This is a nice video that explains how Evolution works. It is very summarizing of course, since it is eleven minutes long, but it is very well explained and the animation helps visualize the mechanisms that allow Evolution to take place.
I was talking about orogenesis the other day with a fellow geologist, and we both came to the conclusion that it would be quite awesome (and I mean this litterally) to stand on the Appalaches or the Urals (http://en.wikipedia.org/wiki/Uralian_orogeny) and realize that during the Primary era these were the highest mountains on Earth. They belong to the first orogenesis event in the history of the Phanerozoic, a time when they weren’t covered in vegetation, but they were culminating higher than this level. We were thinking abou the feeling we’d get by walking on these eroded rocks, that may have been around for more than 250 Ma, but still, they are rather high mountains.
This sort of feeling is something that is always accompanying scientific thought, although not all scientists realize it or understand how deeply romantic it is. Indeed, when one thinks about any problem concerning Nature, the Universe or even about a theoretical problem (i.e. Mathematics), one performs a romantic act since he usually faces a problem with respect to Nature and does not consider his human nature as a factor in his reflection (non anthropocentric vision).
Of course, the Romantic movement of the beggining of the 19th century did influence strongly the scientific tought, and generated the big Naturphilosophie movement in Germany. It represented a scientific view of the world that was at the limits of metaphysics (sometimes well past the limit as well). Despite that, some major discoveries were made by using this kind of philosophy, such as electromagnetism in the field of physics, statistics in the field of mathematics, or the creation of the field of Biology (by Lamarck).
One of the most renouned naturphilosophers is Johann Goethe. His scientific observations are largely poorly known, but he is actually the one who made quite a crutial observation when it comes to angiosperm development. He noticed that the flower of the angiosperms is in fact transfomed leaves. With this simple idea, a very simple yet important observation, he made it possible for other scientists to understand the origin and the development of flowers. The movement came to an end with the rise of Positivism at approximately the middle of the 19th century, which promoted the collection of data and the methodologies used today.
Although the romantic movement has faded away from science (as it has for litterature to tell the truth), there lies in all scientists a deep sense of romanticism in their perception of natural phenomena, in the way they concieve a scientific problem and in their love of nature in general.
How often do we hear that humans only use 10% of their brain? “Imagine what humans would do if they used a greater part of their minds!”
Yet there has been a species with a larger brain than the human one, Homo neanderthalensis.
The final answer is very simple: the humans don’t use the totality of their brain because they don’t need to; the human brain is larger due to its ontogeny.
It is well known that humans do not use but approximately 10% of their brains and often one asks himself what would happen if a bigger part of the brain were used. But is this something that is possible? Sure, it could happen but it would be due to some physiological dysfunction (or some other similar phenomenon) and it wouldn’t mean that it is the way it should normally function.
The case of the human brain is a nice example for the principle of exaptation. During the evolution of the humanoids, Homo neanderthalensis was the one species that had a larger brain than the one of Homo sapiens (humans). The reason is very simple: the brain was larger because it could. Human brains are quite big as well, for the embryological reason that it was able to grow more. This means that we do not actually need more than the 3/4 of our brain, we just have it because during the early ontogenesis, the nervous tissue of the region of the head gets larger than the one of other animals. It is a passive process that does not consist of a specific adaptation or a need. Indeed, it is quite useless to have such a large brain since humans -and much more neanderthals- do not even use half of it. But the organism is not able to find a way to use it from a physiological and histological point of view.
The large brain that we are so proud of is therefore something that we only have a partial use for, and from the moment that we know that, the myth that we could be much smarter if we could use more than 10% of this organ seems irrelevant.
The goal of scientists is to retrieve data and emit hypotheses on a question they ask themselves. They seek the truth about something using logics to guide them through their work. Taking into consideration the facts, the data, they try to treat it correctly, in an objective manner, and have results that reflect the real phenomenon. But how well does this work? There are some examples that reflect this idea, I’m going to talk about the one that I know best, having encountered it during my studies.
There is this known controversy of mathematicians and physicists against evolutionary biologists and palaeontologists: the first two fail to understand how it is possible for organisms with survival rates close to zero to actually survive. Following the laws of probabilities it is indeed impossible for living beings (such as the horse or even humans to take as some popular examples) to survive in the struggle for life. Yet they still exist and others, with better mathematical survival-probabilities, disappear very rapidly. Should these scientists think a bit outside the box, would they understand how evolution works; it is not about what we should find, nature -and life- does not always work that way.
But this is only an example of how scientific logic works. How can we be sure that we are open-minded or that we even can be right in the treatment of data?
In the book of Stephen Jay Gould “Time’s arrow, time’s cycle”, the author refers to F. Engels saying how it is impossible to think out of the trends and the ideas of our times. This is just another point to the fact that scientists do not know everything, as much as they’d like to think they do (I admit that I should include myself in this category…).
So can scientists be certain to explore a problem from every possible aspect?
While reading S.J. Gould’s “Time’s arrow, time’s cycle – Myth and metaphore in the Discovery of Geological Time“, I noticed a few things.
In the first part of the book, Gould describes the ideas on the -brief- history of the earth as seen by Thomas Burnett (late 17th century). It gets far more interesting, as far as the modern thought is concerned, in the second part of the book. There, we find the work of James Hutton, a scottish geologist of the 18th century. He had made very accurate and original observations in his homeland (discordances, discontinuities…). He tried to explain them but in vain. How would it be possible to understand a discontinuity, sediment orientation, etc. without having any knowledge of a mechanism that would allow change of the surface of the earth? How is it possible to study and understand the history of the earth without using tectonics?
The third part of the book is dedicated to the work of Charles Lyell (19th century). There again, we see that he observes faults and other landscape results of earthquakes. As much as Lyell’s work is significant to Geology, the mechanism responsible for some of his observations was still unknown; raising the same problems of the changes of the surface of the earth. All the theories preceding the discovery of tectonics were speculative even if the scientists tried to be realistic.
If we want to do a parallel with evolutionary biology, I remember the famous quote of Theodosius Dobzhansky: “Nothing makes sense in Biology except in the light of Evolution”. Well, I think that something similar can be said about tectonics: “Nothing makes sense in Geology, except in the light of Tectonics”. Therefore, Tectonics is to Geology what Evolution is to Biology.