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Meetings of the Biodiversity & Ecology Journal Club
Department of Biological Sciences, The National University of Singapore
Featuring seminar announcements from Ecotax

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All are welcome!

Current Seminars

Category : admin

Tues 8 Nov 2005: 10.00am, Seminar Room 3
"Evolutionary Computing: Potential Applications in Environmental and Biodiversity Research" by Vladan Babovic [link]

Tues 8 Nov 2005: 11.00am, Seminar Room 4
"Evolutionary Biology of Tarsiers" by Dr Myron Shekelle [link]

Posted at 12:27AM SGT | permalink | , .

Tuesday, 8th November 2005: Department Of Biological Sciences Special Seminar

Category : dbs

Evolutionary Computing: Potential Applications in Environmental and Biodiversity Research

by Vladan Babovic
Associate Professor
Department of Civil Engineering &
Tropical Marine Science Institute
National University of Singapore

Tuesday, 8th November 2005: 10.00am
Seminar Room 3
Blk S2, Level 2, Department of Biological Sciences
The National University of Singapore
Science Drive 4

Visitors may park at Carpark 10

View the map

Host: A/P Peter Ng

About the Talk
Evolutionary algorithms (EAs) are engines simulating grossly simplified processes occurring in nature and implemented in artificial media — such as a computer. Evolutionary algorithms effectively provide an alternative approach to problem solving - where solutions of the problem are evolved rather than the problems being solved directly. Today the family of evolutionary algorithms is divided into four main streams: Evolution Strategies, Evolutionary Programming, Genetic Algorithms and Genetic Programming.

Although different and intended for different purposes, all EAs share a common conceptual base. In principle, an initial population of individuals is created in a computer and allowed to evolve using the principles of inheritance (so that the offspring resembles the parents), variability (the process of offspring creation is not perfect - some mutations occur) and selection (more fit individuals are allowed to reproduce more often and less fit less often so that their ‘genealogical’ trees disappear in time).

In genetic programming (GP) the evolutionary force is directed towards the creation of models that take a symbolic form. In this evolutionary paradigm, evolving entities are presented with a collection of data and the evolutionary process is expected to result in a closed-form symbolic expression describing the data. GP iteratively applies variation and selection on a population of evolving parse trees representing symbolic

expressions. Standard variation operators in genetic programming are subtree mutation (replace a randomly chosen subtree with a randomly generated subtree) and subtree crossover (replace a randomly chosen subtree from a formula with a randomly cho–sen subtree from another formula). The types of functions used in this tree structure are user-defined. This means that they can be algebraic operators, such as sin, log, +, -, etc., but they can also take the form of if-then-else rules, making use of logical operators such as OR, AND, etc.

This talk introduces the genetic programming in the context of aquatic environment. The main idea is the one of using the creative power of genetic programming to discover and optimize the structure of a model, whereas the evaluation of these models is carried out in symbolic math environments. Several practical applications are presented in order to demonstrate effectiveness and usefulness of this approach. The experimental results show that these kinds of algorithms introduce numerous advantages over most available modeling methods.

ALL ARE WELCOME!

Posted at 12:26AM SGT | permalink | , .

Tuesday, 8th November 2005: Dept of Biological Sciences Special Seminar on Evolution and Biodiversity

Category : dbs

Evolutionary Biology of Tarsiers

by Dr. Myron Shekelle
Centre for Biodiversity and Conservation Studies
University of Indonesia,
Jakarta

Tuesday, 8th November 2005: 11.00am
Seminar Room 4
Blk S2, Level 2, Department of Biological Sciences
The National University of Singapore
Science Drive 4

Visitors may park at Carpark 10

View the map

About the Talk
Tarsiers are small-bodied nocturnal primates of the genus, Tarsius, which are classified in their own superfamily, Tarsioidea. The phylogenetic relationship of tarsiers with other primates is unresolved and remains a major debate within primate systematics. Taxonomists alternately classify tarsiers with strepsirhine primates (lorises, bushbabies, and Malagasy primates) in the suborder Prosimii, with Anthropoid primates (monkeys, apes, and humans) in the infraorder Haplorhini, or in their own suborder, Tarsiiformes. A molecular clock divergence estimate, based upon globin genes, indicates a span of 58 million years since tarsiers last shared a common ancestor with other primates, and “long branch attraction” likely confounds accurate reconstruction of phylogenetic relationships among the three major primate clades.

Extant tarsiers are limited in their distribution to islands of Southeast Asia, but fossil tarsiers and tarsiiform primates are known from mainland Asia, Africa, Europe, and North America. Hill (1955) classified tarsiers into three species, each from a distinct biogeographic region: Tarsius bancanus from island areas of Sundaland, T. syrichta from islands of the southern Philippines, and T. tarsier (=spectrum) from Sulawesi and nearby islands.

The alpha-level taxonomy and biogeography of the T. tarsier-complex have been the subjects of several recent studies. Field surveys of these tarsiers’ vocalizations lead to the recognition of several distinct acoustic forms and provide a hypothesis of at least 17 distinct taxa, 16 known acoustic forms within the population that Niemitz (1984) classified as T. spectrum spectrum, plus the enigmatic T. pumilus. The distribution of these acoustic forms points toward a biogeographic hypothesis that offers a compelling synthesis between two seemingly incompatible biogeographic hypotheses for Sulawesi based on geological and biological data, respectively. On the other hand, genetic and morphologic data are broadly compatible with the hypothesis that T. tarsier-complex acoustic forms are discrete taxa. The process of revising tarsier taxonomy and naming so many new primate taxa will take years, and is confounded by a lack of holotypes for key taxa, as well as a lack of reference material for several of the putative new taxa.

One implication for conservation is that biodiversity in Sulawesi may be underestimated by as much as an order of magnitude. While rigorous testing of the hypothesis of so many new taxa will require a large investment of resources and time, regrettably, current rates of deforestation indicate that time may be of short supply. Nevertheless, provided proper conservation, it is clear that tarsiers are, and will remain, a fruitful taxon for further evolutionary research. Indeed, tarsiers may provide the best flagship species to promote conservation in the region.

ALL ARE WELCOME!

Posted at 12:26AM SGT | permalink | , .

Wednesday, 2nd November 2005: "Evolution and radiation of atyid shrimps (Decapoda, Caridina) in ancient lakes on Sulawesi, Indonesia - a molecular and morphological approach"

Category : bejc

by Kristina Zitzler
Humboldt-Universitat zu Berlin
Museum fur Naturkunde
Institut fur Systematische Zoologie
Berlin, Germany

Wednesday, 2nd November 2005: 4.00pm - 5.00pm
DBS Conference Room
Blk S3, Level 5, Department of Biological Sciences
The National University of Singapore
Science Drive 4

Visitors may park at Carpark 10

View the map

Host: Cai Yixiong

About the Talk
The evolution of the often spectacular radiations in ancient lakes, such as in Lake Baikal or in Lake Tanganyika, has always been of high scientific interest. The Malili lake system and Lake Poso on Sulawesi, Indonesia, are hotspots of speciation with several endemic vertebrate and invertebrate radiations. Both lake systems harbour two allopatric species flocks of the freshwater shrimp Caridina (Decapoda: Atyidae) with currently 3 and 10 described species, respectively. Several years of extensive sampling, mainly in the Malili lake system, revealed several novelties. The actual number of species is higher than described so far. Dispersal patterns vary greatly for different species and almost all occur with substrate specific. These shrimps have flamboyant and apparently species-specific colour patterns, and the morphology of their feeding appendages shows trophic adaptations. A molecular phylogeny based on sequences of the mitochondrial genes 16S rRNA and cytochrome-oxidase-I (COI) suggest three independent colonization events for both lake systems. A preliminary molecular phylogeny of Caridina on Sulawesi reveals two clades with medium to large eggs indicative of a complete freshwater life cycle, i.e. the lack of brackish water tolerance. This finding suggests two independent origins of true freshwater species on Sulawesi. Finally, a comparison of the radiation of atyid shrimps and pachychilid snails in the Malili lakes offer valuable clues about possible causes of lacustrine radiations.

About the speaker
In September 2002, Kristina Zitzler graduated from the Humboldt-University of Berlin, Germany with a Masters degree in Biology. After a zoological fieldtrip to the Malili lake system on Sulawesi she started her Ph.D. project on the "Radiation and Evolution of Freshwater Shrimps in an Ancient Lake System on Sulawesi, Indonesia (Crustacea, Decapoda, Atyidae)" in the Museum of Natural History, Berlin. In 2004, Kristina joined the Malacozoological Department of the Museum of Natural History, Berlin, and started working on the research project “Adaptive Radiations and Convergent Patterns of Endemic Freshwater Snails (Cerithioidea: Pachychilidae: Tylomelania) and Freshwater Shrimps (Decapoda: Atyidae: Caridina) in the Ancient Lakes on Sulawesi, Indonesia". For her research she spends time in Indonesia, especially at the Malili lake system on Sulawesi, collecting and observing freshwater invertebrates. Kristina has been working closely with staff from Raffles Museum of Biodiversity Research, NUS, and has visited the museum twice since she started her work.

ALL ARE WELCOME!

Posted at 8:12AM SGT | permalink | , .

Friday, 21st October 2005: "Juvenile Thalassoma amblycephalum Bleeker (Labridae, Teleostei) dwelling among the tentacles of sea anemones: A cleanerfish with an unusual client?"

Category : bejc

by Michael Arvedlund
JSPS Research Fellow
Tropical Biosphere Research Center
Sesoko Station University of the Ryukyus
Okinawa, Japan

Friday, 21st October 2005: 10.00am - 11.00am
DBS Conference Room
Blk S3, Level 5, Department of Biological Sciences
The National University of Singapore
Science Drive 4

Visitors may park at Carpark 10

View the map

Host: Peter Todd

About the Talk
At least 51 species of fishes are facultative symbionts of sea anemones. Most of the behavioural, ecological and physiological aspects of these associations are unknown. We recorded the behaviour and the habitat use of eight assemblages of the juvenile wrasse Thalassoma amblycephalum dwelling among the tentacles of the two sea anemones Entacmaea quadricolor and Heteractis magnifica at a coral reef in southern Japan. The wrasse remained close to and was occasionally in physical contact with the host when foraging amongst the tentacles. When frightened, they took shelter among corals, away from the host anemone. The wrasse co-existed with the anemonefishes Amphiprion frenatus in E. quadricolor and A. ocellaris in H. magnifica. By using forced host contact tests ex situ and scanning electron microscopy examination of the fish epidermis, we show that juveniles of this wrasse are protected from E. quadricolor, but possibly not from H. magnifica. We suggest that juvenile T. amblycephalum dwelling among the tentacles of sea anemones are cleanerfish with an unusual client, in that they appear to clean mucus and, or, necrotic tissue from the sea anemone host. The talk will also include findings on the Japans' reef fishes, as well as research regarding olfactory receptors on reef fishes and how they might look in coral planu larvae.

About the speaker
Michael Arvedlund gained his MSc from University of Copenhagen, Denmark in1994 and his PhD from James Cook University, Queensland Australia in 2000. He has made some amazing discoveries on the behavioral ecology of anemonefishes, especially embryo imprinting to chemical cues from their hosts. Presently, he is working on a variety of projects: 1) mechanisms of settlement in reef fishes, with an emphasis on environmental cues - particularly olfaction, 2) studies of the development of olfactory receptors in reef fishes, 3) studies of olfactory receptors in coral planula larvae, 4) The ecology and behavior of anemonefishes that are facultative symbionts of host sea anemones, and 5) the ecology of tropical sea anemones. He is also the Ecology Editor of XRAY, an international internet magazine for divers and others with an interest in aquatic life and activities.

ALL ARE WELCOME!

Posted at 7:17PM SGT | permalink | , .

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Locations of venues at the Dept. Biological Sciences, NUS
Please refer to this map (Parking at Carpark 10)

DBS Conference Room
Block S3, Level 5
Science drive 4

Seminar Room 1/2
(SR1 / SR2)
Block S2, Level 4
Science Drive 4

Seminar Room 3/4
(SR3 / SR4)
Block S2, Level 2
Science Drive 4

Life Sciences Labs 7A-D
(LSL7A-D)
Block S2, Level 3
Science Drive 4

Lecture Theatre20
(between Blks S3 & S4)
Science Drive 3

Lecture Theatre 32
(LT32, next to Block S1A)
Science Drive 4

Raffles Museum
Block S6, Level 3
Science Drive 2


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