Variation is important and occurs naturally for a species. As was put forward by Darwin's theory, the complex forms of life, that we observe around us today, were actually the result of continuous change and development of simpler forms of life, obviously the process is time consuming and is endless. Speaking lucidly, the gradual change of life forms from simple to complex is known as Organic Evolution.
Embryology is the study of development of an organism from egg to adult. Strikingly it is observed that for different vertebrates, the embryos resemble one another; though they may belong to different species altogether. The fact that the embryos of a fish, a frog, a turtle or a man resemble each other is a direct proof of evolution. We may infer that they have evolved from some common ancestor, over time.
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| Embryos of different vertebrates |
