EVOLUTION EXPLAINS THE DIVERSITY OF LIFE ON EARTH
Darwin, in developing the theory of evolution explained the “origin of the species,” how the incredible variety of life forms which grace the earth arose. He expressly demonstrated the formative role that the environment plays in the exquisite “adaptation” of structure and function by allowing reproductive success among the diverse organisms, and by natural selection, preventing “unfit”individuals from passing their genes on.
EVOLUTION PREDICTS MANY EFFECTS OF ENVIRONMENTAL CHANGE
Evolution is a valuable tool which allows us to predict how changes in the environment, whether “natural” or “man-made,” will impact populations, and alter the abilities and appearance of species over time. In this way, evolution provides the basis for understanding differences in populations which have lived in diverse environmental conditions for many generations .
EVOLUTION EXPLAINS EMERGING DISEASES AND RESISTANCE
For instance, it allows us to understand why poisons such as insecticides, herbicides and antibiotics have only fleeting effectiveness, and instructs us as to why these should be used very sparingly. It instructs us about the profound value of diversity in populations so that the necessary heterogeneity in the population will provide the required rare individual who can survive the natural selection, and go on to have reproductive success.
EVOLUTION REQUIRES DIVERSITY TO WORK
The most difficult aspect of the theory of evolution for many who are new to the theory to understand (or accept) is that the initial origin of this diversity is random chance. Mutations alter the traits of individuals not by intent, but purely by chance. While the vast majority of mutations impair the individual’s ability to live in its environment, in rare instances, mutations can alter an individual so that it survives the environmental challenge and is able to reproduce, passing its genes on to its progeny.
DIVERSITY IS THE RESULT OF MUTATION AND SEXUAL REPRODUCTION
Evolution also explains the extraordinarily powerful role of sexuality in generating a diverse, heterogeneous population. Sexuality is important because it provides a means of “shuffling” the genetic deck. At its base, it takes genetic material from one individual and combines it with genes from another to produce a new, genetically unique individual, with novel traits. At its root, sexuality has evolved in most organisms in order to generate heterogeneity in the population. It is orders of magnitude faster than mutation.
EVOLUTION: A RATIONAL, NOT SUPERNATURAL EXPLANATION TO NATURE
Since before recorded time, man has sought explanations for the events around him. Lacking understanding, mythological supernatural systems of gods and demigods were proposed. Indeed, these myths, based on empirical evidence, were often valuable guides to survival. It is understandable that to this day, some would cling to myths in explaining our world because of the comfort and easily understood supernatural explanation it provides.
EVOLUTION IS RESISTED BY ENTRENCHED REACTIONARY EXPLANATIONS
The ancient Greek philosophers proposed to search for rational explanations of nature, what we now call science. They were met by fierce resistance from reactionary forces. Socrates was executed. Galileo paid dearly for providing clear evidence that the laws of nature applied equally to the heavens as well as the earth, overturning the previous mythological system.
UNDERSTANDING EVOLUTION BENEFITS THE INDIVIDUAL AND SOCIETY
Science, exemplified by application of the theory of evolution, can continue the path promoted by Socrates and the ancient Greeks that rational explanations should be sought, and be the basis for individual and societal decisions for the optimum benefit to both.
David B. Fankhauser, PhD
Professor of Biology and Chemistry
University of Cincinnati Clermont College
January 2009