Question

In the development history of mammalian heart, it is observed that it passes through a two fish like heart, three chambered frog like heart and finally four chambered stage. To which hypothesis can this above cited statement be approximated?

• A. Biogenetic law
• B. Hardy Weinberg law
• C. Lamarck's principle
• D. Mendelian principle

Answer 1

The correct option is A Biogenetic law

Haeckel proposed biogenetic law which states that ontogeny repeats phylogeny. Here, ontogeny refers to life history of an individual and phylogeny is the history of evolution of the individual. Therefore, all organisms recapitulate evolutionary history of their race in abbreviated form during their development. Development of complex four chambered heart of mammals go through two chambered tube like heart of fishes, three chambered amphibian heart and then becomes four chambered structure. Presence of same basic plan during embryonic development of vertebrates proves their common ancestry and the evolutionary sequence. It is established that fishes served as progenitor or amphibian which in turn gave rise to reptiles. Reptiles diversified into birds and mammals. This makes option A correct.

According to the Hardy Weinberg law, the allele frequencies, irrespective of their dominance of recessiveness, in a population remain constant under absence of factors responsible for evolution (natural selection, migration, genetic drift). This makes option B incorrect.

Lamarck proposed theory of inheritance of acquired characters which states that individual acquire characters under influence of needs as posed as changing environmental conditions; these characters are inherited. This makes option C incorrect.

Mendel conducted hybridization experiments on garden pea plant, Pisum sativum and proposed “Laws of inheritance” on the basis of his results. This makes option D incorrect.

Therefore, the correct answer is option A.