Facts in Biology مقاله

خلاصه ماشینی:

This is not surprising, because the manner of an embryo's formation in the egg, the arrangement of its various organs, the methods by which it nourishes itself and breathes, and the growth of all that, are subjects that capture hearts due to their beauty, not to mention the wonders connected to them, such as the transformation of tadpoles that live in water into frogs that live in the air, and the metamorphosis of their gills into lungs suitable for breathing, and the transformation of worms into cocoons, and cocoons into flying butterflies. All of this is nothing compared to the general law that governs every living being: that these changes we observe in animal embryos are not mere playthings of nature, nor do they occur in vain, but rather they are a history of the stages through which the ancestors of those embryos passed in their evolution. Natural scientists have now agreed that all groups of animals living on the surface of the earth, as well as those that lived on it in past ages and became extinct, are connected to one another by blood kinship, and in every individual there are proofs of the history of its ancestors, such that one can even know its lineage and the stages it has ascended in its evolution. If an animal passes through a new stage in the life of its species due to specific reasons and a certain variation, and this becomes established in its offspring through repetition, special apparatuses are formed in its body to manifest that variation. In this manner, animal embryos pass through the stages that their ancestors passed through until they reach the state of their parents; this is the explanation mentioned by Professor Marshall.