Risultati di ricerca
16 lug 2020 · The taxon Bilateria consists of multicellular animals with bilateral body symmetry and constitutes a major and ancient radiation of animals. There is compelling morphological and molecular evidence for the monophyly of bilaterians (Hejnol et al., 2009; Dunn et al., 2014; Cannon et al., 2016), for their subdivision into protostomes and deuterostomes (Aguinaldo et al., 1997; Philippe et al ...
1 ott 2017 · Bilateria. The phylogenetic group of bilaterally symmetric animals, consisting of three germ layers. Bilateria are subdivided into Xenacoelomorpha, Deuterostomia and Protostomia. Chordata. The second major clade of Deuterostomia, including cephalochordates (amphioxus), tunicates (ascidians, larvaceans, etc.) and vertebrates. Deuterostomia.
The bilateria or bilaterians are animals with bilateral symmetry, i.e., they have a downside (“anterior”) and a back front (“posterior”) as well as an upside (“dorsal”) and (“ventral”) side; therefore, they also have a left and a right side. The fundamental bilaterian body form is a tube with a hollow gut cavity running from ...
Abstract. Bilaterally symmetrical animals comprise the overwhelming majority of metazoan species. Bilaterality evolved once, early in the evolution of the clade known as Bilateria. The driving force for bilaterality was probably the evolution of active locomotion in search of food. Once bilateral symmetry and an anterior–posterior axis ...
The animals in these major divisions of the Bilateria differ in other fundamental ways, which are detailed below. Gila monster ( Heloderma suspectum ). Unlike sessile sponges or floating jellyfish , the Bilateria typically move actively in pursuit of food, although many members have further evolved into sessile or radial forms.
21 dic 2022 · Indirect development with an intermediate larva exists in all major animal lineages1, which makes larvae central to most scenarios of animal evolution2–11. Yet how larvae evolved remains disputed.
Most animals are Bilateria. ‘The bilaterians: building a body’ explains that Bilaterians have ‘bilateral symmetry’, meaning they have a single line of mirror-image symmetry running down the centre of the body. Bilaterians also have well-defined blocks of muscle for active movement, almost all have centralized nerve cords with an ...
