Laws of Variation

On November 24th 1859, there was a publication that changed the face of science and blew the notion of a unique human species in an unchanging hierarchy out of the water. The Publication of “Origin of Species” laid the foundation for most of the ideas of modern Biology. In fact most of what we believe in Biology would not be feasible if it weren’t for evolution and natural selection. Evolution is for the greater sense of the term, not a theory but a fact. Over 140 years of scientific data and research have nearly confirmed the original hypothesis. The theory of evolution is no different than theories such as atomic theory, cell theory and Einstein’s theory of relativity; which have amassed sufficient data to be accepted scientists and theologians alike. Regardless of the disputative connotations that evolution brings, there is little doubt that these ideas brought forth in the the enlightenment of humans conscious evolution have changed our view of the world. Of the main points drawn out by Darwin are the “Laws of Variation”. Darwin stated that “When a variation is of the slightest use to a being, we cannot tell how much of it to attribute to accumulative action of natural selection, and how much to the conditions of life.”(Darwin 117) One thing is for certain he did believe more acutely that natural selection played a vital role. The laws of variation set out to explain the differences in species across several continents with the same or similar natural climates and those that have similar traits across areas of opposite climates. The laws of variation are composed of Effects of use and Disuse, Acclimatization, and Correlation of Growth.

Effects of Use and Disuse are simply as it implies in the title, the use and diminishing of certain traits of an organism for survival and reproduction. This modification that enables an organism to drop a certain trait or to pick up a necessary one is inherited. We have no direct observation of continual use and disuse over parent generations because we do not know the parent forms. Nonetheless there are animals that can be explained by the effects of disuse. In “Origin”, Darwin explains how birds seem to have variations in capabilities of flight. He claims that the changes in abilities such as flight might be attributed to a lack of “beast of prey”, as they no longer needed to migrate or flee danger the ability of flight was discarded as it was no longer needed. Another remarkable fact as discovered by Professor Wollaston in 1859 was that of a certain species of beetle in the island of Madeira. These beetles’ wings seem to be so deficient at flight that they can no longer sustain themselves in air. The evidence showed that beetles in this part of the world very frequently get blown to sea and perish, so they adapted to lie concealed until the winds subsided and the sun shined; another function of disuse.

Acclimatization is at times more closely related to plants and algae. Each species is adapted to its home climate, yet there are species that seem to adapt to changing climates. The evidence of this in plants id overwhelming we see this everyday as individuals grow palm trees in Georgia and even the Carolinas. A very good point is brought up by Professor Thomas Henry Huxley aptly named Darwin’s bulldog for his advocacy of Charles Darwin’s Evolutionary theories. He pointed out the resiliency in survival and reproduction of domesticated animals in different climates around the world. “Animals such as cows, sheep, goats and horses have been found to adapt to their surroundings in order to survive, and these traits are inherently passed through generations.”(Huxley 192). In short acclimatization can be found in varying species around the world and the functions of the Laws of Variation are intertwined and not self sufficient.

Perhaps the most important subject is that of Correlation of Growth. Simply put, when the process of natural selection produces variations other parts are also modified. For example the differences in the shape of the pelvis in birds correlate significantly to the remarkable changes in the size of their kidneys. In humans this is also distinguishable, it is believed that when humans were evolving and developing larger brains, mothers needed to have enlarged pelvises in order to give birth safely. This evolutionary change in the size of the human brain led to subsequent changes in the size and proportions of the mothers body, a function of Correlation of Growth. There must be caution when attempting to attribute correlation of growth features that are common to an entire group of species, and that have been handed down from an ancient progenitor. Once fact is for certain, that if a variation arises and is superfluous to the organization of the organism then it will only be temporary.