![]() This behavior frequently occurs in response to danger or a change of emotion (e.g. Together, these two structures are responsible for the ability of cephalopods to change color. All families of cehpalopods, with the exception of Nautilus, possess cells that contain large amounts of pigments, as well as interacting contractile fibers. Cephalopods are also known for their ink glands, which can expel a dark cloud of melanin through the mantle cavity in the face of a threat. Within this mouth is a radula, or a coarse, rasping tongue. AnatomyĬephalopods have a buccal cavity, or mouth, that is usually found at the center of their tentacles. These fluctuations are unpredictably variably and inconsistently patterned. This uniseasonal breeding can cause extreme fluctuations in cephalopod populations and biomass, as most of a generation will die as a new one arises. Most cephalopods die shortly after mating once, reflective of a monocyclic semelparous life cycle. Sexual maturation occurs rapidly, reaching adult size in about one year. Paralarvae are not morphologically distinct from adults instead, they are like "miniature adults." Though they are similar in appearance, these paralarvae may occupy different ecological niches from adults. Upon hatching, cephalopods emerge as paralarvae, surpassing a true larval stage. Īfter being laid by the female, cephalopod eggs are usually covered in a tough coating which helps them attach to hard surfaces. ![]() Females may mate with multiple males and have multiple paternity of offspring, ultimately increasing the genetic diversity of a population. Sometimes after mating, the hectocotylus is left behind in the female's mantle cavity. ![]() Male cephalopods have a specialized arm (called a hectocotylus) which is used to transfer spermataphores, or packets of sperm, into the female's genital pore. Courtship rituals between cephalopods can include a diverse array of color changes and body movements. Reproduction and Life CycleĬephalopods most frequently mate only once, which occurs near the end of their life cycle. Based on fossil record comparisons, it is speculated that there are over eight hundred species of cephalopods that have gone extinct. Belemnoids, an extinct species from the Mesozoic era, may be the ancestors of modern squids. So far, more than 10,000 fossils of cephalopod species have been identified in the fossil record. It is believed that cephalopods evolved from gastropods. Representatives of the class have been found in all the world's oceans. ![]() Today, the class encompasses octopuses, cuttlefish, squid, and nautiluses. Historically, cephalopods have been a prolific class, though research is sparse. Cephalopods are molluscs, but they have many physiological attributes that distinguish them from other molluscs, including predatory lifestyles and sophisticated nervous systems. ![]()
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