Natural Selection and Evolution

¶ … Evolution Is True

What Is Evolution?

This chapter highlights the six elements that make up evolution: 1) growth/evolution; 2) gradualism; 3) speciation; 4) shared origins; 5) natural selection; and 6) nonselective evolutionary change mechanisms (Coyne, 2009). Of these, the foremost is the evolution concept itself, which implies genetic modification of any given species with time. To elaborate, over a number of generations, species of animals may transform into a rather different animal because of DNA modifications whose origins lie in the mutation process within the body. The gradualism concept constitutes the second element of the theory of evolution. Over several generations, a significant evolutionary transformation occurs in the species (e.g., reptiles' transformation into birds). The subsequent elements may be considered two halves of one coin. It is an incredible and unbelievable fact that although innumerable living species exist, each and every one has a few common basic characteristics, including the biochemical routes utilized by all to generate energy, the standard 4-letter DNA codes and the way this is deciphered and converted into proteins within the body (Neuner, 2012).

The above fact is in line with my personal belief that all species can be traced back to one common ancestor, which possessed the aforementioned characteristics that were then inherited by its descendants. However, if the process of evolution only entailed slow genetic transformation in a species, the world would have had just a single, greatly-evolved species descended from the original species. The reality is different -- our world has more than 10 million existing species, while another 250,000 are now fossils. The life forms on earth are diverse, which raises the question of how diversity springs from a single ancestral form. The third evolutionary concept of speciation (splitting) helps answer this question (Neuner, 2012).

Coyne's vehement argument that evolution represents a true occurrence is correct. Every evidence collected since the time of Darwin clearly points to the fact that life forms on Earth evolve and every species is related to other species. The belief that evolution isn't true and has no impact on our species is an illogical one. But Darwinism and evolutionism are two different things, and it is at this point that Coyne's work is misleading. One must note that Jean-Baptiste Lamarck was also an evolutionist, who came before Darwin's time. Further, Darwin was influenced by Lamarck, and believed in organ disuse and use. Biologists are expressing increasing discontent with the traditional Darwinism Coyne supported and Pinker, Dawkins, Dennett and other important Darwinian publicists incarnated. Experts increasingly accept that there is a need for a more pluralistic approach to evolution; this explains the emergence of Third Way evolution (Vecchi, 2009).

2. Written in the Rocks

Professor Jerry Coyne provides a clear rationale for the fossil record's absolute support of evolution and opposition to creationism, in spite of being essentially incomplete. Creationism proponents typically cite the argument of the missing link in the chain, asserting that the lack of transitional beings between plant and animal groups presents a challenge to the evolution argument. But Coyne disagrees; he claims paleontologists are constantly discovering transitional forms of which the most recent is the much publicized Ida flourished before huge crowds of people by New York's famous Natural History museum. Such fossils provide us with an idea of the assumed missing links' nature. Throughout Coyne's account are peppered references to different findings. For example, paleontologists have unearthed fossils to prove amphibians evolved from fish and birds from reptiles. In this chapter of the book, the professor also refutes another longstanding and commonly-cited argument against Darwin's theory of natural selection: that it fails account for biological innovations as this sort of explanation would necessitate proof of every intermediary phase's adaptive benefits. The naturalist supports Darwin's theory by tackling the typically utilized example of a bird's wings: how would one percent, twenty percent, or fifty percent of one/two wings prove beneficial to any animal? Coyne offers quite a hypothetical although convincing scenario, substantiated by startling fossil evidence from China with regard to the evolution of feathers and flight, which ought to prove to creationists that their case against Darwin's school of thought is erroneous (Vecchi, 2009).

My personal view is that fossil formation is a simple phenomenon needing a highly specific group of circumstances. Firstly, an organism's carcass needs to reach a water body, descend to its bottom, and be covered swiftly with sediment (which prevents its putrefaction or susceptibility to scavengers). Considering all the above conditions, one has to expect fossil records to be partial. But how far is it incomplete? Naturalists estimate the overall number of plant and animal species that inhabited the earth from its very beginning at somewhere between seventeen million and four billion. As paleontologists have only unearthed about 250,000 distinct fossil species, the fossil evidence on hand is of a mere 0.1-1% of total species, which is not exactly a reliable sample of species' history. Still, there are sufficient available fossils to provide researchers with a sound understanding of the progress of the evolutionary process and of how key groups separated from each other (Neuner, K. (2012).

3. Remnants: Vestiges, Embryos, and Bad Design

This chapter explicitly reveals that a number of biological actualities like atavisms (like the tail in the human body), cases of poor design (like the Fallopian tube-ovary gap in humans) and organs without any clear function (like the appendix) can only be explained by evolution. They demonstrate unavoidable proof of a shared ancestry, telling us a vital tale about the evolutionary process and how it usually alters old phenotypic and genetic characteristics for diverse reasons or no reason at all through the addition and deletion of features (Vecchi, 2009).

According to Coyne, vestiges may be described as a species' characteristic which was a revision within its forebears, but totally lost its utility or was allocated for a different use (like in the ostrich's case) (Coyne, 2009). The characteristic is considered 'vestigial' on account of the fact that it has ceased to carry out its original intended function and not because it has become functionless. (58) Thus, the appendix found in the human body is merely the vestige of a body part that was extremely vital to humanity's 'herbivorous' forebears, but has no actual value to humanity now. "Bad design" represents the idea that, had species' creation been done from scratch using biological building units of bones, nerves, muscles, etc., the flaws evident in them wouldn't have arisen (Coyne, 2009). An accomplished, smart designer would design things perfectly. But since flaws are evident, it indicates evolution. This, indeed, is just what is to be anticipated from the evolutionary process (Neuner, 2012)

In my opinion, considering the matter's sensitivity, there is a need to emphasize the fact that no biologist questions natural selection's significance in the field of biology. Selection occurs at all times, unavoidably and inescapably. Such a fundamental change in basic tenets as witnessed in the field of physics at the nineteenth century's end is impossibly in the field of biology, as Darwinism is, to a large extent, true. The key point, however, is: selection isn't an independently occurring phenomenon and it definitely doesn't occur as neo-Darwinians say it does (Vecchi, 2009).

4. The Geography of Life

Chief evidence for this chapter comes from the biogeography discipline. Living beings' distribution and diversity patterns again reveal, in the soundest terms possible, that life is evolutionary in nature. Geological and biological proofs align with one another and, without doubt, lead, according to creationists' distorted view, to a novel conspiracy theory. However, the bio-geographical evidence is extremely sound (Vecchi, 2009). It has, in fact, become so strong that creationists are yet to present an article, book, or speech that attempts at refuting it. But creationists just look the other way and behave as though such proof is non-existent. There are now answers to several questions that, in Darwin's time, could not be explained, owing to a couple of developments Darwin never envisaged: molecular taxonomy and continental drift (Coyne, 2009). There has been no reliable justification on creationists' part (whether Noah's Ark creationists or others) for why distinct kinds of animals come in similar forms within different areas. They simple suggest their creator's unreadable thoughts. However, evolution accounts for this pattern by calling upon the straightforward convergent evolution process. Species residing in similar environments encounter similar environmental selection demands and hence, might converge or evolve similar revisions, ending up looking and behaving quite alike despite being unrelated. (94) The convergent evolution phenomenon demonstrates 3 evolutionary theory components functioning together: shared ancestry, natural selection, and speciation (Neuner, 2012).

As I believe in the process of evolution, species residing in a particular locality ought to descend from prior species residing in that very locality. Thus, if the upper rock layers of any area are dug, paleontologists ought to unearth fossils resembling the animals that reside there in the present day, which is actually the case.

Creationists struggle to justify the above patterns using their line of thinking. They will need to hypothesize the existence of innumerable consecutive creations and extinctions worldwide, with each group of new species made similar to the prior ones residing in any given place. The world has progressed far from the Noah's Ark concept and with only some exceptions, oceanic isles' flora and fauna resemble those seen on the mainland closest to them. The key bio-geographical lesson is that: evolution alone accounts for the diverse life forms witnessed on isles and continents. The other, secondary lesson is: life forms' distribution on our planet suggests a combination of lawfulness and chance (Neuner, 2012).

5. The Engine of Evolution

The traditional neo-Darwinian language pertaining to natural selection construction characteristics and the production of adaptive reactions is employed in this chapter. The genetic mutation process (point mutations residing in DNA sequence duplication errors) is assigned the lone function of variation developer, and selection utilizes this basis. This image of evolution is exaggeratedly simplified and rebuffed and disapproved off increasingly in biological circles. The issue is not individuals' doubts regarding the fact that selection is capable of building complexity; rather, it is that one lone, unique focus on selection's creative and constructional role will not explain all things in all situations (Vecchi, 2009).

The development of adaptation through natural selection entails three things. Firstly, the original population must be variable: a population of mice must have coat color variations. Secondly, some measure of this difference must emerge from gene form alterations (in other words, its basis ought to be genetic, to some extent (heritability)) (Coyne, 2009). Mutation happens whether or not it is beneficial to the species, and merely constitutes DNA reproduction mistakes. Thirdly, and finally, genetic variation should impact the entity's possibility of leaving progeny. Selection doesn't denote an externally-imposed mechanism on any species but represents a process or a description with regard to how genes giving rise to improved adaptations increase in frequency with time. Biologists' claim that selection involves acting "on" characteristics, it basically means the characteristics are going through the process. One may use this same meaning to understand that species do not endeavor to adapt themselves to the environment. This process involves no personal will or conscious effort. Environmental adaptation is to be expected if organisms have the right type of genetic difference (Neuner, 2012).

I am of the opinion that evolution through selection combines lawfulness with randomness. Initially, an objective or "random" process of mutations occurs, giving rise to a range of bad and good genetic variants (in the aforementioned example of mice, multiple coats colors). This is followed by the "lawful" (natural selection) process which orders such variation, retaining the good variants and sieving out the bad (desert environments' species prefer light-colored genes over dark-colored ones) (Neuner, 2012).

6. How Sex Drives Evolution

According to this chapter, sexual selection assumes two forms: female choosiness amongst potential mates and direct competition among males for female access (Coyne, 2009). Males vie with one another to mate with females in both the above forms of selection. Why do females not vie for males? The answer to this lies in the size difference between the egg and sperm cells. Female choice, undoubtedly, governed a number of sexual dimorphisms' evolution, thus confirming the Darwinian hypothesis was correct. This chapter gives rise to questions like "why sexual evolution?,"which is among the biggest mysteries in the evolutionary process. Firstly, why are genders only two (instead of three, four or so forth)? Secondly, why are the sexes found in different gamete sizes and numbers (females produce a few large eggs, while males produce a large quantity of tiny sperm cells)? (Coyne, 2009)

To this chapter, my response is: my preferred sexual selection rationale lies in the good-genes theory. When faced with fairly limited proof, this belief might partially suggest evolutionists' preference for strictly Darwinian justifications -- females need to somehow discriminate among male genes. But sexual dimorphism has a third justification as well, which is the most straightforward of them all. Its basis lies in the sensory-bias models whose assumption is that sexual dimorphism evolution is merely guided by established biases within the female nervous systems. And these biases may be a secondary outcome of the natural selection process for seeking food and other such functions besides seeking mates (Neuner, 2012)

7. The Origin of Species

This chapter explains the clusters (individual clusters are termed as "species") perceived in every entity that reproduces sexually (Coyne, 2009). The Origin of Adaptations would make for a more fitting title: although Charles Darwin did discern why and how a given species adapts with time (chiefly through natural selection), the naturalist failed to account for species' division into two. To give an explanation for biodiversity, there is a need to explain the process of emergence of new species rather than the emergence of new characteristics. Without speciation, biodiversity would not exist at all; rather there would only be one, long-evolved offspring of the earliest species. Species are evolutionary communities, and biological species may be referred to as evolutionary units. It is largely the thing which evolves and if one is able to account for the evolution of reproductive obstacles, species' origins can be explained (Neuner, 2012).

In my personal opinion, species are a cluster of entities similar to each other and, at least slightly, dissimilar to entities belonging to other clusters. If one contemplates on the phenomena of human variations and cryptic species, one will reach the idea that species aren't just distinct on account of their looks but also on account of the obstacles between them which ensure interbreeding doesn't occur. One key point to bear in mind here is that, contrary to what Darwin assumed, species do not emerge to fill the empty niches found in nature. Speciation research reveals that species result from chance evolutions. The groups which are deemed as so vital to biodiversity do not evolve for increasing diversity or for providing balanced ecosystems. Instead, they stem inevitably from genetic obstacles surfacing when spatially separated populations evolve along different directions. Biological speciation is, in a number of ways, akin to that of a couple of closely-linked languages traced back to a single ancestor (Neuner, 2012)