(Post by Hayley Galbraith)
Cephalopods are a Class within Phylum Mollusca which includes octopus, squid, and cuttlefish (Barbosa, Mäthger, Chubb, Florio, Chiao, & Hanlon, 2007). There are approximately 2000 species of cuttlefish, ranging in size from small to medium, making up a total of 5 families (Mehanna & Al-Mamry, 2013). Along with other cephalopods, cuttlefish are well known for their ability to blend into their surroundings by changing their skin color in the blink of an eye. This incredible feat leads people cartier jewelry replica to wonder: how exactly is this accomplished?
To change colors, cephalopods use neurally controlled chromatophore organs which are found within the skin (Wardill, Gonzales-Bellido, Crook, & Hanlon, 2012). Chromatophores are made up of 5 main parts: the pigment cell, radial muscle fibers, nerve fibers for each muscle fiber, glial cells, and sheath cells (Cloney & Brocco, 1983). When changing their skin color to match their surroundings, it was found by Chiao, Kelman, & Hanlon (2005) that cuttlefish rely on visual stimuli to choose the appropriate display pattern for their environment. The optic lobe is responsible for taking in these visual cues to determine which pattern is appropriate for their surroundings (Messenger, 2001; Budelmann, 1995). Signals are then sent to different areas within the brain depending on which part of the body needs to be changed. Different regions within the brain’s basal lobe control the muscles which are involved in expanding or contracting the chromatophores in response to different stimuli (Budelmann, 1995). More specifically, stimulation of the lateral basal lobe produces a darkening of the head, arms, and mantle whereas stimulation of the medial basal lobe produces a lightening of the skin within the same region (Boycott, 1961). In response to the signal sent from the neutrally controlled chromatophores, the radial muscles attached to the chromatophore contract causing the chromatophore to expand. This produces either a yellow, red, or brown color due to the pigment granules found within the pigment cells (Cloney & Brocco, 1983).
There are a variety of different display patterns how much cartier bracelet
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that can be accomplished by the expansion of different chromatophore areas at different times. One of the most commonly used patterns is known as passing cloud which is used to distract prey (Hanlon & Messenger, 1988) and is often shown in documentaries about cuttlefish. NatGeoWild’s video (2012) shows a cuttlefish demonstrating the passing cloud display pattern when approaching a prey item. Other display patterns include stipple (for hiding amongst multicolored gravel – see figure 1), weak or intense Zebra (See figure 2), uniform blanching or darkening, and deimatic (for hiding from potential predators) (Hanlon & Messenger, 1988) among many others.
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for cuttlefish. Chromatophores are present in cuttlefish as soon as they hatch which allows them to hide from any nearby replica cartier love bracelet predators (Hanlon & Messenger, 1988). As previously mentioned, cuttlefish also use their color changing abilities when hunting. Display patterns such as disruptive, stipple, and weak zebra were noted in a study by Adamo, Ehgoetz, Sangster and Whitehorne (2006) during hunting but no patterns were associated with a specific prey item. It was also noted during the study that most cuttlefish would change from a darkened pattern (light mottle, dark mottle, or uniform blanching) to a deimatic display pattern (flattening and paling of the body with two dark circles on the dorsal surface [Hanlon & Messenger, 1988]) in response to predator stimuli. Other uses for the color change include communication for the purpose of mating or for threat display towards other males (Messenger, 2001). The use of the intense zebra display is also used by cuttlefish to differentiate between males and females as only males are capable of displaying intense zebra which is displayed all over the body including on the fourth arm whereas females are capable of displaying a similar pattern, weak zebra, which is displayed all over the body excluding the fourth arm (Hanlon & Messenger, 1988).
Cephalopods have the most complex nervous system of all the invertebrates bracelet replica cartier (Budelmann, 1995). When looking at the body-weight ratio of cephalopods, their brain is as big as, if not bigger, than most fish (Packard, 1972) which is evident in their complex behavior. Their unique ability to communicate via color changing patterns and blend seamlessly into their environment truly makes them underwater cartier bracelet of anastasia steele fifty
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Figure 1. A cuttlefish camouflaged in the sand bracelets love awaiting an unsuspecting prey item. Photo by Ben Thompson. Used under Creative cartier love bracelet Commons Attribution-NonCommercial 2.0 Generic Licence.
Figure 2. A male (top) and female (bottom) hooded cuttlefish, Sepia prashadi, displaying the zebra pattern. Photo by prilfish. Used under the Creative Commons Attribution 2.0 Generic licence.