Explore topic-wise InterviewSolutions in Current Affairs.

(a) Internal size of the left ventricle increases. 

(b) The contraction ability of heart increases. 

(c) Stroke volume increases during rest and exercise.

(d) Decrease in resting heart rate. 

(e) The heart rate recovery period decreases. 

(f) Blood volume increases as a result of increase in plasma volume and RBC counts. 

(g) Reduction in resting blood pressure (both systolic and diastolic). 

(h) Blood flow to muscles increases due to more blood volume.

(a) Mobility of nervous systems/Reaction Time 

(b) Muscle fibres 

(c) explosive strength 

(d) flexibility 

(e) Cardio vascular efficiency 

(f) Bio-chemical reserves and metabolic power.

Speed is the ability of the body to perform similar movements consecutively at the fastest rate. The following factors determine the speed. 

(a) Nervous system and its mobility: To generate more speed the muscles have to contract and relax at maximal speed. These actions are possible when moter impulses from C.N.S. initiates. So we call it as mobility of nervous system. 

(b) Composition of muscle fibres: The muscles which have more percentage of fast twitch fibre contract with more speed than in comparison to the muscles which have less percentage of slow twitch muscle fibres. The muscle composition is genetically determined. The sprinters always have more fast twitch fibres and endurance runners have more of slow twitch fibres 

(c) Flexibility: Every individual has different levels of flexibility. Better flexibility around a joint gives more range of movement to the muscle which can be helpful in generating better speed. 

(d) Explosive Strength: It is the ability, of muscles to overcome resistance as fast as possible with sub-max intensity of stimulus. It is a combination of strength and speed abilities, eg. 100 m sprint start, take off in long jump.

Physical exercise/training causes changes in the following parameters of circulatory system, such as: 

(a) Size of the heart 

(b) Heart rate

(c) Stroke volume

(d) Cardiac output

(e) Blood volume

(a) Size of the heart: The blood is supplied to the whole body by heart. The size of heart gets changed as a result of endurance training. Endurance training of more than 12 weeks increases the heart's weight and volume, which further increases the thickness of the left ventricle's wall and chambers' size. Then. contraction ability of the heart also increases. 

(b) Heart rate: It is the number of times the heart beats per minute. Heart rate is decreased as a result of exercise and training. This decreasing heart rate trend shows the improvement of your cardiovascular fitness. 

(c) Stroke volume: It is the amount of blood pumped by the left or right ventricle of the heart per beat. As a result of endurance training the stroke volume increases. Stroke volume for untrained individual at rest is about 55-75 ml. Whereas stroke volume of trained athletes at rest is 80 - 90 ml. In trained athletes the amount of blood pumped is more in one beat as compared to untrained. 

(d) Cardiac output: The cardiac output at rest remains unchanged but at maximum level of exercise it increases considerably. This increase results mainly, from the increase in maximal stroke volume. Maximum cardiac output ranges from 14-20 litres/min. and in trained individuals 25-35 litres/min. or more in highly trained athletes engaged in endurance sports.

(e) Blood volume: Exercise/training results in increase in blood volume which is mainly due to increase in blood plasma volume (liquid portion of blood). The number of red blood cells also increases. Increased blood plasma volume decreases blood thickness that can improve circulation of blood and oxygen availability. Highly trained male athletes may have more than 7 litres of total blood volume as compared to untrained having less than 5.6 litres of total blood volume.

Amount of blood pumped by left ventricle in per beat.

At rest period - 50 to 70 ml/beat 

During Exercise - 110 to 130 ml/beat

                        or

Amount of blood ejected by heart in one stroke.

Functional capacities begin a decline after 30 years of age. Both physical and physiological parameters decline with advancement of age, but not at the same rate. For example. endurance declines very slowly after reaching its peak but agility declines abruptly. If participation in physical activities is continued the parameters of aged population can be maintained within the limits. Research studies show that regular exercise helps in protein retention, resulting in delaying the strength decreases with ageing. Physical activity in later life supports the nervous system to work activity as in the young age. Physical exercise enables aged population to retain cardiovascular functioning. Osteoporosis is a major problem of mass population for people over 60 years of age. Regular physical activity can stop or decline these changes in bone density. F'or middle aged group the exercise programme includes walking, jogging, cycling and calisthenics. If we spread this awareness by conducting sports programmes our population will he healthy and fit. We must understand the importance of physical activity as they lay the real foundation of out' life in later years too.

There are about 650 muscles in our body, and each one helps us in producing a movement. Physical exercise, training particularly resistance or weight training affects our muscular system to a great extent. They are as follows. 

(a) Hypertrophy of the muscle: Due to resistance training the size of muscle fibres increases. Blood supply in the muscles increases. The total amount of proteins increases which is essential for muscle growth. 

(b) Biochemical changes in muscles: 

(i) Aerobic changes: Myocin content increases. Oxydation of carbohydrates and fats increases. Amount of mitochondria increases thus more muscular force is produced. 

(ii) Anaerobic changes: ATP+PC system capacity increases, thereby more energy is released. Glycolytic capacity also increases as a result of training. 

(c) Body composition changes: There can be significant losses of relative and absolute body fat. Fat free weight or muscle mass increases significantly. After training flexibility increases which plays an important role in physical activities to enhance the performance and prevent muscular injury.

Adapting effects in our cardiovascular system for a longer period are: 

(a) Cardiac output increases: The cardiac output at rest remains unchanged but at maximum level of exercise it increases considerably. This increase results mainly from the increase in maximal stroke volume. For highly endurance trained athletes the cardiac output is 40 1/min or more. 

(b) Increase in stroke volume: Physical exercise. especially endurance training, increases the stroke volume. In trained athletes, who endure for long duration, the left ventricle of heart holds more blood during relaxed state than it does in an untrained athlete's heart. It means more blood is available to enter the ventricle, which ultimately increases stroke volume. It also results in decrease in heartrate at rest. 

(c) Lung volume: With endurance training lung volume and capacities increase. vital capacity is also increased after long duration workouts. 

(d) Tidal volume increases: The tidal volume is the amount of air inspired or expired per breath. It also increases as a result of long hours training. In untrained individual the tidal volume is 500 ml,/breath. whereas in trained persons it increases to more than 600-700 ml/breath

(e) Blood flow: It is a well-known fact that active muscles require more oxygen and nutrients. To fulfil this requirement, more blood must be supplied to these muscles during exercise. The adaptive effect that takes place is that the muscle becomes better trained and the circulatory system adapts to increase blood flow to them.

Role of regular exercise on ageing process: Regular exercise always promotes healthy aging process. Getting older is a regular cycle of life. Regular exercise delays the changes which occur due to ageing. The role of regular exercise is as follows. 

(a) Muscles lose strength due to ageing. But we can maintain their strength for longer period if we exercise regularly. 

(b) With increase in age cardiorespiratory fitness decreases but those who continue to exercise keep their cardio system efficient which slows down the process of ageing. 

(c) Muscles and joints become less flexible and agile with age. But regular exercise removes various joint problems and keeps the person healthy and fit, saves from osteoporosis. 

(d) More severe changes in ageing are on skin which lead to wrinkles and decreased elasticity. Regular exercise tones up the muscles and because of aerobic consumption and better flow of circulation to all the parts of the body, there is glow on the skin with less wrinkles. 

Definitely Regular physical activities slow down the ageing process. One day each one of us is going to grow old but regular exercises become an asset to live a good quality life.

The following are the factors that affect the physiological fitness. 

(a) Anatomical structure: An individual must be appropriate in body size, shape and structure essential for the performance. Sometimes genetic impaired organs are responsible for weakness in structure which limits individual performance. 

(b) Psychological factors or stress tension: This can become a barrier to performance by contributing tension and anxiety which affect the fitness level of a person. One must be mentally tough/strong and prepared to perform better. 

(c) Climate: Physical fitness also gets influenced by different climatic conditions such as summer, winter and humid. 

(i) Exercise must be done early morning or late evening. 

(ii) Drink plenty of fluid. 

(iii) Wear light loose fitting, comfortable clothes. 

(iv) In winter dress in layers. 

(v) Stop if you experience dizziness, shivering. cramp, etc. 

(d) Diet: Plays an important role in maintaining physical fitness level. Diet requirement varies from individual to individual game wise. Therefore, while planning fitness programme diet factor must also be given due consideration. 

(e) Healthy surroundings: A healthy environment at home/school/play fields is helpful in proper growth and development of an individual which creates a better learning situation. There is a need for proper working environment for participation in sports activities. otherwise it will affect the fitness of individual.

Important functions of skeletal system: The hard and rigid structure of bone makes the skeletal system to act as a framework, which supports the body and gives it a shape. The major functions are as follows.

(a) It serves as a supporting framework. 

(b) It acts as liner and allows the movement of the body. 

(c) It protects and supports many of the internal organs. 

(d) It releases calcium when there is lack of calcium in the body fluids. 

(e) It produces, maintains and repairs itself. 

(f) It stores the marrow, which produces the blood cells. 

(g) It provides surface for the attachment of skeletal muscles.

Cardiac output: Cardiac output is the amount of blood pumped in one minute by either the left or right ventricle of the heart. 

Cardiac output = Stroke volume x Heart rate

Glycolysis is only source of energy production in erythrocytes, renal medulla, brain and sperm.

Slow-twitch of muscle fibres: The slow-twitch of muscle fibres provides better energy to the exercising muscles during endurance activity. It determines the endurance of a person.

White muscle fibres mainly performs anaerobic respiration.

Inflammation of joints due to accumulation of uric acid crystals is known as Gout.

Red muscles are rich in myoglobin.

(b) Chimpanzee

(a) (i) is correct

(c) Scrapers

(a) (i) is correct

(a) (i) is correct and (c) (i) & (iv) are correct

1. The museum of Ennigaldi Nanna in Mesopotamia.

2. It was established in 530 BCE.

3. The Capitoline museum in Italy is perhaps the oldest surviving museum at present (1471 CE).

4. Ashmolean Museum at Oxford University is the oldest University Museum in the world.

(a) Microliths

1. Rice was probably cultivated in India and China around 7000 BCE or even earlier. 

2. Wheat and barley were cultivated at Mehrgarh in the northwestern part of the Indian subcontinent (Pakistan) before 6000 BCE. 

3. Animal domestication developed as part of symbiotic life. 

4. Dogs may have been domesticated first. Friendly animals were gradually domesticated. Sheep and goat were domesticated around 10,000 BCE in Southwest Asia. 

5. Oxen were used in Sumerian civilization for tilling the land. Mehrgarh in Pakistan has evidence of sheep, goat and cattle domestication in the Neolithic period.

1. They are found at Chennai, North Arcot, Dharmapuri, Salem, Coimbatore, Ariyalur, Trichi, Pudukottai, Madurai, Sivagangai, Tirunelveli and Kanyakumari.

2. The people of this period used small artefacts made of Chert and Quartz.

3. The tool types are scrapers, lunates and triangles.

4. These people hunted wild animals and gathered fruits, nuts and roots for their subsistence.

The DNA of a Chimpanzee is 98% identical to that of a human being.

(b) Archaeology

(a) Acheulian tools are reported to have been found in Isampur in Karnataka and Bhimbetka in Madhya Pradesh.

(b) ‘Lith’ means stone. The methods and techniques involved in the production of stone tools are called lithic technology.

(c) Bifaces are tools that have flaking on both sides (bi = two, face = side).

(d) Core is the main block of stone. Flake is a small chip removed from a large stone block. Levalloisian tools includes long blades and burins. Burin is a stone-made chisel with a sharp cutting edge.

Similarities between apes and man are as follows:

i. Absence of tail.

ii. Comparatively larger head.

iii. Broad chest due to flattening of sternum.

iv. Molar teeth with five cusps.

v. Capable of sound production.

vi. Menstrual cycle in females.

vii. Highly developed facial musculature for expressions.

viii. The remarkable similarity in the DNA, haemoglobin, and albumin molecules of chimpanzee, gorilla and man.

(a) correct 

(b) incorrect 

(c) correct 

(d) incorrect

 Correct Option is (D) all of these.

Lemurs, Lorises, Tarsiers, New world monkeys, Old world monkeys, Apes and Man belong to order primates.

i. Lemurs are small arboreal animals mainly found in Madagascar.

ii. They have grasping hands and feet, flat snouts, large eyes facing more in front than lateral sides and long bushy tails.

Charles R. Darwin was a British biologist. He postulated the “Theory of origin of species by natural selection”.

Principles of Darwinism:

Darwin’s theory of organic evolution by natural selection is based on the following principles:

i. Over production or prodigality of production:

All organisms have a natural tendency to over produce. If this tendency is not checked, then even a single species of a plant or animal will occupy the entire space available on the earth.

ii. Struggle for existence: Organisms multiply in geometric ratio, but space and food remain constant leading to competition for survival. Increase in the number of species leads to a competition called struggle for existence.

iii. Variations and Heredity: The differences which occur between the closely related organisms are called variations. It is universal law of nature. Variations may be favourable or unfavourable.

iv. Survival of the fittest or natural selection: According to Darwin, in the struggle for existence, the fittest individuals survive and reproduce, while the unfit individuals perish.

v. Origin of new species: According Darwin, useful variations appear in every generation and are inherited from one generation to another. Objections to Darwin’s natural selection theory:

i. Natural selection theory explained “survival of the fittest” but not “arrival of the fittest”.

ii. Darwin did not take into account the hereditary principles.

iii. He could not provide a satisfactory explanation for the cause, origin and inheritance of variations.

iv. Certain useless characters are also inherited. He could not explain the inheritance of useless variations.

v. He was unable to differentiate variations as hereditary and environmental variations.

Survival of the fittest or Natural selection:

i. The organisms having favourable variations succeed in the struggle for existence.

ii. The organisms with unfavourable variations are unfit to survive and they perish.

iii. This means survival of the fittest.

iv. Nature selects the organisms with favourable variations and these are fittest to survive, hence, the theory is known as Theory of Natural selection.

i. Tarsiers are arboreal, nocturnal, insectivorous primates found on islands of East Indies.

ii. Their eyes are large, directed forward and have binocular vision.

iii. The limbs have five digits with adhesive pads and most of the digits have nails, except the second and third toes of hind limb bear claws.

iv. Their hind limbs are longer with elongated tarsals. From tarsier like ancestor, evolved the earliest anthropoids.

Erect Posture: The erect posture helped the man in the following ways :

i. Because of this, man is able to have bipedal mode of locomotion.

ii. The feet of man form a kind of stable platform which help him to walk erect and balance properly.

iii. The hands of man are shorter and free to handle work.

iv. The thumb of man is better developed. The thumb closes in on the other fingers of hand.

v. Man can use his hands more delicately. This type of thumb is called opposable.

vi. Man can handle even small tools and other instruments because of the position of thumbs and fingers with great dextricity.

Large Brain Size: Following are the advantages of large brain size:

i. Brain becomes more developed. Its brain ratio is more than the others as compared to body weight.

ii. Large sized brain-greater intelligence, thinking power and correlation of facts and events.

iii. Shifting of information.

iv. Capacity of reasoning developed.

v. Senses became more powerful.

vi. Reflexes became more prominent.

vii. In fact, it is the hand and the brain that made man a super animal.

Australopithecus can be considered as connecting link between ape and man because of the following apelike and man-like characters:

The ape-like characters of Australopithecus:

i. The jaws and teeth are larger than those of modern man.

ii. Face was prognathous and a chin was absent.

iii. The eye-brow ridges projected over the eyes.

iv. Their cranial capacity ranged from 450-600 c.c.

v. They used fire and a variety of tools.

The man-like characters of Australopithecus:

i. It was about four feet in height, walked nearly or completely straight.

ii. The vertebral column had a distinct lumbar curve with broad basin like pelvic girdle.

iii. Dentition was man like because the dental arch was smoothly rounded parabola and a simian gap was absent.

iv. Hands were used for non-locomotory functions like making tools. They used weapons of bones.

Thus, Australopithecus is rightly described as a man with ape brain.

Struggle for existence: According to Darwin, individuals multiply in geometric ratio, but the space and food remain constant. This leads to competition for getting requirements of life. This competition is called Struggle for existence. The struggle may be intra-specific, inter-specific or environmental.

i. Intra-specific struggle:

It is the competition among the individuals of the same species.

This type of struggle is very severe, because the need and approach of all competing organisms is precisely same. e.g. struggle between cow and cow, horse and horse, deer and deer, etc. for getting grass.

ii. Inter-specific struggle:

It is the struggle between the organisms of different species living together. Individuals of one species compete with other species for food, shelter and breeding place. e.g. Struggle between cow, horse nd deer for getting grass.

iii. Environmental struggle:

It is the struggle of all living forms against adverse environmental conditions, i.e. against natural calamities like extreme heat or cold, drought, storms, earthquakes, volcanic eruptions etc.

 Correct Option is (D) Apes and Man

 Correct Option is (D) 1600 c.c.

 Correct Option is (C) environmental struggle

i. The skull of African ape-man resembled the skull of an ape. Its volume was about that of man’s skull, its cranial capacity being about 600 c.c.

ii. Jaws and teeth were like that of man.

iii. Its forehead was also like that of man.

iv. The structure of its pelvic girdle showed that it could walk erect.

The Australopithecus appears to have been animal hunting, flesh eating and shell cracking primate. Zoologist believe that these animals were the ancestors of man or a man with ape brain.

 Correct Option is (C) actual remains

 Correct Option is (B) Australopithecus

1. Fossils are studied under palaeontology. They are used in reconstruction of phylogeny. 

2. Fossil study helps in studying various forms and structures of extinct animals. 

3. By understanding the structure of fossil, record of missing link between two groups of organisms can be deduced. 

4. By studying fossils various body forms and their evolution can be understood. They also help to understand the habit and habitat. 

5. Some fossils provide the evolutionary evidences such a connecting links.

1. Major changes that took place in evolution of man are as follows : 

2. Increase in size and complexity of brain and enhanced intelligence. 

3. Increase in cranial capacity. 

4. Bipedal locomotion. 

5. Opposable thumb. 

6. Erect posture. 

7. Shortening of forelimbs and lengthening of hind limbs. 

8. Development of chin. Orthognathous face. 

9. Broadening of pelvic girdle and development of lumbar curvature. 

10. Social and cultural development such as articulated speech, art, development of tools, etc.

 Correct Option is (D) all of these.