First life on earth was chemoheterotroph. These were formed in the environment of sea having abundant organic molecules. They absorbed the organic materials for the sake of nutrtion and hence were chemoheterotrophs.
62.
Employment of hereditary principles in the improvement of human race is
Eugenics is the science that deals with factors (such as principles of genetics) related to improvement of human race. Improvement of race is positive eugenics and if factors are impaired, then it is negative eugenics.
• Euthenics is the science which improves the condition of life and the environment of human being.
• Ethnology is the study of different races of mankind, their distribution, relationship and activities.
• Euphenics is the study of body functions and treatment of heredity defect through medical means i.e. genetic engineering.
63.
Individuals of same species having non-genetic differences due to environment are called