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Sand Collar
Sand collars are the characteristic egg masses of one family of sea snails, the moon snails, marine gastropod mollusks in the family Naticidae. These egg masses are often found washed up either whole, or sometimes in fragments, on sandy beaches where moon snails are living, either intertidally or subtidally. Description When they are intact, sand collars are shaped rather like an old-fashioned detachable shirt or blouse collar (hence the name). The sand collar consists of sand grains cemented together by a gelatinous matrix, with the embedded eggs contained within the matrix. The collar is laid by the female moon snail, and the size of the sand collar gives an indication of the size of the adult female moon snail that laid it; larger species of moon snail lay larger sand collars. A fresh sand collar feels stiff and yet flexible, as if it were made out of plastic. Each sand collar contains thousands of capsules, each one housing one or several live embryos. In species with pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Collar From Neverita Josephinia (cropped)
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non- tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg (biology)
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the animal hatches. Most arthropods such as insects, vertebrates (excluding live-bearing mammals), and mollusks lay eggs, although some, such as scorpions, do not. Reptile eggs, bird eggs, and monotreme eggs are laid out of water and are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are usually kept within a warm and favorable temperature range while the embryo grows. When the embryo is adequately developed it hatches, i.e., breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark and was in size. Whale shark eggs typically hatch within the mother. At and up to , the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoskeleton
An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the larger kinds of exoskeletons are known as " shells". Examples of exoskeletons within animals include the arthropod exoskeleton shared by chelicerates, myriapods, crustaceans, and insects, as well as the shell of certain sponges and the mollusc shell shared by snails, clams, tusk shells, chitons and nautilus. Some animals, such as the turtle, have both an endoskeleton and an exoskeleton. Role Exoskeletons contain rigid and resistant components that fulfill a set of functional roles in many animals including protection, excretion, sensing, support, feeding and acting as a barrier against desiccation in terrestrial organisms. Exoskeletons have a role in defense from pests and predators, support and in providing an attachment framework f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isola Del Giglio
Isola del Giglio (; en, Giglio Island, lat, Igilium) is an Italian island and comune in the Tyrrhenian Sea, off the coast of Tuscany, and is part of the Province of Grosseto. The island is one of seven that form the Tuscan Archipelago, lying within the Arcipelago Toscano National Park. ''Giglio'' means "lily" in Italian, and though the name would appear consistent with the insignia of Medici Florence, it originally derives from the Latin name of the island, ''Igilium'', which in turn could be related to the Ancient Greek name of the neighbouring Capraia, ''Αἰγύλιον'' (''Aigýlion'', Latinized as ''Aegilium''), from grc, αἴξ, , goat, translit=aíx. In 2012, the cruise ship ''Costa Concordia'' foundered off the coast of the island. Geography The island is separated by a stretch of sea from the nearest point of the mainland, the promontory of Monte Argentario. Mainly mountainous, it consists almost entirely of granite, culminating in the Poggio della Pagana, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropoda
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greifswald
Greifswald (), officially the University and Hanseatic City of Greifswald (german: Universitäts- und Hansestadt Greifswald, Low German: ''Griepswoold'') is the fourth-largest city in the German state of Mecklenburg-Western Pomerania after Rostock, Schwerin and Neubrandenburg. In 2021 it surpassed Stralsund for the first time, and became the largest city in the Pomeranian part of the state. It sits on the River Ryck, at its mouth into the Danish Wiek (''Dänische Wiek''), a sub-bay of the Bay of Greifswald (''Greifswalder Bodden''), which is itself a sub-bay of the Bay of Pomerania (''Pommersche Bucht'') of the Baltic Sea. It is the seat of the district of Western Pomerania-Greifswald, and is located roughly in the middle between the two largest Pomeranian islands of Rugia (''Rügen'') and Usedom. The closest larger cities are Stralsund, Rostock, Szczecin and Schwerin. It lies west of the River Zarow, the historical cultural and linguistic boundary between West (west of the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veliger
A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod taxonomic classes. It is produced following either the embryonic or trochophore larval stage of development. In bivalves the veliger is sometimes referred to as a D-stage (early in its development) or pediveliger (late in its development) larva. This stage in the life history of these groups is a free-living planktonic organism; this mode of life potentially enhances dispersal to new regions far removed from the adult mollusks that produced the larvae. The general structure of the veliger includes a shell that surrounds the visceral organs of the larva (e.g., digestive tract, much of the nervous system, excretory organs) and a ciliated velum that extends beyond the shell as a single or multi-lobed structure used for swimming and particula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euspira Catena (eggs)
''Euspira catena'', previously known as ''Natica catena'', common name the large necklace shell, is a medium-sized species of predatory sea snail, a marine gastropod mollusc in the family Naticidae, the moon snails.Bouchet, P. (2012). Lunatia catena (da Costa, 1778). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=150590 on 2012-08-15 Fossil records The fossil record of this species dates back to the Miocene (age range: 13.65 to 0.012 million years ago). These fossils have been found in Morocco, the Netherlands, Spain, Italy, United Kingdom and Slovakia. Description The rounded shell is thin and polished and brownish-yellow, with a row of reddish markings just below the suture of the last whorl. It can grow to about and has a short spire and seven rounded whorls separated with distinct sutures. The lowest whorl occupies about 90% of the volume. It has a large umbilicus and the operculum is ear-shaped and spirally wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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