Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism.
Hydra is a genus of small freshwater hydrozoans of the phylum Cnidaria. They are native to the temperate and tropical regions. The genus was named by Linnaeus in 1758 after the Hydra, which was the many-headed beast of myth defeated by Heracles, as when the animal has a part severed, it will regenerate much like the mythical hydra's heads. Biologists are especially interested in Hydra because of their regenerative ability; they do not appear to die of old age, or to age at all.
Placozoa is a phylum of free-living (non-parasitic) marine invertebrates. They are blob-like animals composed of aggregations of cells. Moving in water by ciliary motion, eating food by engulfment, reproducing by fission or budding, placozoans are described as "the simplest animals on Earth." Structural and molecular analyses have supported them as among the most basal animals, thus, constituting a primitive metazoan phylum.
Centrarchidae, better known as sunfishes, is a family of freshwater ray-finned fish belonging to the order Centrarchiformes, native only to North America. There are eight universally included genera within the centrarchid family: Lepomis, Micropterus, Pomoxis (crappies), Enneacanthus, Centrarchus, Archoplites, Ambloplites, and Acantharchus. A genetic study in 2012 suggests that the highly distinct pygmy sunfishes of the genus Elassoma are also centrarchids.
Sea spiders are marine arthropods of the class Pycnogonida, hence they are also called pycnogonids. The class include the only now-living order Pantopoda, alongside a few fossil species which could trace back to the early or mid Paleozoic. They are cosmopolitan, found in oceans around the world. The over 1,300 known species have leg spans ranging from 1 mm (0.04 in) to over 70 cm (2.3 ft). Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters.
Planarians (triclads) are free-living flatworms of the class Turbellaria, order Tricladida, which includes hundreds of species, found in freshwater, marine, and terrestrial habitats. Planarians are characterized by a three-branched intestine, including a single anterior and two posterior branches. Their body is populated by adult stem cells called neoblasts, which planarians use for regenerating missing body parts. Many species are able to regenerate any missing organ, which has made planarians a popular model in research of regeneration and stem cell biology. The genome sequences of several species are available, as are tools for molecular biology analysis.
Hornworts are a group of non-vascular Embryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information; the flattened, green plant body of a hornwort is the gametophyte stage of the plant.
Regeneration in biology is the process of renewal, restoration, and tissue growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. Regeneration can either be complete where the new tissue is the same as the lost tissue, or incomplete after which the necrotic tissue becomes fibrotic.
Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals. With the exception of two acoel freshwater species, all known acoelomorphs are marine.
Fragmentation in multicellular or colonial organisms is a form of asexual reproduction or cloning, where an organism is split into fragments upon maturation and the split part becomes the new individual.
Autotomy or 'self-amputation', is the behaviour whereby an animal sheds or discards an appendage, usually as a self-defense mechanism to elude a predator's grasp or to distract the predator and thereby allow escape. Some animals are able to regenerate the lost body part later. Autotomy is thought to have evolved independently at least nine times. The term was coined in 1883 by Leon Fredericq.
Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep branching bilaterian group of animals, which resemble flatworms. Historically they were treated as an order of turbellarian flatworms. About 400 species are known, but probably many more not yet described.
The Agaricomycetes are a class of fungi in the division Basidiomycota. The taxon is roughly identical to that defined for the Homobasidiomycetes by Hibbett & Thorn, with the inclusion of Auriculariales and Sebacinales. It includes not only mushroom-forming fungi, but also most species placed in the deprecated taxa Gasteromycetes and Homobasidiomycetes. Within the subdivision Agaricomycotina, which already excludes the smut and rust fungi, the Agaricomycetes can be further defined by the exclusion of the classes Tremellomycetes and Dacrymycetes, which are generally considered to be jelly fungi. However, a few former "jelly fungi", such as Auricularia, are classified in the Agaricomycetes. According to a 2008 estimate, Agaricomycetes include 17 orders, 100 families, 1147 genera, and about 21000 species. Modern molecular phylogenetic analyses have been since used to help define several new orders in the Agaricomycetes: Amylocorticiales, Jaapiales, Stereopsidales, and Lepidostromatales.
Euphorbiaceae, the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of the type genus of the family. Most spurges, such as Euphorbia paralias, are herbs, but some, especially in the tropics, are shrubs or trees, such as Hevea brasiliensis. Some, such as Euphorbia canariensis, are succulent and resemble cacti because of convergent evolution. This family has a cosmopolitan global distribution. The greatest diversity of species is in the tropics; however, the Euphorbiaceae also have many species in nontropical areas of all continents except Antarctica.
Schmidtea mediterranea is a freshwater triclad that lives in southern Europe and Tunisia. It is a model for regeneration, stem cells and development of tissues such as the brain and germline.
Capitella teleta is a small, cosmopolitan, segmented annelid worm. It is a well-studied invertebrate, which has been cultured for use in laboratories for over 30 years. C. teleta is the first marine polychaete to have its genome sequenced.
Schmidtea is a genus of freshwater triclads. Species of the genus Schmidtea are widely used in regeneration and developmental studies.
Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies, which was then confirmed by phylogenomic analyses of molecular data.
Neoblasts (ˈniːəʊˌblæst) are adult stem cells found in planarian flatworms. They are the only dividing planarian cells, and they produce all cell types, including the germline. Neoblasts are abundant in the planarian parenchyma, and comprise up to 30 percent of all cells. Following injury, neoblasts rapidly divide and generate new cells, which allows planarians to regenerate any missing tissue.
Hofstenia, or panther worms, is a genus of acoels belonging to the family Hofsteniidae.
