AP Inter 1st Year Zoology Question Paper March 2018 with Solutions

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AP Inter 1st Year Zoology Question Paper March 2018 with Solutions

Time: 3 Hours
Max. Marks: 60

Note: Read the following instructions carefully.

• Answer all the questions of Section -A. Answer any six questions in Section – B and answer Any two questions in Section – C.
• In Section -A, questions from Sr. Nos. 1 to 10 are of Very Short Answer Type. Each question carries two marks. Every answer may be limited to 5 lines. Answer all questions at one place in the same order.
• In Section – B, questions from Sr. Nos. 11 to 18 are of Short Answer Type. Each question comes four marks. Every answer may be limited to 20 lines.
• In Section – C, questions from Sr. Nos. 19 to 21 are of Long Answer Type. Each question carries eight marks. Every answer may be limited to 60 lines.
• Draw labelled diagrams wherever necessary in Section – B and C.

Section – A
10 x 2= 20

Note: Answer all the questions in 5 lines each:

Question 1.
What is trinominal nomenclature? Give an example.
Answer:
The trinominal nomenclature is the extension of the binominal system of nomanclature. It permits the designation of subspecies with a three worded name called trinomen’. Ex: Homo Sapiens Sapiens, Corvus splendns spelendns.

Question 2.
What are retroperitoneal organs?
Answer:
Certain organs such as the kidneys of the vertebrates are covered by the parietal peritoneum only on their ventral side. Such a peritoneum is called the retroperitoneum and the organs lined by it are called ‘retroperitoneal organs’.

Question 3.
Mention the animals that exhibited a tube-within-a-tube organisation for the first time. Name their body cavity.
Answer:
Cnidarians and some flat warms are the first animals to exhibit a tube-within-a-tube organisation. Body cavity is pseudocolour.

Question 4.
What are microglia and what is their origin? Add a note on their functions.
Answer:
Microglial cells are the Neurogila (supporting cells) of cells of CNS which are phagocytic cells, of mesodermal origin.

Question 5.
What are the functions of Canal system of sponges?
Answer:
Functions of canal system of sponge are gathering of food, respiratory exchange of gases and removal of wastes.

Question 6.
How do you distinguish a male frog from a female frog?
Answer:
Male frog can be distinguished by the presence of sound amplifying vocal sacs and a copulatory pad on the first digit of each forelimb.

Question 7.
Define conjugation with reference to curates. Give two examples.
Answer:
Conjugation is a temporary union between two senile ciliates that belong to two different ‘mating types’ for the exchange of nuclear material and its reorganization. – Wichterman. Ex : Paramecium and Vorticella.

Question 8.
Draw a labelled diagram of T.S. of Flagellum.
Answer:

Question 9.
Define incubation period. What is its duration in life cycle of Plasmodium vivax?
Answer:
The period between the entry of Plasmodium into the blood in the form of sporozoite and the first appearance of symptoms of malaria in man is called incubation period it is approximately 10 to 14 days.

Question 10.
Distinguish between lotic and lentic habitats.
Answer:

Lotic habitat	Lentic habitat
1. The still water bodies fall under lotic community. Ex: Lakes, ponds.	1. Flowing water bodies are called lentic habitats. Ex: River, canals, streams.

Section-B
6 x 4 = 24

Note: Answer any six questions in 20 lines each:

Question 11.
What is the ‘evil quartet?
Answer:
The following are the four major causes (The Evil Quartet) for accelerated rates of species extinction in the world. Habitat loss and Fragmentation: These are the most important reasons for the loss of biodiversity.

• Deforestation leads to species extinction in forests. e.g.: tropical rain forest once covering 14% of the earth’s land surface is now not more than 4%.
• Conversion of forest land to agricultural land. e.g.: the amazon rain forest, called lungs of our planet, harbouring innumerable species is cut and cleared to cultivate soyabeans or conversion to grass lands for raising beef cattle.
• Pollution enhances degradation of habitats and threatens the survival of many species as pollutants change the quality of the environment.
• Fragmentation of habitat leads to population decline. e.g.: mammals and birds requiring large territories and certain animals with migratory habits are badly affected.

Question 12.
Describe the structure of a skeletal muscle.
Answer:
Skeletal (striped and voluntary) muscles: It is usually attached to skeletal structures by tendons. In a typical muscle such as the biceps muscle, skeletal muscle fibre is surrounded by a thin connective tissue sheath, the endomysium. A bundle of muscle fibres is called a fascicle. It is surrounded by a connective tissue sheath called perimysium. A group of fascicles form a ‘muscle which is surrounded by an epimysium (outermost connective tissue sheath). These connective tissue layers may extend beyond the muscle to form a chord-like tendon or sheet-like aponeurosis.

A skeletal muscle fibre is a long, cylindrical and unbranched cell. It is a multinucleated cell with many oval nuclei characteristically in the periphera1 cytoplasm (a syncytium formed by fusion of cells). Sarcoplasm has many myofibrils which show alternate dark and light bands. So it is called striped or striated muscle.

Question 13.
What are the salient features exhibited by polychaetes?
Answer:

1. These are commonly known as bristle worms.
2. All are marine. Many are burrowing, others art free swimming or crawling or tubicolous.
3. The head is distinct with sensory structures like eyes, antennae, pairs, and cirri.
4. The clitellum is absent.
5. Each segment has a pair of lateral appendages called para podia in which bundles of set are arranged.
6.  Animals are unisexual. Most segments bear glands. Gonoducts are absent.
7. Gametes are shed into coelom.
8. Fertilization is external.
9. The development includes a trochophore larva. Ex: Nereis.

Question 14.
Name the four ‘hallmarks’ of chordates and explain the principal function of each of them.
Answer:
The hail marks of chordates: All the chordates exhibit four fundamental characters. They are Notochord the dorsal tubular nerve cord. Pharyngeal slits or clefts and Post-anal tall.

Notochord: It is a flexible rod-like structure situated along the mid-dorsal line between the gut and the nerve cord. It is derived from the embryonic chorda mesoderm. It is firm but flexible. It is present throughout the life in the lancelets and cyclostomes. It is present in tail of the tadpole larva of an ascidian, It is present in embryonic stages but is replaced partly or wholly by the vertebral column in the adults of higher chordates. Remnants of notochord occur as nuclei purpose in the intervertebral discs of mammals.

Dorsal tubular nerve cord: A single, hollow tubular and fluid-filled nerve cord is situated above the notochord and below the dorsal body wall. It is derived from ectoderm of embryo. In the higher chordates, it gets enlarged to form a distinct brain at the anterior end the rest of it becomes the spinal cord.

Pharyngeal slits of clefts: These are slit opening present on ti. The pharyngeal wall and meant for the exit of the water from the pharyngeal cavity. They are present throughout the life in the protochordate, fishes and some amphibians. These are present in larval stages in amphibians. They develop by in-pushing of ectoderm and corresponding out-passing of the endoderm. In land vertebrates, the gills become vestigial and nonfunctional and are restricted to embryonic Stages only.

Post-anal tail: Chordates have a tail extending posterior to the anus. It losts in many species during the late embryonic development. It contains skeletal elements and muscles, coelom and visceral organs are absent in it.

Question 15.
Describe the process of longitudinal binary fission in Euglena.
Answer:
Binary fission is the most common method of asexual reproduction in protozoans. Longitudinal binary fission is performed by Fuglean. In this type of binary fission, the body divides into two halves longitudinally, hence-called longitudinal binary fission.

During the process of binary fission, the nucleus, basal granules, chromatophores, cytoplasm undergo division. The nucleus divides by mitosis into two daughter nuclei. Then the kinetosomes and the chromatophores also divide. At first, a longitudinal groove develops in the middle of the anterior end. This groove extends gradually towards the posterior end until the two daughter individuals are separated.

One daughter Euglena retains the parental flagella. The other daughter individual develops new flagella. From the newly formed basal granules. The stigma, paraflagellar body and contractile vacuole of the parent disappear. They develop afresh in both the daughter Euglenae. The longitudinal binary fission is known as symmetrogenic division because the two daughters Euglenae resemble each other like ‘mirror images’.

Question 16.
‘Prevention is better than cure’. Justify with regard to TDA abuse.
Answer:
The age-old adage of prevention is better than cure holds true here also. Some of the measures useful for prevention and control of TDA abuse among the adolescents are:

• Avoid undue parental pressure: Every child has his/her own choice. Capacity and personality. The parents should not force their children to perform beyond their capacity by comparing them with others in studies, games etc.
• Responsibility of parents and teachers: They should look for the danger signs and counsel such students who are likely to get into the trap’.
• Seeking help from peers: If peers find someone abusing drugs or alcohol immediately it should be brought to the notice of their parents or teachers so that they can guide them appropriately.
• Education and counselling: Educating and counselling the children to face problems, stress and failures as a part of life.
• Seeking professional and medical help: A lot of help is available in the form of highly qualified psychologists, psychiatrists and de-addiction and rehabilitation programmers.

Question 17.
Draw a neatly labelled diagram of the mouth parts of the cockroach.
Answer:

Question 18.
Write a short note on DFC. Give its significance in a terrestrial ecosystem.
Answer:
The detritus food chain (DFC) begins with dead organic matter (such as leaf litter, bodies of dead organisms). It is made
up of decor posers which are heterotrophic organisms ‘mainly’ ‘fungi’ and ‘bacteria’. They meet their energy and nutrient requirements by degrading dead organic matter or detritus.

These are also known as saprotrophs. Decorn posers secrete digestive enzymes that break down dead and waste materials (such as faeces) into simple absorbable substances. Some examples of detritus food chains are:

• Detritus – Earthworms – Frogs – Snakes
• Dead animals – Flies and maggots – Frogs – Snakes.

In an aquatic ecosystem. GFC is the major conduit for the energy flow. As against this, in a terrestrial ecosystem, a much larger fraction of energy flows through the detritus food chain than through the GFC. Detritus food chain may be connected with the grazing food chain at some levels. Some of the organisms of DFC may form the prey of the GFC animals. For example, in the detritus food chain given above, the earthworms of the DFC may become the food of the birds of the GFC. It is to be understood that food chains are not ‘isolated’ always.

Section – C
2 x 8 = 16

Note: Answer any two questions in 60 lines each:

Question 19.
Describe the structure and life cycle of Ascaris lumbricoides with the help of a neat labelled diagram.
Answer:
Ascaris lumbricoids is commonly called the common roundworm. It lives in the small intestine of man, more frequently in children. It is cosmopolitan in distribution. Mode of infection is through contaminated food and water. Infective stage is the embryonated egg with the 2-stage rhabditi form larva.

Structure: Sexes are separate and the sexual dimorphism is distinct. In both males and females, the body is elongated and cylindrical. Mouth is present at the extreme anterior end and is surrounded by three chitinous lips close to the mouth. Mid ventrally there is a small aperture called excretory pore.

Male: It has a curved posterior end which is considered the tail. The posterior end possesses a cloacal aperture and a
pair of equal-sized chitinous pineal spicules or pineal setae which serve to transfer the sperms during copulation.

Female: It has a straight posterior end the tail. The female genital pore or vulva is present mid-ventrally at about one third the length from mouth. The anus is present a little in front of the tail end.

Life history: Copulation takes place in the small intestine of man. After copulation, the female releases approximately two lakh eggs per day. Each egg is surrounded by a protein coat with rippled surface. Hence the eggs of Ascaris are described as mammillated eggs. The protein coat is followed by a chitinous shell and a lipid layer internally. These eggs come out along with faecal matter. In the moist soil, development takes place inside the egg so that the 15th-stage rhabditi form larva is produced. It undergoes the 1st moulting and becomes the 2’ stage rhabditiform larva which is considered the stage infective to man. They reach the alimentary canal of man through contaminated food and water.

In the small intestine, the shell gets dissolved so that the 2-stage larva is released. Now it undergoes extra intestinal migration. First, it reaches the liver through the hepatic portal vein. From there it reaches the heart through the post canal vein. It goes to the lungs through the pulmonary arteries. In the alveoli of lungs, it undergoes the 2nd moulting to produce the 3rd stage larva. It undergoes the 3 moulting so that the 4th stage larva is produced in the alveoli only. It leaves the alveoli and reaches the small intestine again through bronchi, trachea, larynx, glottis, pharynx, oesophagus and stomach. In the small intestine. It undergoes the 4th and final moulting to become a young one which attains sexual maturity within 8 to 10 weeks.

Question 20.
Describe the respiratory system of Coçkroach with the help of neat labelled diagram.
Answer:
Due to the absence of respiratory pigment, the blood of cock roach is colourless and is cannot carry oxygen to different tissues. Therefore a tracheal system is developed to carry the air directly to the tissues. The respiratory system of cockroaches consists of stigmata, tracheae and tracheoles.

Stigmata or spiracles: The tracheal system communicates with the exterior by ten pairs of openings called stigmata or spiracles. The first two pairs of spiracles are present in the thoracic segments, one pair in mesothorax and one pair in the metathorax. The remaining eight pairs abdominal segments, Spiracles are located in the pleura of their respective segments. The respiratory system in insects is classified on the basis of number and nature of spiracles. The spiracles of cockroach are polypneustic (as they are more than 3 pairs) and holopneustic (as all of them are functional). All spiracles are valvular and each of them is surrounded by a chitinous, ring called peritreme. All spiracles bear small hair like structures called trichomes to filter the dust particles.

Tracheae: From the atrium of each thoracic spiracle several horizontal tracheae run inside. They join with each other in the thorax to form many tracheal trunks like dorsal cephalic, ventral cephalic trunks and their branches. These branches enter all organs of the head. The thoracic region also contains lateral longitudinal trunks. The abdominal spiracles lead into atria. From the atrium of each abdominal spiracle three tracheal tube arise.

All these tracheal tubes of one side open into three separate longitudinal tracheal trunks. They are lateral dorsal and ventral longitudinal trunks. lateral longitudinal trunks are the longest tracheal trunks. The three pairs of longitudinal tracheal trunks of both the sides are interconnected by many commissural tracheae. From all the tracheal trunks several branches are given out, which enter different organs. All tracheal branches entering into an organ end in a special cell called tracheoles cell.

The wall of the tracheae is made of three layers. They are an outer basement membrane, a middle one-cell thick epithe hum and an inner layer of cuticle called intima. The intima is produced into spiral thickening called taenidia. The taenidia keep the tracheae always open and prevent it from collapsing.

Tracheoles: The terminal cell of trachea is called tracheoblast or tracheole cell. It has several intracellular tubular extensions called tracheoles. Tracheoles are.devoid of intima and taenidia. They are formed of a protein called trachein. Tracheolar fluid is present inside the tracheoles. The level of the tracheal or fluid varies with the metabolic activity of the insect. It is more when the insect is inactive and completely reabsorbed into the tissues when the insect is more active. Tracheoles penetrate the cell and are intimately associated with mitochondria (to supply oxygen to them).

Question 21.
List out the major air pollutants and describe their effects on human beings.
Answer:
Air Pollutants cause injury to all living organisms. They reduce growth and yield of crops. They are harmful to the respiratory system of humans and animals. Increase in the concentration of pollutants or duration of exposure increases the harmful effects on the organisms.

The major air pollutants:
1. Carbon monoxide (CO): It is produced mainly due to incomplete combustion of fossil fuels. Automobiles are a major cause of CO pollution in larger cities and towns. Automobile exhausts, fuels from factories, emissions from power plants, forest fires and even burning of firewood contribute to CO pollution. Haemoglobin has greater affinity for CO and SO, CO competitively interferes with oxygen transport. CO symptoms such as headache and blurred vision at lower concentrations. In higher concentrations, it leads to coma and death.

2. Carbon Dioxide (CO₂): Carbon dioxide is the main pollutant that is leading to global warming. Plants utilize CO₂ for photosynthesis and all living organisms emit carbon dioxide in the process of respiration. With rapid urbanisation, automobiles, aeroplanes, power plants and other human activities that involve the burning of fossil fuels such as gasoline, carbon dioxide is turning out to be an important pollutant of concern.

3. Sulphur Dioxide (SO₂): It is mainly produced by burning of fossil fuels. Melting of sulphur ores is another important source for SO₂ pollution Metal smelting and other industrial processes also contribute to SO₂ pollution. Sulphur dioxide and nitrogen oxides are the major causes of acid rains, which cause acidification of soils,lakes and streams and also accelerated corrosion of buildings and monuments; High concentrations of sulphur dioxide (SO₂) can result in breathing problems in asthmatic children and adults. Other effects associated with long-term exposure to sulphur dioxide, include respiratory illness, alterations in the lungs defenses and aggravation of existing cardiovascular problems.

To control SO₂ pollution, the emissions are filtered through scrubbers. Scrubbers are devices that are used to clean the impurities in exhaust gases. Gaseous pollutants such as SO₂ are removed by scrubbers.

4. Nitrogen Oxides: Nitrogen oxides are considered to be major primary pollutants. The source is mainly automobile exhaust. The air polluted by nitrogen oxide is not only harmful to humans and animals but also dangerous for the life of plants. Nitrogen oxide pollution also results in acid rains and formation of photochemical smog.

The effect of nitrogen oxides on plants includes the occurrence of necrotic spots on the surface of leaves. Photosynthesis is affected in crop plants and the yield is reduced. Nitrogen oxides combine with volatile organic compounds by the action of sunlight to form secondary pollutants called Peroxyacetyl nitrate (PAN) which are found especially in photochemical smog. They are powerful irritants to eyes and respiratory tract.

5. Particulate matter/Aerosols: Tiny particles of solid matter suspended in a gas or liquid constitute the particulate matter. Aerosols refer to particles and /or liquid droplets and the gas together (a system of colloidal particles dispersed in a gas) Combustion of ‘fossil fuels” (petrol, diesel etc) fly ash produced in thermal plants, forest fires, cement factories, asbestos mining and manufacturing units, spinning and ginning mills etc., are the main sources of particulate matter pollution. According to the Central Pollution Control Board (CPCB) particles of 2.5 micrometres or less m diameter are highly harmful to man and other air-breathing organisms.

An electrostatic precipitator is a widely used filter’ for removing particulate matter from the exhaust of thermal power plants. It can remove 99% particulate matter. It has high-voltage electrodes which produce a corona’ that releases electrons. These are collected by collecting plates which attract the charged particles. The air flowing between the plates is kept in low velocity so as to allow the dust particles to fall. Thus clean air is released into the atmosphere.