DIGESTIVE SYSTEM

Alimentary canal is straight tube running throughout the length of the body the whole of the alimentary canal is not uniform in diameterand the nature of the digestive wall is aldi different in different regions there fere it can be diveded inro the following parts .
Mouth is a crescentric aperture ventrl to the prostomium ditiuated in thefirstsegment or peristomium or buccal segmint.Buccal chamber mouth leds into a cavity called bucca; cvity or buccal chmber it is a short thinwalled chamber and extinds from first segment to the middle of the 3rd segment During movement earth buccal chamber with the help of muscular stramds wjoch[ass baclwards and forwards from the outer walls of the buccal chamber and the pharync to the body wall.
Pharynx.Buccl cavity leads into the pharynx which is a pearshaped wide swollen and muscular chamber it is continued slightly beyond the fourth segment buccal cavity is clearly separated from the pharynx by a groove in which dorsally a ceret ral ganglion is situated pharyngeal cavity is narroe and dorsoventrally compressed due to the presence of larg thick mass known pharyngeal mass or pharyngeal bulb which swpresses the phryngeal roof pharyngeal mass is made up of darkly stained irregular glandular cells or chromophil cells and muscle fibres.the glandular cells produce a salivary secretion which is poured into the cavity of the pharynx by means ofchannels of the pharyngeal mass the lateral phryngeal walls are pushed inside to form a horizontal shelf on ech side the two shelves thus divide the phryngeal cavity into a dorsal or salivary chamber and ventral or conducting chamber

RAT(RATTUS)

phylum- chordata.
class-mammlia.
1.Most wide spread rodents.
2.snout is elongated.
3.Incisors are long sharp chisel like and slightly curved. incisors re rootless one pair in each jaw.
4.Body is black or grey coverd with small soth hairs.
5.tail is long without hairs.
6.Adapred for various modes of lige viz arboresl terrestrial and undergrpund.
7.Rats are a great menace to mankind They are carriers of deveral disease germs viz cholera typhus rat bite fever plague jaundice tuberculosis of poulatry and trichinosis of swine.there are many type of rats viz shiop rat sewer rat house

RABBIT{oryctolagus or Lepus}

phylum-chordata.
class-mammalia.
1.leping mammal lives in grasslands.
2.warm blcoded or homiothermal animal.
3.jBody is bilaterally symmetrical and covered with short soft hairs the fur which is dusty brown in colour with a white patch under the tail.
4.The body is divisible into four regions (a)head; neck ;trunk; tail.
5.The snout possesses a number of special hairs called feelers or vibrissae or whiskers which are tactile organs.
6.Above the head there is a pair of long movable trumpet shaped external ears called pinnae.
7.Nares nd a pair of prominent eyes are also present in the head .
8.jTrunk is divisble into two anterior narrow thorax and posterior abdomen.
9.on theventral side of the trunk female possesses four or five pairs of teats or mammae.

FROG

phylum-chordata.
Genus-Rana.
species-tigrina.
Rana tigrina is the common indian frog which is found in fresh wter ponds ditches pools under stones and in damp p;aces except arid parts of the country the periods of its great activity re spring and rainy seadond As soon as the winter starts the activitiesof the frog cease and it becomes sluggish. Hibernation frogs are cold blooded animals or poikilothermal or ectothermal the temperature of the animals is not ccoustant but it varies according to the tempreture of the environment During winter the frog digs down into the damp earth at the atthe bottom of the ponds or in damp places almost near the source og lakes ponds or streams This is called as winter sleep or hiberation in this conditoon they lie in a dormant condition until the next spring the skin is moisttherefore respiration takes place through the skin.The general vital activities of the animal areso low that the little expenditure of the energy is needed to maintain life frog does not respire with the lungs the temperature of the body also becomes so low that it os only a few degrees above that of the surrounding medium frog does not take any food but maintains all itsphysiological activities at the expense of foos material stored in the tissues in the form of glycogen is very essential as certain amount of combustible material is required even when the temperature of the frog stored during the summer when frog feeds voraciously and it is expanded gradually through the wintermonths heart beating goes on during winter and various physiological activities are supported by the food during winter growth of thw sexul products increase at the expense of the other parts of the animal.

FIRE

Recently it has been found thte fire is one of the major ecological factors s it is part of normal climre.jTherefore bioticcommunities dapt and compensate for this factor .Odum (1971)writes that failure to recognize that ecosystems may be fire adapres has resulted in a great deal of mismanagement of mano of natural resources. He further mentions that properly used fire can be an ecological tool of great value the fire is an extremely important limiting factor as mankind is able to control it to a far greater extent than we can control mny other limiting factors Fire is very important especilly in forest and grassland regions of temperate zones in tropical areas with dry seasond protection forms fire hs resulted in ore productive environment for man the use of fire depends on its inteligent knowledge and control.

FASCIOLA(LIVER FLUKE)

Phylum- platyhelminthes.
class-Trematoda.
1.Body flattened leaf like covered with spines
2.Endoparasites living in two or more hosts
3.The anterior end has a projecting lobe called apical or head
4.At the apex of the head lobe is mouth which is surrounded by anterior sucker
5.Behind the head lobe is situated a ventral sucker or ace.

SHREW(suncus)

Phylum-chordata.
sub-phylum-Gnathostomata.
super-class-Tetrapoda.
class- Mammalia.
1.size small.
2.snout usually long and tapering.
3.Limbs five-toed provided with claws.
4.Teeth are sharp and pointed.
5.mouse like animals witch usually burrow.
6.Feed on insects smaller invertebrates and rodents.
7.Nocturnal in habit.
8.There is a poisonous substance in the saliva of the shrew which helps to capture the prey .