\n
![\"KSEEB](\"https:\/\/live.staticflickr.com\/65535\/48141650898_97e7e45678_o.png\")
\nAnswer:<\/p>\n
I. Four alternatives are given to each of the following incomplete statement \/ question choose the right answer.<\/p>\n
Question 1.
\nThe term not dilute soup was used by.
\n(a) Oparin
\n(b) Darwin
\n(c) Haldane
\n(d) Pasteur
\nAnswer:
\n(c) Haldane<\/p>\n
Question 2.
\nWhich gas was absent in the atmosphere at the time of origin of life.
\n(a) Ammonia
\n(b) Hydrogen
\n(c) Oxygen
\n(d) Methane
\nAnswer:
\n(c) Oxygen<\/p>\n
Question 3.
\nThe first organisms on primitive earth were
\n(a) Autotrophic
\n(b) Heterotrophic and anaerobic
\n(c) Parasitic
\n(d) Prokaryotic and autotrophic
\nAnswer:
\n(b) Heterotrophic and anaerobic<\/p>\n
Question 4.
\nThe greatest weakness in Darwin\u2019s theory was his Failure to explain.
\n(a) Over production
\n(b) Survival of the fittest
\n(c) Struggle for existence
\n(d) Variations
\nAnswer:
\n(d) Variations<\/p>\n
II. Fill in the blanks with suitable words:<\/p>\n
Question 1.
\nEarth was a hot revolving ball of ………… about 4.8 billions of years age.
\nAnswer:
\nGas<\/p>\n
Question 2.
\nLightest element hydrogen was found in the ………… layer of the earliest earth.
\nAnswer:
\nOutermost<\/p>\n
Question 3.
\nVariations caused by sudden genetic changes are called ………..
\nAnswer:
\nMutation<\/p>\n
Question 4.
\nDarwin explained the survival of the fittest but not their ………..
\nAnswer:
\nArrival<\/p>\n
III. Match the following:
\n
\nAnswer:<\/p>\n
IV. Answer the followings:<\/p>\n
Question 1.
\nWhat is organic evolution
\nAnswer:
\nThe slow gradual process by which living organism have undergone changes from the single celled forms to the many celled forms of life is known as organic evolution.<\/p>\n
Question 2.
\nExplain Lamarck’s theory of use and disuse of organs with suitable example.
\nAnswer:
\nA Lamarck’s theory is based on three main ides namely new needs, use and disuse of organs and inheritance of acquired characters. The appearance of new needs forces the organism to put in additional efforts to fulfill. It may put a part of a body into more and more frequent use.<\/p>\n
Similarly, it may also be necessary for an organism to put a part of its body into less use or may not use at all. This idea is known as use and disuse of organs. Any part of the body that is more and more used is likeiy to grow larger and become better and stronger.<\/p>\n
In the same way any part of body which is less frequently used has the tendency to become less prominent and may even ultimately disappear. Thus by a differential over use and disuse of various body parts, an organism would change to some extent and acquire new characters.<\/p>\n
For example: for over use: Giraffe\u2019s ancestors were small as deer. Giraffes started stretching their neck and forelimbs in order to reach the leaves of taller plants due to the severe competition from other herbivores and drought. This continued for several generations and as a result neck and forelimbs became longer. Example for disuse: The ancestors of snake had four well developed limbs. Snakes were hunted by more advanced group of animals. In order to survive they started crawling on the ground and spent most of -heir time hiding in crevices and holes. This resulted in the limbs becoming degenerate and ultimately disappear.<\/p>\n
Question 3.
\nWhat is the role of variations in evolution?
\nAnswer:
\nDarwin found that generally, the young ones of an organism show differences compared to the parent. He described the differences as variations which are the rule of nature which helps an organism to adjust better to the environment.<\/p>\n
Question 4.
\nWhat is the mutation?
\nAnswer:
\nSudden changes to the genetic makeup of an organism when it is subjected to higher environmental temperature or high energy radiation is called a mutation.<\/p>\n
Question 5.
\nWhat is neo – Darwinism?
\nAnswer:
\nNeo Darwinism is the modern theory on organic evolution, the synthesis of ideas from the theory of natural selection, and mutation theory in the light of present knowledge on how mutation occurs.<\/p>\n
Question 6.
\nWhich organisms changed the earth\u2019s atmosphere from reducing to oxidizing type?
\nAnswer:
\nThe appearance of autographs in the form of blue-green algae changed the situation on earth. These organisms released free molecular oxygen into the atmosphere, gradually transforming it into an oxidizing type.<\/p>\n
Question 7.
\nWhat were the limitations found in Darwinism and Lamarck ism?
\nAnswer:<\/p>\n
I. Answer the following :<\/p>\n
Question 1.
\nWho is the scientist conducted a swan-necked flask experiment?
\nAnswer:
\nThe famous swan-necked flask experiment was conducted by Louis Pasteur.<\/p>\n
Question 2.
\nExplain swan-necked flask experiment.
\nAnswer:
\nThe famous swan-necked flask experiment was conducted by Louis Pasteur. and he proved beyond doubt that all forms of life arise only from preexisting life.<\/p>\n
Question 3.
\nWho proposed theory of chemical evolution?
\nAnswer:
\nTheory of chemical evolution was proposed by oparin and Handane independently.<\/p>\n
Question 4.
\nWrite the assumptions of theory of chemical evolution.
\nAnswer:
\nAssumptions of theory of chemical evolution are:<\/p>\n
Question 5.
\nExplain the initial days of Earth\u2019s.
\nAnswer:
\nIn the initial days of earth\u2019s formation, heavy elements such as iron and nickel were present in the center of the earth. Comparatively lighter ones like aluminum and silicon formed the middle layer, elements like hydrogen, oxygen and carbon were found in the outermost layer. Due to the high temperature, the atoms of these elements could not combine to the molecule as the earth started cooling gradually the atoms started combining to form molecules.<\/p>\n
Question 6. Question 7. Question 8. Due to their affinity towards water molecules an envelope of water molecules formed which increased the chemical reactions and stalled exhibiting the basic properties of life such as metabolism growth and reproduction. In course of time coacervates became established in to the first living system known as prolobionts.<\/p>\n Which functioned as the first enzymes and leading to the formation of first cells. The first forms of life obtained energy by the fermentation of organic compounds they were thus heterotrophs and anaerobic organisms.<\/p>\n Question 9. Question 10. Question 11. Question 12. Question 13. Question 14. Question 15. Question 16. Question 17. Question 18. Question 19. Karnataka Board Class 8 Science Chapter 22 Evolution of Life KSEEB Class 8 Science Chapter 22 Textual Questions & Answers I. Four alternatives are given to each of the following incomplete statement \/ question choose the right answer. Question 1. The term not dilute soup was used by. (a) Oparin (b) Darwin (c) Haldane (d) …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/5129"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=5129"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/5129\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=5129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=5129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=5129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nMention the earliest molecules formed which became the basic molecules for the origin of life.
\nAnswer:
\nThe earliest molecules formed were those of H2, <\/sub>N2,<\/sub> NH3,<\/sub> CH4,<\/sub> CO2<\/sub> and water vapor which became the basic molecules for the origin of life.<\/p>\n
\nName the earliest organic molecules formed.
\nAnswer:
\nSimple sugars, fatty acids, glycerol, amino acids and nitrogen bases were the earliest organic molecules formed which helped in the origin of life.<\/p>\n
\nExplain Haldane\u2019s view on origin of life.
\nAnswer:
\nAs the earth cooled. The simple organic compound combined among them selves to form complex organic compounds, due to the accumulation of these complex organic molecules, the sea water ultimately became a sort of a \u2018hot dilute soup\u2019. In this soup, molecules interacted and aggregated to form more complex molecules called coaCervantes.<\/p>\n
\nWhat is organic evolution?
\nAnswer:
\nThe slow gradual process by which living organisms have undergone changes from the single-celled forms to the many-celled forms of life is known as organic evolution.<\/p>\n
\nMention the principles of Lamarck ism theory.
\nAnswer:
\nThe Lamarck ism theory is based on three principles they are:<\/p>\n\n
\nMention the drawbacks of Lamarck’s ideas.
\nAnswer:
\nLamarck\u2019s ideas had some-drawbacks.<\/p>\n\n
\nWho proposed a theory of Natural Selection.
\nAnswer:
\nCharles Darwin proposed a theory of Natural selection in 1859. It is more popularly known as \u2018Darwinism\u2019.<\/p>\n
\nMention the principles of Darwinism theory.
\nAnswer:
\nDarwinism theory is based on the following principles.<\/p>\n\n
\nExplain Darwin\u2019s theory of overproduction.
\nAnswer:
\nOverproduction: All organisms have a natural capacity to produce a large number of young ones. This capacity is known as overproduction.<\/p>\n
\nExplain Darwin\u2019s theory of the struggle for existence.
\nAnswer:
\nAs a result of high rate of reproduction, there must be competition between individuals. It is for sharing food water, living space and other resources. This competition was described by Darwin as a struggle for existence.<\/p>\n
\nExplain Darwin\u2019s principles of variation.
\nAnswer:
\nGenerally, the young ones show differences compared to the parents. This is variation and they help the organisms to adjust better to the environment.<\/p>\n
\nExplain Darwin\u2019s principles of Natural selection.
\nAnswer:
\nAccording to Darwin nature selects only those organisms that have favorable variations.<\/p>\n
\nExplain the survival of the fittest.
\nAnswer:
\nThe naturally selected organisms which have developed advantageous variations have a better chance of survival less adopted or not adopted get eliminated. This idea is known as survival of the fittest.<\/p>\n
\nMention the drawbacks of Darwin\u2019s theory.
\nAnswer:
\nDarwin failed to recognize the source of variations in organisms. He had no idea of the mechanism of inheritance. He explained the survival of fittest but not their arrival.<\/p>\n KSEEB Solutions for Class 8 Science<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"