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Question
During primitive times oceans contained (I) fishes only, (II) algae only, (III) water only (IV) ammonia, methane and minerals only.
During primitive times oceans contained (I) fishes only, (II) algae only, (III) water only (IV) ammonia, methane and minerals only.
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Solution
The correct option is D III and IV
The primitive reducing atmosphere and prevailing high temperature facilitated reaction between hydrogen and free oxygen, nitrogen and carbon to form water (present in form of superheated steam due to high earth temperature), ammonia, methane and cyanides. Gradual cooling down of earth atmosphere caused condensation of superheated steam into water resulting in rainfall. Due to high temperature, the earlier rain water got evaporated immediately reaching the earth surface. Cooling down of earth surface in million of years allowed accumulation of rain water and formation of water bodies. The early gases (ammonia, cyanide and methane) got dissolved and wash down with rain water into sea/oceans thereby adding organic compounds to sea water. Thus, primitive sea contained water, ammonia, cyanide and methane. The metal ions and clay (composed of minerals) of mineral rocks, as got dissolved in rain water and was carried to sea. This makes option D correct. The organic molecules (as formed by polymerization and condensation of primitive gases in sea) served as source of carbon and energy source for first living organisms of the earth. The organisms that use organic compounds as their carbon and energy source as referred to as chemoheterotrophs. Due to limited supply of organic compounds, organisms evolved into chemoautotrophs that use the energy released by decomposition of inorganic compounds to form organic compounds. This was followed by chance appearance of chlorophyll to capture sunlight to be used as source of energy and evolution of photoautotrophs (algae). This makes option B incorrect as algae evolved much later during evolution. The jawless fishes were the first vertebrates and evolved during Devonian period. Options A and C are incorrect. Therefore, the correct answer is option D.
The primitive reducing atmosphere and prevailing high temperature facilitated reaction between hydrogen and free oxygen, nitrogen and carbon to form water (present in form of superheated steam due to high earth temperature), ammonia, methane and cyanides. Gradual cooling down of earth atmosphere caused condensation of superheated steam into water resulting in rainfall. Due to high temperature, the earlier rain water got evaporated immediately reaching the earth surface. Cooling down of earth surface in million of years allowed accumulation of rain water and formation of water bodies. The early gases (ammonia, cyanide and methane) got dissolved and wash down with rain water into sea/oceans thereby adding organic compounds to sea water. Thus, primitive sea contained water, ammonia, cyanide and methane. The metal ions and clay (composed of minerals) of mineral rocks, as got dissolved in rain water and was carried to sea. This makes option D correct.
The organic molecules (as formed by polymerization and condensation of primitive gases in sea) served as source of carbon and energy source for first living organisms of the earth. The organisms that use organic compounds as their carbon and energy source as referred to as chemoheterotrophs. Due to limited supply of organic compounds, organisms evolved into chemoautotrophs that use the energy released by decomposition of inorganic compounds to form organic compounds. This was followed by chance appearance of chlorophyll to capture sunlight to be used as source of energy and evolution of photoautotrophs (algae). This makes option B incorrect as algae evolved much later during evolution.
The jawless fishes were the first vertebrates and evolved during Devonian period. Options A and C are incorrect.
Therefore, the correct answer is option D.
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