HIGHER ORDER CHROMATIN STRUCTURE

INTRODUCTION Higher order chromatin structure comprises of nucleosomes and DNA which further form compact structures to fit 1-2 meter DNA into a very small nucleus. Earlier studies of chromosomes divided chromosomes divides chromosomal region into two categories : euchromatin and heterochromatin. Heterochromatin was characterized by dense staining with a variety…

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KINDS OF ENVIRONMENTAL POLLUTION

INTRODUCTION Environmental pollution is defined as the contamination of air, water, or food in such a manner as to cause real or potential harm to human health or well-being, or to damage or harm nonhuman nature without justification. Pollution is an undesired change in the physical, chemical, or biological properties…

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NOISE POLLUTION

INTRODUCTION Noise pollution, or noise disturbance, is annoying or excessive noise that can affect the activity or balance of human or animal life. Most of the world's external noise sources are primarily caused by machinery, transportation systems, cars, planes and trains. External noise is summarized in the term environmental noise.…

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ENERGY FLOW IN ENVIRONMENT

INTRODUCTION Energy flow in environment is the important function in the ecosystem. The storage of the energy in the ecosystem is based on two basic laws of thermodynamics. The first law of thermodynamics states that when energy is converted from one form into another, energy is neither created nor destroyed.…

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COMMUNITIES OF THE ENVIRONMENT

INTRODUCTION All the living organisms of an ecosystem form a single biotic component, the community or biotic community (communities of the environment). All the organisms of a community live together, share same habitat, influence each other's life directly or indirectly and have reached a survival level within a given radiant…

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BIOTIC FACTORS

INTRODUCTION Biotic factors and abiotic factors are two types of factors that have an influence on ecosystem. Biotic factors are the living factors that have an influence on ecosystem. Organisms do not exist alone in nature but in a matrix of other organisms of many species. Many species in an…

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ABIOTIC FACTORS

INTRODUCTION Abiotic and biotic factors or components are present in environment of an organism. The abiotic factors includes the atmosphere(air), hydrosphere (water), and lithosphere( land including soil).The abiotic factors are characterized by physical and chemical factors such as light, temperature, rainfall, pressure, pH, the content of oxygen and other gases.…

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ENVIRONMENT AND BIOSPHERE

INTRODUCTION  Environment and biosphere: Every living organism has its own surrounding, medium of environment to which it interacts and is adapted to it. The environment is the sum total of physical or abiotic and biotic conditions influencing the organisms. The life supporting environment of planet earth is biosphere. The biosphere…

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CANCER CELLS VS NORMAL CELLS

INTRODUCTION Cancer, also called malignancy, is an abnormal growth of cells. Cancer is more than 100 types, including breast cancer, skin cancer, lung cancer, colon cancer, and lymphoma. Cancer cells are uncontrolled division of cells. Conversion of normal cell into cancerous cell is called transformation. And the cell is called…

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AERIAL ADAPTATIONS IN VERTEBRATES

The aerial adaptations are concerned with the flight. The flight is a form of locomotion in the air under which the body has to be firstly prevented from falling down and secondly moved forwards, the speedier the better. Thus, aerial adaptations must include modifications in the animals body for reducing the weight of the body and also for the formation of organs capable of executing the flight.

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TYPES OF TAXONOMY​ – CHEMOTAXONOMY, CYTOTAXONOMY AND MOLECULAR TAXONOMY​

TYPES OF TAXONOMY​ -Chemotaxonomy, also called chemosystematics, is to classify and identify organisms according to confirmable differences and similarities in their biochemical compositions. In a nutshell, the biological classification of plants and animals based on similarities and differences in biochemical composition.How scientific literature must cite names

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BINOMIAL SYSTEM OF NOMENCLATURE​

The binomial system classifies organisms into groups at various hierarchic levels, on the basis of easily observable and shared morphological features like shape, number and position of limbs etc. in a descending order of group size. As the word binomial suggests, the name of a species is made up of two parts: one indicating the genus and indicating the species. Binomial nomenclature means “two part name” or “system of two part names”.Which name must be used in case of name conflicts How scientific literature must cite names

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TAXONOMIC KEYS​

A Taxonomic key is a device, which when properly constructed and used, enables a user to identify an organism.In lifesciences, an identification key is a printed or computer-aided device that aids the identification of biological entities, such as plants, animals, fossils, microorganisms, and pollen grains.How names are correctly established in the frame of bionomial nomenclature Which name must be used in case of name conflicts How scientific literature must cite names

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GENERAL ORGANISTION OF GNATHOSTOMATA

The Gnathostomata includes all vertebrates with upper and lower jaws. It comprises a wide range of animals, from fish to the various tetrapod classes, which have in turn been derived from a fish or fish-like ancestor. An entirely satisfactory classification of fishes is not easy to construct, because of the incompleteness of several parts of the fossil record, and the consequent lack of connecting links.

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MEDIAN – DEFINITION AND CALCULATION

Mean, median and mode all three are Central Tendency or Averages. The Arithmetic mean lies under Mathematical Average and the other two Median and Mode are types of Positional Averages. A measure of central tendency is a typical value around which the figures congregate". The value of central tendency or average always lies between the minimum and maximum values.

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GENERAL ACCOUNT OF DIPNOI

The origin and evolution of Dipnoi remains problematic due to diverse opinions. They combine characteristics in which they resemble almost all the other groups of fishes as well as Amphibia. Fossil primitive Dipnoi (e.g. Diptems), shows geater similarity with fossil crossopterygians (e.g. Osteolepis), than do their living members.

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ORIGIN OF CHORDATA​ (PROTOCHORDATA AND EUCHORDATA)

We shall now consider the origin of the earlier chordate ancestors of vertebrates. That the chordates have originated from the invertebrates is not doubted by most zoologists now-a-days. Since the earlier chordate ancestors were all soft bodied forms, they left no fossil remains to give us clues as to origin of chordata. Therefore, the only basis for judging the origin of the group comes from the resemblances between the lower chordates (protochordates and the invertebrates).

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INTERNATIONAL CODE OF ZOOLOGICAL NOMENCLATURE​ (ICZN)

The International Code of Zoological Nomenclature (ICZN or ICZN Code) is a widely accepted convention in zoologythat rules the formal scientific naming of organisms treated as animals. The rules principally regulate: How names are correctly established in the frame of bionomial nomenclature Which name must be used in case of name conflicts How scientific literature must cite names

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GENETIC POLYMORPHISM

Polymorphism is most apparent when it affects a visible or behavioral phenotype, but is not at all restricted to such traits. R. Lewontin and J. Hubby, in 1966, undertook the first extensive analysis of protein polymorphisms in natural population of Drosophila pseudoobscura by subjecting extracts of individual flies to get electrophoresis and observing the rates of migration of various proteins, which represented 18 gene loci.

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HARDY WEINBERG EQUILIBRIUM LAW

The equation derived based on the Hardy Weinberg equilibrium concept is called the Hardy Weinberg law. In this particular equation, p is represented as the dominant allele’s frequency and q is the representation of the recessive allele’s frequency. This is explained with an example to conclude a Hardy Weinberg equation. Consider a single locus with the presence of only two alleles namely A and a.

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MODES OF SPECIATION

New species form by speciation, in which an ancestral population splits into two or more genetically distinct descendant populations. Speciation involves reproductive isolation of groups within the original population and accumulation of genetic differences between the two groups.

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TRENDS IN EVOLUTION

Evolution is change in the heritable characteristics of biological population over successive generation. Molecular evolution is change in the sequence of molecule of cell. Evolutionary genetics is study where how change in genes leads to change. Molecular markers have ability to detect genetic variation. TRENDS IN EVOLUTION

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LARVAL FORMS OF ECHINODERMS

LARVAL FORMS OF ECHINODERMS :- Echinoderm larva is strikingly bilaterally symmetrical in marked contrast to radially symmetrical adult. It swims about by means of a ciliated band, which may be complicated by a number of short or long slender projection or arms from the body wall. Based upon the nature and position of the arms or their absence, lame of different classes of Echinodermata may distinguished.

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LARVAL FORMS OF MOLLUSCA

LARVAL FORMS OF MOLLUSCA :- Molluscan life histories do not perfectly correspond with taxonomy, but in general it is true that the archaeogastropods and the bivalves begin life as a trochophore and rapidly pass on to a veliger. There are different types of molluscan larvae according to the importance of the pelegic phase and amount of planktonic food taken. G. Thorson (1950) recognised three ecological types of larvae in Mollusca.

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LARVAL FORMS OF TREMATODA, CESTODA AND ANNELIDA

LARVAL FORMS OF TREMATODA, CESTODA AND ANNELIDA :- The trematods or flukes are either external or internal parasites, the cestodes or tap worms are internal parasites. The termatoda class includes three order . The fasciola hepatica which is an example of order digenea have mainly 5 larval forms (i) miracidium (ii) sporocyst (ii) redia (iv) Cercaria (v) metacercaria.

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OSMOREGULATION OF FRESHWATER AND MARINE INVERTEBRATES

Regulation of osmotic pressure of an organism body fluid is refer to as osmoregulation. It allow to maintain balance of water content, fluid content and electrolytes. Hence due to osmoregulation body neither become too dilute nor become too concentrated. Right concentration of solute and amount of water must be maintain by any aquatic [fresh or marine] and terrestrial organisms. It can be mostly achieved by excretion.

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EXCRETION IN HIGHER AQUATIC INVERTEBRATES

EXCRETION IN HIGHER AQUATIC INVERTEBRATES :- Process by which nitrogenous waste produce during metabolism is removed is known as excretion. Some animals such hydra, echinoderms and other may not posses proper excretory organs the reason is quite clear that they are aquatic and it is supposed that nitrogenous material may be diffuse out of there body through their body surface.

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