ adaptation and resilience to environmental variability, studying reproductive evolution can support biodiversity conservation by shedding light on how species evolve and adapt to changes to their habitats, especially in the face of climate change and habitat loss,” said Asst Prof Nalini.

The ReproLab studies micro- and macro-evolutionary processes of various insects: From ecosystem service providers like dung beetles, disease vectors like mosquitoes, and even to food waste recyclers like black soldier flies.

For instance, a recent study published by Asst Prof Nalini’s team in Ecology and Evolution, investigated how resource constraints affect dung beetle fitness in secondary rainforests. Dung beetles are important for nutrient recycling and forest health but are often sensitive to habitat changes and resource variations. Asst. Prof. Nalini’s team found that parental provisioning is crucial and that there was a trade-off between early offspring fitness and resource quality. This discovery documents genotype by environment interactions that are relevant for understanding dung beetle ecology in the face of climatic and environmental changes.

Seeking sustainable solutions to challenges

The ReproLab also investigates the interactions between insects and their bacterial symbionts, like gut microbes in black soldier flies that aid in breaking down food waste as well as the reproductive bacteria Wolbachia in mosquitoes. Their study on Aedes albopictus documented that the dispersal of this secondary dengue vector was not limited to green spaces, and that urban and forest populations of Ae. albopictus are naturally infected with more than one strain of Wolbachia. “Untangling these interactions has implications for vector management and combating disease transmission in a city with heterogenous landscapes like Singapore,” explained Asst Prof Nalini.

Asst Prof Lim Jun Ying and his team are analysing how the interactions between frugivores, such as the male Oriental Pied hornbill (shown here eating an Annonaceae fruit in Pulau Ubin, Singapore), and plants help to shape biodiversity. Photo: Hanci Liang

Shaping biodiversity of tropical ecosystems: The role of fruit-eating animals

In tropical ecosystems, plant-frugivore interactions — where animals help disperse seeds of fruiting plants — play a critical role in maintaining biodiversity. Approximately 90 per cent of woody plant species in tropical forests rely on animals to disperse their seeds. Assistant Professor Lim Jun Ying and his team from the NUS Department of Biological Sciences are investigating how these interactions shape plant biodiversity and ecosystem dynamics. This is especially pertinent as human activities such as habitat loss and hunting are threatening these crucial relationships.

“The loss of fruit-eating animals or frugivores can disrupt plant populations, preventing them from migrating to new areas in response to climate change. Understanding how plant-frugivore interactions evolve is important for quantifying the long-term effects of human activities on tropical ecosystems,” said Asst Prof Lim.

In a recent study published in Global Ecology and Conservation, Asst Prof Lim and his team studied large-bodied birds known as hornbills, which are essential for dispersing large-fruited plants. Many of these birds are under threat from habitat loss and hunting. As the gapes – mouth-openings – of these hornbills are larger than most birds, plants with large fruits and seeds depend on them for seed dispersal.

Asst Prof Lim noted, “Evolution in fruits is shaped by a complex web of interactions with various animals and other factors, suggesting that co-evolution between plants and frugivores must be understood at a community level. This broader perspective is essential for grasping the full complexity of ecological evolution in tropical forests and helping to conserve their biodiversity.”

Asst Prof Chang Ying and her team cultured fungi from local mangrove sediments found at Sungei Buloh and Pulau Ubin. They are screening these samples for their decomposing capabilities, including hydrocarbon degradation, to develop bioremediation strategies.

Understanding fungi: From a billion-year evolutionary journey to addressing environmental challenges

Fungi represent one of the most diverse and ancient groups of organisms on Earth, with an evolutionary history spanning over a billion years. Despite their widespread presence and ecological importance, our understanding of fungal diversity is still limited.

“Less than 10 per cent of the estimated fungal diversity has been documented. The challenge lies in the fact that many fungi remain microscopic throughout their life stages, and a vast majority cannot be cultured in laboratories, hindering direct observation and experimentation,” said Assistant Professor Chang Ying from the NUS Department of Biological Sciences.

At Asst Prof Chang’s lab, her team is dedicated to finding the hidden diversity of fungi, with a focus on marine and coastal environments. Their research tackles two key aspects of fungal ecology: reconstructing the evolutionary history of fungal adaptations using genomic tools, and exploring fungal diversity in natural habitats through metagenomics. By studying the genetic, structural, and ecological traits of existing fungal species, Asst Prof Chang and her team are able to infer a fungi’s common ancestor and understand the traits that allowed ancestral fungi to diversify and adapt to a range of ecological and environmental conditions.

An ongoing project by Asst Prof Chang and her team, in collaboration with the One Thousand Fungal Genomes (1KFG) consortium, investigates the evolution of digestive enzymes across the fungal kingdom. This study could help to predict the ecological capabilities of unknown or newly discovered fungi, as well as entire fungal communities.

“Insights from this research also has practical applications, particularly in the field of bioremediation, where fungi are increasingly valued for their potential to break down environmental pollutants,” added Asst Prof Chang.

By analysing the distribution of hydrocarbon-degrading enzymes across a large set of fungal genomes and mapping their evolutionary trajectories, NUS researchers could identify fungal groups that are especially suited to utilising petroleum hydrocarbons as nutrient sources, making them strong candidates for bioremediation strategies.

Source: NUS News