Students get through the TN Board 11th Bio Zoology Important Questions Chapter 4 Organ and Organ Systems in Animals which is useful for their exam preparation.
TN State Board 11th Bio Zoology Important Questions Chapter 4 Organ and Organ Systems in Animals
Answer the following.
Define the following: (i) Morphology, (ii) Anatomy.
- Morphology: Morphology refers to the study of form or externally visible features.
- Anatomy: The word anatomy is used for the study of internal organs in animals.
Name some common Indian earthworms.
The common Indian earthworms are Lampito mauritii (Syn. Megascolex mauritii), Perioynx excavatus and Metaphire posthuma.
Write down the classification of earthworms based on their ecological strategies.
Earthworms are also conveniently classified based on their ecological strategies as epigeics, anecics and endogeics. Epigeics are surface dwellers, eg. Perionyx excavatus and Eudrilus eugeniae. Anecics are found in upper layers of the soil, eg. Lampito mauritii, Lumbricus Terrestris. Endogeics are found in deeper layers of the soil.
eg. Octochaetona thurstoni.
Describe the morphology of earthworms with a neat diagram.
Lampito mauritii is commonly found in Tamil Nadu. It has a long and cylindrical narrow body that is bilaterally symmetrical. L. mauritii is 80 to 210 mm in length with a diameter of 3.5-5 mm, and is light brown in colour, with purplish tinge at the anterior end. This colour of the earthworm is mainly due to the presence of porphyrin pigment. The body of the earthworm is encircled by a large number of grooves which divides it into a number of compartments called segments or metameres. L. mauritii consists of about 165 – 190 segments. The dorsal surface of the body is marked by a dark mid-dorsal line (dorsal blood vessel) along the longitudinal axis of the body. The ventral surface is distinguished by the presence of genital openings. 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 upper lip or prostomium. The last segment has the anus called the pygidium. In mature worms, segments 14 to 17 may be found swollen with a glandular thickening of the skin called the clitellum. This helps in the formation of the cocoon. Due to the presence of clitellum, the body of an earthworm is divided into pre clitellar region (1st – 13th segments), clitellar region (14th – 17th segments) and the post-clitellar region (after the 17th
segment). In all the segments of the body except the first, last and clitellum, there is a ring of chitinous body setae. This body setae arises from a setigerous sac of the skin and it is curved as S-shaped. Setae can be protruded or retracted and their principal role is in locomotion.
What is metameric segmentation in earthworm?
The body of the earthworm is encircled by a large number of grooves which divides it into a number of compartments called segments or metameres. This is called metameric segmentation
Write the external apertures found in the body of the earthworm with a neat sketch.
The external apertures are the mouth, anus, dorsal pores, spermathecal openings, genital openings and nephridiopores. The dorsal pores are present from the 10thsegment onwards. The coelomic fluid communicates to the exterior through these pores and keeps the body surface moist and free from harmful microorganisms. Spermathecal openings are three pairs of small ventrolateral apertures lying intersegmentally between the grooves of the segments 6/7, 7/8 and 8/9. The female genital aperture lies on the ventral side in the 14thsegment and a pair of male genital apertures are situated latero-ventrally in the 18thsegment.
Nephridiopores are numerous and found throughout the body of the earthworm except for a few anterior segments, through which the metabolic wastes are eliminated.
Differentiate pre-clitellar region and post-cliteliar region.
Due to the presence of clitellum in the 14-17 segment, the body of an earthworm is divided into pre clitellar region (1st – 13th segments), clitellar region (14th – 17th segments) and the post-clitellar region (after the 17th segment). In all the segments of the body except the first, last and clitellum, there is a ring of chitinous body setae.
Write down any ten points to make morphological and anatomical differences between Lampito mauritti and Metaphire posthuma.
Describe the anatomy of the earthworm.
The body wall of the earthworm is very moist, thin, soft, skinny, elastic and consists of the cuticle, epidermis, muscles and coelomic epithelium. The epidermis consists of supporting cells, gland cells, basal cells and sensory cells. A spacious body cavity called the coelom is seen between the alimentary canal and the body wall. The coelom contains the coelomic fluid and serves as a hydrostatic skeleton, in which the coelomocytes are known to play a major role in regeneration, immunity and wound healing. The coelomic fluid of the earthworm is milky, which consists of granulocytes or eleocytes, amoebocytes mucocytes and alkaline, leucocytes.
Write about the digestive system of earthworm with neat diagram.
The digestive system of the earthworm consists of the alimentary canal and the digestive glands. The alimentary canal runs as a straight tube throughout the length of the body from the mouth to anus. The mouth opens into the buccal cavity which occupies the 1st and 2nd segments. The buccal cavity leads into a thick muscular pharynx, which occupies the 3rd and 4th segments and is surrounded by the pharyngeal glands.
A small narrow tube, the oesophagus lies in the 5th segment and continues into a muscular gizzard in the 6th segment. The gizzard helps in the grinding of soil particles and decaying leaves. The intestine starts from the 7th segment and continues till the last segment. The dorsal wall of the intestine is folded into the cavity as the typhlosole. This fold contains blood vessels and increases the absorptive area of the intestine. The inner epithelium consists of columnar cells and glandular cells. The alimentary canal opens to the exterior through the anus.
How is cutaneous respiration made possible in earthworm?
The earthworm has no special respiratory organs like lungs or gills. Respiration takes place through the body wall. The outer surface of the skin is richly supplied with blood capillaries which aid in the diffusion of gases. Oxygen diffuses through the skin into the blood while carbon dioxide from the blood diffuses out. The skin is kept moist by mucous and coelomic fluid and facilitates the exchange of gases.
Write an account on the circulatory system of Lampito mauritii.
Lampito mauritii exhibits a closed type of blood vascular system consisting of blood vessels, capillaries and lateral hearts. Two median longitudinal vessels run above and below the alimentary canal as dorsal and ventral vessels of the earthworm. There are paired valves in the dorsal vessels which prevent the backward flow of the blood. The ventral vessel has no valves and is non-contractile, allowing the backward flow of blood. 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 6thto 13thsegments. 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. Blood glands are present in the anterior segments of the earthworm. They produce blood cells and haemoglobin which is dissolved in the plasma and gives a red colour to the blood.
Give a short note on the nervous system of the earthworm.
The bilobed mass of nervous tissue called supra-pharyngeal ganglia, which lies on the dorsal wall of the pharynx in the 3rd segment, is referred to as the “brain”. The ganglion found below the pharynx in the 4thsegment is called the sub-pharyngeal ganglion. The brain and the sub -pharyngeal 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 ventral nerve cord runs backwards from the sub – pharyngeal ganglion. The brain along with other nerves in the ring integrates sensory inputs and command muscular responses of the body.
Write about the type of receptors found in earthworm.
The earthworm’s receptors are stimulated by a group of slender columnar cells connected with nerves. The Photoreceptors (sense of light) are found on the dorsal surface of the body. Gustatory (sense of taste) and olfactory receptors (sense of smell) are found in the buccal cavity. Tactile receptors (sense of touch), chemoreceptors (detect chemical changes) and thermoreceptors (changes in, temperature) are present in the prostomium and the body wall.
Describe the nephridial system of the common earthworm, and write how it is helpful in removing the waste materials.
Excretion is the process of elimination of metabolic waste products from the body. In earthworm, excretion is affected by segmentally arranged, minute coiled, paired tubules called nephridia. There are three types of nephridia:
- Pharyngeal or tufted nephridia – present as paired tufts in the 5th 9th segments.
- Micronephridia or Integumentary nephridia – attached to the lining of the body wall from the 14th segment to the last which open on the body surface.
- Meganephridia or septal nephridia – present as pair on both sides of intersegmental septa of the 19th segment to the last and open into the intestine. The meganephridium has an internal funnel-like opening called the nephrostome, which is fully ciliated.
The nephrostome consists of three distinct divisions, the ciliated, the glandular and the muscular region. The waste material collected through the ciliated funnel is pushed into the muscular part of nephridium by the ciliated region. The glandular part extracts the waste from the blood and finally the wastes exit out through the nephridiopore.
Besides nephridia, special cells on the coelomic wall of the intestine, called chloragogen cells are present. They extract the nitrogenous waste from the blood of the intestinal wall, into the body cavity to be sent out through the nephridia.
Write an account of the reproductive system of earthworm.
Earthworms are hermaphrodites or monoecious i.e., male and female reproductive organs are found in the same individual.
In the male reproductive system, two pairs of testes are present in the 10th and 11th segments. The testes give rise to the germ cells or spermatogonia, which develops into spermatozoa in the two pairs of seminal vesicles. Two pairs of seminal funnels called ciliary rosettes are situated in the same segments as the testes. The ciliated funnels of the same side are connected to a long tube called vas deferens. The vasa deferentia run-up to the 18th segment where they open to the exterior through the male genital aperture. The male genital aperture contains two pairs of penial setae for copulation. A pair of prostate glands lie in the 18th – 19th segments. The secretion of the prostate gland serves to cement the spermatozoa into bundles known as spermatophores.
What is protandrous?
Earthworms are hermaphrodites or monoecious i.e. male and female reproductive organs are found in the same individual. Self-fertilization is avoided because two sex organs mature at different times, which means the sperm develops earlier than the production of ova to promote cross-fertilization. This phenomenon is called Protandrous.
How cocoon is formed in earthworms and what is the use it.
Mature egg cells in the nutritive fluid are deposited in the cocoons produced by the gland cells of the clitellum which also collects the partner’s sperms from the spermthecae. Fertilization and development occur within the cocoons, which are deposited in the soil. After about 2-3 weeks, each cocoon produces baby earthworms.
Why earthworms are called “Friends of Farmer?”
Earthworms are known as “friends of the farmer” because they make burrows in the soil and make it porous which helps in respiration and penetration of developing plant roots.
What is “VERMITEC”.
Vermiculture, vermicomposting, vermiwash and wormery are interlinked and interdependent processes, collectively referred to as Vermitech.
Lampito mauritti helps in recycling dead and decayed plant material by feeding on them. Artificial rearing or cultivation of earthworms involves new technology for the betterment of human beings. This process is known as Vermiculture.
What is vermicomposting?
Lampito mauritti helps in recycling dead and decayed plant material by feeding on them. Artificial rearing or cultivation of earthworms involves new technology for the betterment of human beings. This process is known as Vermiculture. The process of producing compost ‘ using earthworms is called Vermicomposting.
What is vermiwash.
Vermiwash is liquid manure or plant tonic obtained from an earthworm. It is used as a foliar spray and helps to induce plant growth. It is a collection of excretory products and mucus secretion of earthworms along with micronutrients from the soil organic molecules.
What is “wormery” or “worm bin”.
Earthworms can be used for recycling waste food, leaf, litter and biomass to prepare a good fertilizer in a container known as wormery or worm bin.
Describe the economic importance of earthworm.
Earthworms are known as “friends of the farmer” because they make burrows in the soil and make it porous which helps in respiration and penetration of developing plant roots. Vermiculture, vermicomposting, vermiwash and wormery are interlinked and interdependent processes, collectively referred to as Vermitech. Lampito mauritti helps in recycling dead and decayed plant material by feeding on them. Artificial rearing or cultivation of earthworms involves new technology for the betterment of human beings. This process is known as Vermiculture. The process of producing compost using earthworms is called Vermicomposting. Vermiwash is liquid manure or plant tonic obtained from an earthworm. It is used as a foliar spray and helps to induce plant growth. It is a collection of excretory products and mucus secretion of earthworms along with micronutrients from the soil organic molecules. Earthworms can be used for recycling of waste food, leaf, litter and biomass to prepare a good fertilizer in a container known as wormery or worm bin. It makes superior compost than conventional composting methods: Earthworms are also used as bait in fishing.
Why cockroaches are called vectors.
Cockroach carries with them harmful germs of various bacterial diseases like cholera, diarrhoea, tuberculosis, and typhoid and hence are known as “Vectors”.
Describe the morphology of Periploneta Americana.
The body of the cockroach is compressed dorso-ventrally, bilaterally symmetrical, segmented and is divisible into three distinct regions – head, thorax and abdomen. The entire body is covered by a hard, brown coloured, chitinous exoskeleton. In each segment, the exoskeleton has hardened plates called sclerites. The sclerites of the dorsal side are called tergites, those on the ventral side are called stemites and those of lateral sides are called pleurites.
The head of the cockroach is small, triangular lies at a right angle to the longitudinal body axis, the mouthparts are directed downwards so it is hypognathous. It is formed by the fusion of six segments and shows great mobility in all directions due to a flexible neck. The head capsule bears a pair of large, sessile, and reniform compound eyes, a pair of antennae and appendages around the mouth. Antennae have sensory receptors that help in monitoring the environment. The appendages from the mouthparts are of biting and chewing type (Mandibulate or Orthopterus type). The mouthparts consist of a labrum (upper lip), a pair of mandibles, a pair of maxillae, a labium (lower lip) and a hypopharynx (tongue) or lingua. The thorax consists of three segments – Prothorax, Mesothorax and Metathorax. The prothoracic segment is the largest. The head is connected with the thorax by a short extension of the prothorax called the neck or cervicum. Each thoracic segment bears a pair of walking legs.
The cockroach has two pairs of wings, the first pair arises from the mesothorax and protects the hind wings when at rest, and is called elytra or tegmina. The second pair of wings arise from the metathorax and are used in flight, The abdomen in both male and female consists of 10 segments. Each segment is covered by the dorsal tergum, the ventral sternum and between ‘ them a narrow membranous pleuron on each side.
In males, the genital pouch lies at the hind end of the abdomen. It contains the dorsal anus and ventral male genital pore. In both sexes, genital apertures are surrounded by sclerites called gonapophysis. Male bears a pair of short and slender anal styles in the 9th sternum which is absent in the female. In both sexes, the 10th segment bears a pair of jointed filamentous structures called anal cerci and bears a sense organ that is receptive to vibrations in air and land.
Name the parts of the mouth in cockroaches.
The mouthparts consist of a labrum (upper lip), a pair of mandibles, a pair of maxillae, a labium (lower lip) and an Irypopharynx (tongue) or lingua.
Write down the difference between male and female cockroaches.
|Long and narrow.
|Short and broad.
|In the abdomen, nine segments are visible.
|In the abdomen, seven segments are visible.
|7th tergum covers 8th tergum.
|The 7th tergum covers the 8th and 9th terga.
|Longer in length.
|Shorter in length.
|Extends beyond the tip of the abdomen.
|Extends up to the end of the abdomen.
Write about the description of the digestive system of cockroaches with a neat sketch.
The digestive system of cockroach consists of the alimentary canal and digestive glands. The alimentary canal is present in the body cavity and is divided into three regions: foregut, midgut and hindgut. The foregut includes the preoral cavity, mouth, pharynx and oesophagus. This in turn opens into a sac-like structure called the crop which is used for storing food. The crop is followed by the gizzard or proventriculus which has an outer layer of thick circular muscles and thick inner cuticle forming six highly chitinous plates called “teeth”. Gizzard helps in the grinding of the food particles. The midgut is a short and narrow tube behind the gizzard and is glandular in nature. At the junctional region of the gizzard are eight fingers like tubular blind 100 – 150 yellow coloured thin filamentous malphigian tubules which are helpful in the removal of the excretory products from the haemolymph. The hindgut is broader than the midgut and is differentiated into the ileum, colon, and rectum. The rectum opens out through the anus.
The digestive glands of cockroach consist of the salivary glands, the glandular cells and hepatic caecae. A pair of salivary glands are found on either side of the crop in the thorax. The glandular cells of the midgut and hepatic or gastric caecae produce digestive juices.
What are the digestive glands of cockroach?
The digestive glands of cockroach consist of the salivary glands, the glandular cells and hepatic caecae. A pair of salivary glands is found on either side of the crop in the thorax. The glandular cells of the midgut and hepatic or gastric caecae produce digestive juices.
Describe the circulatory system of Periplaneta americana.
Periplaneta has an open type of circulatory system. Blood vessels are poorly developed and opens into the haemoeoel in which the blood or haemolymph flows freely. Visceral organs located in the haemoeoel are bathed in blood. The haemolyph is colourless and consists of plasma and haemocytes which are ‘phagocytic’ in nature. The heart is an elongated tube with a muscular wall lying mid dorsally beneath the thorax. The heart consists of 13 chambers with Ostia on either side. The blood from the sinuses enters the heart through the ostia and is pumped anteriorly to the sinuses again. The triangular muscles that are responsible for blood circulation in the cockroach are called alary muscles (13 pairs). One pair of these muscles is found in each segment on either side of the heart. In a cockroach, there is an accessory pulsatile vesicle at the base of each antenna which also pumps blood.
Write an account on the nervous system of cockroach.
The nervous system of cockroach consists of a nerve ring and a ganglionated double ventral nerve cord, sub-oesophageal ganglion, circum-oesophageal connectives and double ventral nerve cord. The nerve ring is present around the oesophagus in the head capsule and is formed by the supra-oesophagial ganglion called the ‘brain’, The brain is mainly a sensory and an endocrine centre and lies above the oesophagus. A sub-oesophageal ganglion is the motor centre that controls the movements of the mouthparts, legs and wings. It lies below the oesophagus and formed by the fusion of the paired gangalia of mandibular, maxillary and labial segments of the head. A pair of circum-oesophageal connectives is present around the oesophagus, connecting the supra-oesophageal ganglia with the sub-oesophageal ganglion. The double ventral nerve cord is solid, ganglionated and arises from the sub-oesophageal ganglion and extends up to the 7th abdominal segment. Three thoracic ganglia are present, one in each thoracic segment and six abdominal ganglia in the abdomen.
What are the sense organs present in Periplaneta americana and write the position and function of each?
In cockroach, the sense organs are antennae, compound eyes, labrum, maxillary palps, labial palps and anal cerci. The receptor for touch (thigmo receptors) is located in the antenna, maxillary palps and cerci. The receptor for smell (olfactory receptors) is found on the antennae. The receptor for taste (gustatory receptors) is found on the palps of the maxilla and labium. Thermoreceptors are found on the first four tarsal segments on the legs. The receptor chordotonal is found on the anal cerci which respond to air or earth borne vibrations. The photoreceptors of the cockroach consist of a pair of compound eyes at the dorsal surface of the head. Each eye is formed of about 2000 simple eyes called the ommatidia (singular: ommatidium), through which the cockroach can receive several images of an object. This kind of vision is known as mosaic vision with more sensitivity but less resolution.
How do the malpighian tubules of cockroaches do the function of excretion?
The malpighian tubules are thin, long, filamentous, yellow coloured structures attached at the junction of the midgut and hindgut. These are about 100-150 in number and are present in 6-9 bundles. Each tubule is lined by glandular and ciliated cells and the waste is excreted out through the hindgut. The glandular cells of the malpighian tubules absorb water, salts, and nitrogenous wastes from the haemolymph and transfer them into the lumen of the tubules. The cells of the tubules reabsorb water and certain inorganic salts. By the contraction of the tubules, nitrogenous waste is pushed into the ileum, where more water is reabsorbed. It moves into the rectum and almost solid uric acid is excreted along with the faecal matter.
What are the organs that constitute the male reproductive system in Periplaneta Americana?
The male reproductive system consists of a pair of testes, vasa deferentia, and ejaculatory duct, utricular gland, phallic gland and external genitalia.
What, are the female reproductive organs of cockroach.
The female reproductive system of cockroach consists of a pair of ovaries, vagina, genital pouch, collaterial glands, spermathecae and external genitalia.
Write short note on ootheca of cockroach.
Ootheca is a dark reddish to blackish brown capsule about 12mm long which contains nearly 16 fertilized eggs and dropped or glued to a suitable surface, usually in a crack or crevice of high relative humidity near a food source. On average, each female cockroach produces nearly 15-40 oothecae in its life span of about one to two years. The embryonic development occurs in the ootheca, which takes nearly 5-13 weeks. The development of cockroach is gradual through the nymphal stages (paurometabolous). The nymph resembles the adult and undergoes moulting. The nymph grows by moulting or ecdysis about 13 times to reach the adult form.
Write about the features showing the morphology of the frog.
The body of a frog is streamlined to help in swimming. It is dorsoventrally flattened and is divisible into the head and trunk. The body is covered by smooth, slimy skin loosely attached to the body wall. The skin is dark green on the dorsal side and pale ventrally. The head is almost triangular in shape and has an apex that forms the snout. The mouth is at the anterior end and can open widely. External nostrils are present on the dorsal surface of the snout, one on each side of the median line. Eyes are large and project above the general surface of the body. They lie behind the external nostrils and are protected by a thin movable lower eyelid, thick immovable upper eyelid and a third transparent eyelid called the nictitating membrane. This membrane protects the eye when the frog is underwater. A pair of tympanic membranes form the eardrum behind the eyes on either side. Frogs have no external ears, neck and tail are absent. Trunk bears a pair of forelimbs and a pair of hind limbs. At the posterior end of the dorsal side, between the hind limbs is the cloacal aperture. This is the common opening for the digestive, excretory and reproductive systems.
Forelimbs are short, stumpy, and helps to bear the weight of the body. They are also helpful for the landing of the frog after leaping. Each forelimb consists of an upper arm, forearm and hand. Hand bears four digits. Hind limbs are large, long and consist of thigh, shank and foot. Foot bears five long webbed toes and one small spot called the sixth toe. These are adaptations for leaping and swimming. When the animal is at rest, the hind limbs are kept folded in the form of the letter Z Sexual dimorphism is exhibited clearly during the breeding season. The male frog has a pair of vocal sacs and a copulatory or nuptial pad on the ventral side of the first digit of each forelimb (Figure 4.16). Vocal sacs assist in amplifying the croaking sound of the frog. Vocal sacs and nuptial pads are absent in the female frogs.
Differentiate frogs from toads.
|Smooth and moist skin
|Dry skin covered with wart-like glands.
|Maxillary and vomerine teeth.
|Lays eggs in clusters.
|Lays eggs in strings.
Write the anatomy of the digestive system in Rono hexadactyla.
The Digestive System: The alimentary canal consists of the buccal cavity, pharynx, oesophagus, duodenum, ileum and the rectum which leads to the cloaca and opens outside by the cloacal aperture. The wide mouth opens into the buccal cavity. On the floor of the buccal cavity lies a large muscular sticky tongue. The tongue is attached in front and free behind. The free edge is forked. When the frog sights an insect it flicks out its tongue and the insect gets glued to the sticky tongue. The tongue is immediately withdrawn and the mouth closes. A row of small and pointed maxillary teeth is found on the inner region of the upper jaw. In addition vomerine. teeth are also present as two groups, one on each side of the internal nostrils. The lower jaw is devoid of teeth. The mouth opens into the buccal cavity that leads to the oesophagus through the pharynx. The oesophagus is a short tube that opens into the stomach and continues as the intestine, rectum and finally opens outside by the cloaca. The liver secretes bile which is stored in the gall bladder. The pancreas, a digestive gland produces pancreatic juice containing digestive enzymes.
How digestion process takes place in common Indian frog.
Food is captured by the bilobed tongue. Digestion of food takes place by the action of Hydrochloric acid and gastric juices secreted from the walls of the stomach. Partially digested food called chyme is passed from the stomach to the first part of the intestine, the duodenum. The duodenum receives bile from the gall bladder and pancreatic juices from the pancreas through a common bile duct. Bile emulsifies fat and pancreatic juices digest carbohydrates, proteins and lipids. Final digestion takes place in the intestine. Digested food is absorbed by the numerous finger-like folds in the inner wall of the intestine called villi and microvilli. The undigested solid waste moves into the rectum and passes out through the cloaca.
Describe the different blood vessels associated with the heart and its supply of blood to a different region in Rana hexadactyla.
The Blood-Vascular System- The blood vascular system consists of a heart with three chambers, blood vessels and blood. The heart is covered by a double-walled membrane called the pericardium. There are two thin-walled anterior chambers called auricles (Atria) and a single thick-walled posterior chamber called the ventricle. Sinus venosus is a large, thin-walled, triangular chamber, which is present on the dorsal side of the heart. Truncus arteriosus is a thick-walled and cylindrical structure that is obliquely placed on the ventral surface of the heart. It arises from the ventricle and divides into the right and left aortic trunk, which is further divided into three aortic arches namely carotid, systemic and pulmo-cutaneous. The Carotid trunk supplies blood to the anterior region of the body. The Systemic trunk of each side is joined posteriorly to form the dorsal aorta. They supply blood to the posterior part of the body. Pulmo-cutaneous trunk supplies blood to the lungs and skin. Sinus venosus receives the deoxygenated blood from the body parts by two anterior precaval veins and one post caval vein. It delivers the blood to the right auricle; at the same time, the left auricle receives oxygenated blood through the pulmonary vein. Renal portal and hepatic portal systems are seen in the frog.
What are the three types of nervous system seen in frog?
The Nervous system of the frog is divided into the Central Nervous System [CNS], the Peripheral Nervous System [PNS], and the Autonomous Nervous System [ANS].
Give a short note on the structure of the brain in Rana hexadactyla.
The brain is situated in the cranial cavity and covered by two meninges called piamater and duramater. The brain is divided into forebrain, midbrain and hindbrain. Forebrain (Prosencephalon) is the hindbrain (Rhombencephalon) consists of the cerebellum and medulla oblongata. The cerebellum is a narrow, thin transverse band followed by medulla oblongata. The medulla oblongata passes out through the foramen magnum and continues as the spinal cord, which is enclosed in the vertebral column.
In frogs how the elimination of nitrogenous waste takes place with the help of excretory organs.
Elimination of nitrogenous waste and salt and water balance is performed by a well developed excretory system. It consists of a pair of kidneys, ureters, urinary bladder and cloaca. Kidneys are dark red, long, flat organs situated on either side of the vertebral column in the body cavity. Kidneys are Mesonephric. Several nephrons are found in each kidney. They separate nitrogenous waste from the blood and excrete urea, so frogs are called ureotelic organisms.
A pair of ureters emerges from the kidneys and opens into the cloaca. A thin-walled unpaired urinary bladder is present ventral to the rectum and opens into the cloaca.
Write shortly about the metamorphosis process in the frog.
In frogs within few days of fertilization, the eggs hatch into tadpoles. A newly hatched tadpole lives off the yolk stored in its body. It gradually grows larger and develops three pairs of gills.
The tadpole grows and metamorphosis into an air-breathing carnivorous adult frog. Legs grow from the body, and the tail and gills disappear. The mouth broadens, developing teeth and jaws, and the lungs become functional.
In what way the frogs are economically important.
Economic importance of Frog:
- The frog is an important animal in the food chain; it helps to maintain our ecosystem. So ‘frogs should be protected’.
- Frog is beneficial to man since they feed on insects and helps in reducing the insect pest population.
- Frogs are used in traditional medicine for controlling blood pressure and for their anti-ageing properties.
- In the USA, Japan, China and the North East of India, frogs are consumed as delicious food as they have high nutritive value.
Which is the longest species of earthworm in South India and in Africa?
In South India – Drawida nilamburansis.
In Africa – Microchaetus rappi.
How do the earthworms crawl?
The earthworms normally crawl with the help of their body muscles, setae, and buccal chamber.
The outer circular and inner longitudinal muscle layers lies below the epidermis of the body wall. The contraction of circular muscles makes the body long and narrow, while that of the longitudinal muscle makes the body short and broad. The locomotion of the earthworm is brought about by the contraction and relaxation of the muscular body wall and is aided by the turgence of the coelomic fluid hence called the Hydrostatic skeleton. The alternate waves of extensions and contractions are aided by the leverage afforded by the buccal chamber and the setae.
Are the cockroaches are oviparous or viviparous? Give example.
Cockroaches are generally oviparous, but the Diploptera punctata is a viviparous cockroach found in Myanmar, China, Fiji, Hawaii, and India.
Choose the correct answer.
1. The earthworm in gardens, can be traced by their faecal deposits known as:
(c) worm castings
(c) worm castings
2. The common Indian earthworms are:
(a) Perioynx excavatus
(b) Lampito mauritii
(c) Pheretima posthuma
(d) Eudrilus eugeniae
(b) Lampito mauritii
3. The locomotory organ of earthworms is:
4. The colour of the earthworm is mainly due to the presence of the pigment called:
5. A small flap found hanging on the mouth of earthworm is called:
6. The muscle fold found in the dorsal wall in the intestine of the earthworm is:
7. The chioracogen cells on the wall of the intestine of the earthworm meant for:
8. Match the following and choose the correct answer:
(a) Photoreceptors (i) detect chemical changes
(b) Gustatory (ii) sense of touch
(c) Chemoreceptors (iii) sense of smell
(di Olfactory receptors (iv) sense of taste
(e) Tactile receptors (v) sense of light
(a) (a)-(v), (b)-(iv), (c)-(i), (d)-(iii), (e)-(ii)
(b) (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i), (e)-(v)
(e) (a)-(i), (b)-(ii), (c)-(iii), (d)-(v), (e)-(iv)
(d) (a)-(ii), (b)-(iv), (c)-(iii), (d)-(v), (e)-(i)
(a) (a)-(v), (b)-(iv), (c)-(i), (d)-(iii), (e)-(ii)
9. Development of sperm earlier than the production of ova is called:
10. The zoological name of the cockroach is:
(a) Periplaneta americana
(b) Lampiro mauritti
(c) Rana hexadactyla
(a) Periplaneta americana
11. The respiratory organ of cockroach is:
12. The triangular muscles of cockroaches responsible for blood circulation is:
(a) Sphincter muscles
(b) Pulsatile vesicle
(c) Alary muscles
(d) Smooth muscles
(c) Alary muscles
13. Cockroaches excretes uric acid, so it is:
14. The egg case of cockroach is called:
(a) Collateral glands
15. The zoological name of common Indian green frog is:
(a) Rana hexadactyla
(b) Rana tigiris
(a) Rana hexadactyla
16. During the aestivation and hibernation period of frog, gaseous exchange takes place through:
17. Frogs are:
18. The tadpoles of frog respire through: