Short Answer TypeGive reasons for the following:
Nitrogenous fertilisers are not applied in fields where leguminous crops grow.
Give reasons for the following:
At higher temperatures, green plants start evolving CO2 instead of O2.
State the best known contribution of:
(i) Alec Jeffery
(ii) P.K. Sethi
(iii) Hugo de Vries
Describe the Miller and Urey experiment on the origin of life.
They created probable conditions of primitive earth in the laboratory. They used spark discharge apparatus that had two tungsten electrodes to provide electric discharge (simulating lightning of primitive atmosphere). An atmosphere of gases (CH4, NH3, H2O, H2) was created in a chamber and condensed liquid allowed to accumulate in another chamber. Energy supplied by heating water in another chamber. After some days amino acids like glycine, alanine and some more complex organic compounds were collected in vitro like purine, pyrimidine, sugar,glycerol, formic acid,short chain etc. This indicated the possibility of origin of life from inanimate matter on the earth, when atmosphere was reducing (containing no free oxygen), containing gases like methane, ammonia, hydrogen sulphide, frequent lightning and enough water was present. Simple amino acids which are building blocks of proteins might have given rise to complex molecules that are building blocks of cells.
Long Answer Type(a) Name and define the three types of natural selection.
(b) State the following:
(i) Hardy Weinberg’s principle
(ii) Theory of recapitulation
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