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4 apr 2008 · Finally, many bilateral animals show a concentration of sensory structures and nerve cells at the anterior end of the body (e.g. cephalization). These features are widely considered basic apomorphies for the Bilateria. However, two questions remain.
13 feb 2024 · Bilateria are animals that have bilateral symmetry (a clear left and right side that are mirror images of each other) during embryonic development. Bilaterians have a front (head) and back (tail), with a right-left symmetrical belly and back. This body plan is extremely important for very physical animals who can move effectively through 3D space.
Other articles where Bilateria is discussed: animal: Bilateria: an organ level of organization: All animals except those in the four phyla mentioned above have bilaterally symmetrical ancestors and contain three body layers (triploblastic) with coalition of tissues into organs. The body plans that are generally recognized are acoelomate, pseudocoelomate, and coelomate.
Nephrozoa is a proposed major clade of bilaterian animals. It includes all bilaterians other than Xenacoelomorpha. It contrasts with the Xenambulacraria hypothesis, which instead posits that Xenacoelomorpha is most closely related to Ambulacraria. Which hypothesis is correct is controversial.
The Bilateria are animals which are bilaterally symmetrical. They have front and a back end, an upside and downside, and a left and right side. Most animals are bilateral. Main subgroups. Deuterostomia. Echinodermata (20,000 species, 7000 living) Chordata. mostly Vertebrata (63,000 species) Hemichordata; Protostomia
28 mag 2004 · Abstract. Over 99% of modern animals are members of the evolutionary lineage Bilateria. The evolutionary success of Bilateria is credited partly to the origin of bilateral symmetry. Although animals of the phylum Cnidaria are not within the Bilateria, some representatives, such as the sea anemone Nematostella vectensis, exhibit bilateral symmetry.
To make objective inferences about the genetic programs that bilaterian animals deploy to build their circulatory pumps, we represented mesoderm and endoderm Isl-1/2, NK4, and GATA-4/5/6 ortholog expression as characters in a cladistic analysis in which the phylogenetic topology is fixed according to the known evolutionary relationships between these animals (Figs. 3.4, 3.5, 3.6).
