Animal mesoderm forms by enterocoelic pouching, through invagination of the endoderm. The main deuterostome phyla are the Echinodermata and the Chordata. Echinoderms are exclusively marine and include starfish, sea urchins, and sea cucumbers. The chordates are dominated by the vertebrates (animals with backbones), which consist of fishes, amphibians, reptiles, birds, and mammals. The deuterostomes also include the Hemichordata (acorn worms). The Ecdysozoa are protostomes, named after their shared trait of ecdysis, growth by moulting. They include the largest animal phylum, the Arthropoda, which contains insects, spiders, crabs, and their kin. All of these have a body divided into repeating segments, typically
Subgroups of Amish Subgroups of Amish Subgroups of Amish developed over the years, as Amish churches have divided many times over doctrinal disputes. The 'Old Order' Amish, a conservative faction that withdrew from fellowship with the wider body of Amish in the 1860s, are those that have most emphasized traditional practices and beliefs. There are many different subgroups of Amish with most belonging, in ascending order of conservatism, to the Beachy Amish, New Order, Old Order, or Swartzentruber Amish groups. Donald B. Kraybill, Karen M. Johnson-Weiner and Steven M. Nolt speak in their book "The Amish" of different Amish "affiliations". They define an