TEXT-BOOKS OF ANIMAL BIOLOGY A General Zoology of the Invertebrates Vertebrate Zoology. Syllabus for XI Standard. ZOOLOGY - Textbooks Online. This book has been prepared by The Directorate of School from appropriate websites and reference books. Standard XII - Biology (Zoology) Syllabus. Bio Zoology 11th - Free ebook download as PDF File .pdf), Text File .txt) or read book online for free.
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Text book published by Government of Tamil Nadu. Tamilnadu 11th New Books Free Download PDF Online | 11th Advanced Tamil | 11th Bio- Botany|11th Bio – Zoology. Tamilnadu 11th New School Text Books Download | 11th New School Books Download Tamilnadu 11th New School Books Download.
Description Zoology is the scientific study of behavior, structure, physiology, classification, and distribution of animals. Zoology is a flagship subject that leads to the studies of human biology, that is why it is appointed as one of the most compulsory subjects for the students of Pre-medical by BISE Punjab. Zoology is especially necessary for those students who are aspiring to become doctors and medical practitioners in the future. The first-year zoology gives the students an in-depth view of knowledge that is required by students in the process of becoming an expert. It also shares professional knowledge with students which they had not learned in their previous classes. The Zoology paper is made up of three parts: part one being objective with short multiple choice questions and answers, while subjective section consists of detailed questions and answers and last but not the least, the practical examination. For further studies of students and with the sole aim for providing them with best yet low cost alternative to expensive studies.
The forelimbs are shorter than the hindlimb. The limbs have five digits and all the digits end in flat nail. The pollex or thumb or first toe are smaller than other digits and are opposable except the hallux of man. The brain is highly developed. The cerebral hemispheres are much. The eyes are directed forward and the vision is binocular and stereoscopic. Mammae are two and thoracic in position. Type study - 1. Members of the genus Plasmodium are collectively known as malarial parasites.
They cause a febrile disease called malaria. Malaria as a chill and fever disease is known to mankind for a long time. Eradication of malaria is an important problem in public health. For a long time it was believed that malaria was caused by harmful vapours produced in marshy land Gr.
Charles Laveran, a french military surgeon, for the first time, noticed Plasmodium in the blood of a malarial patient, in Its connection with the intermediate host and the modes of transmission were experimentally worked out in Calcutta by Sir Ronald Ross in For this discovery he was awarded the nobel prize for medicine in Grassi provided absolute scientific proof for the specific relationship between Anopheles mosquito and the human malarial parasite.
The plasmodium is an intracellular sporozoan blood parasite. For the completion of life cycle it requires two hosts, a vertebrate and a blood sucking invertebrate. Transference of the parasite is effected by the invertebrate host. In man, the infection takes place by the inoculation of the slender, sickle shaped nucleated sporozoite in the blood by the bite of an infected female mosquito belonging to the genus Anopheles. At least four species of Plasmodium, P.
The life cycle of the malarial parasite involves two hosts, the man and the mosquito. The modes of development in these two hosts are different.
In man the mode of reproduction is asexual and in mosquito it is sexual. Man is the intermediate host and the mosquito is the definitive host.
Life cycle in Man - Schizogony There are two phases in the life cycle of malarial parasite in man.
They are 1 Pre erythrocytic cycle or Exoerythrocytic cycle in liver cells and 2. Erythrocytic cycle or Endo-erythrocytic cycle inside the red blood corpuscles. Pre-erythrocytic cycle: The pre-erythrocytic cycle comprises the asexual reproduction of the parasite in the liver. When an infected female Anopheles mosquito bites a person, thousands of slender, sickle shaped nucleated sporozoites are injected in the blood.
The sporozoites first enter the capillary vessels of the skin and then enter the general circulation. These parasites circulate in the blood for about 30 minutes and enter into the pre-erythrocytic cycle in the reticuloendothelial cells of the liver. Sporogony exflagellation microgamete. The sporozoites penetrate the liver cells and develop into forms known as cryptozoites. A cryptozoite has a compact nucleus and no pigment or. Cryptozoites rapidly grow feeding on the liver cells.
When a cryptozoite has reached its full growth it fills the entire cell. In this stage it is known as the crypto-schizont. It undergoes schizogony and the resulting cells known as crypto-merozoites are set free in the blood by the rupture of the liver cells. The released crypto-merozoites invade fresh liver cells or red blood corpuscles. This cycle is considered as a period of incubation before the parasites could start the erythrocytic cycle.
During this period of 7 - 17 days, the parasites are not seen in the blood stream. Erythrocytic or Endo-erythrocytic cycle. Each cryptomerozoite makes its way into a red blood corpuscle and feeds on its contents. After some time, the parasite gets an amoeboid shape. This growing stage is known as the trophozoite stage. Soon it develops a vacuole which gradually increases in size. Thus the nucleus is pushed to one side. This stage is called the signet ring stage.
With further growth the vacuole disappears and the amoebula occupies the entire interior of the corpuscle. This stage is known as the schizont stage. In the schizont, the nucleus breaks up into bits and each becomes surrounded by a small amount of cytoplasm.
These cells are known as merozoites. By the rupture of the wall of the red blood corpuscles the merozoites along with wastes haemozoin are released into the blood. This causes the malarial fever. The liberated merozoites attack another set of corpuscles and start the life cycle anew. This method of infection is known as autoinfection. The life cycle in the blood of man is called the cycle of Golgi or schizogony or endoerythrocytic cycle. Schizogony keeps up the multiplication of the parasites and their maintenance in the blood.
After schizogony has taken place for several generations some of the meroziotes which invade the red corpuscles, instead of developing into trophozoites and schizogonts, develop into gametocytes. The gametocytes are of two types - marco-gametocytes and micro-gametocytes. The macrogametocyte has a small nucleus and a dense food laden cytoplasm. The micro-gametocyte has a relatively large nucleus and clear cytoplasm. Their further development depends on their entry into the stomach of a female anopheles.
If it does not take place they disintegrate. Life cycle in the mosquito - sporogony When a female anopheles mosquito bites an infected person, it sucks blood along with all the stages of parasite. But in the gut of the mosquito, only the mature gametocytes survive and the rest of the stages are destroyed. From the gametocytes develop gametes. The process of development of gametes from gametocytes is known as gametogony. The nucleus of the micro-gametocyte divides into many fragments and the cytoplasm is thrown into flagellated structures.
There may be as many cytoplasmic structures as there are nuclei. This process is known as exflagellation. The resultant cells are called the microgametes. The nucleus of the macro-gametocycte divides equally into two. The cytoplasm divides unequally. So among the resulting cells one is bigger and the other is smaller.
The small cell is thrown out. This process is known as maturation. The resulting bigger cell is known as female gamete or macrogamete. Syngamy and sporogony: Inside the stomach of the mosquito the microgamete and the macrogametes come into union and nuclear fusion takes place.
This kind of union is called syngamy and the resultant form is known as zygote. The zygote assumes an elongated form and is capable of movement. It is known as ookinete. It pierces the wall of the stomach and comes to lie under the outer layer of stomach wall. There, it ceases to move, becomes round and forms a membranous cyst-wall.
This stationary zygote enclosed in a cyst-wall is known as oocyst. It grows in size absorbing the nourishment from the host. The nucleus of the oocyst divides repeatedy, each being surrounded by a fragment of cytoplasm.
Thus inside the oocyst, a large number of cells develop into minute, slender, sickle shaped bodies called sporozoites. The cyst wall breaks, liberating the sporozoites into the body cavity haemocoel of the host.
They wriggle forward and enter the salivary gland. When such an infected female anopheles mosquito bites a healthy person, it injects into his blood a stream of sporozoites. This kind of transmission is called inoculation. Types of Malaria: The disease caused by Plasmodium is known as malarial fever.
It is charcterised by recurring bouts of fever, each lasting several hours. There are four species of Plasmodium known to cause malaria in man. The commonest and most widely distributed species is P. It causes benign tertian malaria in which the fever recurs every third day every 48 hours.
This type of malaria has a high death rate. Blood corpuscle parasitised by this species tend to clump together and block up small blood vessels and damage the essential organs. It is a dangerous species and the disease often appears in an epidemic scale. The fourth species is P. It is principally found in west Africa but occassionally in S.
America, Russia and Palestine. These four species differ from each other in the details of structure, time needed to complete the schiogzony, the incubation period, number of merozoites released and duration of sexual cycle. Control of Malaria The control measures fall under the following three categories. Treatment of infected patient 1 Plasmodium does not produce antitoxins or antibodies in human blood.
Therefore malaria cannot be treated by inoculation or vaccination with immune sera. It can only be treated with drugs that may kill all stages of the parasite without poisoning the patient.
Quinine, which is extracted from the bark of cinchona trees, had been used effectively for the past years to cure malaria. The various synthetic drugs, such as Paludrine, Atabrin, Camoquin, Chloroquine, Resochin, Pamaquin etc are used as suppressants of various stages of the parasites. It can be effected in two ways. It is the most effective and surest way of controlling malaria.
It is achieved by using effective insecticides and by draining swamps. It destroys the breeding places of mosquitoes. Adult mosquito can be most effectively controlled by spraying DDT, malathion or any other insecticide in the houses; fumigating pyrethrum cresol and other compounds of naptha; sterilization of male mosquitoes. The young stages of mosquito can be controlled by introducing larvivorous fishes like Gambusia and Lebistes in ponds, lakes, canals and tanks.
Type study - 2. Earthworms are nocturnal animals. They lie in the burrows during the day and come out at night for food. Earthworms leave the burrow only during the rainy season when their burrows are flooded with water. External features Lampito Megascolex mauritii is a common earthworm found in South India. The body is long, slender, cylindical and bliaterally symmetrical. It is about 8 to 21 cm long and 3 to 4 mm in thickness.
The dorsal surface is dark purplish brown, and the ventral surface is paler in colour. It is marked by a series of segments. The segments are separated from one another by intersegmental grooves.
The division is both external and internal. Inside the body, each cavity of the segment is separated from the next, by a thin partition called the septum. All the segments look alike. This kind of repetitive arrangement of the segments is called metamerism. The mouth is found in the centre of the first segment of the body, called the peristomium.
Overhanging the mouth is a small flap called the upperlip or prostomium. The last segment has the anus. It is called the pygidium. In mature worms, segments 14 to 17 may be found swollen with a glandular thickening of the skin called clitellum.
Body setae Tiny curved bristles called setae are found embedded in small pits of the body wall. These pits are called the setigerous pits. The setae are arranged around the body. They are made of chitin and have a swollen middle part and pointed curved ends. The setae resemble the mathematical symbol.
They can be moved in any direction and extended or withdrawn by the action of muscles. They are used for locomotion. External apertures: Dorsal pores: These are minute openings situated in the mid dorsal line in the intersegmental grooves commencing from the 10th segment. The coelom communicates to the exterior through these pores and keep the body surface moist and free from harmful micro organisms.
Spermathecal openings: Three pairs of openings are situated ventrolaterally in the intersegmental grooves between segments six and seven, seven and eight and eight and nine.
These opening can be easily seen in mature worms. Openings of oviduct: These are a pair of apertures lying close together on the ventral surface of the 14th segment. Openings of Spermiduct: A pair of apertures are situated on the lowerside of the 18th segment.
Numerous minute openings scattered on the body wall from 14th segment onwards. Body wall: The body wall of earthworm is thin soft and moist. It consists of the following layers arranged from outside. It is a thin, transparent, iridescent layer secreted by the underlying epidermis.
It is in the form of a single layer of columnar cells. This layer contains gland cells and receptor cells. It is a very thin sheet of connective tissue forming a basement for the epithelial cells on the outside and muscles on the inside. The muscles are arranged in two layers, namely the outer circular and inner longitudinal. Coelomic epithelium: It is the inner most layer of the body wall forming the lining of the body cavity. Body Cavity: A spacious body cavity called the coelom is seen between the alimentary canal and the body wall.
It is divided into a series of compartments by the transverse partitions of connective tissue called the septa. The coelom is lined with the coelomic epithelium and filled with coelomic fluid.
It is a colourless fluid with amoeboid coelomic corpuscles floating in it. The fluid oozes out through the dorsal pores. It keeps body surface moist as a condition quite. The coelomic cavity communicates to the exterior through reproductive and excretory apertures.
The germ cells are budded off from the wall of this cavity. Earthworms move about by contraction and expansion of its body wall.
When the circular muscles of the body wall contract, the body becomes thin and elongated. This process results in the forward extension of the body. Then it fixes itself firmly to the ground with help of the body setae and mouth. Subsequently when the longitudinal muscles contract, the body becomes thick and shortened. As a result, the body is drawn forward towards the anterior end which is already fixed to the ground.
Thus by a repeated process of alternate contraction and expansion of muscular body wall locomotion is effected. Digestive System: The digestive system runs as a straight tube from mouth to anus.
The mouth is situated in the first segment. The mouth opens into the buccal cavity which occupies segments 1 and 2. The buccal cavity in turn leads into a thick muscular Pharynx. The pharynx occupies segments 3 and 4 and is surrounded by the pharyngeal glands. The oesophagus is a short narrow tube lying in 5th segment. It leads into the gizzard lying in the 6th segment.
Its inner surface has a chitinous lining. The intestine is a large tube extending from the gizzard to the anus. The intestine upto the 14 th segment is narrow and the remaining part is sacculated. The dorsal wall of the intestine is folded into the cavity as the typhlosole. This fold contains blood vessels.
It increases the absorptive area of the intestine. The inner epithelium consits of columnar cells and glandular cells. The earthworm feeds on decaying organic materials contained in the soil. It takes the soil into its alimentary canal where the organic matter is digested and absorbed. The unwanted soil particles are sent out as worm casts.
Circulatory System: In the body of earthworm there are two median longitudinal vessels. The dorsal longitudinal vessel runs above the alimentary canal. The ventral longitudinal vessel runs below the alimentary canal. The dorsal vessel is contractile and blood flows forwards in it. There are paired valves inside this vessel which prevent the backward flow of the blood.
The ventral vessel is non contractile and blood flows backwards in it. The ventral vessel has no valves. In the anterior part of the body the dorsal vessel is connected with the ventral vessel by eight pairs of commissural vessels or the lateral hearts lying in the segments 6 to These vessels run on either side of the alimentary canal and pump blood from the dorsal vessel to the ventral vessel.
The dorsal vessel receives blood from various organs in the body. The ventral vessel supplies blood to the various organs. Excretory System: Excretion is the process of elimination of metabolic waste products from the body. In earthworm, excretion is effected by minute paired tubes called nephridia. These are found, one pair, in each segment. A typical nephridium has an internal funnel like opening called the nephrostome. It is fully ciliated. The nephrostome is in one segment and the rest of the tube will be in the succeeding segment.
This tube has three distinct. The first part following the nephrostome is ciliated inside. This is called the ciliated region. The next part is wider and is thrown into coils.
This part has glands on its wall. It is called the glandular region. The last part has neither cilia nor glands. It is called the muscular region. This region opens outside by an aperture called the nephridiopore. The waste material is collected from the body cavity by the ciliated funnel. The ciliated region pushes the waste into the nephridium.
The glandular part extracts waste from the blood and add it on to the waste inside. Finally the waste goes out through the nephridiopore. In the South Indian earthworm, Megascolex, there are certain modifications. There are three types of nephridia in the megascolex. They are: Meganephridia, ii. Pharyngeal nephridia. Besides nephridia there are some special cells on the wall of the intestine called Chlorogogen cells.
They collect the waste and then drop down into the body cavity. These are then sent out through nephridia. The brain is formed of the supra pharyngeal ganglia.
It is a bilobed mass of nervous tissue situated on the dorsal wall of the pharynx in 3rd segment. The ganglia found below the pharynx in the 4th segments is called the subpharyngeal ganglia. The brain and the subpharyngeal ganglia are connected by a pair of circum pharyngeal connectives. They run one on each side of the pharynx. Thus a nerve ring is formed around the anterior region of the alimentary canal.
The double, solid ventral nerve cord runs backwards from the subpharyngeal ganglia, in the mid ventral line to the hind end of the body. The ventral nerve cord has segmental ganglion one in each segment. From the brain nerves are given off to the peristomium. From each ganglion of the ventral nerve cord, three pairs of nerves are given off to the body wall and other organs.
Receptors which are stimulated by the sense of touch tactile receptors , Chemical changes chemoreceptors and changes in temperature thermoreceptors are present in the body wall. These receptors are in the form of groups of slender columnar cells with short hairs projecting at the free end and connected with sensory fibres at the inner end. Receptors stimulated by changes in the intensity of light Photoreceptors are found on the dorsal surface of the body. Gustatory receptors sense of taste and olfactory receptors sense of smell are found in the buccal cavity.
Reproductive System: Both male and female reproductive organs are present in the same worm. Hence the earthworms are known as hermaphrodites. Since the sperms develop earlier than production of ova, self-fertilization is avoided. It is known as protandry. Male reproductive organs: The male sex organs are formed of two pairs of testes and a pair of vasa deferentia.
Testes are found in segments 10 and They are tufts of finger shaped processes attached to the anterior septa of segments 10 and There are two pairs of seminal versicles formed as outgrowths of the testicular segments. Further two pairs of seminal funnels called ciliary rosettes are situated in the same segment as the testes. The ciliated funnels of the same side are connected to a long tube called vas deferens.
The two vasa deferentia of both sides run backwards along the ventral body wall upto the 18th segment where they open to the exterior through the male gential aperture. Male genital apertures contain penial setae for copulation. A pair of prostate glands, each in the form of a much coiled tube are situated in segments 18 and The prostate glands open to the exterior along with the vas.
The secretion of the prostate glands help to arrange the sperms into bundles called spermatophores. Female reproductive organs. A pair of ovaries are found lying in segment They are attached to the anterior septum of the 13th segment.
Each ovary is a flat structure with a number of finger like processes. The ova are arranged in a linear order in the ovaries. There are a pair of oviducts. They open internally into the 13th segment and externally on the ventral surface of the 14th segment. Three pairs of spermathecae are present in segments 7, 8 and 9.
These external openings are situated in the intersegmental grooves of segments 6 and 7, 7 and 8, and 8 and 9. The spermatozoa received from another individual during copulation are stored in spermathecae.
During copulation the head ends of the two worms are directed in the opposite directions and the clitellum of one worm is opposite to the spermathecal segments of the other. The spermatozoa of one worm pass into the spermathecae of the other worms. The worms separate after the mutual exchange of spermatozoa.
Later the glandular cells of the clitellum secrete a thick fluid which hardens into a girdle surrounding the clitellum. Earthworm - Sperm transfer, storage and fertilization. The girdle is moved forward by the wriggling movements of the body. As the girdle is moved forwards it receives the ova and spermatozoa. The girdle containing the germ cells ova and sperms and the nutrient albuminous fluid is slipped off at the anterior end and it becomes a closed sac called the cocoon.
Fertilization and the development of the eggs into worms takes place within the cocoon. Young worms come out of the cocoon after complete development. Type study - 3. Birds are easily recongnised group of vertebrates. In birds every part of the body is modified to suit their aerial mode of life.
Birds possess feathers, beak and feet modified in relation to their aerial life. The Pigeons are flying birds carinate. They are known both as wild and domesticated forms. The Pigeons are seen both in tropical and temperate. About 10 species of Pigeons are found in India. The pigeons fly in flocks and roost together.
The domestic pigeons have many varieties, namely panter, fantail and tumblers. They differ in size, colouration and feather arrangement. All of them are, however, descendants of the rock pigeon-columba livia. The Body is spindle shaped. Their size varies from cm.
They are covered by coloured feathers leaving beak and a small portion of the hindlimbs. The body is divisible into head, neck, trunk and a small, conical tail. The head is round and drawn out anteriorly into a strong, hard, pointed beak. The mouth is a terminal wide gape, guarded by elongated upper and lower beaks. The beaks are covered with a horny sheath or rhampotheca. A swollen area of soft skin, the cere, surrounds the nostril.
It is present on each side of the upper beak. The eyes are large and guarded by upper and lower eyelids and a transparent nictitating membrane. A pair of ear openings are situated at a short distance behind the eyes. Each opening leads into a short external auditory meatus, ending in the tympanic membrane forming the ear drum. The neck is long and mobile. It helps in the movement of the head in various directions. The trunk is compact, heavy and bears a pair of wings and a pair of legs.
The cloacal aperture is at its hind end on the lower surface. Projecting behind the cloacal aperture is the tail. Above the tail is a knob on which opens an oil gland or preen gland or uropygeal gland. It secretes a fluid used for preening the feathers. The forelimbs as modified wings are located in the anterior region of the trunk.
The limbs are of the pentadactyl type. The wing has three typical divisions as - the upper arm, forearm and hand. The hand has three imperfectly marked digits.
While the pigeon is at rest the three divisions of the wing are bent upon one another in the form of the letter Z. During flight the wings are straightened and extended. A fold of skin the alar membrane or prepatagium, stretches between the upper and forearm along the anterior border of the limb. A smaller fold known as postpatagium is present between the trunk and upperarm.
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The great Swedish naturalist Linnaeus Caroli Linnaei - exerted an important influence on further advancement in taxonomy. Hence he has been called the father of taxonomy. In he published his famous book, systema naturae. He first introduced the hierarchic system, both in animal and plant kingdoms.
He followed four categories namely class , order , genus , species for the animal world. His greatest contribution to taxonomy was the use of binomial nomenclature for all species of animals and plants. Lamarck - made the first attempt to improve Linnaen system. He arranged animals according to evolution. He displayed the groups of animals in the form of a branching tree. It was the beginning of the use of phylogeny in systematics.
Cuvier - insisted that extinct fossil forms should be included in the table of classification. He divided animals into four branches.
They are Vertebrata -fishes to mammals, Mollusca- mollusca and barnacles, Articulata- annelids, crustaceans, insects and spiders and Radiata - echinoderms, nematodes and coelenterates.
The new evolutionary concept of Darwin had an immediate acceptance among biologists. Due to the influence of evolutionary ideas, taxonomy was studied as an important evidence in favour of evolution.
The taxonomists were encouraged to learn that evolution theory of Darwin gave meaning to their classifying activities.