Q. In the development history of mammalian heart, it is observed that it passes through a two chambered fish like heart , three chambered fish like heart and finally four chambered stage. To which hypothesis can this above statement be approximated ?
(a) Biogenetic law
(b) Hardy Weinberg law
(c) Lamarck’s principle
(d) Mendelian principle
Solution :
Correct option : A (i) Biogenetic law or Recapitulation theory states that stages of development of a one animal embryo are same as other animals. this law also theorizes that ontogeny (embryonic development) of an individual repeats phylogeny, during each stage of development. (ii) On other hands, Lamarck’s principle states that if one organism changes in order to adapt its environment, those changes are passed on to its offsprings. which means it doesn’t repeat its phylogeny. (iii)Hardy Weinberg laws theories that genotypic frequencies remain constant from generation to generation. (iv)While in Mendelian law genes or units of inheritance passes from one generation to other.
