Context: Dickinsonia is a genus of iconic fossils of the Ediacaran biota. The individual "Dickinsonia" typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth is consistent with a bilaterian affinity, though some have suggested that it belongs to the fungi, or even an "extinct kingdom"., Biodiversity, a contraction of "biological diversity," generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species, between species and between ecosystems. It is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation (number of species) within an area, biome, or planet. Terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth. It is richest in the tropics. Marine biodiversity tends to be highest along coasts in the Western Pacific, where sea surface temperature is highest and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future., A body plan (also written bodyplan), Bauplan (German plural Baupläne), or ground plan is "an assemblage of morphological features shared among many members of a phylum-level group". The vertebrate body plan is one of many: invertebrates consist of many phyla., The Erniettomorphs are a form of Ediacaran fossil consisting of rows of airbed-like tubes arranged along a midline with a glide symmetry. Representative genera include "Ernietta", "Phyllozoon", "Pteridinium", "Swartpuntia" and possibly "Dickinsonia".
There is no record of Erniettomorphs after the end of the Ediacaran period. Their affinity is uncertain; they probably form a clade and are most likely a sister group to the rangeomorphs, which bear a similar (though fractal) construction. Placements within the metazoan crown-group have been rebutted, and it is most likely that these peculiar organisms lie in the stem group to the animals. There is no evidence that they possessed a mouth or gut. Because they are often found in water which was too deep to permit photosynthesis - and in some cases, lived half-buried in sediment, it is speculated that they fed by osmosis from the sea water. Such a lifestyle requires a very high surface area to volume ratio - higher than is observed in fossils. However, this paradox can be resolved if much of the volume of the organisms was not metabolically active. Many "Pteridinium" fossils are found completely filled with sand; if this sand were present "within" the organism while it was alive, this would reduce its metabolically active volume enough to make osmotic feeding viable., A clade (from , "klados", "branch") is a group of organisms that consists of a common ancestor and all its lineal descendants, and represents a single "branch" on the "tree of life"., Ernietta plateauensis, the sole species of the genus "Ernietta", is a bag-shaped erniettomorph genus that lived half-buried in sediment, and probably fed by osmosis. It had chambered walls., A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the large leaves of cycads and palms (Arecaceae). "Frond" is commonly used to identify a large, compound leaf, but if the term is used botanically to refer to the leaves of ferns, it may be applied to smaller and undivided leaves., Pteridinium is an erniettomorph found in a number of Precambrian deposits worldwide . It is a member of the Ediacaran biota ., Swartpuntia is a monospecific genus of erniettomorph from the terminal Ediacaran period, with at least three quilted, leaf-shaped petaloids  probably five or six. The petaloids comprise vertical sheets of tubes filled with sand. "Swartpuntia" specimens range in length from 12 to 19 cm, and in width from 11.5 to 140 cm. The margin is serrated, with a 1 mm wide groove. A 14 mm wide stem extends down the middle, tapering towards the top, and stopping 25 mm from the tip. The stem has a V shaped ornamentation on it. The original fossils were found at, and named after, the Swartpunt farm between Aus and Rosh Pinah in Namibia. The generic name comes from "Swartpunt", meaning "black point" in reference to the colour of the rocks. The specific name "germsi" honours Gerard Germs, who studied the Nama formation of geological beds. , The Precambrian (or Pre-Cambrian, sometimes abbreviated p) is the earliest period of Earth's history, set before the current Phanerozoic Eon. The Precambrian (colored green on the right) is a supereon that is subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.567 billion years ago (Ga) to the beginning of the Cambrian Period, about million years ago (Ma), when hard-shelled creatures first appeared in abundance. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 89% of geologic time., Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the choanoflagellates. Sponges are the most basal clade of animals. Animals are motile, meaning they can move spontaneously and independently at some point in their lives. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs: they must ingest other organisms or their products for sustenance., Cambria is a name for Wales, being the Latinised form of the Welsh name for the country, "Cymru". The term was not in use during the Roman period (when Wales had not come into existence as a distinct entity). It emerged later, in the medieval period, after the Anglo-Saxon settlement of much of Britain led to a territorial distinction between the new Anglo-Saxon kingdoms (which would become England) and the remaining Celtic British kingdoms (which would become Wales). Latin being the primary language of scholarship in Western Christendom, writers needed a term to refer to the Celtic British territory and coined Cambria based on the Welsh name for it. , The Cambrian Period (or ) was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established (as Cambrian series) by Adam Sedgwick, who named it after Cambria, the Latinised form of "Cymru", the Welsh name for Wales, where Britain's Cambrian rocks are best exposed. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian biology surpasses that of some later periods., Wales is a country that is part of the United Kingdom and the island of Great Britain. It is bordered by England to the east, the Irish Sea to the north and west, and the Bristol Channel to the south. It had a population in 2011 of 3,063,456 and has a total area of . Wales has over of coastline and is largely mountainous, with its higher peaks in the north and central areas, including Snowdon, its highest summit. The country lies within the north temperate zone and has a changeable, maritime climate., The Cambrian explosion or Cambrian radiation was the relatively short evolutionary event, beginning around in the Cambrian period, during which most major animal phyla appeared, as indicated by the fossil record. Lasting for about the next 2025 million years, it resulted in the divergence of most modern metazoan phyla. Additionally, the event was accompanied by major diversification of other organisms. Prior to the Cambrian explosion, most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 to 80 million years, the rate of diversification accelerated by an order of magnitude and the diversity of life began to resemble that of today. Almost all the present phyla appeared during this period, with the exception of Bryozoa, which made its earliest known appearance later, in the Lower Ordovician., The Ediacaran (formerly Vendian) biota consisted of enigmatic tubular and frond-shaped, mostly sessile organisms that lived during the Ediacaran Period (ca. 635542 Mya). Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The Ediacaran biota radiated in an event called the Avalon explosion, , after the Earth had thawed from the Cryogenian period's extensive glaciation. The biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate., Subject: pteridinium, Relation: taxon_rank, Options: (A) branch (B) form (C) genus (D) group (E) kingdom (F) order (G) phylum (H) series (I) species (J) variety
Output: genus