Functional morphology of cephalopod gills

There is a wealth of literature dealing with fish gills (Review, see Hoar & Randall, 1984), yet hardly anything is known about the gills of cephalopods. This is rather surprising considering the commercial importance of the cephalopods. In view of the paucity of information available it was necessary to start by establishing the morphology of the gills. This is covered in the first section of this thesis. Of all the cephalopods, Octopus vulgaris was singled out for more detailed investigation (see chapters 2 & 3) as its physiology is comparatively well understood (Wells, 1978). The gills of cephalopods are the major sites for respiratory gaseous exchange. It follows that their dimensions might be expected to govern their potential for absorbing oxygen. Section two deals with the morphometries of cephalopod gills, and predicted values are compared with physiological measurements of oxygen uptake for four representative The final section describes the physiological experiments I performed on octopuses. These experiments were designed to find out whether the animals could regulate the gills' potential to take up oxygen through changes to the gills themselves

Population structure of graptolite assemblages

Graptolite rhabdosomes display a diverse suite of morphologies. The range of morphotypes present within most moderate to high diversity assemblages from the Ordovician and Silurian is similar, despite the different taxonomic composition of the faunas at different times. Survivorship analyses of graptolite faunas from the Ordovician and Silurian demonstrate strong similarities in the mortality rates of unrelated graptolites of similar functional morphology. It also shows a strong correlation of decreasing mortality rates amongst more mature colonies with increasing rhabdosome complexity. This similarity in both functional morphology and life history of graptolites suggests that they lived within a very stable planktic community structure

The impact of ocean acidification on the functional morphology of foraminifera

This work was supported by the NERC UK Ocean Acidification Research Programme grant NE/H017445/1. WENA acknowledges NERC support (NE/G018502/1). DMP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.Publisher PDFPeer reviewe

An annotated bibliography of C.J. van der Klaauw with notes on the impact of his work

Van der Klaauw was a professor of Descriptive Zoology in the period 1934–1958. This paper presents a concise annotated overview of his publications. In his work three main topics can be recognized: comparative anatomy of the mammalian auditory region, theoretical studies about ecology and ecological morphology, and vertebrate functional morphology. In particular van der Klaauw developed new concepts on functional morphology, based upon a holistic approach. A series of studies in functional morphology of Vertebrates by his students is added. An overview of recent morphological and theoretical studies show that this new approach had a long lasting impact in studies of functional morphology

Functional Morphology and Fluid Interactions During Early Development of the Scyphomedusa Aurelia aurita

Scyphomedusae undergo a predictable ontogenetic transition from a conserved, universal larval form to a diverse array of adult morphologies. This transition entails a change in bell morphology from a highly discontinuous ephyral form, with deep clefts separating eight discrete lappets, to a continuous solid umbrella-like adult form. We used a combination of kinematic, modeling, and flow visualization techniques to examine the function of the medusan bell throughout the developmental changes of the scyphomedusa Aurelia aurita. We found that flow around swimming ephyrae and their lappets was relatively viscous (1 < Re < 10) and, as a result, ephyral lappets were surrounded by thick, overlapping boundary layers that occluded flow through the gaps between lappets. As medusae grew, their fluid environment became increasingly influenced by inertial forces (10 < Re < 10,000) and, simultaneously, clefts between the lappets were replaced by organic tissue. Hence, although the bell undergoes a structural transition from discontinuous (lappets with gaps) to continuous (solid bell) surfaces during development, all developmental stages maintain functionally continuous paddling surfaces. This developmental pattern enables ephyrae to efficiently allocate tissue to bell diameter increase via lappet growth, while minimizing tissue allocation to inter-lappet spaces that maintain paddle function due to boundary layer overlap

Insects: Functional Morphology, Biomechanics and Biomimetics

Insects are the most diverse animal taxon, both in terms of the number of species and the number of individuals. There are roughly one million described insect species, and their real number is estimated to be five to ten times this figure [...]

Functional morphology of mammalian rhinariumn skin

The naked skin surrounding the nostrils in most mammals is called a rhinarium. Rhinarium skin exhibits several unique characteristics, including an ultrastructure of pits or furrows on surface corneocytes, formed in a unique epidermal differentiation process (Paper I). Rhinarium skin is often assigned a mechanosensory function because the rhynoglyphic pattern of epidermal domes, ridges or polygons resemble the digital skin in higher primates. This is corroborated by the presence of mechanosensory Eimer’s organs in the rhinarium skin of various insectivores, indicating that it is indeed a tactile surface in these species. Interestingly, the rhinarium skin of a distantly related prosimian primate, the ring-tailed lemur also contains Eimer’s-like mechanosensory organs (Paper II). Although rhinarium skin structure in all studied mammals exhibits comparable features, differences in innervation pattern suggest that its sensory function varies amongst species (Paper III). The rhinarium function becomes even more curious if we consider its peculiar temperature dynamics in carnivorous mammals. In alert dogs, the rhinarium skin surface is normally kept a few degrees below ambient temperature. The rich vascularization and the arrangement of blood vessels in the canine rhinarium (Paper IV) suggests that it may be cooled actively and that the low tissue temperature is of functional importance. Due to the risk of tissue damage, this relative reduction in skin temperature cannot be sustained in freezing climates. Nevertheless, the rhinarium surface temperature in cold-acclimatized dogs can decrease below the cold pain threshold previously measured in mammals without eliciting any behavioural signs of distress (Paper V). In addition, the cold-transducing channels TRPM8 and TRPA1 in dog behave similarly to their human orthologs, suggesting that the cold tolerance observed in naked rhinarium skin does not rely on the innate characteristics of these channels (Paper V). Considered together, the findings presented in this thesis lay the groundwork for future studies into this enigmatic structure