Phylum

Ivermectin is active against two significant phyla of animal parasite the Nemathehninthes or nematodes (roundworms) and the Arthropoda (insects, ticks, and mites). Ivermectin is inactive against platyhehninthes (flukes and tapeworms). 

The invertebrate phyla are often neglected in ecotoxicological testing protocols. A token invertebrate species such as the copepod Daphnia may be used to evaluate the effects on extremely diverse phyla. This neglects the diversity of biochemical and physiological functions that may render different phyla vulnerable to different classes of compound at different stages of their life cycles. 

Culture a range of invertebrate species from the major phyla, preferably species with short life cycles. The effects of potential endocrine disrupting chemicals on growth rate, reproductive output, viability of offspring and sex ratio, and the vulnerability of different stages of the life cycle, can then be determined. 

Proterozoic 2.5 Gyr O2 levels increase to > 1% of current level. Eukaryotes evolve several animal phyla appear... 

Paleozoic Cambrian 600 Myr Climate warms, O2 levels approach current level most animal phyla present, including some that failed to survive algae and cyanobacteria diversify... 

Ordovician 500 Myr Diversification of echinoderms, other invertebrate phyla, jawless fishes. Mass extinction at end of period (ca. 85To of all species disappear)... 

Kingdom Animalia (only the major phyla are listed) ... 

Fig. 1. (a) Schematic representation of the three types of anoxygenic ([1] and [2]) and oxygenic ([3]) photosynthesis found in plants and bacteria, (b) Phylogenetic tree based on 16S-rRNA sequence comparisons featuring only photo synthetic phyla. 

Hildebrand J.G. and Shepherd G.M. (1997). Mechanism of olfactory discrimination converging evidence for common principles across phyla. Ann Rev Neurosci 20, 595-631. 

Comparison of Signal-Transduction Pathways Downstream of a Protein Tyrosine Kinase Receptor in Species of Three Separate Phyla... 

Intracellular symbiosis is extremely widespread in invertebrates. For example, mutualistic symbioses with intracellular bacteria can be found in almost all animal phyla, including sponges, cnidaria, nematodes, anellids, mollusca and arthropoda. Buchner (1965) thoroughly reviews most information published on bacterial symbiosis in animals up to 1964. After this monumental work, various reviews on more specific subjects have been published (e.g. Baumann, 1998, and references therein) including some recent reviews on Wolbachia (O Neill et al., 1997 Werren, 1997). In most of these papers, the term symbiosis is apparently used with a broad meaning the intracellular bacterium is usually referred to as an endosymbiont even in the absence of data on effects on host fitness. Here only key points on intracellular symbiosis and Wolbachia will be summarized, so as to put the information available on symbiosis in filarial nematodes into a broader context. 

Oxido-reductase Dehydrogenases Cytochrome oxidase All phyla... 

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