Dr Alex Ball

Research background

My PhD concentrated on the ontogeny of the foregut of neogastropod molluscs. I still have an interest in this area, but no longer have the time to continue to carry out research in this subject.

Molluscs are fascinating creatures and offer great opportunities as model organisms to study a variety of different problems. My own research investigated the link between ontogeny and phylogeny.

On a practical level I worked with a species called Nucella lapillus which has encapsulated development. By collecting egg capsules at different stages in development I was able to build a development sequence for the larval stages.

Specimens were fixed using conventional techniques for SEM and TEM.

Whole larvae were photographed using SEM and specimens for light microscopy and TEM were prepared in the normal way for TEM.

I then serial-sectioned the specimens for light microscopy at 1 micron intervals and used a fairly primitive computer-aided 3D reconstruction programme to work out the internal anatomy in three dimensions.

TEM filled in the last gaps in the puzzle by allowing me to positively identify tissue types in the developing embryos and to compare the histology between different organs.

All of this work has been published (see the refs in the publication record).

After working on Nucella, I turned my attention to cone snails. I wanted to see how different the development in the Conoidea was from the Muricoidea. Cone snails have a very different proboscis, highly evolved buccal mass and have a venom gland which seems to be a derivation of the midgut gland (gland of Leiblein) found in Nucella.

Once again, I picked a species with encapsulated development and spent several weeks collecting egg capsules of Conus anemone in Western Australia. I was not able to get as complete a developmental sequence with this species, but the stages were informative enough to show that there are some very interesting parallels between the two species. Again this work has been published.

It's clear that studying development in a model group which has a high degree of morphological diversity with "proper" organs offers a great opportunity for understanding both the development and evolution of complete organ systems.

Modern techniques, such as micro CT, still can't quite match up to the tedious and technically demanding challenge of preparing serial sections of specimens, but at least now we can photograph the specimens with a digital camera rather than having to draw the sections using a camera lucida!

Louise Page at The University of Victoria is also carrying out research in this field, see her webpages here.

http://web.uvic.ca/~lpage/WebSite2000ResProgr.htm

and some of her publications:

Page, L.R. 2000. Development and evolution of adult feeding structures in caenogastropods: overcoming larval functional constraints. Evolution & Development 2: 25-34.

Page, L.R. and Pedersen, R.V.K. 1998. Transformation of phytoplanktivorous larvae into predatory carnivores during the development of Polinices lewisii (Mollusca, Caenogastropoda). Invertebrate Biology 117: 208-220.

My current research interests are really methodology-driven towards trying to get the best out of the wide range of instrumentation that we have available in the EMMA labs at the Natural History Museum.

We have an incredible number of visitors to our laboratories and a bewildering diversity of different specimens to examine. Finding the appropriate technique to meet the demands of the researchers requires experience and a willingness to experiment. I try to attend as many scientific meetings as I can and am active in several microscopy societies, including organising the occasional large meeting to try and bring researchers from different disciplines together.