Thu 30 Nov 2017: 10.00am [PhD Defense] – Cros Emilie Sidonie on “The emergence and loss of phenotypic and genomic diversity in Southeast Asian passerines”

PhD Defense Seminar cum Oral Examination
Department of Biological Sciences, NUS

“The emergence and loss of phenotypic and genomic diversity in Southeast Asian passerines”

Speaker:      Cros Emilie Sidonie (Graduate Student,Dept of Biological Sciences, NUS)         
Date:            30 Nov 2017, Thursday
Time:            10am
Venue:         DBS Conference Room
Supervisor: Asst Prof Rheindt, Frank Erwin

Abstract –  “While half of the earth’s biodiversity resides in tropical regions, studies on the mechanisms and causes of recent biotic differentiation have mostly focused on the northern hemisphere. Understanding the biogeographical history of species in tropical regions is, however, important as it may help us predict their response to future changes and conserve tropical species diversity. Southeast Asia is a major biodiversity hotspots, and because of the periodical connectivity of its land masses due to sea level changes during Pleistocene glaciations, this region is particularly interesting for studying the evolutionary mechanisms governing differentiation. Southeast Asia’s biodiversity is particularly threatened by deforestation and habitat modifications associated with human growth, which makes this region also interesting for studying the mechanisms underlying the loss of diversity.

Using vocal and genomic data I studied the emergence and loss of phenotypic and genomic diversity in sylvioids of Southeast Asia. I found that Pleistocene glacial cycles have led to important vocal and genomic differentiation in populations found on different Sundaic landmasses. Additionally, genome-wide data suggest that those divergences happened after approximately 800 kya, a point marked by an increase in the intensity and length of Pleistocene glacial cycles. Finally, using comparative studies of species with a wide range of ecological characteristics, I found that characteristics that make some species genetically and phenotypically diverse also render them more prone to local extinction.”

All are welcome

Fri 17 Nov 2017: 3.00pm [QE] – Zeng Yiwen on “Natural and human-mediated interactions between freshwater crabs and crayfish”

PhD Defense Seminar cum Oral Examination

“Natural and human-mediated interactions between freshwater crabs and crayfish”

Speaker:   Zeng Yiwen (Graduate Student Dept.of Biological Sciences, NUS)
Date:         17 Nov 2017, Friday
Time:         3pm
Venue:       Seminar Room 1 (S2 Level 4, #04-14)
Supervisor: Asst Prof Darren Yeo Chong Jinn

Abstract –  “Present day natural distributions of primary freshwater crabs and crayfish are largely allopatric, with crayfish being generally restricted to subtropical to temperate habitats globally, and crabs distributed around most tropical and sub-tropical regions. These non-overlapping distributions have been attributed to the two taxa being functionally similar, thereby having a high likelihood of interacting and competing with each other. Inter-taxa interactions can be an important biogeographical barrier to natural species dispersal. Such barriers, however, are breaking down as a result of the increased anthropogenic translocation and introduction of crayfish species beyond their native ranges into habitats containing native freshwater crabs. In spite of the implications associated with natural and human-mediated interactions between freshwater crabs and crayfish, few empirical studies have investigated such inter-taxa interactions to date, and the patterns and processes involved remain poorly understood.

I address this gap in knowledge and understanding via a series of studies at varying scales—ranging from global to regional to local. These studies involve the modeling of taxa richness and species distribution patterns (both spatially and temporally), in-situ field studies, and ex-situ behavioral experiments. Through such efforts, natural inter-taxa interaction is identified as a biotic factor that can influence biogeographical patterns of primary freshwater crabs and crayfish in some areas (e.g., the Mediterranean region), but not in others. The widespread introduction of non-indigenous crayfish species increases the chances for (human-mediated) inter-taxa interaction and competition to occur. The crayfish species Cherax quadricarinatus, for example, is predicted to co-occur and impact the greatest number of freshwater crab species in Southeast Asia regardless of future climate scenarios. This crayfish species already appears to have a negative impact on populations of the native freshwater crab, Parathelphusa maculata, within Singapore’s forest streams, with predation as well as competition for shelter being likely mechanisms for such impacts. These findings inform our understanding of the role that biotic factors can play in biogeographical processes, as well as the development and implementation of conservation strategies for native freshwater crabs.”

All are welcome

Fri 17 Nov 2017: 10.00am [QE] – Nicholas Yap Wei Liang on “Sea anemone phylogeny, taxonomy and population genetics, with special reference to the frilly anemones, Phymanthidae”

Department of Biological Sciences, NUS
Qualifying Examination

“Sea anemone phylogeny, taxonomy and population genetics, with special reference to the frilly anemones, Phymanthidae”

Speaker:            Yap Wei Liang Nicholas (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                  17 Nov 2017, Friday
Time:                  10am
Venue:                DBS Conference room  (S3 Level 5)
Supervisor:        Asst. Prof Huang Danwei
Co-supervisor:  Dr Tan Koh Siang

Abstract: – Sea anemones (Cnidaria: Actiniaria) are one of the most successful and cosmopolitan marine invertebrates on Earth. Found across a range of latitudes and depths, many are engaged in important ecological processes. Despite this, there are few studies on anemones in biodiversity hotspots such as the Coral Triangle and the Indo-Pacific region. Inventories of tropical sea anemones, as well as knowledge about their ecological roles and conservation status remain scarce due to the challenges of identifying and inferring phylogenetic relationships among them. Because anemones have great morphological diversity, traits used to identify them appear to contradict their phylogeny. To date, molecular phylogenetic relationships inferred among many lineages are inconsistent with taxonomy and are poorly supported, a problem exacerbated by the lack of sampling for tropical species.

My dissertation will re-evaluate conventional sea anemone taxonomic characters and their impact on systematics. I focus on a group of tropical, frilly anemones that are understudied and taxonomically unresolved—Phymanthidae.  I aim to: i) test the reliability of taxonomic characters associated with the anemone’s stingers [=cnidae], ii) revise the taxonomy of Phymanthidae, iii) reinterpret phylogenetic relationships with the inclusion of a larger sampling of tropical shallow-water species, iv) determine genetic connectivity of common tropical species around the Malay Peninsula and v) characterize the reproductive modes of Phymanthidae members. Also, I intend to deliver (vi) an updated checklist of anemones found in Singapore to facilitate further research here and in nearby regions.

All are welcome

Thu 26 Oct 2017: 2.30pm [QE] – Emily Curren Ern-Min on “Diversity, distributions and ecology of tropical marine cyanobacteria”

Department of Biological Sciences, NUS
Qualifying Examination

“Diversity, distributions and ecology of tropical marine cyanobacteria”

Speaker:          Emily Curren Ern-Min (Graduate Student, Dept. of Biological Sciences, NUS)
Date:               26 Oct 2017, Thursday
Time:               2.30PM
Venue:             DBS Conference Room (S3 Level 5, #05-01)
Supervisor:      Professor Wong Sek Man

Abstract: – Cyanobacteria are oxygenic photosynthetic organisms that play important roles in primary production in the marine environment. The characterisation of cyanobacterial blooms and the diversity of cyanobacteria in the tropics have not been well documented. In this study, the diversity of marine cyanobacteria in Singapore is explored, with species characterisation using morphological and phylogenetic approaches. The invasive toxic cyanobacterium Moorea producens was prevalently distributed along the coasts of Singapore and I investigated its phylogeography, with divergence dating analysis.

The global dissemination of toxic cyanobacteria is of an increasing environmental concern. The bio-invasion of these marine organisms has been suggested to originate from the ballast water of ships and hitchhike on vectors such as microplastics. These non-indigenous cyanobacteria threaten local biodiversity and act as seeds of future harmful cyanobacterial blooms.  I intend to investigate microplastics as vectors for the introduction of invasive cyanobacteria, to understand the diversity of cyanobacterial biota hitchhiking on these surfaces.

All are welcome

Fri 20 Oct 2017: 2.00pm [PhD Defense] – Chia Yi-Hou on “Spatial evaluation of the effects of human, livestock and wildlife systems on infectious disease emergence: implications for surveillance and management”

PhD Defense Seminar cum Oral Examination
Department of Biological Sciences, NUS

“Spatial evaluation of the effects of human, livestock and wildlife systems on infectious disease emergence: implications for surveillance and management”

Speaker:            Chia Yi Hou (Graduate Student, Dept. of Biological Sciences, NUS)  
Date:                   20 Oct 2017, Friday
Time:                   2pm
Venue:                DBS meeting room (located at DBS admin office, Blk S3 Level 5)
Supervisor:        Asst Prof Carrasco T, L Roman
Co-supervisor:  Prof John D. Mumford

Abstract – 

“Emergence of zoonotic infectious diseases has health, social, and economic implications for human populations. Hosts and reservoirs for zoonoses are diverse and come from different taxa. Areas of high biodiversity may be sources for new pathogens for humans. Understanding of spatial and temporal patterns of where interactions may occur between human and animal populations will give insights for surveillance and planning for eventual outbreaks.

The research aims of this dissertation were to assess spatially explicit emerging infectious disease (EID) probabilities at the national level across the globe, assess emergency funding resource gaps, investigate routes for through which air travel facilitates disease transfer, and project changes in the probabilities of EID occurrence events relating to changes in livestock density in Africa through 2050. In this dissertation, modeling studies were conducted with aims to identify what socioeconomic and ecological variables may predict infectious disease emergence and how they may interact to lead to future emergence events.”

All are welcome

Thu 28 Sep 2017: 10.00am [QE] – Samantha Lai Wen Ya on “The role of vegetative fragments in the propagation of seagrasses”

Department of Biological Sciences, NUS
Qualifying Examination

“The role of vegetative fragments in the propagation of seagrasses”

Speaker:           Lai Wen Ya Samantha (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                28  September 2017, Thursday
Time:                10am
Venue:             DBS Conference Room (S3 Level 5)
Supervisor:      Assoc Prof Peter Alan, Todd

Abstract: – The study of the movement ecology of seagrasses is critical to understanding how they disperse, exchange genetic material, and persist in changing environments. Seagrasses can disperse at several life stages, although long-distance dispersal beyond the parent meadow is often attributed to buoyant fruits or reproductive shoots which, depending on hydrodynamic conditions, can travel up to hundreds of kilometres from the source meadow. However, vegetative fragments can also re-establish elsewhere following detachment from the parent plant to create a new independent ramet. This process could potentially be important for Singapore’s meadows as the data available thus far about sexual reproduction seems to indicate that it is quite limited.

The focus of my thesis is the connectivity of seagrass meadows in Singapore, with an emphasis on the much-overlooked vegetative fragment dispersal mechanism. Broadly, I aim to experimentally investigate a variety of factors that can affect each step of this mechanism. The resulting data will be integrated into a hydrodynamic model to understand the potential magnitude of this kind of dispersal in our local system. This model will be referenced against a key species, Thalassia hemprichii, to determine if the model can explain the observed population structure across the meadows. My work will help improve our understanding of the population connectivity of our local meadows, and the extent to which they may rely on vegetative fragments for dispersal.

All are welcome

A Chat about Research in NUS Biological Sciences (Mon 25 Sep 2017: 6.30pm @ S2-04 SR1)

The event is an informal discussion about research in NUS that might be useful for students thinking ahead toward internship, UROPS, FYP, or graduate studies.

Three graduate students, representing research labs in Environmental Biology & Biomedical Sciences will share their research experiences.

Join them on Mon 25 Sep 2017: 6.30pm – 7.30pm @ S2-04 Seminar Room 1 (Blk S2 Level 4)

Do indicate your interest so that we know how many students to expect – tinyurl.com/chalk2017.

If you have any other queries, feel free to email Jerome Kok (jeromekok@u.nus.edu).

Tue 13 Jun 2017: 2.00pm – Wang Yang on Predicting future plant distribution globally and developing a framework incorporating natural dispersal into MaxEnt”

Department of Biological Sciences, NUS
Qualifying Examination

“Predicting future plant distribution globally and developing a framework incorporating natural dispersal into MaxEnt”

Speaker:          Wang Yang (Graduate Student, Dept. of Biological Sciences, NUS)
Date:                 13 June 2017, Tuesday
Time:                2pm
Venue:             Seminar Room 1 (S3 Level 4, #04-14)
Supervisor:     Assoc Prof Webb, Edward Layman

Abstract: – Understanding the future distribution of plant species can provide fundamental information on future biodiversity, community structure and composition. However, the majority of previous distribution studies focused on small taxonomic groups or small geographical range, and the few large scale studies were outdated in terms of data and methodology used. Therefore, my PhD aims at summarizing previous studies on species distribution modelling (featuring MaxEnt), predicting future distributions of more than 2000 species on the global scale through MaxEnt, investigating the effects of climate change on invasive plant species, and developing a new framework for incorporating natural dispersal process into MaxEnt from the perspective of dispersal vectors.

All are welcome

PhD Defense Seminar cum Oral Examination: 11 April 2017, Tuesday, 10am (Zarina Zainul / Assoc Prof Peter A Todd), DBS Conference Room

PhD Defense Seminar cum Oral Examination

The Ecology of Early Fouling Biofilms on Antifouling Surfaces in a Tropical Marine Environment

Speaker:         Zarina Zainul (Graduate Student Dept. of Biological Sciences, NUS)
Date:              11 April 2017, Tuesday
Time:              10am
Venue:           DBS Conference Room (S3 Level 3)
Supervisor:    Assoc Prof Peter Alan, Todd

All are welcome

Abstract – 

“Fouling, or the unwanted accumulation of organisms, affects marine activities like shipping and desalination, and usually begins with the formation of biofilms. My work investigates biofilm fouling from both ecology, as well as applied, antifouling perspectives. This study is the first to look at marine biofilms of tropical Southeast Asia and characterize them by microscopy and next-generation sequencing (NGS). Tropical seasonality and surface type were strong drivers behind changes in bacterial composition. Bacterial biofilms were also shown to interact with both other biofilm microorganisms (diatoms) and macrofouling organisms (tubeworms). Two novel materials with antibiofilm performance were also identified. This understanding of environmental biofilms and its interaction with other marine organisms can inform both antifouling and restoration ecology solutions.”

All are welcome”

QE : 31 March 2017, Friday, 2pm (Tan Ming Kai / Assoc Prof Hugh Tan & Prof Meier R) Conference Room II

Department of Biological Sciences, NUS
Qualifying Examination

Flower-visiting, florivory, and pollination by Orthoptera in Southeast Asia

Speaker:          Tan Ming Kai (Graduate Student, Dept. of Biological Sciences, NUS)
Date:               31 March 2017, Friday
Time:               2pm
Venue:            DBS Conference Room-II (S1, Level 3, Mezzanine)
Supervisors:    Assoc Prof Hugh Tiang Wah Tan & Prof Rudolf Meier

Abstract: –

Interactions between plants and insects can be complex and intriguing and studies of insect‒plant interaction can help to shape our understanding of (i) ecology and coevolution, (ii) resource management (agriculture, etc.), and (iii) conservation. Florivory is one aspect of insect‒plant interaction that is less well studied but equally as widespread as herbivory. Florivory, defined as any type of consumer-caused damage to developing flower buds or mature flowers, can have a direct or indirect effect on floral adaptations, interspecific interactions, and community dynamics. Florivory is also considered as a precursor to pollination in coevolution. I specifically focus on the study of orthopterans (grasshoppers, crickets, and katydids), as florivores and potential pollinators. While Southeast Asia is a biodiverse region, comprising of numerous biodiversity hotspots, there has been no report of florivory and pollination by orthopterans in this region. Only one neotropical cricket had been shown to pollinate flowers and I hope to discover more pollinators among orthopterans here. There is also a dearth of knowledge of florivory including the applicability of the hypotheses involving herbivore‒plant interaction in florivory. Specifically, I investigate in depth the neural constraint hypothesis and density-dependency (e.g., switching, associational resistance, and susceptibility) to examine how floral resources can influence foraging behaviour of florivores. I thus aim to (i) document flower-visiting orthopterans and their roles as florivores (antagonists) and pollinators (mutualists), (ii) test hypotheses driving florivore‒flower interaction and (iii) show that orthopterans can be useful model organisms for insect‒plant interaction and research in tropical ecology

 All are welcome