Organizer tissue variation

Finally, a novel proxy is introduced by Craven et al, who provide empirical data to show that stable carbon isotopic variability in organic tissue of the inter-tidal acorn barnacle, Semibalanus bala-noides, is related to immersion/emersion times. With more work, this technique could potentially provide critical information about small-scale, but rapid, variations in past sea-level such information is crucial for assessing the likely impact of anthropogenic-induced climate change. 

The nitrogen isotope composition of barnacle organic tissues varies erratically along the section, ranging between 7.6%c and 8.8%c (Fig. 4f), with no significant relationship evident between immersion time and 8 N value (Table 2). This suggests that the variation observed in carbon isotope ratios is not caused by a difference in diet. 

There are significant relationships between the values of both shell carbonate and organic tissues with immersion time. There are a large number of explanations for variations in the carbonate skeletons of organisms in nature, however few of the available explanations would produce the small, systematic change of c. l%e observed over the 3.5 m of sample profile. Only kinetic effects, metaholic effects, varying pH or the local influx of C-depleted waters are likely to have been able to significantly influence shell isotope composition over the spatial scale sampled. An influx of C-depleted meteoric water derived from adjacent terrestrial areas should lead to covariance between and 8 0 in the shell carbonate. This is not observed and hence can be discounted as the mechanism behind the observed relationship. 

Some authors use the term mutation as a synonym for genetic polymorphism. However, it is recommended to reserve the term mutation for genetic variations acquired within the life span of an organism such as those mutations acquired in tumor tissues during multi-step carcinogenesis. 

Proteins are also important nitrogen compounds. They constitute much of the cell materials, and are present in every type of organism known. In humans, muscle tissue, skin, and hair is mostly protein, about half of the dry weight of our bodies. From a chemical point of view, proteins are polymers of amino acids, alpha amine derivatives of carboxylic acids. Only about 20 different amino acids are actually found in proteins. It is the large number of variations in the protein chain, using only these... 

The connection between hydrophobicity and tissue compatibility has been noted for classical organic polymers (19). A key feature of the polyphosphazene substitutive synthesis method is the ease with which the surface hydrophobicity or hydrophilicity can be fine-tuned by variations in the ratios of two or more different side groups. It can also be varied by chemical reactions carried out on the organo-phosphazene polymer molecules themselves or on the surfaces of the solid materials. 

The variation of the lutein concentration across the wide yellow bands of Monarch may be related to growth within this tissue. Growth occurs at a remarkable rate for these organisms, and it is probable that the carotenoid concentrations within the rapidly growing regions may lag behind slowly growing regions. Alternatively, the tissue thickness and microstructure, which were not measured, may vary and contribute to the observation. 

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