We have discussed in class that fossils show evidence for evolution. This is sho

Question

We have discussed in class that fossils show evidence for evolution. This is shown with stunning clarity when the fossil record is complete as with the horse. However, there are instances where the fossil record is not complete which means there are gaps. Someone comes to you and states that because there are gaps in the record for species "A" this shows that evolution is not true. How do you argue against this statement? In other words how do you argue in favor of evolution when gaps are present? Or do these gaps invalidate evolution? Restrict your discussion to the fossil record only.

Explanation / Answer

Charles Darwin, the great naturalist who intoduced the world with the theory on evolution, once wrote ."The history of the world is imperfectly kept. Of the history we posses the last volume alone,relating to only two or three countries.Of this volume,only a short chapter has been preserved and of each page only a few lines".

Thus we see, Darwin himself accepted the gaps present in fossil records and knew their is still a lot of records to be discovered for the dots to connect and form the perfect image. The fossil records found in case of an creature like the "archaeopteryx" clearly denotes the gradual evolution of aves from reptiles and thus is a connecting link, however the presence of gaps in a fossil link does not invalidate evolution nor retrogates its authencity. Presence or absence of fossils cannot be the sole critera to validate evolution. This is can be expalined as-

1) Just because an organism is present, doesnt mean that will change into a fossil. Fossilization in reality is a rare phenomenon like the dead body geting covered in amber, nearby volcanic ash etc. Even the presence of these fossilizing materials, does not guarantee fossilization and only increases the probability of it happening.

2) Fossilization generally occurs in the hard parts of the body like bones,teeth which can get preserved such as in case of the horse. But what about soft bodies creatures like worms, slugs, jellies? Their fossilization is practically very difficult.

3) Lets take an example of evolution of amphibians from fish.Through the adding variations,fish would have evolved into amphibians.At every stage, the new form would have been better adapted to an amphibious life than the last. In the struggle for life, the new ones woud out compete the previous.This lead to two distict class of animals today as we know them, the fish and amphibians. Thus, the presence of gaps in evolutionary fossils is only because they were out competed very easily, and did not get the chance to get fossilized as often as the ones at the other extreme ends.

4)As to the contrary believes, evolution is not a very slow gradual process, but a quiet sudden process. This is also called the "punctuated equillibrium" model of evolution according to which only a major change leads to a evolution stress.

CONCLUSION
Thus, we can conclude that presence of all fossil links definitely creates a sure image of evolution. But just because there is a gap in the records, reasons of which are explained above does not invalidate evolution. Just because the fossil recors have not been formed, or not yet excavated by plaeontologist does not deny their existence. This is just like saying that since I dont posses a picture of my grandfather, he never existed, or he is not a part of my family.

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