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Class 11 Anthropology Chapter 4 Human Evolution
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Human Evolution
Chapter – 4
EXERCISES
1. In which geological period man appeared on this earth?
Ans: Miocene epoch, man appeared on this earth.
2. Who discovered the fossil remains of Java man? They belong to which geological period?
Ans: Dr. Eugene Dubois discovered the fossil remains of Java man.
They belong to Middle Pleistocene.
3. Write three characteristics features of Cro-Magnon man.
Ans: Three characteristics features of Cro-Magnon man are:
(a) The skull is large the length and breadth of the skull are 203mm and 150mm.
(b) The vault is low.
(c) The cranial index is 73.7.
4. Write briefly on organic evolution.
Ans: According to organic evolution, life was originated once on this earth. In that initial stage life was restricted to very minute simple cell organism. Through a long and continuous process of change these organisms tried to adapt themselves with the changing atmosphere of the earth and thereby became complicated. Single cellular organism became multicellular and this is the principal spirit of organic evolution. Thus, the gradual change and development of simple and lower categories of life forms to more complex and higher categories of life forms in consequence of the geo- environment are known as organic evolution.
5. Write briefly on human evolution.
Ans: Human evolution consists of a large number of organisms which exhibits a wide variation in size, shape and complexity of structure, from the simple unicellular protozoa to the complex multicellular organisms. Interpreting the causes and phenomena of the variation in the living forms nature has long been remaining as an area of interest of scientist and philosophers. It is assumed that the present living organisms have arisen from its pre- existing from undergoing modification through time. The scientists and philosophers regarded this phenomena of nature as a gradual but continuous process leading to the arrival of more complex forms derived from the pre-existing simpler forms as “Evolution”.
6. From where fossil remains of Neanderthal man is discovered?
Ans: Neanderthal valley near Dusseldorf, Germany, Neanderthal man is discovered.
7. Write shortly on Neanderthal man.
Ans: Neanderthal man were first discovered in the year 1856 in the Neanderthal valley near Dusseldorf, Germany. Before this discovery, other fossil remains akin to Neanderthal man were discovered as early as 1829 in a Belgium cave, but were not recognized at that time. In 1848 another skull of women was discovered in Gibraltar, but again was not recognized til 1908. Regarding the identity of Neanderthal man the scientists of that time differed amongst themselves.
Neanderthal were identified as the immediate ancestors of modern man. They were able to exploit the environment to create a cultural perspective of their own. Neanderthal people through their devices developed a culture named Mousterian culture known after the site Le Moustier in France. It corresponds to the middle Palaeolithic period. Mousterian culture was the only way of life of the Neanderthal people. The typical implements were the scrapers and points.
Neanderthal man flourished during great ice age. During this period Northern Europe was covered with thick ice sheets and other parts of Europe experienced bitter cold. The chief animals of this period were mammoth, the woolly rhinoceros, cave lion, cave bear, cave etc. All these animals were provided with a thick coat of fur.
8. Write the names of two books written by Charles Darwin.
Ans: The names of two books written by Charles Darwin are:
(a) Origin of Species.
(b) Descent of man.
9. Who discovered the fossil remains of Australopithecus Africanus?
Ans: Prof. Raymond Dart discovered the fossil remains of Australopithecus Africanus.
10. Who discovered the fossil remains of Pithecanthropus erectus? Why are they termed Homo erectus?
Ans: Dr. Eugene Dubois discovered the fossil remains of Pithecanthropus erectus.
(Do yourself)
11. Which fossil man is considered as Homo Sapience? Write four characteristics features of that fossil man.
Ans: Do yourself.
12. What are the two types of Neanderthal man?
Ans: The two types of Neanderthal man are:
(a) Conservative Neanderthal.
(b) Progressive Neanderthal.
13. Who is Lamarck? Discuss the theory of Lamarckism.
Ans: Lamarck was the first naturalist to put forward the fact that the animals could modify themselves to adapt to the environmental situations.
The theory of Lamarckism are:
(a) Role of environmental factors: Lamarck believed that environment plays an important role in influencing the form of living organisms. The influence leads to change in their habits. The change in habits results in unusual activity of an organ or structure. Lamarck demonstrated several cases where individuals of the same species, grown under different environmental conditions exhibited marked differences. Lamarck tried to explain the nature and extent of adaptation of different species to their environment.The webbed feet to aquatic birds were the root cause of the challenge of these birds to search for food in swampy areas. In that environment the birds made continuous efforts to swim spreading their toes and this had developed a condition of stretching skin between the toes. The ostrich cannot fly though they have got wings. Formerly they possessed regular flying habits. But owning to certain circumstances the ostrich did not used their wings and these became weak and inactive.
(b) Use and disuse of organs: The classic example used to explain the concept of use and disuse of organs is the elongated neck of the giraffe. According to Lamarck’s giraffes had neck and other body proportions just like other animals. The giraffe felt the necessity to stretching their necks and shoulders continuously for having leaves on the high branches of trees during the scarcity of food, the neck of the giraffes grew longer; and this particular trait was transmitted through generations. Ultimately giraffes have become the possessor of unusual long neck. Another example is deep- sea fishes which are found at the sea bottom where no sunlight is present. So, they had to lead an inactive life. The eye of one side which lies on the bottom then migrates towards the upper side. Thus, both eyes are on the single side of the body. These two examples demonstrate how use could change a trait. Lamarck believed that disuse would cause a trait to become reduced. The wings of penguins, for example, would be smaller than those of other birds because penguins do not use them to fly.
(c) Inheritance of acquired characters: All that has been acquired by the organism during its life time due to direct or indirect environmental effects is preserved by the generation and is transmitted to the offspring. In the offspring these modifications become more and more pronounced if they are exposed to similar stress of the environment as was faced by their parents or ancestors. Such cumulative effects will ultimately result in the appearance of new species.
14. Discuss Darwin theory of natural selection.
Ans: Darwin theory of natural selection is based on the following principles:
(a) Overpopulation: Every organism shows a tendency to increase in numbers. The organism produces more number of offspring than will be able to survive and reproduce. The population of each species remains more or less constant because offspring die in large number before they become reproductively active. The food and other sources do not increase in the same manner.
(b) Struggle for existence: Darwin noticed that all organism increase in geometric ratio, but the food and space are not increase correspondingly. The organism should face competition for survival. Darwin called it struggle for existence.
Thus struggle is of three types:
(i) Intraspecific struggle.
(ii) Interspecific struggle.
(iii) Struggle with the environment.
(c) Natural selection or survival of the fittest: The organism with beneficial variation will survive and those with less fit and unfavorable variation will be eliminated. The organisms which are selected by nature are said to be the fittest. Variation which is useful to the individual in a particular environment would increase that individual’s ability to reproduce. In the struggle of existence, nature eliminates those that are not fit. Those which are having favorable traits to adapt and survive produce more offspring.
(d) Origin of new species: The overproduction of animals leads to struggle for existence. The animal survive with favourable variations are better adapted to the environment. All the modifications caused by variations and selected by nature are accumulated from generation to generation till a generation is produced that is more adapted and has more chances of survival. Thus a new species originated by gradual accumulation of favorable variations in a number of generations.
(e) Variations and heredity: Those traits which are favorable are produced more and inherited to the following generation. The unfavorable ones are less in numbers and in course of time if their variations are not more favored by nature are eliminated from the surface of the earth.
15. Write the synthetic theory of evolution.
Ans: Darwin’s theory lacked an input of modern concepts of genetics and the mechanisms how characters appear and persist in a population. The synthetic theory appeared by the synthesis of the original idea given by Charles Darwin and addition of new knowledge of genetics, population dynamics, statistics, and heredity to the theory. This is the most modern theory of evolution and has been constantly improved during 20th century by the contribution of the following scientists such as R.A. Fischer, J.B.S. Haldane , Ernst Mayr, Julian Huxley, and G.G. Simpson with their studies on population dynamics. Dobzhansky, H.J. Muller, H. De Vries, G.L. Stebbins added information on genetics and mutation. Gm Hardy, W. Weinberg, Sewall Wright did extensive work on population genetics and statistics, which helped to understand the mechanism of heredity. It describes the evolution of life in terms of genetic changes occurring in the population that leads to the formation of new species. It also describes the genetic population or Mendelian population, gene pool and gene frequency. The major concepts coming under this theory include genetic variations, reproductive and geographical isolation and natural selection.
According to this theory some factors operate for the formation of new species. These factors are genetic recombination, mutation, natural selection, genetic drift, gene flow and isolation.
16. What are the different mechanisms of evolution? Discuss.
Ans: The different mechanisms of evolution are:
(a) Mutation: Hugo de Vries, a Dutch botanist, one of the independent rediscoveries of Mendelism, put forward his views regarding the formation of new species in 1901. According to him, new species are not formed by continuous variations but by sudden appearance of variations, which he named as mutations. Hugo de Vries stated that mutations are heritable and persist in successive generations. Mutation is the sudden change in the genetic material of an organism results to the formation of new traits thereby producing variation in the population of the organism.
(b) Genetic Drift: The American scientist Sewall Wright gave the principles of gene frequency fluctuations in small populations which he termed as genetic drift. Genetic drift also called as genetic sampling error or Sewall Wright effect, a change in the gene pool of a small population that takes place strictly by chance. Genetic drift can result in genetic traits being lost from a population becoming widespread in a population without respect to the survival of reproductive value of the alleles involved.
(c) Gene flow: Gene flow also called as gene migration, the introduction of genetic material from one population of a species to another thereby changing the composition of the gene pool of the receiving population. The introduction of new alleles through gene flow increases variability within the population and makes possible new combinations of traits. In humans gene flow usually comes about through the actual migration of human populations, either voluntary or forced.
(d) Inbreeding: The last evolutionary force that needs to discuss is non- random mating. Non- random mating occurs when the probability that two individuals in a population will mate is not the same for all possible combinations of genotypes. Non- random mating can be assortative, when individuals are more likely to mate with similar individuals, or it can be disassortative, when individuals prefer to mate with dissimilar individuals.
Additional Questions
1. Write in short:
(a) Write the name of a book written by Lamarck?
Ans: The name of a book written by Lamarck is “Philosophic Zoologique”.
(b) Who was Charles Darwin?
Ans: Charles Darwin was a renowned British naturalist.
(c) What is a recombination?
Ans: Recombination is a process where new combinations of alleles are formed.
(d) Define genetic recombination?
Ans: The genetic recombination occurs during sexual reproduction at the time of gamete formation.
(e) Define Isolation?
Ans: Isolation is one of the significant factors responsible for the synthetic theory of evolution.
(f) Who was the first philosopher who made an attempt to put forward a natural explanation for the origin of life?
Ans: Thales was the first philosopher who made an attempt to put forward a natural explanation for the origin of life.
(g) Who was the scholar who identified the fossil as the remains of formerly living animals?
Ans: Xenophanes was the scholar who identified the fossil as the remains of formerly living animals.
2. Write in long:
(a) Write the four laws given by Lamarck?
Ans: The four laws given by Lamarck are:
(i) 1st law-Life tends to change continuously to increase the volume as well as to increase the size as a whole in a particular environmental situation.
(ii) 2nd law- This need is fulfilled by means of the production of a new organ. The new need initiate new movement and which is continued.
(iii) 3rd law- When an organ is continuously used it is subject to grow and ultimately its full development is reached. On the other hand disuse of an organ causes its degeneration and ultimately results in disappearance.
(iv) 4th law- The characters which are acquired in the species are transmitted to the next generation. These would become hereditary features.
(b) Write a short note on Criticism of Lamarckism?
Ans: The theory of evolution though it was the pioneering attempt in the formulation of biological explanation of evolutionary process is not given any serious scientific value during the present period. The theory of Lamarck has been criticized because of the fact that it has not been possible to establish that characters acquired during lifetime of any species are transmitted to the succeeding generation. The environment can effect the animal but it is doubtful that a new need forms new structures. The use and disuse of the organs is correct up to some extent. The inheritance of acquired characters is disputed.
Charles Darwin was a renowned British naturalist. Darwin put forward a conspicuous scientific thinking on the theory of evolution. Darwin explained his understanding in relation to the evolutionary principal on the basis of his direct observation of nature at the difference part of the world. In the early years of his life Darwin sad highly influence by Charles Lyell’s remarkable book entitled “Principles of Geology” published between 1830 and 1833.
Charles Darwin sailed around the world 1831 to 1836 as a naturalist on a ship HMD Beagle. His experiences and observations helped him develop the theory of evolution through natural selection. Darwin sailed round the world for 5 years and during that time he observed and collected numerous events and factual matters relating to life throughout the different parts of the world. After the competition of his journey Darwin started thinking deeply on specimens collected during the period.
(c) Write a short note on Criticism of Darwinism?
Ans: The following points have been raised against the theory of natural selection:
(i) All of the variations in organisms may not be a result of adaptation to new demands.
(ii) Environmental factors are not the only causes of variations. They may be caused even by other factors.
(iii) Darwinism was unable to explain the various reasons for variation as well as the mode of variation transmission.
(iv) There was no differentiation made between somatic and germ cell variants.
(v) Natural selection is an important component, but it is not the only one that contributes to evolution.
(vi) Small variations in small groups cannot result in speciation.
(vii) No consideration was given to the genetic basis of inheritance.
(d) Write briefly about the Ardipithecus group?
Ans: A team led by American paleoanthropologist Tim White discovered the first Ardipithecus ramidus fossils in the Middle Awash area of Ethiopia between 1992 and 1994. Since that time, White’s team have uncovered over 100 fossil specimens of Ar. ramidus. White and his colleagues gave their discovery the name Ardipithecus ramidus. At the time of this discovery, the genus Australopithecus was scientifically well established, so White devised the genus name Ardipithecus to distinguish this new genus from Australopithecus.
The Ardipithecus group is the earliest human and our closest link to the other primates. They evolved in Africa and took the first steps towards walking upright on two legs. Walking upright may have developed them to survive in diverse habitats like grassland and forest. They show both ape like and human-like features. They had a small brain, sloping face, prominent brow ridges and elongated skull. Two defining human anatomical characteristics are the small canine tooth and walking upright on two legs. Evidence of walking upright comes from the position of the foramen magnum, femur and reconstructed pelvis.
(e) Write the characteristics features of Ardipithecus?
Ans: The characteristics features of Ardipithecus are:
(i) The limb proportion resembles those of modern Old World monkeys.
(ii) The upper canines were relatively short and small, like those of Australopithecus.
(iii) The incisors were not broad as in modern apes.
(iv) They more closely resembled later hominids in size and shape.
(v) The size of the premolars and molars was smaller, relative to body size, than those of Australopithecus.
(vi) The skull of Ar. ramidus most closely resembled earlier hominids.
(vii) The cranial base and face were short, and the cranial capacity was similar to that of chimpanzees.
(viii) The skull in Ar. ramidus lacked the specializations for heavy chewing.
(ix) The hands and feet of Ar. ramidus were also unique. The hands lacked the wrist- stabilizing features and long metacarpals of knuckle- walking apes; the wrist could bend upward, and the fingers were long.
(x) The proportions of the hands were similar to those seen in the hands of later members of Australopithecus, and there was no evidence of any knuckle- walking adaptation in its arms or hands.
(f) Write the characteristics features of Australopithecus Africanus?
Ans: The characteristics features of Australopithecus Africanus are:
(i) The skull closely resembles that of the chimpanzee in size and facial portion.
(ii) Head is dolichocephalic.
(iii) Faint supra orbital ridges.
(iv) The orbits are circular like that of an Orangutan.
(v) The premaxilla is well marked as found among the apes.
(vi) The face is slightly prognathous.
(vii) The teeth are arranged in the jaw in human fashion.
(viii) The canines are small.
(ix) The grinding teeth resemble human in every details.
(x) The palate is parabolic in shape.
(g) Write the characteristics features of Pithecanthropus erectus ?
Ans: The characteristics features of Pithecanthropus erectus are:
(i) The maximum length of the skull cap is 185 mm and maximum breadth is 130 mm.
(ii) The cranial index is 70 and therefore the skull is dolichocranial.
(iii) The cranial capacity of the skull is 850 cc.
(iv) The vault of the skull is low and almost like those of the Apes.
(v) The forehead is narrow and slanting.
(vi) The Supra orbital ridges are continuous and fuse across the middle line forming a torus. This is found in gorillas and chimpanzee.
(vii) Pithecanthropus erectus most probably had the power of speech.
(viii) The temporal region of the skull is not very prominent and the temporal lines are widely separated as in gibbon, chimpanzee and man.
(ix) The teeth are of enormous size.
(x) The roots of the teeth are widely separated as in apes. The roots are more akin to human types.
(h) Write the characteristics of a La Chapelle -aux Saint?
Ans: The characteristics of a La Chapelle -aux Saint are:
(i) The skull in general is very large and heavy.
(ii) It is dolichocranial.
(iii) The length of the skull is 208mm and breadth is 155 mm.
(iv) The cranial index is 74.5
(v) The cranium capacity is 1600c.
(vi) The forehead is very receding.
(vii) The Supra orbital ridges are continuous forming a torus. The orbits are large and round.
(viii) The upper jaw is prominent.
(ix) The nose is very broad and short.
(x) The base of the skull presents many primitive features.
3. Choose the correct answer:
(a) R.S Lull classified the theories into how many categories?
(i) Three.
(ii) Four.
(iii) Six.
(iv) Two.
Ans: (ii) Four.
(b) Who proposed the theory of eternity?
(i) Father Suarez.
(ii) Thales.
(iii) Preyer.
(iv) Georges Cuvier.
Ans: (iii) Preyer.
(c) Who proposed the theory of special creation?
(i) Father Suarez.
(ii) Preyer.
(iii) Georges.
(iv) Thales.
Ans: (i) Father Suarez.
(d) In which year the theory of eternity was proposed?
(i) 1808
(ii) 1880
(iii) 1828
(iv) 1888
Ans: (ii) 1880
(e) Who proposed the theory of Catastrophism?
(i) Thales.
(ii) Preyer.
(iii) Georges Cuvier.
(iv) Father Suarez.
Ans: (iii) Georges Cuvier.
(f) When did Georges Cuvier was born?
(i) 1769
(ii) 1832
(iii) 1796
(iv) 1823
Ans: (i) 1769
(g) Who proposed the theory of organic evolution?
(i) Preyer.
(ii) Father Suarez.
(iii) Georges Cuvier.
(iv) Thales.
Ans: (iv) Thales.
(h) Who first persuasive theory of evolution was presented?
(i) Thales.
(ii) Lamarck.
(iii) Preyer.
(iv) Father Suarez.
Ans: (ii) Lamarck.
(i) When did Lamarck was born?
(i) 1745
(ii) 1829
(iii) 1830
(iv) 1744
Ans: (iv) 1744
(j) Who entitled the book “ Principles of Geology”?
(i) Charles Darwin.
(ii) Lamarck.
(iii) Father Suarez.
(iv) Georges Cuvier.
Ans: (i) Charles Darwin.
(k) When did Charles Darwin was born?
(i) 1890
(ii) 1809
(iii) 1822
(iv) 1892
Ans: (ii) 1809
(l) When did Charles Darwin bring the idea of natural selection to the attention of the world in his book, the Origin of Species?
(i) 1859
(ii) 1759
(iii) 1869
(iv) 1795
Ans: (i) 1859
(m) When did “The descent of Man” was published?
(i) 1881
(ii) 1771
(iii) 1871
(iv) 1871
Ans: (iv) 1871
(n) Who discovered the fossil remains of Australopithecus Africanus?
(i) Eugene Dubois.
(ii) Prof. Raymond Dart.
(iii) M. Louis Lartet.
(iv) Hooton.
Ans: (ii) Prof. Raymond Dart.
(o) What is the cranial capacity of the skull?
(i) 860 cc
(ii) 870 cc
(iii) 850 cc
(iv) 890 cc
Ans: (iii) 850 cc
(p) When did the Neanderthal man were first discovered?
(i) 1856
(ii) 1756
(iii) 1956
(iv) 1865
Ans: (i) 1856
(q) What is the cranial index of La Chapelle -aux Saint?
(i) 75.5
(ii) 74.5
(iii) 74.6
(iv) 75.6
Ans: (ii) 74.5
