The Health Blog

BIO-DIVERSITY: MEASUREMENT OF BIOLOGICAL DIVERSITY
Scientists from different disciplines are of different opinion regarding the methods of measurement of biodiversity.
Systematics, a fundamental discipline of bio-divefsity, provides the basic frame work for the whole of biology. The main task of systematics is to document and understand the extent and significance of biological diversity. A number of activities including classification, identification and Nomericla-ture often grouped as Taxonomy which forms four basic functions :
i. Differentiation (Recognition of taxa)ii. Identification (Universal diagnosis of taxa)iii. Symbolization (Application of universal names)iv. Comparison (Relative relationship of the taxa)
Individuals and characters are the most basic unit of biological classification on the basis of features hold in common (attributes or characters) individual can be grouped together into a large number of different classes, categories like genera, families and orders and so on in artificial natural or phylogenetic classification depending upon the characters on which it is based. On the basis of the shared and unshared attributes between taxa, a number of taxonomic diversity indices for example, root-weight, higher taxon richness and taxonomic dispersion have now been developed.
Diversity can also be expressed as percentages. A site with viable population of all species in a group would have diversity score of 100% while a site without any species of the group in question would score zero. Such assessment allows us to compare all sites with each other and rank them individually from highest to lowest diversity.
Ecologists measure diversity either by estimating species richness (number of species) in an area or by one or more indexes combining species richness and relative abundance within an area. Application of such methods for measuring biodiversity are limited.i) The species richness measures which is based onsamples (a complete cataloguing of all species in aparticular taxonomic group) is of limited interest, be-cause.Species richness take no account of the differences between species in relation to their place in the hierarchy.When the biological diversity of a very small area is compared with longer area in a global context.ii) Relative abundance is not a fixed property of speciesvarying widely from time to time and place to place.iii) Further, most taxa are virtually or even completelyunknown in many environments.
Conservationists measure the diversity either directly by measuring the genetic differences or indirectly through use of the taxanomic (cladistic) hierarchy.
Whittakar, introduced the concepts of alpha, beta and gamma diversity. Alpha diversity refers to the diversity value for single sites whereas, Beta and Gamma diversity concepts related to change in diversity between sites, the former at local, and latter at over larger area or geographical scale such as continents.An important and essential part of these relational concepts is the idea of species turnover, which simply means thje degree to which species present at one site are replaced by other at different sites.
PROBLEMS IN MEASURING BIODIVERSITY
One of the most important problem in the maintenance of biological diversity is an assessment of the relative importance in terms of diversity of different areas, habitats or ecosystems. This importance can be assessed in different related ways. The overall diversity of any given area will be reflection both of its range of habitats. The greater the differences between the various component habitat in terms of species composition, then the greater the overall diversity will be. By measuring species abundance, a number of models have been developed to find out diversity indices. As different mathematical and biological assumptions are made in these models, they often generate different diversity measures from the same set of data.
DIVERSITY AT DIFFERENT GRADIENT
The overall diversity of any given area is a reflection both of the range of habitat it includes and the diversity of the components habitats. In terms of species composition of differences between the various component is more, the overall diversity will also be more. Biological diversity is not evenly distributed throughout the world. It varies from region to region.
In terrestrial ecosystem diversity generally decreases with increasing altitude. This is apparently clear from an example showing very low species diversity at highest region at all altitudes. This is called as elevational gradients.
In aquatic ecosystems diversity almost invariably decreases when salinity increases above 35 ppt. in sea water and 2 ppt in fresh water. Oceanic islands (smaller) continental mountain regions are examples of geographical entities which typically have comparatively low species diversity. This may be due to problems of long distance dispersal for plants. But the low total number of species frequently include a large endemic element. In Mauritius, out of 878 higher plant species 329 are endemic, in Socotra, 268 species are endemic out of 788 flowering plant species and in Helena 74 out of 89 species. Larger oceanic islands in tropical and high temperate latitude show a high level of diversity and endemism. The richest island flora is probably that of Madagaskar estimated up to 10,000 species with 8,000 endemics including eight endemic families of flowering plants. Cuba has 6,400 species of higher plants out of which 3,233 of them are endemic. Japan has 2,000 endemic species out of 5,372 species, New Zealand has 1,942 out of 2,371.
On the other hand, relatively poor levels of diversity and endemisms can be seen in drier tropical and subtropical regions. In these regions drought resistant and economic plants are the main dominating species.
BIO-DIVERSITY VALUE
One of the most fundamental value of plants biodiversity is in supplying the world’s food. Originally plants were consumed directly from the wild and gathering of wild products continue throughout the world today. The evaluation of crop plants began between 5,000 and 10,000 years ago. It is now generally thought that plants of agriculture originated were more or less simultaneously in various parts of the world. Of the estimated 250,000 species of flowering plants only about 3,000 have been regarded as a food resource. Relatively few botanical families account for the world’s main domesticated plants. Gramineae and Leguminosae are most important families followed by the Cruciferae, Rosaceae, Umbelliferae, Solanaceae, and Labiatae. Other important families are the Chenopodiaceae, Araceae, Cucurbitaceae and Compositae.
The discovery, domestication and cultivation of ornamental plants have a long history comparable to that of food crops. Ornamental plants are important commodity in international trade. Today, the diversity of decorative plant species established in cultivation surpasses the variety of plant commonly grown for food around the world. In UK alone a estimated 3,000 species are in general cultivation in addition to the wide range of cultivers and hybrids. In Peru, fruits of 1 93 species are regularly consumed of these 1 20 species are exclusively wild.
The introduction of genes from wild and weed relatives increased the availability of crop genetic diversity for further selection and improvement by farmers. Many cultivated species may not have survived in domestication without the interchange of genes between wild and crop populations.
LOSS OF BIODIVERSITY
Plant diversity as a global resource remains poorly understood inadequately documental and often wasted, but still remains immense potential for further development of natural products. Human population explosion and application of economic processes to natural resources are the main causes for substantial losses of biological diversity. Humans continue to modify their natural environment so that it can better satisfy their needs. However, it is also predicted that this process is unlikely to target an adequate amount of diversity because persons deciding to com ert their local environment do not consider the global cost of so doing. Globally the forest has been reduced to 55% of ,ts original cover and the rate of deforestation is in excess ct 1,00,000 Sq.km. every year. In India the rate of destruction of forest is 13,000 sq.km. annually.*16\218\2*

DRUGS FOR PARTIAL SEIZURES AND TONIC-CLONIC SEIZURES: REACTIONS TO PHENYTOIN – OTHER SIDE EFFECTSPhenytoin also affects behavior and learning. The child’s mood may change, and she may seem to have less energy. The child’s motor abilities and her alacrity in performing tasks may also be affected. Hyperactivity is less common than with phenobarbital, however, and the effects on learning may be less severe than with phenobarbital.Some of the dose-related side effects of phenytoin are cosmetic, that is, they affect the appearance of the child. Gum hyperplasia (overgrowth of the gums) occurs in almost one-half of the children who have therapeutic blood levels. The overgrowth is made much worse by poor dental hygiene; thus, when children are wearing braces gum overgrowth becomes an even more severe problem. Children taking phenytoin should be taught good tooth-brushing techniques, and young children should have their teeth brushed by their parents. Good hygiene will diminish the gum swelling but not necessarily prevent it entirely. Overgrown gums can be cut back by the dentist. Overgrowth of the gums may make secondary teeth come in with wide spaces and may later require extensive orthodontic care.Children who have been on high doses of phenytoin for long periods of time often develop coarse facial features and more extensive body hair. The hair does not disappear when the drug is discontinued, although it may decrease. Such a side effect may become a cosmetic problem, especially for young women. Although phenytoin is an excellent anticonvulsant, we prefer not to use it as our initial drug in young children because of its cosmetic side effects. The cosmetic effects seem to be a lesser problem with adolescents and adults.*121\208\8*

THE CARBOHYDRATE ADDICTION: CURRENT RESEARCH AT MOUNT SINAI MEDICAL CENTERIn order to explore the effect of food intake on these chemical workings, we have conducted controlled studies of carbohydrate addicts and nonaddicted subjects. We instructed both groups to consume comparable foods during two four-week time periods, with one important difference—during each of the two time periods the distribution of carbohydrates was different.For one period, the carbohydrates were distributed among three meals each day; for the other, the carbohydrates were confined to one meal.We measured the subjects’ experience of hunger and their weight change. The results showed that the frequency of carbohydrate intake affected both the carbohydrate-addicted and nonaddicted group’s experience of hunger and weight. But it affected carbohydrate addicts at a much higher level. Both weight levels and hunger increased in direct proportion to increases in carbohydrate meal frequency. In the carbohydrate addict, these changes showed significant differences when the total daily food intake was the same and only the carbohydrate frequency was changed.In summary, we have found, then, that by consuming only one carbohydrate-rich meal per day, the carbohydrate addict experienced less intense hunger and fewer cravings as well as significantly greater weight loss.This appears to be caused by:Lowered insulin production and/or releaseAn increase in receptor sites (due to the decrease in insulin), with an accompanying increase in the rate at which insulin is removed from the blood
For carbohydrate addicts, this means that by changing the number of times they consume carbohydrates each day, they can reduce the intensity and recurrence of hunger and cravings and increase their body’s tendency to lose weight.
We are pursuing other avenues of research involving triglyceride levels and cholesterol levels in relation to frequency of carbohydrate intake.Our research and that of others indicate that carbohydrate addicts differ greatly in the biological processes that govern their food cravings. Carbohydrate addicts are also different in the ways in which their bodies use and store food energy.Scientists have discovered that these differences in biological processes can make some people predisposed to overweight. These people find themselves craving carbohydrates, and often have difficulty controlling their eating; their bodies may actually, in some sense, be destined to store fat. These processes have been observed in animals that are genetically predisposed toward obesity.The research suggests that, because of their genetic makeup, many overweight people are carbohydrate addicts and have strong, biologically based tendencies to become fat. If their underlying disorders are left untreated, they are equally predestined to remain overweight.At the same time, the evolving body of research reveals a new understanding of the cause of the underlying biological problems, and offers new hope to the carbohydrate addict.*12\236\2*