Biological evolution

Scientific theories of evolution seek to explain the mechanisms of the observable fact of biological evolution. Yes, organisms have indeed evolved over time – most former species are now extinct, many species remain much as they are in the fossil record, and new species continue to evolve.

Historically, scientists observing biological evolution first sought to explain observed morphological (body shape) changes over time – the phenotypic evidence of changes in body structure found in the fossil record. Bacteria were the first life-forms on the planet, and ruled until the advent of nucleated cells with membranous organelles, such as those of which we are constructed. The earliest known fossilized evidence of early life forms are found in stromatolites – large reef structures created by communities of Cyanobacteria. Mistakenly called ‘blue-green algae’, the Cyanobacteria are believed to have “invented” oxygenic photosynthesis over 1 billion years ago. As oxygen levels rose, organisms were forced into endosymbiotic unions as – to them – toxic levels of oxygen threatened their continued existence. Anaerobic bacteria, which are killed by oxygen, persist to this day in environments with very low levels of oxygen.

Since the advent of modern molecular genetics, biological evolution has come to be understood as a change in genotype – a genetic alteration in the intergenerational frequency of alleles in populations. That is, an alteration in the frequency of alternative forms of genes between generations. By this definition, the human species is still evolving.

Biologist Ersnt Mayr suggested that a biological species be defined by its inability to produce fertile offspring when mated with another species. Mules are an example of such a mating – between a horse and a donkey. Mules do rarely produce offspring, but the gene-based, phylogenetic classification of species remains more useful than taxonomies based on physical characteristics. Molecular geneticists are able to compare the genomes, the total complement of nucleic acids, of different species and to estimate the evolutionary distance between species. This is time since the compared species last shared a common ancestor.

Speciation depends upon genetic change, yet morphologic changes may reflect alterations in the regulation of genetic expression without a major alteration in genotype – body type may appear very different without considerable change in genes.

If this seems unlikely, just consider the considerable differences that selective breeding has wrought in size and configuration within one canine species. Mechanics might prevent the union of a Chihuahua with a Great Dane, but such a union could produce fertile offspring.

Similarly, the paramount importance of gene regulation almost certainly explains much of the morphological difference between humans and chimps – two species who share 98% of their DNA.

Along the same lines of modification of genetic expression, the epigenetic mechanism of alternative splicing enables a single gene to give rise to multiple versions of a protein. Proteins are much, much more variable in structure, and hence in biochemical activity, than are nucleic acids such as DNA and RNA. Formed from amino acids, proteins regulate cellular metabolism (as enzymes), regulate genetic expression (cofactors), and regulate communication between cells (ion channels, pumps, receptors). Structural proteins form the cytoskeleton that supports cells, and specialized transport proteins move materials and organelles within cells and effect muscular contraction.

There are two basic types of mechanism involved in biological evolution. First are the genetic causes of alteration of genes within the genotype of individuals. Most genetypic alterations are not the result of point mutations, which may, or may not result in abnormal proteins through alteration of a single nucleobase in the genetic code. Creationists create fallacious strawman arguments by focussing their arguments on point mutations, conveniently ignoring the other, more important mechanisms of genetic change.

Single nucleotide polymorphisms, as point mutations are correctly termed, as well as alteration of longer segments of DNA may be neutral, beneficial, or deleterious. Clearly, neutral or beneficial alterations, whatever their genetic mechanism, will persist while deleterious alterations will ultimately be eliminated if they render the organism less capable of reproductive success.

This brings us to the second type of mechanism operating in biological evolution, the statistical mechanisms that determine the fate of an altered gene. These are the mechanisms that increase or decrease frequency of an allele – an alternate gene at a particular chromosomal position –within a population. Natural selection, the Darwinian explanation for biological evolution, remains one of the mechanisms acknowledged by biologists, yet not the only recognized mechanism.

Answers to Creationist Nonsense

15 Answers to Creationist Nonsense
Science & Technology at Scientific American.com: 15 Answers to Creationist Nonsense -- Opponents of evolution want to make a place for creationism by tearing down real science, but their arguments don't hold up: "Embarrassingly, in the 21st century, in the most scientifically advanced nation the world has ever known, creationists can still persuade politicians, judges and ordinary citizens that evolution is a flawed, poorly supported fantasy. They lobby for creationist ideas such as 'intelligent design' to be taught as alternatives to evolution in science classrooms. "

Comment: In this Scientific American article, the author contends that evolutionists ought to counter creationist claims with scientific facts. While this is good advice, many creationists simply refuse to acknowldge the empirical evidence provided by science. I contend that evolutionists can also specifically refute the illogical arguments of creationists and id-ists by calling attention to the glaring fallacies of logic inherent in those arguments.

See Fallacies of Logic.

Creationist and ID confusion about Entropy

Creationist and "Intelligent Design" confusion about Entropy
The Woodstock of Evolution -- The World Summit on Evolution (ScientificAmerican.com): "Creationists and Intelligent Design theorists like to inquire how information can increase in a world filled with entropy and the decay of information. "

Ignorance in Kansas

Those Kansans, creationists, idists, and proids who welcomed the anti-evolution and anti-cosmology decision of the Kansas Board of Education did so at the expense of education in both science and in critical thinking of the schoolchildren of Kansas.

ScienceWeek: "KANSAS, EVOLUTION, AND IGNORANCE IN AMERICA
Concerning the recent decision by the Kansas (US) State Board of Education to purge evolution and cosmology from the science curricula of all Kansas public schools, R.B. Hanson and F.E. Bloom (_Science_) present an editorial, with the authors making the following points:
1) The authors suggest that two aspects of 'this
intellectual cleansing atrocity' are most troubling: a) No political leaders from either party have as yet elected to step forward and challenge the lunacy of removing from the educational opportunities of the future voters of Kansas two of the best established theories of our era. 'Such reluctance emphasizes a growing public ignorance of the methods by which scientific observations are formulated into testable hypotheses and, when sufficiently strongly supported, are elevated into... theories.'
b) Second, and more troubling, is the shrewdness of the strategy used by the creationists in achieving their ends. No longer are they attempting to overturn the series of court decisions that have banned the teaching of creationism as a science. The new strategy, representing a far more threatening menace to future generations, is not only not to teach evolution and cosmology, but to undermine the solidity of their scientific acceptance."

Comment: Politicians care about one thing, and one thing only, and that is to ensure that they are re-elected to public office. When a politician's constituents include a vocal minority of religious fundamentalists and a large number who know nothing of science and care little for scientific truth, then few politicians would care to step forward on the side of knowledge, science, or logic. The battle against ignorance has since been brought to the courts by parents who are concerned about the education of their children. Keeping up with the Jones decision

Ignorance in the White House

Yes, I refer to Giorgio W. Borgia, Idiot-in-Chief who endorsed "teaching alternatives to evolution in public schools".

Ahem, might I point out that there are no alternatives to evolution ... biological evolution is a fact. How can there be alternatives to facts? Nonfacts?

Bush: "Both sides ought to be properly taught . . . so people can understand what the debate is about," he said, according to an official transcript of the session. Bush added: "Part of education is to expose people to different schools of thought. . . . You're asking me whether or not people ought to be exposed to different ideas, and the answer is yes."

Debate is the key word in that statement. Debate falls under the aegis of philosophy, yet debate has little merit and ought to be abandoned when one side of the debate is clearly superior in terms of empirical facts and logic.

Almost four hundred years ago, Francis Bacon promoted empiricism and scientific induction. Science, which derives from the Latin root for knowledge, has long-since supplanted metaphysical philosophy for those who seek to comprehend the physical world. Scientific debate is a process directed toward better understanding of empirical facts.

As I have argued elsewhere, so-called "intelligent design" theory could be utilized as an exercise in philosophy classes. It is not science, it is not scientific, it is religion, it offers NO viable alternative explanation for the observable fact of biological evolution.

Why would Bush endorse an anti-science policy for public education? One can only assume that he is pandering to the conservative voters.

There are abundant reasons to consider Bush a fool who cares nothing for truth. This policy is yet another example. That Bush has blundered into a job far beyond his intellectual capabilities is testament to the problems inherent in the democratic process (voters) and to rigged elections. That Bush is allowed to remain in office despite uncovery of lies designed to instigate invasion of Iraq, when Clinton was impeached over a mere sexual peccadillo, is evidence of the intellectual malaise that has overtaken the US.

The Constitution insists upon separation of Church and State. Is Bush too dense to realize that his declared policy of putting ID theory into science classrooms is in violation of the Constitution? Does Bush not care to uphold the Constitution? Does Bush believe that most voters care nothing for the Constitution? Perhaps Bush knows that conservative voters do not know the difference between fact and fantasy. After all, some deluded souls voted for him.

Purpose

The author of this site is an atheistic evolutionist.

However, the intent of this site is not an attack on religious beliefs. Religious beliefs are personal and provide much emotional comfort. Those who carry such beliefs to extremes often cause distress to others, but extremism reflects human failings and is not the fault of religious beliefs as such.

The intent of this site is to employ creationist and idist* arguments to illustrate fallacies of logic.

Most creationists who debate on the Internet (including proids) are not interested in learning science, rather they are typically interested only in attacking specific areas of science, presumably in the illogical belief that this could prove their cherished beliefs correct. Most proids* display very little knowledge of science and are merely following the fallacious arguments of other apologists. Creationists and idists typically misrepresent the facts of science, employing fallacious straw man arguments in an attempt to diminish the strength of scientific evidence.