“Always remember that you are absolutely unique. Just like everyone else.” (Margaret Mead)
Have you ever wondered how the human race can be so alike but at the same time there’s only one like you? How everyone has the same number of limbs, the same pair of eyes, of ears, of noses but how can he have green eyes and you have brown? How can she be taller and you shorter? Would you agree that you were a descendant from a long line of apes and King Kong might have probably been your super great greatest grand grandest grandfather?
Well, let’s take look at how Gregor Mendel’s work have influenced our belief of evolution and how Charles Darwin’s work may not be as perfect as he thought it would be.
Charles Darwin is one of the famous people of his time in having been able to establish one of the proposed reasons behind evolution with his famous Theory of Natural Selection.
He suggested that a certain trait or variation is preserved throughout generations if it has proven to be useful for that certain individual. Those individuals who possess characteristics that make them more suitable and adapted to their environment tend to pass on these characteristics to their offspring while traits that have not proven to be beneficial were eventually erased over time.
Although these arguments may be acceptable, there are still loopholes to this theory, hence it still remained a theory up until now. Taking a closer look in the foundations of this theory through modern day genetics, scientists were able to reveal that this theory can never be applied outside the concept of DNA. All dogs have the same DNA with many recessive traits. Natural selection could explain and support the fact that if you want to arrive at a dog with a particular set of traits, you could easily select desirable traits from a certain breed and pair it with another different breed until you have arrived with the perfect dog, a process known as selective breeding. However, your products will only be dogs, you can never produce a cat by crossbreeding a Maltese with a Dalmatian, right? No new species can be developed rather there is only formation of new variations or traits.
This is also proven by Mendel when he studied pea plants. A new species of pea plant was not produced rather they were only the same pea plants but with varying characteristics. If so, the claim of natural selection that different species were derived from a single ancestor is terribly false.If you come to think of it, Darwin’s famous book “On the Origin of Species by Means of Natural Selection” should be revised sinceit is scientifically impossible for new species to evolve by natural selection. If only Darwin had collaborated with Mendel on his work considering that Mendel was able to publish his work two years earlier, they would’ve come up with a better theory. Such bad timing for these two.
In addition to natural selection, Darwin has also acknowledged the Theory of Inheritance of Acquired Characteristics by Jean Baptiste Lamarck in which he presented in his first book in 1801 and in his theory of pangenesis in which variations experienced by the individual during its lifetime are transmitted to the germ cells by “gemmules”. Lamarck’s theory or Lamarckism focuses on the idea that a certain organism can pass on its characteristics that it has acquired during its lifetime to its offspring. Lamarck believed that through the influence of an organism’s environment, certain traits can be developed over time and thus passed on to further generations.
A classic example of such is the case of giraffes, Lamarck explained that the reason why giraffes have long necks because their ancestors often stretched their necks in order to reach their food which was located in high trees. Due to this constant action, their to the discoveries of Mendel and the studies of other scientists, the field of genetics have highly evolved and is now a useful tool in studying heredity and applying it to various fields of interests. One of which is evolutionary genetics.
It has been established that since a genetic population is described as the sum of gene frequencies for all genes represented by that population, it follows that for evolution of a species to take place, the gene frequencies of that particular population must initially undergo change. Darwin has initially started to shed light in this topic but his claims were not thoroughly laid out due to the lack of supporting evidences at that time.
A recent discovery by Sewell Wright has attempted to utilize genetics to try and explain evolution in terms of changes in gene frequencies. He proposed that a species evolves when gene frequencies changes and the species moves it to a higher level of adaptation for a specific ecological niche. Several factors such as mutation of alleles and migration of individuals with those new alleles will create variation in the population. Selection will then choose the better adapted individuals, and the population will have evolved. Other modern day ideas such as the genetic drift phenomena in which variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce; and also selective neutrality which is a situation wherein the phenotypic manifestations of certain mutant alleles are equivalent to that of the wild-type allele in terms of their fitness values were derived by using genetics as its main tool. In fact, the concept of selective neutrality has become a foundation for modern tests of natural selection.
Thanks to genetics, one can now relate fitnesses to the differences among individuals within a single natural population, sometimes using data on undisturbed individuals, a phenomenon known as the ecological genetic approach. Methods such as reciprocal transplant experiments were made possible in order to test for the selective importance of organisms between population differences given that there are presence of more disturbances which in fact have led to the understanding of unexpected characteristics such as the inversion polymorphisms of Drosophila.
Another breakthrough of genetics is that it can now be used to relate differences in ecological conditions experienced by different evolving lineages to differences in the outcome of evolution by natural selection. This is known as the comparative approach and was first used by Darwin in his work on plant mating evolution which showed inbreeding plants having smaller flowers and being generally less attractive to pollinators as opposed to crossbreeding them. Both ecological and comparative genetic approaches have utilized genetics in the study of modern biology however, there are still limitations to these concepts. One of which is that the ecological approach may miss instances of selection as proven by competition between strains of yeasts or bacteria that even the largest and most sensitive experiments cannot detect selective differences. Also, the comparative approach is incapable of providing estimates of the intensity of selection involved in causing observed changes. Thus the need for further studies regarding this field. A good side though is that after several decades of using these two approached in detecting selection in nature on visible or physiological traits, biologists can now test for selective effects of specific genetic differences between individuals without needing to know their phenotypic effects. Modern DNA sequencing technology has provided population geneticists with the ability to study the extent to which selection acts on variants across the genome, as opposed to mutation and random genetic drift.
Genetics have been paving the way in shedding light to the unanswered mysteries of how things came to be. Mendel and Darwin’s works were mere jump starters that has since then inspired man to discover how this mechanism of life works. Further studies are needed to arrive with a concrete answer to our questions.
DNA is the instruction book for life.
It contains genetic information which directs and gives instructions to the cells on how to grow and function. It explains how things came to be which practically answers the questions aforementioned in this article’s introduction. The way your body looks and operate has been pre-written in your DNA.
We can all agree on the fact that a book can’t be created unless someone must have written it, right? That letters cannot just magically appear from nowhere and form themselves into coherent sentences until one has arrived with a certain novel. Something cannot just be created from nothing. With that being said, DNA (the instruction book for life) must have been written and arranged by someone or something. The smallest single-cell creature houses millions of atoms forming millions of molecules that must each be arranged in an exact pattern for it to be fully functional. The cell has an energy-producing system, a protective housing, a security system to let molecules into and out it, a reproductive system, and a central control system. There is a certain pattern on how traits are being passed on from one generation to another. This design of life is too complex to just happen by chance.
Darwin and Mendel were merely instruments that strived to explain how these things work but the answer to the question on the origin of things is just so obvious yet millions still deny it. We could go on and on and talk about the discoveries and theories of man. Man’s quest for knowledge is a never ending spiral which would only lead to one thing: the sovereignty of God. “The more I study nature, the more I stand amazed at the work of the Creator.” (Louis Pasteur)
Charlesworth, B. & Charlesworth, D. 2009 Darwin and genetics. Genetics 183, 757–766. doi:10.1534/genetics.109. 109991
What Lamarck believed. (n.d.). Retrieved from http://necsi.edu/projects/evolution/lamarck/lamarck/lamarck_lamarck.html
Why we believe Darwin. (n.d.) Retrieved from http://necsi.edu/projects/evolution/lamarck/webelieve/lamarck_webelieve.html
9 Scientific facts prove the “Theory of Evolution” is false. (n.d.). Retrieved from http://humansarefree.com/2013/12/9-scienctific-facts-prove-theory-of.html
Selective neutrality. In A dictionary of Genetics (7th ed.).
Author: Alyssa Faye Azarraga