Sunday, 29 July 2012


Astraea or star-coral is a colonial coral with closely-placed polygonal cups bearing polyps. The thecae are so close together as to have common walls.The colony is compact and massive and produced by budding,the buds  growing more or less parallel with one another.The coenchyme is formed by calcifications of the coenosarc and gives origin to individual corallites. The polyps in cups are elevated rounded widely separated and spirally arranged.

Thursday, 26 July 2012


Teredo is commonly called as shipworm.It is a highly specialized marine bivalve which is very destructive to wood in sea water.The body is long and slender with a small anterior shell. The shell is used  for burrowing in the wood of ships.The foot is extremely reduced and acts as an adhesive organ for attachement to the wall of its hole-habitat. The mantle cavity bears paired and elongated gills and gonads. The inhalent and exhalent siphons are also elongated.

Wednesday, 25 July 2012


The pearl oysters are sedentary marine bivalves found in all seas except in colder .The indian pearl oyster is PINCTADA VULGARIS that is known  for yielding precious pearls. The two shells are unequals, with the left one comparatively larger than the right one and remain attached to a rock. The adductor muscles is single and large. The foot is lacking in the adult. Pearl is formed as a result of nacreous secretion from the mantle around a small particle.

Sunday, 22 July 2012

D D T(Dichloro-diphenyl trichloroethane),B H C

It is a white amorphous powder practically insoluble in water but dissolves in most organic solvents .D D T is used extensively safe.
B H C(Benzene hexachloride or gammexene)-It is white or chocolate-coloured power which is insoluable in water but soluable in organic solvents.It is used like D D T as spray for killing mainly the aphids on fruit and nut crops.

Thursday, 19 July 2012


It is commonly called as mussel shrimp.It is a small ostracodan crustacean.It bears in large numbers in stagnant ponds.The segmented body is completely enclosed in a protective bivalved carapace which makes it appear like a miniature clam.The anterior end of the body bears a large median eye.The antennules and the antennae are large and also help in swimming.The only appendages are two pairs of thoracic legs. It swims with the first pair of legs .The abdomen lacks appendages but ends in a pair of small caudal ramii. It is omnivorous, feeding on small organisms and detritus. The females are common and their eggs usually develop parthenogenetically as males are not known in certain genera.


Lepas commonly known as ship or goose barbacle.It is a stalked crustacean.It is found as in seas attached by a peduncle to wooden ships.The peduncle is highly movable and the oral end of the body contains the vestiges of the antennules.The proper or capitulum is protected by a bivalved mantle or carapace which is further strengthened by five large calcareous plates-two proximal scuta,two distal terga and a single dorsal carina.The larva is cypris which after a free swimming period settles to the bottom and growth into the stalked adult.The ventral mantle opening are protruded six pairs of delicate filament like or cirriform thoracic appendages .They feed upon minute organisms gathered from the water by the thread like feet and kicked into mouth.The lepas is hermaphrodite.

Wednesday, 18 July 2012


Hippa,commonly called as mole crab.It is found in the sand near the coasts. The body is oval with a large more or less cylindrical cephalothorax with carapace.The head bears a pairs of stalked compound eyes, a pair of short antennules and a pair of long antennae bearing hairs on the hinder surface.The rostrum is very much reduced .The five pairs of walking legs are thoracic and adapted for digging,being curved and flattened.The first legs are chelate.

Monday, 16 July 2012


It is commonly called rock barnacle.It is marine crustacean found attached to rocks, shell of hermit crabs.The mantle surrounding the body is covered by six calcareous plates an unpaired carina unpaired rostrum and two pairs of lateral plates.The opening of the mantle is provided with the fourfold lid,consisting of two  scuta and two terga.There is six pairs of delicate ,fringed legs. In water this legs propel food to mouth .When the tide is out the mantle plates close for protections. Rock barnacles are serious pests on the bottom of ships.


The sting of apis is modified ovipositor and is used for injecting poison.It is composed of two straight grooved stylets or lancets.The muscles associated with the sting help in the operations of the lancets and a set of three chitinous plates on either side acts as levers to move the barbs.The poison glands secreats the acidic materials that is stored in a sac like poison sac located at the base of the sting.There is associated alkaline gland that secreats alkaline materials. The two materials mix to form the poison or bee venom that flows down the sting into the wound of the victim .After performing there duties the workers bee leaves the sting apparatus and dies.

Sunday, 15 July 2012


Amoebiasis,also known as amoebic dysentery,is caused by Entamoeba histolytica. Its trophozites, that penetrate the wall of the intestine secrete histolytic enzymes and feed upon its cells causing the formation of ulcers. The trophozoites under certain cirumstances reach the liver and brain also causes abscess formations.Transmissions of the parasites from man to man takes place through tetranucleate cysts.The trophozoites changes into a smaller minuta cyst.Amoebic dysenteries is endemic in warm countries.These cysts are foivoided with the faecal matter and contaminate food and water and spread into new hosts.

Saturday, 14 July 2012


Three kinds of individuals or castes 1>WORKERS-Which are strile females.
2>drones-Which are fertile males.
3>Queen-Which are fertilefemales.
The workers have job of producing the royal jelly, building the bee hives, caring the larvae and disposing of the debris and dead bees. The drone and queen are used for reproductive purposes.The average sized colony conists of one queen, about 100 drones and 60,000 workers.

Friday, 13 July 2012


The mouthparts of honey bee are of chewing and lapping type.The labrum lies below the clypeus and the mandibles are situated on either side of the labrum. The labrum are used for moulding the wax and manipulating the pollen.The glossae of the second maxillae or labium form a tongue-like process or ligula with a spoon like depressions at its tip called the labellum or honey spoon. It constitutes a tube or proboscis for sucking up the nectar.The labial palps are well developed and they help to make the ligula. The apparatus is protected by the long galeae of the first maxillae.


VORTICELLA is a type of ciliate almost bell-shaped or campanulate with free anterior end surrounded by cilia.It is solitary and stalked ciliate often found in freshwater ponds,lakes rivers .There are 200 species all of which solitary.They occur in large groups but are never colonial. They can live only in uncontaminated waters where bacterial growth does not become too great.Some species are marine,or epizoic and are few parasitic.V.microstoma is the one which is more frequently seen in laboratory infusions.
SHAPE AND SIZE-It is bell-shaped asymmetrical body.The long contractile stalk. Both the body and the stalk are capable of great individual variations in size and form. The body of smaller V.microstoma measures 55 mew to 35mew. The largest species V.campanula in size with the lenght of 53 to 4150 mew.

Thursday, 12 July 2012


Respiration takes place by the diffusion of gases through the body surface.The gaseous exchance i,e intake of oxygen and giving out of carbondioxide takes place between the blood capillaries of the outer epidermis and the surface film of moistures contributed by secreated mucus excreated wastes and coelomic fluid.Haemoglobin dissolved in the plasma of blood acts as a respiratory pigments transporting oxygen to the body tissues.

Saturday, 7 July 2012


Two type of respirations-AEROBIC AND ANAEROBIC.
ANAEROBIC RESPIRATIONS-It works in the absent of oxygen.e.g tapeworm living inside the human intestines.It occur inside our own body i the fast-working skeletal muscles temporarily. During physical exercise like running,walking for long distance ,wrestling,weight-lifting,etc our muscles work too fast but not getting enough oxygen. In this situations the muscles are working in the absence of oxygen to provide extra energy. The product of anaerobic respirations in such  muscles is lactic acid. The lactic acid gives the feeling of fatigue.This conditions is called oxygen-debt.When you rest for some time this lactic acid slowly get oxidised by the oxygen and so debt is cleared.
AEROBIC RESPIRATIONS-It works in the presence of oxygen.
SHIVERING and CLATTERING of teeth-In winter when we feel cool this is emergency activity of the muscles cells to produce extra heat.

Friday, 6 July 2012


Respiration is vital process in all living organisms.It gones non-stop through out life.It is process in which the raw materials used ,the end-product used and the amount of energy liberated.So it is process in which the raw material used or the chemical process of releasing energy by breaking down giucose for carrying the life process.There is five points to be rembeber this part of respiration yielding energy occurs inside the living cells and hence it is better known as cellular or tissue respiration.
2>The breakdown of glucose to carbon dioxide and water does not occur in a single steps but in a series of chemical steps.some of the steps occur in cytoplasm and inside the mitochondria.
3>The breakdown of process is envolve the enzyme citrase kinase.
4>ATP release from the adenosine triphosphates first discovered by KARL LOHAMM IN 1929.We get energy in the form heat  in which adp first converted into ATP .It is also called as currency of energy in side the cell. One mole of glucose on complete oxidations yields 28 molecules of ATP.
5>The essensials steps of cellular respirations are same in plants and animals.
WHY WE NEED ENERGY-We need energy for a vast variety of activities in them.Some of these are:
1>Synthesis of protein from aminoacids.
2>productions of enzymes.
3>contractions of muscles for movements.
4>conductions of electricals impulse in a nerve cell.
5>By cell divisions formations of new cells.
6>For keeping the body warm i,e warm-bloded animals e,g birds and mammals.