Tag: theory of natural selection

Evolution is the gradual change in the traits in order to adjust to the changing environmental conditions. Relative dating helps in evolution to detect the relative order of past events in comparison to other organisms. Similarly, carbon dating is used to know the age of the fossils on the basis of which evolutionary relationship is determined. It also helped to study the origin of life. So, the given statement is true.

• The Miller-Urey experiment was an experiment that simulated hypothetical conditions present on the early Earth in order to test what kind of environment would be needed to allow life to begin. The experiment is considered to be the classic experiment on the origin of life. 
• It was conducted in 1953 by Stanley L. Miller and Harold C. Urey at the University of Chicago. The experiment used water (H2O), methane (CH4), ammonia (NH3) and hydrogen (H2) - materials which were believed to represent the major components of the early Earth's atmosphere. The chemicals were all sealed and circulated inside a sterile array of glass tubes and flasks connected together in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes. 
• The liquid water was heated to add water vapor to the chemical mixture and the resulting gases were circulated around the apparatus, simulating the Earth's atmosphere. The flask with heated water represents water on the Earth's surface and the recycled water vapor is just as water evaporates from lakes and seas, before going into the atmosphere and forming into the rain. Sparks were fired between the electrodes to simulate lightning storms (believed to be common on the early earth) through the water vapors, and then the vapors were cooled again so that the water could condense (simulating the oceans) and trickle back into the first water flask in a continuous cycle. 
• At the end of one week of continuous operation, Miller and Urey observed, by analyzing the cooled water, that as much as 10-15% of the carbon within the system was now in the form of organic compounds. Two percent of the carbon had formed amino acids, including 13 of the 22 that are used to make proteins in living cells, with glycine as the most abundant. 

A- The Miller-Urey experiment or Miller experiment was an experiment that instigated the condition which were thought to be present in early earth or primitive earth. Hecreated electric discharge in a closed flask containing a mixture of ammonia(NH3), methane(CH4), hydrogen(H2) and water vapour(H2O) at 800 degree celcius and observed formation of amino acids The ratio of CH4,NH3 and H2 was 2:1:2.

Moeritherium is extinct mammals. They are one of the first group of mammals that were present in the prehistoric era. They are also said to be distant relatives of modern-day elephants. Some of their features show remarkable similarities to modern-day elephants. So, they are said to direct evidence of the evolution of modern elephants and animals, 

• In biology, an atavism is a modification of a biological structure whereby an ancestral trait reappears after having been lost through the evolutionary change in previous generations. For example, the Appearance of ancestral characters in the new borne, such as the tail, multiple mammae, etc in humans, Extra toes of the modern horse, Reappearance of prothoracic wings in insects, etc.
• Hence Appearance of ancestral characters in the new borne, such as the tail, multiple mammae, etc., are known as an atavism.
• So, the correct answer is 'Atavism'.

• There are different reasons for the origin of s=new species from older ones. 
• One of these reasons is the development of random and sudden mutations. Mutations are nothing but changes that occur in DNA sequences. Certain environmental factors cause mutations. Thus, change in DNA sequence leads to the generation of a species with some altered character.
• Continental drift describes the relative change in geographical locations of the continents. This theory was first established by Abraham Ortelius saying that there must have been drift in the location of continents. This theory also explains the reason behind similar-looking animals on different continents.
• Natural calamities like earthquakes, tornadoes, volcanoes, hurricanes, etc cause large scale destruction of life and biodiversity. They also lead to the development of some characters in living organisms that are altered or modified forms of their original character. 
• So, they too lead to change inn current species character and form new species.
• So, all the given options are correct.