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Early deuterostomes and their modern counterparts. Bilateria, one of the five major lineages of animals, is split into two groups; the protostomes and deuterostomes. Deuterostomes consist of chordates (which include the vertebrates) and ambulacrarians. [20] It seems likely that the Kimberella was a member of the protostomes.
Human composting is emerging as an end-of-life alternative that is friendlier to the climate and the Earth — it is far less carbon-intensive than cremation and doesn’t use chemicals involved ...
Protostomes evolved into over a million species alive today, compared to ca. 73,000 deuterostome species. [6] Protostomes are divided into the Ecdysozoa (e.g. arthropods, nematodes) and the Spiralia (e.g. molluscs, annelids, platyhelminths, and rotifers). A modern consensus phylogenetic tree for the protostomes is shown below.
In an age when the potential exists for large profits from the discovery of, for example, new food crops or medicinal plants, modern ethnobiologists must consider intellectual property rights, the need for informed consent, the potential for harm to informants, and their "debt to the societies in which they work".
The human population exploits and depends on many animal and plant species for food, mainly through agriculture, but also by exploiting wild populations, notably of marine fish. [10] [11] [12] Livestock animals are raised for meat across the world; they include (2011) around 1.4 billion cattle, 1.2 billion sheep and 1 billion domestic pigs. [12 ...
In protostomes, the coelom forms by a process known as schizocoely. [6] The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm , forming the parietal layer and the second surrounds the endoderm or alimentary canal forming the visceral layer .
The terms "deuterostomes" and "protostomes" originally defined distinct ways of forming the mouth from the blastopore, a depression that appears in an early stage of the embryo. However, some "protostomes" form the mouth using a process more like that typical of deuterostomes.
Pharyngeal slits are filter-feeding organs found among deuterostomes. Pharyngeal slits are repeated openings that appear along the pharynx caudal to the mouth. With this position, they allow for the movement of water in the mouth and out the pharyngeal slits.