Crabs in the context of "Centriole"

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⭐ Core Definition: Crabs

Crabs are decapod crustaceans, either the Brachyura (the "true crabs") or various groups within the closely related Anomura, characterised by having a heavily armoured shell, their tail segments concealed under the body, the ability to run sideways, and the habit of hiding in rocky crevices. They do not form a single natural group or clade, but have convergently evolved multiple times from the ancestral decapod body plan through the process of carcinisation. As a group they are thus polyphyletic.

Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to 4 m (13 ft). Many crabs are free-living marine omnivores; others are specialist herbivores or carnivores, while some are parasitic. A substantial number of species are adapted to freshwater or other non-marine habitats.

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👉 Crabs in the context of Centriole

In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells, but are not present in conifers (Pinophyta), flowering plants (angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and Ginkgo. A bound pair of centrioles, surrounded by a highly ordered mass of dense material, called the pericentriolar material (PCM), makes up a structure called a centrosome.

Centrioles are typically made up of nine sets of short microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and Drosophila melanogaster embryos, with nine doublets, and Caenorhabditis elegans sperm cells and early embryos, with nine singlets. Additional proteins include centrin, cenexin and tektin.

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Crabs in the context of Talon (anatomy)

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 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 grooming, in those and other species.

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Crabs in the context of Eye movement (sensory)

Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of animals (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of interests. A special type of eye movement, rapid eye movement, occurs during REM sleep.

The eyes are the visual organs of the human body, and move using a system of six muscles. The retina, a specialised type of tissue containing photoreceptors, senses light. These specialised cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as vision in the visual cortex.

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LINKED FROM (PARENTS)
← Talon (anatomy) ← Claw ← Centriole ← Eye movement (sensory) ← Eye movement
LINKS TO (CHILDREN)
Cancer pagurus → Brachyura → Decapod → Anomura → Clade → Convergently evolved → Carcinisation → Polyphyletic → Pea crab → Japanese spider crab → Omnivore → Parasitic → Freshwater crab → Terrestrial crab →