Glossary (Ruppert et al. 2004)
Bilateral Symmetry: The symmetrical arrangement of an organism along a central mid-plane axis into two halves, so that each half (left and right) is a mirror image of the other.
Central Nervous System: The central part of the nervous system, dominated by either a brain or a supraeosophagal ganglion, that integrates information, and controls and coordinates all the workings of the body.
Cerata: Dorsal and lateral appendages, usually long and tapering at a point, which considerably increase the surface area of an organism. They can be used to increase respiratory and digestive surfaces, and for defence.
Chemosensory: The perception of chemical stimuli in the environment, either odours or tastants, by sensory receptors (olfactory or gustatory).
Chloroplasts: The energy producing, photosynthetic organelles in plant and algae cells. Chloroplasts contain the photosynthetic pigment chlorophyll that absorbs light energy, which is converted into chemical energy in the form of ATP.
Ciliated: Having cilia. Cilia are long, thin, microscopic hair-like structures extending from cell bodies. They can be either motile or non-motile, and many perform important sensory roles.
Coelomate: Possessing a coelom. A coelom is a fluid-filly cavity in the body which is separate from the gut, that is lined by mesodermal-derived epithelium. The coelom plays roles in circulation, reproduction, excretion, and sometimes functions as a hydrostatic skeleton.
Detorted: Animals that have undergone detorsion, the reversal of the process of torsion (see Torsion).
Epithelial cells: The cells that form the epithelium of animals. An epithelium is a layer or adjoining cells covering the surface of an animal or lining its internal cavities.
Ganglia: A structure in the nervous system, formed by a concentration of neuron cell bodies linked by synapses, which serves as an integration centre. Singular: Ganglion.
Genera: Plural of genus. A genus is a taxonomic rank, situated after family and before the species level, which is used to classify organisms.
H&E stain: Hematoxylin and eosin stain. The staining of biological tissues in a histological section (for example a cross-section). Hematoxylin is a dye which stains the nuclei of cells a blue-purple colour, and eosin is an acidic dye which stains the cytoplasm of cells pink.
Haemocoel: The major cavity of the hemal system. The hemal system is part of the connective-tissue compartment which a function in circulation, consisting of a haemocoel and a network of interjoined vessels and cavities.
Hermaphrodite: An organism with both male and female sex organs. During copulation, each partner can act as either the 'male' or the 'female'.
Kleptoplasty: The retention of functional chloroplasts and use of photosynthetic byproducts by host organisms. Hosts ingest algae or plant material, but instead of digesting the chloroplasts, they are kept intact and maintained in the cells of the host (Maeda et al. 2010)
Metamorphosis: A relatively abrupt process by which an animals body plan is changed, and may even be transformed entirely. For example, the larvae of a species metamorphose into the juvenile form.
Monophyletic group: A taxonomic group or clade which contains an ancestor and all of its descendants.
Nuclei: Plural of nucleus. A nucleus is a membrane-bound structure found in all eukaryotic cells which contains the cells genetic material (the DNA).
Photosynthesis: A process by which light energy from the sun is converted into chemical energy that can be utilised by organisms.
Planktotrophic larvae: Larvae that spend a long time in the water column before settling and metamorphosing into a juvenile or adult form. Species with this type of larvae have a great potential for dispersal over long distances.
Rhinohores: A pair of tentacle-like structures at the anterior end of an organism which are specialised for chemoreception.
Species: Species is the basal taxonomic rank (aside from subspecies), positioned after the level of genus, which is used to classify organisms. Organisms are considered to be members of the same species if they can breed and produce fertile offspring.
Torsion: The 180º rotation of the visceral mass, mantle, and shell of an organism during development, so that the anus and posterior of the organism is situated above the head and sensory region. Torsion is unique to gastropod molluscs. Much of the evolution in some derived gastropods has partially reversed this process of torsion.
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