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Cnidaria are diploblastic animals; in other words, they have two main cell layers, while more complex animals are triploblasts having three main layers. The two main cell layers of cnidarians form epithelia that are mostly one cell thick, and are attached to a fibrous basement membrane , which they secrete .
The visible part is called the auricle, also known as the pinna, especially in other animals.It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue.
In agreement with the latter point, the analysis of a very large sequence alignment at the metazoan taxonomic scale (1,719 proteins totalizing c. 400 000 amino acid positions) showed that ctenophores emerge as the second-earliest branching animal lineage, and sponges are sister-group to all other multicellular animals. [8]
The main components of their bodies are syncytia in which large numbers of cell share a single external membrane. [29] Calcarea have skeletons made of calcite, a form of calcium carbonate, which may form separate spicules or large masses. All the cells have a single nucleus and membrane. [29]
The mouth is located on the underside of the animal, and contains a tongue-like structure called a radula, which has numerous rows of 17 teeth each. The teeth are coated with magnetite, a hard ferric/ferrous oxide mineral. The radula is used to scrape microscopic algae off the substratum.
In zoology, megafauna (from Greek μέγας megas "large" and Neo-Latin fauna "animal life") are large animals. The most common thresholds to be a megafauna are weighing over 46 kilograms (100 lb) [ 2 ] [ 3 ] [ 4 ] (i.e., having a mass comparable to or larger than a human ) or weighing over a tonne , 1,000 kilograms (2,205 lb) [ 2 ] [ 5 ] [ 6 ...
Amplification of sound by the pinna, tympanic membrane and middle ear causes an increase in level of about 10 to 15 dB in a frequency range of 1.5 kHz to 7 kHz. This amplification is an important factor in inner ear trauma resulting from elevated sound levels .
Xenophyophorea / ˌ z ɛ n ə ˌ f aɪ ə ˈ f oʊ r iː ə / is a clade of foraminiferans.Xenophyophores are multinucleate unicellular organisms found on the ocean floor throughout the world's oceans, at depths of 500 to 10,600 metres (1,600 to 34,800 ft).