- To identify the sort, shape and great quantity of chromatophores present in Crustacea put through different coloring backgrounds
- To identify the form, type and abundance of chrmatophores on the scales of seafood put through different color backgrounds
The ability of your animal to change their coloration, corresponding to their history, allows cover from predators through camouflage and mimicking. Chromatophores own numerous granules where pigments are stored. The various types of pigments take into account the several colouration seen in the animal.
Melanophores are chromatophores that store the black pigment melanin, thus this enables the animal to seem black. By holding carotenoids rather than the melanin, a yellow pigment is obtained. This pigment is now known as a Xanthophore. Erythrophores store the red pigments, pteridine, while Leucophores absence pigments. Iridophores store guanine or other purine crystals which mirror light supplying an iridescent or shimmering appearance. (Gelfond & Rogers, 2006)
If the pigment granules in the chromatophore migrate right out of the cell centre an elevated coloration of the animal is seen. Alternatively these pigment granules may aggregate in the cell centre and the pet appears less coloured. If these granules move, the speed of which they move, and the way in which in which this motion is managed varies in different pets or animals and between types. (Nyquist & Toner, 1997)
In the sensible below the chromatophores of crustaceans, seafood and cephalopods should be studied and likened. During the useful the sort and distribution of chromatophores on the several parts of the body of Ligia italic are to be observed regarding the different colored backgrounds. The cephalopod octopus is also put through differently coloured backgrounds and the change in the animals' coloring is detected.
In the fish, the types of chromatophores present on the scales were observed and the effect of different chemicals such as acetylcholine and sodium chloride on the condition of the size chromatophores is to be observed.
Apparatus
Stereomicroscope Adrenalin ( 1mg/ml of sea drinking water)
Light microscope Acetylcholine (100mg/mL of sea water)
2 microscope slides 0. 1 M NaCl
Blu-tac 0. 2 M NaCl
Petri dish 0. 1 KCl
Red pack 0. 2 M KCl
Yellow container 0. 1 M CaCl2
White pack 0. 2 M CaCl2
Black pack red rocks
Fish scales Blue rocks
Pipette White rocks
Aquarium
Ligia italic
Vulgaris
Method:
Refer to attached sheet
Precautions:
- Care was taken when controlling the animals to avoid damage and stress to the animal
- The pets or animals were left for quite a while in their appropriate backdrop to allow them to acclimatise and adapt to the new environment.
- The same types were found in the different colored background to acquire fair comparable results. This due to the fact that different microorganisms may adapt in a different way.
- Scales were cleaned out before addition of your different chemical.
- The least possible disturbance was inflicted on the octopus when changing the colored rocks.
Sources of problem:
The animal was not researched in its environment and thus was inevitably stressed.
More than one pet in each history must have been analyzed for similar fairer results
Due to inescapable weather circumstances the octopus was not left in a single day to acclimatise to its environment. This thus must have stressed the pet.
The octopus was inevitably put through stress due to the constantly changing environment
Results
Discussion:
Crustacean
The isopod crustacean Ligia italica is a monochromatic crustacean that shows only a restricted range of shade change with dark and pale as its two extremes. Pigment dispersal is seen to change in different background colours. This is also called the albedo response. Colour change will depend on the ration of occurrence to reflected light so the dark pigments disperse on the dark background as it reflects less light, as the change happens on white backgrounds. (O'HAlloran, 1986)
An increase in light strength will boost the amount of event and mirrored light and will cause an aggregation of the dark pigments as the increased light may cause the background to appear lighter.
As seen in the results, yellow Xantophores have emerged to truly have a punctuate condition and are seen to be sent out all around the body at different densities. These are seen to be there at high density all over the body, when the isopod was put through a red qualifications. However, it was present at very low density when the animal was subjected to a black track record.
Erythrophores have emerged to have a stellate or reticulostellate condition. This pigment was seen to be absent when the isopod was subjected to red or yellow light. And yes it was found in relatively high densities in the white and black backgrounds. The black melanophores using a reticulate, reticulostellate, punctate or punctostellate figures are seen at high density in all the isopods researched.
The pigments, although distributed all over the body, are seen to be at highest density in the abdominal area and thorax region. The results, however, didn't consider temperature change which could have significantly damaged the results obtained.
In order to adjust to increasing conditions the darker pigments in the animal's body concentrate in the centre and thus would appear lighter. This might permit the isopod to reflect more light and for that reason absorb less warmth. (O'HAlloran, 1986)
The eye are known to be the receptors in charge of colour change in isopods and other crustaceans. Chromatophores that respond right to changes in illumination are grouped as primary responses. Chromatophore responses that involve visible receptors and pathways are grouped as secondary reactions. (Oguro, 1962)
Also hormones one group of hormones have emerged to be responsible for body lightening and darkening, and another collection for the tail region. The sinus gland at the base of the eyestalk is known to be the immediate source of chromatophore hormones called chromatophorotropins. The hormones are believed to happen from the neurons of the x-organ, brain, or ventral ganglia and are then stored in the sinus gland at the base of the eyestalk. (Parker, 1940)
Fish
Fish chromatophores have a dendritic cell body in which the granules of pigments are able to move accordingly. Fish mainly possess melanophores and erythrophores that take place in colaboration with microtubules and also involve the utilization of motor unit nucleotide triphosphate, ATP. The hydrolysis of ATP drives the displacement of the granules to their adjacent filaments. This device sometimes appears to entail both neural and endocrine mechanisms. (Parker, 1940)
Neural rules is via the sympathetic element of the autonomic nervous system. This has both a pre and post ganglionic component which forms area of the efferent stressed system. Kinesin motors, which can be in charge of the activity of pigments from the positive end of the microtubule, result in dispersion of the melanophore pigments. Dynein motors, on the other palm cause an aggregation. (Parker, 1940)
Melaophores in fish are seen to acquire neural connections in which their presynaptic areas contain dense-cored granules with synapses. These seem to be of the alpha adrenergic type. Stimulation of the a1-adrenergic system brings about aggregation of the pigment granules, and the resultant lightening of the seafood size coloration; whereas excitement via the 2-adrenergic system inhibits aggregation. Also, on the surface of the melanophore, the adenosine receptor is also present. (Currie, 2004)
Pigment dispersion is triggered by an increase in cAMP levels while aggregation occurs when cAMP levels are reduced. In seafood, Adrenalin binds to a cell-surface receptor, which interacts with a G-protein. G-proteins have GTP binding and would cause the hydrolysis of GTP to GDP. When this hydrolysis occurs the G-protein is turned on. This activation causes the inhibition of adenylate cyclase. The Function of the turned on enzyme is to convert ATP to cAMP. The cAMP activates cAMP reliant proteins kinase which can phosphorylate many targets. (Currie, 2004)
Although not seen in the results, when treating the fish scales with isotonic sodium chloride, melanophores disperse and appearance to increase. This effect is obtained when dealing with the black scale to 2M NaCl. Treatment of potassium ions should increase pigment dispersion in xanthophores and reduce it in melanophores. (Messenger, 2001)
Thus adrenalin causes the melanophores in seafood to inhibit adenylate cyclase. This in turn may cause the cAMP levels to drop, protein kinase will be inhibited, and the pigment granules aggregate. Acetylcholine triggers the opposite to happen and therefore dispersion of the granules.
During the experiment the addition of acetylcholine to dark-colored and red scales induced a rise in the melanophores possessing a reticulate and reticulostellate form. This made an appearance increase was because of the dispersal of the granules in the chromatophore. However, no change was seen with the white scales. Adrenalin triggered the reticulate and stelloreticulate melanophores to appear in smaller densities because of the aggregation of the granules. That is present in also within all the coloured scales.
Potassium ions action on the melanophores, aggregating nerve endings and leading to the pigment granules to aggregate. The potassium during the experiment was present as potassium chloride.
Hormonal control is also in charge of changes in the chromatophores in seafood. The Melanocyte- stimulating hormone (MSH) is produced in the intermediate lobe of the pituitary and recognized to focus on the melanophore where it triggers pigment dispersion. This peptide hormone is specific to receptors present on the top of melanocytes. For this hormone to be there calcium ions must be present. (Nyquist & Toner, 1997)
In reality as can be seen in the results, the addition of calcium ions, due to the addition of calcium mineral chloride caused the reticulate melanophores to seem denser. The density increasing with additional amount of the calcium ion. This, however, was only present in the fish with scales exposed to red and white colouration. The dark scales seemed to show a decrease.
Another hormone causing a lightening of the seafood scales is the Melanin contracting hormone. That is stated in the posterior lobe of the pituitary and causes the aggregation of the pigment granules. The final hormone to target the melanocyte is Melatonin. This is synthesised in the pineal gland and aggregates pigment granules. (Currie, 2004)
Cephalopod:
Octopus macropus is mainly within the Mediterranean and Caribbean Seas, as well as shallow temperate tropical european and eastern Atlantic Ocean. It is dark brown-red in coloring with large white spots over its human body and combined white spots down the forearms. O. macropus is a nocturnal pet and has a small range of prey species. (Wiston & Lumber, 2006)
Octopus vulgaris lives in tropical and semitropical waters in oceans across the world; from the Atlantic, Indian, Pacific Oceans and the Mediterranean Sea. They inhabit shallow waters and is seen up to 200 meters, but the common octopus is generally within the near shore zone. (Wiston & Timber, 2006)
Octopus vulgaris unlike O. macropus, is diurnal and thus active during the day. O. macropus is a lot less dynamic and intense than O. vulgaris. O. macropus also has a narrower selection of prey because of its activity at night time. These variations may reduce competition through temporal spacing of activity since these types stay in the same habitat.
Light penetration into the sea is of utmost importance for photosynthesis to occur, and so the creation of air and removal of carbon dioxide. Water scatters almost all of the obvious light getting into the sea and absorbs certain wavelengths. Light rays with an extended wavelength, such as red, orange and yellowish, are seen to be the first to be assimilated. Yellow, having the smallest wavelength of the three can only just penetrate around 50 meters. This is dependent, however, how clean the drinking water is. Murky waters allow less penetration. Blue sometimes appears to have the longest wavelength and so can penetrate the furthest into the ocean. Thus this is why the deep in to the ocean everything appears blue. (Bernol, 2006)
Unlike the chromatophores other family pets, those of the cephalopods are not manipulated hormonally. Instead they have emerged to be managed by neuromuscular organs that have engine systems that operate automatically to the surroundings and do not need to use any force for its shade change. They constitute a distinctive electric motor system that performs upon the surroundings without making use of any pressure to it. (Anonymous, 2007)
Neural control of the chromatophores enables a cephalopod to change its appearance almost instantaneously, a key feature in some get away behaviours and during agonistic signalling. When excited the muscles contract, extending the chromatophore when they relax, energy stored in the stretchy sacculus retracts it. The size and density of the chromatophores varies according to behavior and lifestyle of the octopus. (Messenger, 2001)
Cephalopods are able to change their shade because of this of colour cells called chromatophores. Each chromatophore organ includes an flexible sacculus filled with pigment, to which is attached a set of obliquely striated radial muscles, each with its nerves and glia. The colorings they produce range from reddish darkish to yellow-orange. They contain pigment granules and are surrounded by radial muscles. Along with the contraction and enlargement of the muscles, the pigmentation of the chromatophores changes. These muscles are independently handled by the central nervous system. When excited the muscles contract, growing the chromatophore, when they relax, energy stored in the elastic sacculus retracts it. Although some chromatophores grow others may long term contract. This allows cephalopods to change color almost instantaneously
The chromatophores are complemented by reflecting skin cells. These cells produce various colors by refracting light, and white by reflecting light. A couple of three types of reflecting skin cells. The first typeare the Iridophores that can mirror mainly pinks, yellows, greens, blues and silvers. Reflector skin cells, which are known only in octopuses, mirror blues and greens, and produce these colorings by disturbance or diffraction. The third type are the Leucophores that are broad-band reflectors. These are able to reflect white light or the wavelength that is most prevalent in the environment. (Anonymous, 2007)
Octopus vulgaris own dim light chromatophores that are present on the uppermost coating of the dermis. Inside the existence of dim light they are able to expand and act as a neutral density display to complement the brightness of the backdrop. The ambient light rays do not reach the deeper-lying leucophores that are also within this species. In glowing light, however, the chromatophores retract allowing the ambient light to attain leucophores. These then permits accurate reflection of spectral characteristics.
During the experiment O. macropus was seen to improve to the backdrop color quicker and nearer to the background shade. Time may have been so accurate since the octopus was at the mercy of many stresses. The actual fact that O. macropus obtained a color very near to the backdrop could be due to the fact that it's within shallower waters. This which means that this animal enable you to living in a more substantial selection of wavelengths including the longer wavelength.
Conclusion
Through the experinemnt above one may note that different animals respond differently to diferent colour backgrounds. One may also remember that the time used for the change in the pet also varies. For instance, coloring change in the isopod Ligia italic can take up to a day, while that of the octopus will take just a few minutes. These adaptations are all important in the animal's respective environment for successful escape from prey together with communication.
