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  • Class Bivalves Essay

    Literature Review of Class Bivalves 1. Introduction Freshwater and marine bivalves Taxonomy, ecological value, economical value, current Issues, current threats 2. Taxonomy According to Treatise on Invertebrate Paleontology, the Bivalves class was divided into six subclasses which cover 13 orders. The first subclass, Palaeotaxodonta, have characteristics such as small body, taxodont, protobranch, infaunal and aragonitic shells. This subclass has only one order, Nuculoida. In the second subclass Cryptodonta, there are two orders, Solemyoida and Praecardoida. The main feature of this subclass same with previous subclasses except the absence of tooth (dysodont). Subclass Pteriomorpha includes order Arcoida, Mytiloida and Pterioida which is heterogeneous. The shell made from calcites or aragonite. Paleoheterodonta as the fourth subclasses have mostly aragonitic basic shells includes order Modiomorphoida, Unioidia, and Trigonoida. Order Unioidia is known as freshwater bivalves. The fifth subclass, Heterodonta, mostly has a shells made of aragonites. The crossed-lamellar shells feature in these subclasses is a morphology adaptation as filter feeder. Veneroida, Myoida, and Hipputitoida are the order of Heterodonta subclasses. The last bivalve subclass was Anomalodesmata which has only one order, Pholadomyoida. This subclass was much modified and it might be burrowing or boring form. The shells is aragonitic and desmodont detition (Clarkson, 2009). 3. Ecological importance 3.1.…

    Words: 832 - Pages: 4
  • Mussels And Water Quality Essay

    1987. The unionid mussels (Mollusca, Bivalvia) of the Belgian upper River Meuse: an assessment of the impact of hydraulic works on the river water self-purification. Biological Conservation 42: 115-132. Ligon, F.K., Dietrich, W.E., and W.J. Trush. 1995. Downstream ecological effects of dams. BioScience 45: 183-192. Loar, J.M., Dye, L.L., Turner, R.R., and S.G. Hildebrand. 1980. Analysis of environmental issues related to small-scale hydroelectric development. I. Dredging. Unpublished report, Oak…

    Words: 9708 - Pages: 39
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