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Core Experiments: Unit - 2 In this unit you will study the museum specimen or slides of examples belonging to different groups such as bacteria, fungi, plants and animals. While doing this, you have to identify, classify and write comments on the specimens you observe. According to the syllabus the slides and specimens will be available in the school laboratory but if you get the opportunity to see them live then observe carefully. If you see plant specimens during your trip then collect them and prepare them slides and specimens. In the following pages every slide / specimen given in the syllabus have been described and some additional easily available examples have been given. Under ferns your syllabus suggests selaginella but Pteris and Dryopteris are more easily available. Among the animals instead of snails, the pond snail Pila is more easily available. Among the birds the common house sparrow instead of pigeon, common house lizard, among the reptiles and among the mammals the house rat other than rabbit have also been described. Try to observe the characteristics mentioned in the lab manual, draw labelled diagram and write comments on them. In the following pages every specimen has been classified and the identifying feature of every group has been given in brackets - pay more attention to these. 4. BACTERIA, FUNGI AND PLANTAE Comments: (i) Bacteria are very minute organisms. (Its diameter in less than 3 microns and size is 1 to 80 microns). They may be spherical rod shaped, spiral shaped, filament like and comma shaped. (ii) It’s cell is prokaryotic type that is nucleic acid are scattered in the protoplasm. The nucleus has no nuclear membranne. (iii) Some bacteria have flagella. (iv) The cell has a rigid cell wall. The cell wall is made up of peptidoglycane and not like plant cell which is made of cellulose. (v) It has no plastids. (vi) Asexual reproduction is by amitosis. (vii) They can normally survive in the temperature ranging from 75-800C to 1900C. 1. BACTERIA Identification and Classification : Bacteria are ultramicroscopic monerans. The body is a prokaryotic cell. Kingdom - Monera (Prokaryotic) Phylum - Schizomycetes (all type of bacteria). Class - Eubacteria (cell is surrounded by cell wall and has not true nucleus). 2. OSCILLATORIA Identification and Classification: These are filamentous blue green algae. These are simple structured monerans. Their classification is as follows : Fig. 4.1 Typical Bacterium (Rod shaped) 8 CORE EXPERIMENTS Kingdom - Monera (Prokaryotic) Division - Cyanophyta (Blue-green algae) Genus - Oscillatoria (filamentous blue green algae). 9 Kingdom - Plantae (Eukayotic, multi-cellular algae). Division - Chlorophyta (Green AlgaeChlorophyll a and b present). Genus - Spirogyra (Rectangular cells having spiral chloroplast). Fig. 4.2 Oscillatoria (A) A few filaments. (b) Magnified view of a filament. Comments: (i) These are commonly found on the surface of moist walls, pots, water falls, ponds, lakes etc. These are also found in the stagnant water of ponds where the other algae are not found. (ii) The body is cylindrical, filamentous and unbranched. The filaments have no sheath like other blue-green algae. (iii) The upper part of the filament is generally straight but can also be round or bent (like sickle or screw). (iv) Oscillatoria filaments can move, oscillate, twist or rotate on one place. (v) There are vacuoles in the cytoplasm. (vi) The asexual reproduction is by separation of filament or by formation of hermogonia. 3. SPIROGYRA Identification and Classification: It is found in fresh water of lakes and is filamentous green algae. Its rectangular cell contains spiral ribbon shaped chloroplast which is the main distinguishing character. The classification is as follows: Fig. 4.3 Filaments of Spirogyra Comments: (i) It is found as a filament floating in the ponds, springs and between scum of slow flowing rivers. (ii) Each filament is unbranched, smooth and green in colour. Length of filaments can reach upto few inches. (iii) The cells of teh filaments are rectangular and are linear. (iv) In the centre of each cell is a nucleus and cytoplasm is present as radiating stripes. Therefore, vacuoles are divided into compartments. (v) Green chloroplast is flat and spirally coiled like a ribbon. (vi) Only sexual reproduction takes place, which is completed by lateral conjugation or scalariform conjugation methods. Sometimes due to breaking of filaments asexual reproduction also takes place. (vii) They synthesise their food by photosynthesis that is why they are known as autotrophic. 10 PRACTICAL BIOLOGY - XI 4. RHIZOPUS (The Bread mould) Identification and Classification: This black coloured fungus is usually found on moist bread, decaying vegetables, fruits, jelly etc. This is similar to pinfungus that is Mucor. The classification is as follows: Kingdom - Fungi (Without chlorophyll, eukaryotic, multinucleated cell, hetrotrophic) Division - Zygomycota (Sexual reproduction by conjugation hence also known as conjugation fungi). Genus - Rhizopus (Blackish filamentous, branched fungi which grows on bread). (b) Roots like rhizoids - which penetrate into the food materials to digest and absorb it, (c) Sporangiophores - which grow erect on the bread surface. Each hyphae bears sporangium at the tip. When these sporangia burst, large number of spores are spread which grow when they get favourable conditions. (iii) The sexual reproduction takes, place like Spirogyra by conjugation method. 5. MUSHROOM Identification and Classification: Commonly known as Toad’s stool. It’s shape is like an umbrella and grows on wood and decaying matters. the classification is as follows: Kingdom - Fungi (Chlorophyll absent, eukaryotic, multinucleate, hetrotrophic). Division - Basidiomycota (Reproduction by club shaped basidia). Genus - Agaricus Fig. 4.4 Rhizopus Comments: (i) (ii) (a) It grows on bread, jelly, fruits etc. Blackish in colour and that is why it is known as Black Bread Mould. The body of the fungus is formed by many white or ash coloured mycellia. Number of fine branches (branched structures) come out of the mycelium, called hyphae they are of 3 types On the surface of the bread net like hyphae (stolon), Fig. 4.5 A. Mushroom (Agaricus) Comments: (i) (ii) Mushrooms are macroscopic, fleshy, umbrella like forms. They grown on rotten logs of wood, tree trunks, decaying organic matter rich in organic compounds. CORE EXPERIMENTS (iii) Several varieties of this are used as food. It is rich in minerals and believed as nutritive food. Some of the species are poisonous also. (iv) Some portion of the mushroom body is embeded in the ground or substratum on which it grows. Inside there are plenty of branched hyphae. Above the ground a stalk is visible which has cap like expanded umbrella known as pileus. The lower side of the cap has thin vertical plate shaped structures called gills. (v) The stalk and the umbrella are fleshy and are interwoven with each other by number of hyphae. On the top of the gills of umbrella reproductive organ are present known as basidia from which basidiospores are formed. These are clubshaped structures. That is why it is known as Club Fungi. (vi) The mushrooms, used for eating purpose are nowadays grown in large quantities. 6. YEAST Identification and Classification: Yeast are microscopic fungi. The Classification is as follows: Kingdom- Fungi (Chlorophyll absent, eukaryotic, multinuclear cell, saprophytic). Division- Ascomycota (Spores produced in ascus). Genus - Saccharomyces (Unicellular which grow in sugar medium). 11 Comments: (i) This fungus is usually found in sugar containing substances like date palm fluid, soil of grape orchards and grapes. (ii) It is unicellular and microscopic in size. (iii) The cell is oval in shape with specific vacuoles present in nucleus. (iv) Cytoplasm consists of stored food vacuoles. (v) Cell wall is distinct, rigid and made up of chitin. (vi) Asexual reproduction takes place by budding and ascus formation. (vii) In some species sexual reproduction takes place by conjugation. (viii) It has the capacity to convert carbohydrates into alcohol. This action is known as fermentation. (ix) The spongyness of bread is due to the release of carbondioxide by yeast. (x) Due to enormous vitamin contents yeast is also good as medicine. 7. LIVER WORT Identification and Classification: Commonly found growing on moist and shady walls, these flat ribbon shaped green plants are seen to cover the whole ground. They hold the soil with the help of rhizoids. It resembles the liver of animals and hence it is called liver wort. It has many genera like Riccia, Marchantia etc. The classification is as follows : Kingdom- Plantae (Green, multicellular, autotrophic). Fig. 4.6 Yeast Cell Division- Bryophyta (Vascular tissue is absent, gametophytic stage is present). 12 Class PRACTICAL BIOLOGY - XI - Hepaticeae (Prostrate thalloid body). Genus - Riccia Comments: Identification and Classification: In the rainy season the moss plants can be seen like green carpets on the moist walls and grounds. Classification is as follows: Kingdom - Plantae (Green, multicellular, autotrophic). Division - Byrophyta (Vascular tissue is absent, gametophytic stage is dominant). Class - Musci (erect like the flowering plants). Fig. 4.7 Riccia (i) (ii) (iii) (iv) (v) (vi) (vii) They are simple plants having flat thalloid body (Ribbon shaped). The thallus is divided into two branches from each side and therefore the thallus is rosette shaped. It is found on moist soil and in humid atmosphere. On the lower surface of the thallus rhizoids are present by the help of which it fixes itself to the soil. True roots are absent. Vasular tissue xylem and phloem are absent. Dorsally the thallus has number of cup like outgrowths called gemmae. Vegatative propagation takes place with the help of these gemae. Main plant is gametophyte, therefore it develops male reproductive organ antheridium and female reproductive organ archegonium. Male and female gametes are produced for sexual reproduction. Oospores develop into sporophyte. Asexual reproduction is by producing spores in sporophyte. Spore produces haploid gametophyte. In this way alternation of generations takes place. 8. MOSS (FUNARIA) Genus - Funaria Comments: Fig. 4.8 Moss Plant (i) Funaria is commonly found on moist tree barks, moist walls or other moist places. (ii) It is about 2 to 3 cms. tall plant. Main plant is in gametophytic stage. From the apex of the main plant sporophyte is developed. (iii) Gametophyte of moss remains attached to the ground with the help of rhizoids. The stem is like an axis and may be branched or unbranched. It bears flat, green spirally arranged leaves, which are abundant towards apex. True root or stem is absent. (iv) The sporophyte consists of a foot, seta and capsule. CORE EXPERIMENTS (v) (vi) Capsule is covered by operculum. Spores develop in the capsule. Gametophyte develops from spores. Like Riccia they also show regular alternation of generations in their life cycle. 9. FERN Identification and Classification: The fern plant grows in the cool moist place having pinnately compound leaves. They are grown as ornamental plants in the garden. The classification is as follows: Kingdom - Plantae (Green, multicellular, autotrophic). Division - Tracheophyta (Vasular tissue present). Subdivision- Pteriodophyta (Plant is divided into true root, stem & leaves). Genus - Dryopteris 13 can be grown in pots. (ii) The plant is in sporophytic stage. (iii) Plant is distinguished into root, stem and leaves. Some type of ferns are prostate but majority are erect like flowering plants. (iv) Stem is underground roots are adventitious. Stem grows parallel to the ground in the form of rhizome which bears leaf on it. (v) The leaves are pinnately compound. Each leaf has a rigid, scaly petiole which is prolonged to form rachis that bears two rows of leaflets called pinnae. (vi) The underside of leaf pinnae has sporangia by which spores are produced through asexual reproduction. (vii) Spores grow and develop heart shaped gametophyte which by sexual reproduction produce sporophtye. Hence fern plants also show alteration of generations. Comments: 10. SELAGINELLA Identification and classification : This is found in the plains and hithy regions where the climate is humid. Quite commonly grown in gardens and plant nurseries. Its classification is as follows : Kingdom - Plantae (green, multicellur, autotrophic) Division - Tracheophyta (Vascular tissues and embryo present) Sub division -Pteriophyta (plants divided into true roots, stem, leaves) Genus - Selaginella Comments : Fig. 4.9 Fern Plant (Dryopteris) (i) Fern plants commonly grow in cool, moist, high altitude places. In tropical climates it (1) Found in cold, humid places like other ferns. (2) Plant is a sporophyte. 14 PRACTICAL BIOLOGY - XI Identification and Classification: spike leaf Pinus is a tall, evergreen, cone shaped tree found mostly on high altitudes and cool mountain areas. Some species of Pinus are also grown in gardens and pots. Classification is as follows: Kingdom - Plantae (Green, multicellular, autotrophic). rhizophore Fig. 2.1 Selaginella (3) Plant body differentiated into stem, root and leaves. It spreads on walls or the soil in the form of a creeper. (4) The stem is cylindrical with four rows of leaves. Two rows of small leaves are situated on the upper surface and two rows of bigger leaves are present on the two sides. At the base of the stem scaly ligules are present. (5) Root like structures arise from the stem called rhizophores. (6) Plant bears two types of sporophylls which are situated in cones on unisexual or bisexual plants. On the same cone or on two different cones, the two types of sporophylls are found. (7) The spores fall four the sporophyte and give rise to male and female gametophyle. The male and female gametophytes reproduce by sexual reproduction to give rise to the sporophyte. 11. PINUS Division - Tracheophyta (Vasular tissue present). Subdivision- Spermopsida (Flowering and seed producing). Class - Gymnospermae (naked seed plants) Genus - Pinus (needle shaped long leaf). Comments: Leaf Stem Cone Fig. 4.10 Pinus Tree (A portion) (i) The tall cone shaped pinus trees grow at the height of about 10,000 feet on the Eastern and Western Himalayan region. (ii) Pine tree can grow upto 125 feet & the stem upto 8-9 feet in diameter. (iii) The tap root is well developed and CORE EXPERIMENTS (iv) (v) (vi) 15 number of branches emerge from the stem. The stem is covered by scales which separates out in the form of bark. Needle like leaves are present on the shoots. Kingdom - Plantae (Green, multicellular, autotrophic). There are two types of shoots - long shoots or the branches of unlimited growth and dwarf shoots or the branches of limited growth. Needle shaped leaves are present on the dwarf shoots. Scaly leaves are present on both types of shoots. Subdivision- Spermopsida (Flowering and seed bearing plant). The main plant shows sporophytic stage. It develops male and female cones by asexual reproduction. These are also known as male and female strobila. Male cones grow every year on the apex of each shoot in a group and are about 1 inch long. Division - Tracheophyta (Vasular tissue present). Class - Angiosperm (fruits enclosing seeds) Subclass - Monocotyledoneae (monocot plants) Genus - Allium Species - cepa Comments: (i) This monocot plant grows underground. (ii) The stem is modified into a bulb. Food is (vii) Female cone grows singly or in a group of 2-3 and is about 2 to 4 inches long. (viii) Gametes develop from male and female cones. Embryos are formed by sexual reproduction. Fruits are not formed, hence seed are naked and exposed. Therefore, plants are known as “Gymnosperm”. (ix) Pine tree is of much economical importance. 12. A MONOCOT PLANT ONION Fig. 4.11 Onion Plant Identification and Classification: Monocot plants can be easily recongnised by adventitious roots and long narrow leaves. palm tree, lilly plants, onion, garlic, wheat, maize, banana etc. are monocot plants ie. they have a single cotyledon in their seeds. As an example of a monocot plant, onion is described below. The classification is: stored in the bulb. An ariel stem is developed from the bulb which is called scape. A bunch of flower grows on this scape. Bulb is underground. (iii) From the base of the bulb (stem) number of adventitious roots are developed. (iv) From the apex of the bulb number of 16 PRACTICAL BIOLOGY - XI elongated cauline leaves develop. The base of the leaves form fleshy part of the bulb. Comments: (i) Mustard plant is grown as rabi crop. (v) It has no branches. (ii) (vi) No leaves are present on the scape. On the apex of the scape a bunch of flowers make an umbellate type of inflorescence. The root system, stem and leaves are well developed. (vii) Each flower has two circles of 3 white petals. Female reproductive organs containing ovary, style and stigma are present inside the flower. 6 stamens are present as male reproductive organs. The ovary has 3 ovules. (viii) It is used as a vegetable and has many medicinal properties, due to which it is a economically very important plant. 13. DICOT PLANT - MUSTARD Identification and Classification: The trees and plants found in the gardens, on the road sides, fields, mountains, bushes and most of the flowering plants are mostly dicots. The plants with seeds which have 2 cotyledons are known as dicotyledens. gram, pea, mustard, ground nut, neem, mango, guava, pepal, teak etc. are included in the dicot category. Mustard plant is described here a typical dicot plant. The classification of a dicotyledon plant is: Kingdom - Plantae (Green, multicellular, autotrophic). Division - Tracheophyta (Vasular tissue present). Subdivision- Spermopsida (Flowering and seed bearing). Class - Angiospermae Subclass - Dicotyledonae (Dicot plant) Genus - Brassica Species - juncea Fig. 4.12 Mustard Plant (iii) It contains main root that bears branches on lateral sides - tap root system. (iv) Stem is long, erect, solid, tubular and green in colour. On the lower parts of the stem the leaves are arranged in a linear fashion. On the upper region flowers and fruits are also arranged in the same way. (v) Leaves have petiole with narrow base and are broader towards the apex. Leafmargins are incised. (vi) On the upper end of the stem fruits are present as pods. The pods contain yellow mustard seeds. Seeds are spread when the pod bursts. (vii) Flowers are yellow and attractive. It has four sepals and four petals. In the centre of flower, a long pod like ovary, small CORE EXPERIMENTS 17 styple and a round top known as stigma is present. 6 stamens attached to the thalamus surround the ovary. Pollen grains are present on the apex of the stamen. (viii) Edible oil is obtained from the seed, hence it is a commercially important plant. 14. LICHENS Lichen plants grow on moist stones and barks of trees and appear in patches. It is a group which represents symbiotic association between alga and fungus. Usually symbiotic association is between a fungus from Ascomycota or Basidiomycota Fig. 4.13 Different types of Lichens divisions and chlorophyta (green algae) or (A) Parmellia (B) Cladonea (C) Usnea mycophyta (Blue green algae). Hence the classification of lichens is done according to the type of fungus present. Hence, these can be ascolichen or basidiolichen. In their symbiotic associationship algal filaments perform lichens are the first to appear. The soil formation by these helps in growing moss and fern plants in that area. photosynthesis and fungus provide protection to Some lichen are used for feeding animals. algae. If blue green algae are present then these Some have medicinal value. the litmus used for perform nitrogen fixation also. finding the pH value is obtained from lichens. Lichens can be or various shapes (i) Broad & Flat - Crustose Lichen (ii) Leaf like - Foliose Lichen (iii) Branched - Fruiticose Lichen In a place where no vegetation grows, Many varieties of litmus paper, aromate substances and tannings are also prepared from lichen. Main examples of lichens are : (i) Granular Lichen, Graphis (ii) Beared like lichen, Parmellia (iii) Bread like lichen, Usnea 18 PRACTICAL BIOLOGY - XI 5. ANIMAL FORMS 1. AMOEBA Identification and Classification : It is a microscopic, unicellular organism. Its body is infact a eukaryotic cell. They move slowly by forming temporary structures called pseudopodia. Kingdom - Animalia (Eukaryotic cellular organism) Phylum - Protozoa microscopic, nutrition) (unicellular holozoic Class - Rhizopoda (Locomotion by pseudopodia) Genus - Amoeba Species - proteus (vi) There is a prominent nucleus and a contractile vacuole. Some food vacuoles present as stored food. (vii) It exhibits holozoic nutrition. (viii) Reproduces only by asexual methods binary or multiple fission. (ix) When the pond water dries, they are surrounded by a cyst for protection. This is called as encystment. When the favourable conditions are resumed they come out of teh cyst. Amoebae do not die of a natural death because they go on dividing and forming new amoebae. Therefore, it is considered as an immortal organism. Comments: 2. SPONGE Identification and classification : It is a sponge of simple structures. Its classification is as follows : Kingdom - Animalia (multicellur, haterotrophic) Phylum - Porifera (pores present, no tissues) Class - Calcarea (calcareous spicules present) Found in ponds, ditches, lakes etc. Its proteus species is very common. Genus - Leucosolenia Live an independent life. 1. Found on sea shores sticking to objects. 2. They live in colonies. 3. Body cylindrical. At the base of the colony branches join each other to form a network like structure. 4. At the distal end of the branch large osculum present. Fig. 5.1 Amoeba (i) (ii) (iii) Irregular in shape. Cell itself is its body. (iv) Protoplasm is distinguished into an outer ectoplasm and an inner endoplasm. Protoplasm is seen protruding in different directions in the form of pseudopodia. (v) Locomotion is done by putting forth and withdrawing these pseudopodia. Comments : CORE EXPERIMENTS 19 osculum Mouth Hypostome ostia Teutacle Bud base Body substratum Fig. 5.2 Hydra Fig. 2.2 Leucosolenia ( A sponge) 5. The body cavity is called spongocoel. 6. The body surface has numerous ostia. Water enters the body constantly through the ostia and leaves the body through the osculum. This forms a special kind of canal system. 7. It is through the water entering the canal system, nutrition, respiration and excretion are carried out. 8. Reproduction both by asexual and sexual methods. 9. They show great power of regeneration. 3. HYDRA Identification and Classification: Kingdom - Animalia (multicellular, heterotrophic) Phylum - Coelenterata gastrovascular diploblastic) (hollow cavity, Class - Hydrozoa (Simple body cavity) Genus - Hydra Comments: (i) It is found in ponds, pools or ditches filled with water and is attached to some object. Sometimes it moves also. (ii) Body is cylindrical & elastic. (iii) The distal end is free and has a small conical projection called hypostome having at star shaped mouth opening. (iv) Surrounding the mouth are 6-10 tentacles. The tentacles possess nematocysts. (v) The mature Hydra may have a bud near the base and gonads in the middle of the body. (vi) With the help of tentacles and nematocysts it catches the prey. (vii) It reproduces by asexual and sexual methods. In the asexual reproduction the buds come out of the body and move away by separating themselves from the parent body. (viii) It has a great power of regeneration. (ix) It exhibits symbiosis with algae present in the water. 4. LIVER FLUKE (Fasciola) Identification and Classification: Kingdom - Animalia (Multicellular, Helerotrophic) 20 PRACTICAL BIOLOGY - XI Phylum - Platyhelminthes (Triploblastic, acoelomate, flat worms) Class - Trematoda (Unsegmented flatted parasites.) Genus - Fasciola (Leaf shaped, endopara sites in liver) of the body bears an excretory pore. (vii) Its colour is light rosy and it is semi transparent. Therefore, digestive canal and vitelline glands can be seen from outside. 5. ASCARIS Identification and Classification: It is thead like intestinal parasite. It is multicellular, bilaterally symmetrical and pseudocoelomete. Kingdom - Animalia (Multicellular, heterotrophic) Phylum - Nemathelminthes (Triploblastic, pseudocoelomate) Class - Nematoda (Round worm, unsegmented parasites). Genus - Ascaris Fig. 5.3 Fasciola hepatica Species - hepatica. Comments: (i) Dorsoventrally flattened and leaf like body hence called ‘flukes’. (ii) It is an endoparasite in the bile passage of vertebrates like sheep, cow, pig etc., It completes the life cycle in two hosts therfore it is knows as digenetic parasits. (iii) Its hepatica species makes sheep its primary host and a Gastropod mollusce as secondary host. (iv) These are 1.8 cms to 3 cms long and the maximum width at the centre is 0.5 to 1.5 cms. Species (v) Comments: Outer covering is thick and smooth. (vi) A mouth opening present at the anterior end which is surrounded by an oral suckers a little below the mouth. On the ventral side, close to the acetabulum a gonopore is present. The posterior end Fig. 5.4 (A) Male and (B) Female Ascaris - lumbricoides. (i) It is an intestinal parasite of human beings. The most common species is lumbricoides. (ii) The body is round slender and tapering at both the ends. When it is alive the colour is CORE EXPERIMENTS 21 light rosy or yellowish white. (iii) The animal shows sexual dimorphism with separate male and female individuals. (iv) Males are smaller in size than the females. Male is 15 to 30 cms. in length & 2.4 cms in breadth. Female is 20 to 50 cms in length and 3 to 6 cms in breadth. (v) Posterior end of the male is curved having cloacal aperture and penial setae. (vi) Female Ascaris has genital aperture at 1/3 of the anterior ends. Class - Hirudinea (Definate number of body segments, suckers on both ends, setae absent) Genus - Hirudo (Ectoparasite vertebrates) Species - medicinalis of (vii) The male and female have 2 lateral lines from one end of the body to another. In addition to this there is one white line (mid dorsal line) on the dorsal side. Similarly, there is a mid ventral line on the ventral side. (viii) It is a harmful parasite for man. It is commonly found in children. To reach from one host to another, it passes through the intestine and various other organs and thus damages them. In the mature stage it blocks the intestine. The presence of this causes stomachache, indigestion, loss of apetite, diarrhoea, appendicitis, anaemia and the host becomes very weak. Fig. 5.5 Leech Comments: (i) The most common species is H. medicinalis, which is found floating on water in ponds, swamps and is an ectoparasite on buffalow, fish, frog, human beings and other animals. It is named medicinalis, because in the olden days it was used to suck the blood from injuries. (ii) It sucks the blood of its host. (ix) The larva reaches another host through contaminated water by faecal matter. 6. LEECH (Hirudo) Identification and Classification: The fresh water ectoparasite feeding on the blood of vertebrates. The segmented, elongated and flattened organism is classified as follows: Kingdom - Animalia (Multicellular, hetrotrophic) Phylum - Annelida Coelomate) (Segmented, (iii) It is 10 cms long but after sucking the blood. it measures up to 20 to 30 cms. (iv) They are yellowish brown organisms and are flattened dorsoventrally. The body is divided into 33 true segments. It is broad at the posterior end. The body segments are sub divided into 2-5 subsegments. Therefore, it is difficult to count the segments. 22 (v) (vi) PRACTICAL BIOLOGY - XI There is one sucker each on posterior and anterior end. The anterior sucker is round and is on the ventral surface. In the centre of this is mouth opening. The porterior sucker is large, round and is like a disc. On the base of posterior sucker, anus opens dorsally. Clitellum Genital papillac They are hermaphrodite. There is a made genital pore in the 10th segment and a female genital pore in the 11th segment. 7. EARTHWORM Identification and Classification: Earthworm is a segmented animal. It has a prominent band like structure, clitellum in the anterior part. The integument is provided with setae. Kingdom- Animalia (multicellular, heterotrophic) Phylum - Annelida (segmented, eucoelomate, triploblastic) Class - Oligochaeta (setae for locomotion) Division- Ascomycota (Spores produced in ascus). Genus - Pheretima (Earthworm) Species - posthuma Comments: (i) It burrows hole in the earth and that is why it is known as Earthworm. (ii) The Indian species posthuma is brown coloured. (iii) On the top of the burrows excreta is deposited in the form of pellets. The presence of pellets indicates its presence in the soil. (iv) It is elongagted, cylindrical and segmented. There are about 100-125 segments. (v) In the first segment lies the mouth and in the last segment lies the anus. Fig. 5.6 Fern Plant (Dryopteris) (vi) There is a prominent circular band known as clitellum. Which covers three segments viz 14th, 15th and 16th. (vii) Each segment has a ring of chitinous setae for locomotion. (viii) A single female genital aperture is present ventrally in the 14th segment, and paired male genital apertures are present on the ventral surface of the 18th segment. In the 17th and 19th segments, the genital or copulatory papillae are located. (ix) It is a hermaphrodite animal. Cocoons are produced by sexual reproduction, from which minute young earthworms hatch out. (x) It has immense economic value, It makes soil fertile and therefore it is also known as “Farmer’s friend.” 8. PRAWN (PALAEMON) Identification and Classification: It is found in rivers and ponds. Its body is curved in the abdominal region. The cephalothorax is covered by an exoskeleton, called carapace. They CORE EXPERIMENTS 23 are jointed legged animals. with 8 segments of thorax) and a large laterally compressed abdomen (6 segments). Kingdom- Animalia (Multicellular, heterophic). Phylum - Arthropoda (Jointed legs, chitinous ex-oskeleton) Class - Crustacea (5 pairs of walking legs, body divided into cephalothorax and abdomen.) Genus - Palaemon. Comments: (i) (vi) The thorax has got eight pairs of appendages, out of these five pairs are walking legs. The appendage of abdomen are used for swimming. (vii) They exhibit sexual dimorphism i.e., males and females can be identified by some external features. The second pair of legs in males are comparatively longer and more powerful then in females. During breeding season egg mass can be seen on ventral side of females at the base of legs. The base of the third pair of legs in females have female reproductive pores. The males have male reproductive openings on the base of the 5th pair of legs. It is found in ponds, waterfalls, water pools, rivers and lakes. It is nocturnal in nature, (viii) In the lakes they are reared for commercial production. Fig. 5.7 Palaemon during the day time it hides in the deeper layers of the lake. (ii) (iii) It is omnivorus. It feeds on microorganisms, algae and decaying matter present in the water. It is a long and cylindrical, curved at the abdomen and is coma shaped, it is compressed on the lateral sides. (iv) The body is divided into cephalothorax and abdomen. The cephalothorax is covered by a chitinous exoskeleton called carapace. 7 pairs of the gills can be seen by lifting the carapace. (v) The head bears two pairs of antennae, a pair of compound eyes and other appendages. Its body is divided into a cephalothorax (5 segments of head fused CRAB Identification and Classification: This is a well known amphibious animal which can live in and out of water for a long period. It is characters are just like prawn. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Arthropoda (Jointed legs, chitinous covering) Class - Crustacea (5 pairs of walking legs, Body divided into cephalothorax and abdomen) Genus - Carcinus (Crab) Comments: (i) It is well known crustacian arthropod. It can live in the water and outside without any difficulty. The various species can survive in the fresh and marine water. 24 PRACTICAL BIOLOGY - XI Order three pairs of walking legs and body divided into head, thorax and abdomen) - Lepidoptera Genus - Bombyx Species - mori Comments: (i) Fig. 5.8 Crab (ii) The body is dorsoventrally compressed and circular. (iii) The body is divided into cephalothorax & abdomen. The abdomen is reduced and is visible only from the ventral surface. The cephalothorax is broader than longer. Its locomotion is by 5 pairs of thoracic jointed legs which are clawed. (iv) Antennae are small. It has a pair of compound eyes near the antennae. (v) The male abdominal part comparatively narrow than female. Fig. 5.9 Silkworm is (vi) There are less appendages in the abdominal region. In the male 2 pairs and in female 4 pairs of appendages are present. is reared in most of the silk producing centres is scientifically known as Bombyx mori. (ii) (vii) For non vegetarians it is the food of choice. 9. SILKMOTH Identification and Classification: It is a medium sized cream coloured insect known as silkmoth. Kingdom - Animalia (Multicellular, heterotrophic) Phylum - Anthropoda (Jointed appendages, chitinous covering) Class - Insecta (Two pairs of wings, It is a medium sized insect, found on mulberry shrubs. The silkworm which The larvae of this work develops into pupa by wrapping itself in the silk thread which are called cocoons. The silk is obtained from cocoons and that is why these are known as silk worms. (iii) The body is divided into head, thorax and abdomen. The body and the wings are covered with minute scales. (iv) Head bears a pair of compound eyes and a pair of short and the thick antennae. The siphoning type of mouth parts are present for sucking liquid nectar. (v) The thorax is divided into three segments. The second & third segment of thorax bear two pairs of dull coloured wings. Three pairs of legs are present - one pair in each thoracic segment. CORE EXPERIMENTS (vi) The life cycle shows eggs, larva, pupa and adult stages. The adult female lays eggs on the mulberry leaves and grows. After the full growth, the larvae stops eating the leaves and start secreting a sticky substance from its salivary glands. This sticky substance becomes silk when comes in contact with air. The larvae develop into pupae under the cover of this silk thread around it. After sometime the developing small worm breaks the cocoon and young moth hatches out. After 3-4 days it becomes adult and female starts laying the eggs. (vii) The silkworms are reared at silk centres to get silk and before the insect gets out of the cocoon, the silk thread is separated and reeled. In this way this insect is of immense economical value. About 1000 to 1500 metres of silk thread can be obtained from a single cocoon. 10. HONEY BEE Identification and Classification: It is slightly bigger than the housefly and is a social insect. They form a bee hive and live in it and are easily recognised. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Anthropoda (Jointed appendages, chitinous covering) Class - Insecta (Two pairs of wings, three pairs of walking appendages and body divided into head, thorax and abdomen). Genus - Apis Species - indica Comments: (i) The Indian species is scientifically known 25 as Apis indica. The larger variety is known (A) Worker (B) Queen (C) Male Fig. 2.25 Honeybee as Apis dorsata, the smaller variety is known as Apis florae. (ii) It is a social insect. They form hives and live in it. It is a colonial animal and the colony consists of queen, drones (males) and workers. (iii) The work is distributed among the members of the hives. The queen bee is largest of all and its work is only to lay eggs. The worker bees are sterile females and they make the hives and keep it neat and clean. The males are less in number. Their work is to copulagte with fertile female bees. (iv) The body character is just like another insects. It has 2 pairs of wings, three pairs, of legs, a pair of compound eyes and a pair of antennae. (v) The worker bee have pollen basket on hind legs and pollen brush is present on fore legs for collection of pollen grains. Wax glands are present for the manufacture of wax. The mouth parts are suitable to suck nectar from flowers and give shape to wax. (vi) Honey and wax are two main important substances obtained from honeybee. These are economically very valuable. (vii) Honeybee rearing centres - the apiaries are established to obtain honey and wax commercially. 26 PRACTICAL BIOLOGY - XI bears two pairs of tentacles. The posterior pair bears a pair of eyes. 11. SNAIL Identification and Classification: Slow moving soft bodies snail is usually found in the gardens and lawns. It is classified as under Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Mollusca (Soft bodied, shelled) Class - Gastropoda (spirally coiled shell or without a shell) Genus - Helix and Pila (iii) (iv) On the ventral surface of the head mouth is present. On the right side of the shell an opening is present which is used for breathing. (v) Comments: (i) Helix can be seen creeping slowely in the gardens, lawns and moist earth. Other than this snails found on the earth, snails are also Fig. 2.26 It is herbivorous. It feeds on leaves, buds, fruits and destroys plants. They are hermaphrodite. In the rainy season they lay eggs and cover them. Young snails come out of the eggs in about a month. (vi) In the foreign countries some species are also used as food. PILA (i) It is found in ponds, rice fields, lakes, rivers and swamp places. Is nocturnal in habit. (ii) It is herbivorous. It eats the vegetation with great speed. (iii) The whole body lies in the shell. 6-1/2 coils are present in the shell. On the base there is an operculum by which the base can be closed. (iv) According to the need when it opens the operculum head, eyes and tentacles can be seen. Fig. 2.27 Fig. 2.26 Helix Fig. 2.27 Pila found in the ponds, rivers, swamps, and rice fields. Pila is a very commonly found snail. Helix (i) (ii) Helix are nocturnal and while creeping secrete a sticky chemical. This chemical facilitates in locomation. About 4 cms in size this soft organism has a coiled shell on the dorsal surface. The head protrudes from anterior part which 12. STARFISH Identification and Classification: This star shaped marine organism is actually not a fish. They can be observed lying in sand on sea shore or swimming in water with its five radiating arms. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Echinodermata (Radially symmetrical, spines on skin) CORE EXPERIMENTS Class - Asteroidea (Star shaped) Genus - Asterias Comments: (i) 27 helps in feeding, circulation and movement. (ix) It has a great power of regeneration. (x) The male and female individuals are separate. They reproduce sexually. The larval stage shows bilateral symmetry. It is a marine animal crawling on sandy shores under big stones embedded in the muddy water. 13. SHARK Identification and Classification: Shark fishes are found only in sea. They are of many shapes and sizes. Placoid scales are present all over the body. This shark is known as dogfish. Fig. 2.28 (ii) Starfish (A) Aboral view (B) Oral view It is carnivorous and eats crustaceans, mollusc and microorganisms. (iii) It’s body is compressed on the oro-aboral axis. (iv) There is a central disc from which five arms arise. Ventral surface of the disc is oral surface having mouth and the dorsal surface is known as aboral surface bearing anus. (v) Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord during embryonic stage, Pharyngeal gill slits and dorsal tubular nervous system) Class - Chondrichthyes (Cartilagenous fish, open gills) Genus - Scoliodon Comments: (i) This shark is popularly called as ‘Dog fish’ and is widely distributed. (ii) The body is spindle shaped and laterally Oral surface is kept towards the sea bottom and the aboral surface is away from it. On the ventral surface ambulaeral grooves are present in each arm containing tube feet for locomotion. (vi) The locomotion is by tube feet. (vii) The disc is slightly elevated at the aboral surface. On this surface spines and forceps shaped pedicillariae are present. The anus opening is slightly away from the disc centre. (viii) A distinct area called madreporite is present on the aboral surface leading to water vascular system of the animal. This system Fig. 2.29 Dogfish — A Shark compressed on both the ends. The head is dorsoventrally compressed. Semicircular mouth opening is present on ventral surface. Sharp teeth are present in the mouth. 28 PRACTICAL BIOLOGY - XI (iii) Placoid scales are present all over the body. Lateral line acts as a sense organ. (iv) On the lateral sides of the body, there are 5 pairs of gill slits. These are respiratory organs. (v) The body has paired and unpaired fins. The shark has two dorsal, two ventral, two pectoral, two pelvic and a caudal fin. (vi) Entire endoskeleton is made up of cartilage. Therefore dogfish has been kept in cartilaginous group of fishes. (vii) Cloacal aperture is present in between pelvic fins. On the inner surface of these pelvic fins claspers are present in the males for copulation. (viii) The female fish gives birth to young ones and thus it is a viviparons fish. 14. ROHU Identification and Classification: It is a fresh water fish found in rivers and ponds. The body is covered with scales. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord in embryonic stage and pharyngeal gill slits and tubular nervous system are present) Genus - Labeo Species - rohita Comments: (i) It is commonly found in the rivers, lakes, ponds of Northern India. It attains a length of 3-4 feet. (ii) It is a carnivorous fish which feeds on smaller fishes. (iii) the colour of the fish is greenish black. The scales are raddish in colour and that Fig. 2..30 Rohu is why it is known as Rohu. (iv) The head is slightly elevated and is compressed above eye. Two small barbels are present just above mouth on upper jaw. The gills are covered by operculum on both the sides from the hinder end of opercula. (vi) Like other fishes, these also have paired pelvic and pectoral fins. Besides these, one dorsal, one anal and a caudal fin is also present. (vii) They breed in rainy season. Female lays eggs which are settled at the bottom. Male fish drops sperms on these eggs. This is known as external fertilization. (viii) This fish has a great economic value. 15. FROG Identification and Classification: This is a well known amphibious animal which is found near the ponds & lakes. They jump into the water when ever they hear some noise or feel some danger. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord and pharyngeal gill slits persent only during embryonic stage and dorsal tubular nervous CORE EXPERIMENTS Class Genus Species system present throughout life) - Amphibia (Skin moist, amphibian.) - Rana - tigrina Comments: (i) Found in or around lakes and ponds. (ii) The skin is smooth and is covered by mucous. 29 (viii) The trunk region comprises of two pairs of limbs - fore limbs and hind limbs. (ix) The hind limb is much larger and consists of foot and toes. A membranous foot web is present in between the toes. (x) During breeding season the male frog can easily be recognised by its shining colour and while making sound (croaking) enlarged vocal sacs can be seen easily. (xi) A cloacal aperture is present towards the posterior end of the body. (xii) They breed during rainy season. The female lays eggs in a cluster in the water and male release the sperms over them. Hence external fertilization takes place. 16. TOAD Cloacal aperture Identification and Classification: Fig. 2.32 Frog (iii) The dorsal surface has greenish colour and the ventral surface has yellowish coloured skin. (iv) The body is boat shaped suitable for swimming. (v) The body is divided into head and thorax. There is no neck and tail. (vi) On the top of the head there are two bulging eyes. The head is pointed in front and is broad at the back. On the pointed snout there are two external nares and behind the eyes are tympanic membranes. In between the eyes is a brow spot. On opening of the mouth teeth can be seen in the upper jaw. The tongue is bifurcated at the anterior end. (vii) On the dorsal surface in the centre is a dorsal line. When the frog sits on the ground a hump can be seen. The toads are usually seen at night in the house courtyard or under the lamppost. The mouth is less pointed as compared to the frog. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord and pharyngeal gill slits present during embryonic development. Dorsal tubular nerve cord throughout life) Class - Amphibia (amphibian, wet skin.) Genus - Bufo Species - melanostictus Comments: (i) The toad which resembles frog in many 30 PRACTICAL BIOLOGY - XI Phylum Class Genus heterotrophic). - Chordata (Notochord and pharyngeal gill slits present during embryonic development. and dorsal tubular nerve chord throughout life) - Reptilia (skin dry and covered with horny scales, creepers) - Calotes. Fig. 2.33 Toad Comments: respect is found on the earth in moist places and never in water. (ii) They are nocturnal. They are not timid but are fearless. (iii) The lower jaw is not triangular but is semilunar in shape. (iv) The skin is dry and bulging in places. It has less mucous glands and more poison glands. (v) Eyes, nostrils, brow spot, tympanic membrane etc. are present similar to frog. But it has no teeth and the tongue is not bifurcated. (vi) The hind limbs are larger than the forelimbs but comparatively smaller than the frog. It has no foot web in the toes. Fig. 2.34 Calotes (i) Calotes is about 1 foot long, very active animal and found in bushes and on trees. (ii) It changes its colour just according to the place where is lives. The neck is reddish in colour and that is why it is also known as blood sucker. (iii) It’s skin is dry and is covered by scales. (iv) The body is divided into head, short neck, trunk and tail. The tail is long and cannot be regenerated. (v) The small head is pointed anteriorly. The head bears two nostrils and two eyes. Two external ear openings can be observed behind the eyes. (vii) There are no vocal sacs in the male. 16. LIZARD a. The garden Lizard - Calotes Identification and Classification: A little bigger than house lizards, this greenish brown lizard is a familiar animal. It’s colour changes in different seasons. At the same time it can change its colour according to the colour of the wall or tree. That is why it is also known as ‘girgit’. Kingdom - Animalia (Multicellular, (vi) The trunk is long and narrow. A pair of fore limbs are present anteriorly and a pair of hind limbs are present posteriorly. CORE EXPERIMENTS 31 The hind limbs are slightly bigger than the fore limbs. Both have five clawed digits. The scales of trunk region bulge out like spines. 6. Claws present on forelimbs. 7. It runs swiftly on walls and roofs. 8. Male lizard has femoral pores on the thighs. (vii) During breeding season and to frighten the enemy, the side of the head becomes red and the head turns yellow. Males are bigger in comparision to females. The colour of male is brighter than the female during the breeding season. The female lays shelled eggs. 9. It is not posionous as generally thought by man. 10. It is helpful to man as it feeds on insects and gets rid of them. 17. A BIRD (a) House Sparrow (b) Wall Lizard Comments : 1. Common house lizard found in old houses and dirty places. 2. It is nocturnal and feeds on insects near the light at night. 3. It is black, brown or grey coloured. Sometimes dark spots may be present. It is capable of changing body colour. 4. Body divided into head, trunk, and tail. A short neck in present between head and trunk. 5. Head is large and triangular. The house sparrow is a well known small bird. They live in the houses and verandah. Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord and pharyngeal gill slits seen during embryonic development and life long dorsal tubular nervous system present) Class - Aves (feathers on skin, toothless break, flying animals) Genus - Passer Species - domesticus Comments: Head Tympanum Identification and Classification: external eares eyes claws Forelimbs Trunk Tail Hind Limbs Fig. 2.35 Wall Lizard (Hamidactylus) Fig. 2.36 House Sparrow 32 (i) (ii) PRACTICAL BIOLOGY - XI This is a small (about 4-5 inch long) bird which lives in the houses with human beings. It feeds on grains and insects. Genus beak, flying animals) - Columba Its dorsal surface is slaty coloured brown with black stripes are present and the ventral surface is white in colour. (iii) The neck and thorax of the male have a black area. (iv) The body is divided into head, neck, trunk and tail. It is boat shapped. The anterior portion of the head has one beak without teeth. Thorax has two wings anteriorly and 2 limbs posteriorly. The tail is small but the feathers are large. The whole skin of the body is covered with feathers. The body is stream-lined and light due to the presence of air cavities in the bones. (v) Hind limbs have four digits provided with claws. Three digits are directed forwards and the fourth one is backwards. Wing feather Fig. 2.37 Pigeon Species Comments: (i) Pigeon is simple in nature. It is easily domesticated. The pigeon found in the old and large buildings is known as Blue rock pigeon. They usually live in groups. They are active in the day time and feed on grains. At night they rest on the ventilations, holes in the walls, deep wells and on hanging things. (ii) Pigeons are usually grey coloured. A shining band of green feathers is present on the neck, below which voilet colour is observed. Other than this combination, many other coloured pigeons are also seen. (vi) They make nests in the walls with straw etc. During breeding season the colour of male becomes bright yellowish. (b) Pigeon Identification and Classification: Like house sparrow this is also a well known bird. Pigeon lives in large Ware houses or palaces. It’s classification is also like house sparrow. Kingdom - Animalia (Multicellular, heterotrophic nutrution). Phylum Class - Chordata (Notochord and pharyngeal gill slits seen during embryonic development and life long dorsal tubular nervous system present) - Aves (feathers on skin, toothless - livia (iii) Like other birds, the skin of the pigeon has feathers, a toothless beak, a pair of wings, a pair of limbs and a tail. The body is narrow anteriorly and posteriorly but is broad at the centre. (iv) It forms nest of grass, straw etc. The female lays round white eggs twice a year. The nest is made on the ventilators of houses, wells or gaps in walls. (v) Pigeons can be trained. The domesticated CORE EXPERIMENTS 33 pigeon when made to fly comes back to the master’s house. 18. A Mammal (a) Rabbit nature. They run with high speed (30-40 kmph). (iii) They are about 1-1/2 feet long, the skin is covered thickly with hairs (fur). Hairs are muddy white in colour. Domestic rabbits are of many colours. (iv) The body is divided into head, neck, trunk and tail. Trunk is further divided into thorax and abdomen. (v) Snouted head is large. In between upper lip and nostrils hair like vibrissae are present. The upper lip has a gap and the teeth can be seen from this gap. These teeth are called incisors. On the head a pair of eyes and a pair of long ears are present which can be moved to any direction. Identification and Classification: Rabbit is medium sized very beautiful mammal. They live in the open fields by making burrows and tunnels. It can be domesticated also. Classification is as follows: Kingdom - Animalia (Multicellular, heterotrophic). Phylum - Chordata (Notochord and pharyngeal gill slits present in the embryonic stage. Dorsal tubular nervous system present.) Class - Mamalia (Skin with hairs. Presence of external ears and mammary glands) (vi) Neck is small. (vii) Between the thorax and abdomen 4-5 pairs of mammary glands are present on ventral surface. The nipples of glands are better developed in females. Young rabbits suck milk from these gland. (viii) The tail and anus is situated on the posterior end of the abdomen. Below the anus scrotal sacs and penis are present in the male. The female has a vulva below the anus. (ix) Hind limbs and fore limbs are present in the trunk. The fore limb has 5 clawed digits and the hind limb has 4 digits with claws. The palm and the soles have pads. The forelimbs are used for digging. Fig. 2.38 Rabbit Genus - Oryctolagus. Species - cuniculus Comments: (i) Rabbit is simple in nature and beautiful animal. They live in grassy grounds and live in hole or tunnels in a group. (ii) Rabbit is herbivorous and nocturnal in (x) Rabbits are economically important animals. Many articles are made out of its skin and the flesh is eaten. They destroy the crops. (b) House Rat 34 PRACTICAL BIOLOGY - XI Classification: Classification: Phylum - Chordata (Notochord present in some stage of life.) Phylum - Chordata (Notochord present in some stage of life.) Class - Mammalia (Body hair present mammary glands present) Class - Mammalia (skin covered with hair with mammary gland) Order - Rodentia (upper incisors - 1 pair well developed) Order - Insectivora (Insectivorous) Genus - Corcidura Genus - Rattus Comments: Comments: 1. Found in homes and food granaries. head external eye ear neck external ear Trunk head Trunk hair eye nostrits Tail snoul vibriosae Forelimb Hindlimb claws Tail Hind limb Fig. 2.39 Rattus Forelimb Fig. 2.40 Corcidura 1. It lives in burrows inside homes. 2. It is nocturnal and carnivorous. Feeds on small insects. 2. Body covered with brown hair. 3. Long hairy whiskers present called vibrissae. 3. Body is approximately 15 c.m long and brown in colour. 4. On the ventral surface of chest mammary glands present which are developed in the females. 4. Snout is long and pointed. 5. Eyes are very small and external ears not clearly visible. 5. Different types of teeth present. In total 16 teeth are present. 6. 6. Claws present on digits of both forelimbs and hind limbs. Forelimbs and hind limbs are small. Each of them have 5 digits with claws. They help in making burrows. 7. Tail is long. 7. It is man’s enemy as it destroys food grains and spreads diseases like plague. 8. Teeth sharp and pointed. 9. Being insectivorous it destroys harmful household insects, thus useful to man. (c) Mole