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Sacculina Calva
''Sacculina'' is a genus of barnacles that is a parasitic castrator of crabs. They belong to a group called Rhizocephala. The adults bear no resemblance to the barnacles that cover ships, whales, and piers; they are recognised as barnacles because their larval forms are like other members of the barnacle class Cirripedia. The prevalence of this crustacean parasite in its crab host can be as high as 50%. Habitat ''Sacculina'' live in a marine environment. During their larval stage they are pelagic, but as they form into adults they live as ectoparasites on crabs. Their primary host is the green crab, which is native to the Eastern Atlantic Ocean. Though these crabs have spread to other bodies of water, it is not believed that ''Sacculina'' barnacles have traveled with them to these new localities. Anatomy The body of the adult parasite can be divided into two parts: one part is called the "externa" where the bulbous reproductive organ of the parasite sticks out of the abdomen o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swimming Crab
Portunidae is a family of crabs which contains the swimming crabs. Its members include well-known shoreline crabs such as the blue crab (''Callinectes sapidus'') and velvet crab ('' Necora puber''). Description Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong, sharp claws, allows many species to be fast and aggressive predators. Taxonomy Swimming crabs reach their greatest species diversity in the Pacific and Indian Oceans. Portunidae consists of the following subfamilies and genera: ;Achelouinae ;Caphyrinae ;Carupinae ;Coelocarcininae ;Lupocyclinae ;Necronectinae ;Podophthalminae ;Portuninae ;Thalamitinae ;''incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molting
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at specific times of the year, or at specific points in its life cycle. In medieval times, it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the epidermis (skin), pelage (hair, feathers, fur, wool), or other external layer. In some groups, other body parts may be shed, for example, the entire exoskeleton in arthropods, including the wings in some insects. Examples In birds In birds, moulting is the periodic replacement of feathers by shedding old feathers while producing new ones. Feathers are dead structures at maturity w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacculina Anceps
''Sacculina'' is a genus of barnacles that is a parasitic castrator of crabs. They belong to a group called Rhizocephala. The adults bear no resemblance to the barnacles that cover ships, whales, and piers; they are recognised as barnacles because their larval forms are like other members of the barnacle class Cirripedia. The prevalence of this crustacean parasite in its crab host can be as high as 50%. Habitat ''Sacculina'' live in a marine environment. During their larval stage they are pelagic, but as they form into adults they live as ectoparasites on crabs. Their primary host is the green crab, which is native to the Eastern Atlantic Ocean. Though these crabs have spread to other bodies of water, it is not believed that ''Sacculina'' barnacles have traveled with them to these new localities. Anatomy The body of the adult parasite can be divided into two parts: one part is called the "externa" where the bulbous reproductive organ of the parasite sticks out of the abdomen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinus Maenas
''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab or green shore crab. In North America and South Africa, it bears the name European green crab. ''C. maenas'' is a widespread invasive species, listed among the 100 of the World's Worst Invasive Alien Species. It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America, and both Atlantic and Pacific Ocean, Pacific Coasts of North America. It grows to a carapace width of , and feeds on a variety of Mollusca, mollusks, worms, and small crustaceans, affecting a number of fisheries. Its successful dispersal has occurred by a variety of mechanisms, such as on ships' hulls, sea planes, packing materials, and bivalves moved for aquaculture. Description ''C. maenas'' has a carapace up to long and wide, but can be larger outside its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: Asexual reproduction, asexual and Sexual reproduction, sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to unicellular organism, single-celled organisms. The cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes.John Maynard Smith ''The Evolution of Sex'' 1978. Sexual reproduction typically requires the sexual interaction of two specialized reproductive cells, called gametes, which contain half t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or Arthropod leg, tarsus for gripping a surface as they walk. The pincers of crabs, lobsters and scorpions, more formally known as their chelae, are sometimes called claws. A true claw is made of a hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense and Personal grooming, grooming, in those and other species. Similar appendages that are flat and do not come to a sharp point are called nail (anatomy), nails instead. Claw-like projections that do not form at the end of digits but spring from other parts of the foot are properly named Spur (zoology), spurs. Tetrapods In tetrapods, claws are made of keratin and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
