In the beginning of the Torah reading of Bereshit, we find the verse, “And G-d made the beast of the earth according to its kind, and the animal according to its kind, and every creeping being of the ground according to its kind, and G-d saw that it was good” (Bereshit 1:25). On this verse, the famous Biblical and Talmudic exegete R. Shlomo Yitzchaki, known as Rashi, comments that “He established them [the various living creatures] in their [full] form and in their [full] stature”. This comment of Rashi is in accordance with our Sages’ view as expressed in the Babylonian Talmud, Chullin 60a and Rosh Hashana 11a.
The Sages, as echoed in Rashi’s commentary, are informing us that all living creatures were created in their full mature forms, in contradistinction to their normal development following their creation whereby creatures are born small and develop with time. This unusual phenomenon of being created in full form goes hand in hand with another comment of Rashi on the verse, “This is the account of the descendents of Adam, on the day of G-d’s creating of Man, He made him in the likeness of G-d” (Bereshit 5:1). Rashi, in line with our Sages’ view as mentioned in Bereshit Rabbah 24:7, points out “that on the day he was created, he begot children”. Both of these comments amplify how different living beings were at the very onset of creation from what they are since then.
In his Avnei Azel, the early 20th century Torah scholar, R. Isser Zalman Meltzer notes the ramifications of the aforementioned. It brings forth a major fallacy in the arguments of modern day scientists who seek to prove the earth’s existence for longer than the almost 6,000 years that Judaism tells us we have been in existence, as they attempt to prove based on various early fossils and the like. Their argument basically goes that these creatures, in accordance with the way creatures develop today according to nature, would indicate a development of millions of years, in contradiction to our tradition. However, initial created beings did not abide by today’s laws of nature. Today an ox is not born in full form nor is a human able to give birth the day he appears on this world.
This is analogous, R. Meltzer suggests, to someone wishing to prove matters of development of an already born child based on the development of that child prior to his or her birth while still in the mother’s womb. Similarly conditions are different in the development of humanity and the animal kingdom after its creation and birth to those that prevailed during the birth of the world. One cannot provide any indication for the other.