Evolution is known fact. It can be demonstrated. No reasonable person can dispute it. Evolution is by far the most important natural process to the human. His very thought and structure came from this process. No human can properly assess his own position in the universe without knowledge of the evolutionary process. Evolution developed the modern human species, and so has a bright side. Evolution also has a dark side. The future of the species depends on knowledge about evolution becoming widespread.
The evolutionary process is bidirectional in its effect. It may, depending on the environment, either improve a given characteristic or decay it. Since the first step in the process is largely random and most organisms are quite complex, almost all of the variations are harmful. A characteristic of a species advances if the environment is harsh, since most harmful variations to that characteristic will be eliminated through death and suffering at a rapid rate, leaving only the inconsequential and helpful changes in the lineage. If the environment is benign with respect to the capability of the species then the harmful changes are not eliminated and the species will degenerate to a point of balance with the environment.
DNA and Replication
About 100 billion copies of our DNA are distributed throughout our body. Each copy is alive (it can reproduce itself) and is identical to every other copy. DNA has many functions within the life-form. Without DNA, we could not be born. We could not live. We could not grow. Nothing in our body would function. We could not reproduce. In fact, our body could not form. It controls our growth and development from conception. It determines our appearance (size, weight, color of eyes, skin texture, etc.). Indirectly it controls all of our bodily and mental functions (since it details the physical and operating characteristics of all of our components). It even to some extent controls our length of life. DNA functions in all life-forms in the same way.
No other tissue in our body is alive. None can reproduce without DNA. All tissue other than DNA is built in response to action taken by DNA and its only purpose is to serve the needs of the DNA. DNA performs functions necessary for its own survival. It performs functions necessary for our survival. It reproduces itself. It performs functions that allow us to reproduce. Even in our own reproduction, it is our DNA that is reproducing. DNA works in the same way in all other life-forms. Of the entire body of any life-form, whether plant or animal, the parts of its body that bring life to its existence are the DNA in each cell in its body. Life is distributed throughout the body of every living thing.
DNA has a code that is quite similar in construction to that used in modern digital computers. The code used in computers is called binary and consists of two numbers: 0 and 1. These numbers are then combined to specify entities needed by humans: 0001 becomes the binary equivalent of our number 1, 1111 is the binary equivalent of our number 15, and 01010001 is the binary equivalent of the capital letter Q. Although the computer works in binary, its output to us is then converted to our language so that we can understand it. DNA encodes with a slightly more complex system. Unlike the computer that uses 0 and 1, and unlike humans that use a decimal system 0 through 9, DNA uses a system of four conditions. This system could be symbolized as 0, 1, 2, and 3, but is not normally done so. Instead, DNA may be visualized as a code made up of four conditions: A, T, C, and G. These are called bases and they may appear along the length of the DNA in any order. These bases are complex organic molecules that provide the fundamental genetic building blocks for the description of the overall organism that the DNA will construct and maintain.
The upper and lower red lines indicate the sugar-phosphate "glue" that holds the sequence of bases together. Between these two "rails" are shown four bases in schematic form. The two vertical base combinations are called base pairs and are joined with hydrogen bonds. Note that the base pairs are not joined with adjacent pairs except through the common rails. In physical form, DNA consists of two strings of bases in the form of a ladder with base pairs forming each rung. The ladder is then twisted to form a helix. Each rung of the ladder is constructed of only four possible combinations of base pairs. Two of these are shown. The other two are obtained by inverting those shown. A will only pair with T and C will only pair with G. The four possible conditions for any rung on the DNA ladder are AT, TA, CG, and GC.
To describe an organism, these bases are coded into a long string of DNA. This DNA coded string must be quite long. The human description is about 3 billion base pairs long and consists of 24 DNA strings, called chromosomes. The overall genetic material that describes any organism is called its genome. The genetic material in each human consists of 2 sets of 23 chromosomes in each of about 10 billion cells in the body.
The top row in the figure below provides a code for making the substances used in the organism. The lower row of the pair contains the same genetic information, but its code is the reciprocal of the code in the upper row. Wherever a T appears in the top row, its reciprocal A appears in the lower. AT, CG and GC are the other possibilities.
DNA reproduces by division. The top two rows in the above figure show a fragment of DNA before it starts to reproduce. When the DNA replicates, it is immersed in a soup of bases from which it will select the "food" that it needs as it grows. Other "helper" chemicals are also present. The DNA unzips on one end. The zipper moves down the strand at a steady pace. Behind the zipper, the two strands are separated. Unattached bases are floating on all sides. One by one, the proper complementary base is selected and attached to the free-floating half-strand. When the zipper has completely separated the two halves of the original strand of DNA and the two halves have completely filled their new complementary halves, the process is complete. The two separate but identical DNA strands result.
DNA coding resembles computer binary coding in another way. Early personal computers used a series of binary numbers that were eight positions long, such as 11001110 or 00011101. This was termed an eight bit wide word. An eight bit word can encode all of the letters of the alphabet, for use in a word processor, for example, or it can provide numbers from 0 to 255 for use in computation. Modern personal computers are much more versatile, using word lengths of 32 or even 64 bits in length. Another common coding system is used in our written language. It uses 26 possible conditions (a...z) and variable word lengths to provide a written symbol (code) for every spoken word. DNA uses a much simpler system, which is only three positions wide, called codons. ATC, TCG, and TTT would be examples of individual codons. Since a word length has three possible positions and four possible conditions in each position, sixty-four possible combinations are possible. Not all these combinations (codons) provide unique functions. DNA codons specify the construction of 20 possible amino acids. These amino acids may be further combined to form more than 100,000 substances to be used in cell construction and maintenance (in turn building and maintaining the host organism).
The Genome is a Digital Program.
When executed, it produces a human.
This section is repeated in Man, the Digital Machine. It is included here for continuity of thought.
The DNA which describes each individual is in a digital code. The code is made up of four possible values. In number form, these could be expressed as 0, 1, 2, 3, but are normally expressed as four letter values: A, C, G, and T. These are always paired with their reciprocal value (see the text OneLife for more detail). Note that the DNA description of all living things is made up of only four basic construction blocks. There are about three billion of these base pairs in the human genome. These are used in groups of three, called codons. Each codon consists of three base pairs, each of which may carry one of four possible values. The number of codon values which can be expressed in three elements of four values each is 64. Normally these values would be assigned as 0, 1, 2, etc. through the number 63. Instead, all possible codons are expressed in the following table:
Note that this list contains all of the possible codons, there are no CAA.5 or CTT 1/2 codons. The beauty of things digital is the simplicity and precision. There are 64 precise arrangements of base pairs and only 64. All life is constructed in response to these precise codon values, and no other.
Most of these sixty-four combinations are used to produce 20 protein building blocks, called amino acids, from which the human organism is constructed. Some of the others are duplicates, and some are called "stop" codes. The following list shows the correspondence between the codon values and the 20 amino acids which in man will be produced from that coding:
The substance of the human body is constructed from proteins, which in turn are constructed from these 20 amino acids.
As the program in the genome is read codon by codon from a starting code to a codon stop code, the sequence of codons dictate the construction of a protein. A particular series of codons will describe a particular protein which the cell can produce. Such a sequence is called a gene. In the case of man, more than 80,000 different proteins are manufactured in the cells from these digital formulas to form and maintain the overall organism. Some of these proteins are quite complex. The final assembly may total many thousands of various amino acids, all arranged precisely. The genome, then, is a precise digital formula which describes the construction of an entire human being. These instructions include precise formulas for the material used to build the body and precise assembly instructions as well.
Modern computers use binary arithmetic, where each position (bit) has a value of 0 or 1. Since larger numbers are needed, a handier concept is a byte, consisting of eight bits and capable of a value from 0 to 255. The codon set can be represented by assigning values from 0 to 63 and so fits well within a byte. The three billion byte genome representation will fit in any hard disk of 3 gigabytes are more, well within the size range of modern desk-top computers. This is the data base which describes man in such detail that it can actually construct an entire human including all of the instructions for his development and demise. This is the raw data from which knowledge may be obtained. Every particle of man is described in precise detail. Since his instinct detail is also fixed by this coding, that will also be analyzed and cataloged. Since man is driven by his instinct in all social actions, the initial propensity for a particular set of social drives is inherent in his DNA coding and so may be uncovered individual by individual.
The gene is the primary carrier of inherited characteristics. The gene that controls a certain characteristic has a particular physical location in the genome. Due to past mutations, many genes will have structural variability within the population of a species. When two genes have the same purpose (for example eye color) but differ in physical construction (same example blue and brown), they are called alleles. A gene may have many alleles within a given species. The total of all of the genes in the population, including their alleles, is called the gene pool of that species.
The Evolution Process
Evolution is the change with time of the gene pool of a species. The mechanisms of evolution are mutation, natural selection, recombination and gene flow.
Mutation provides all initial change. A mutation occurs when the DNA does not replicate perfectly. When a mutation occurs, a new allele is created. As a first approximation, these accidents (mutations) are random (can occur at any location along the DNA). The rate of these accidents is relatively constant within a given species. If the accident occurs in a critical location (believed to be less than 10% of the total in man), the result is usually disastrous. Other areas will accept change with no immediate consequence. Once made, the mutation is perpetuated and variability within the gene pool of the species is increased. Mutations add variability to the gene pool.
Natural selection occurs when the viability of an allele is tested in real life. It makes only one test. Contrary to popular opinion, evolution does not select the fittest, strongest, or most superior organism. It is instead a question of how many offspring the organism will have which in turn will reach sufficient maturity to have its own offspring. If the effect is positive, the allele will become a permanent part of the gene pool. If the effect is very successful, it will quickly become a dominant allele. If the effect is neutral or negative, the allele will not spread rapidly through the gene pool and, usually, will disappear from the gene pool. If more than one mutation is being tested at the same time, usually the case, then it is the summed effect tested. Not all good mutations make it. Some mutations would be good at one time and bad at another, depending on the environment then. A mutation that was necessary at one time may become unnecessary at another time and be consequently negated. Most of the time, the alleles removed or negated are those that harm the organism in that environment. Natural selection removes variability from the gene pool.
The environment which an organism faces and must survive is a complex one, one which is more than climate and food supply, although those are the essential elements that serve as a starting point in the study of evolution.
First of all, the mutation process is not altogether random. An intricate process called recombination developed early in sexual animals. This process serves to mix the alleles available in the two parental gene sets to provide more variability against the environment. It also results in many reproduction errors (mutations). Repair functions were developed by evolution for DNA errors to offset this error propensity. Since both the dissection means and the repair means are relatively fixed processes, then both the dissection errors and the errors in repair will follow certain patterns. When these coincide, a new allele is formed. Mutations, then, occur in clusters around particular loci not yet known or cataloged. Certain defects occur, therefore, with a given frequency, which are wholly the result of the process and not the assumption of a defective ancestral gene.
Another factor which enters into genetic change is that the product of a purely random process (and a large part of human mutations fit that description) will drift to one side or another until an outside force interferes with the drift. For example, the human is now growing larger. If this is the result of genetic drift, it will continue until some other process interferes, such as a shortage of food.
Most of the struggle in life is the struggle for enough food to avoid starvation and an ability to survive the climate. This was the entire struggle at the beginning, but as life became more complex, the selection process also became more complex. Once life began, however, other life became a part of its environment. The food chains were started.
The basic element of species survival is the ability of the individual to survive long enough to insure the survival of its offspring to the point when they also have offspring. If the offspring require no care, then the immediate death of the parent is of no consequence. In the case of the higher animals, those which require care during their maturation, the life of the caring parent must extend through that maturation period (and, of course, the parent must perform its function properly).
If an animal must endure an environment in which its population is normally controlled by predators, it is usual that the young suffer a higher death rate than the adults. In such cases the parents will usually live through several breeding seasons, to offset losses of their young. Some animals resort to large numbers of offspring, thereby feeding the predators, with enough left over to continue the species.
As animals became more complex, they themselves began to be an appreciable part of their own selection (survival) environment. Herein lies the most complex of all genetic processes, and examples abound. Sexual selection (based on an appearance which is sexually attractive) is probably (not for sure) the most common of these. There are times when sexual selection actually harms the ability of the species to survive. There are thousands of examples, but to select one, consider the Cardinal, a beautiful small bird that is quite common in North America. Somewhere back in time, the drab little hens, who had drab little roosters as soul-mates, took a liking to the color red and began choosing mates based on a hint of red in their feathers. Since they mated with roosters who had red in their makeup, their offspring tended to have red in their feathers, which suited the next generation of hens just fine. Quite quickly the rooster was a bright red, and the best target in the world for a predator. The predator, usually a hawk, could lock on to that bright red target and have a meal in no time. As a result the Cardinal rooster is quite skittish, and he should be, but without the red there is no sex and his genes end.
Recombination occurs in sexually reproducing organisms, such as the human. The parent has two sets of chromosomes in each cell, one from its father, the other from its mother. The sperm and the egg carry only one set in each. The one set carried by the sperm or egg is not a whole set from either grandparent but is a mixture of the two. Both original sets of chromosomes, in the case of each parent, are dissected and scrambled, then reformed with entirely new combinations of alleles from both grandparents. This process adds variability to the offspring and allows testing of new allele combinations. Recombination allows new combinations of the variability in the gene pool
Gene flow occurs when populations of a species that have been separated are united and the differing sets of alleles in each gene pool flow into the gene pool of the other. Our species, suddenly reunited with widespread transportation, is an excellent example of this effect. Gene flow distributes the variability in the gene pool.
This section contains conclusions derived from the study of the evolution process.
CONCLUSION 1: Evolution is a cruel and brutal process.
Evolution is not a planned process. It does no engineering. The end products were never visualized. No goals exist. There is no thought of failure or success. There is no seeking of perfection. There is no seeking of anything. Evolution does not do anything. It only happens. Mutations produce chaos with genetic accident after accident, most of which is eventually fatal. Evolution uses misery and death to sort it all out. Evolution produces the strongest organism when the organism is in absolute misery. Rapid and early deaths make allele selections quickly.
We are at the mercy of a merciless idiot that survives with no regard for the comfort of the organism. The process of evolution has no goal, but its result is as if its only goal was to reproduce.
CONCLUSION 2: Evolution produces the worst possible organism that will still survive.
Evolution has no goals. It is a mechanism without intelligence. It does not seek excellence. It does not seek creature comfort. Genes that describe characteristics that are better than required in the current environment, will suffer the same mutation rate as any other. A mutation is an accident. It is not a respecter of right and wrong or of bad and good. Most mutations degrade the organism. When the characteristic, which was better than required, suffers mutation, the environment will not weed out much of the degradation. The degradation will then spread in the gene pool. The degradation of the once superior characteristic will continue with time until the characteristic becomes so bad that it adversely affects the evolutionary reproduction rate. Further degradation will be halted at that point and there it will stabilize at the point of the maximum misery that can still be survived. If by chance a mutation should improve an already superior characteristic, it in time will suffer the same fate.
CONCLUSION 3: Evolution is not compatible with any acceptable social structure.
Conclusion 2 shows that evolution degrades the organism when the organism is environmentally comfortable, since alleles that would otherwise fail can probably survive. Any form of compassionate culture interferes with nature, since it subsidizes alleles that would otherwise fail and by that promotes their spread. If the criminals, malcontents, insane, indolent and genetically crippled are condoned and subsidized so that their genes are returned to the gene pool, evolution will see those conditions as beneficial for survival. The degrading alleles will spread in the gene pool. The fastest growing segment of our species today is the welfare/prison population. If that continues, evolution will see those conditions as beneficial. Another evolutionary effect concerns health care. The more medicine and surgery we use, the more evolution will see to it that we need them. If we treat (subsidize) physical and mental weaknesses instead of allowing nature to weed out the carriers of these deficient genes, man will require ever increasing amounts of corrective medicine. Further to complicate the picture, the above analysis is written from the perspective of the US. The human gene pool encompasses the entire world. Our contribution to the overall pool is small. Many unseen problems lie in the rest of the world, in particular in the underdeveloped nations, which could eclipse the above concerns.
CONCLUSION 4: Evolution is ongoing and inevitable.
As long as we have DNA and are constructed from the patterns in our genome, accidents will occur in our reproduction, most of them bad. If those accidents are not constantly weeded out by the environment (if we do not suffer and die to rid ourselves of them), our species is in a constant state of degradation. Mutations are inevitable.
CONCLUSION 5: Evolution inevitably leads to species extinction.
Since evolution has no planning ability, its effect adjusts the species to bare survival under the current environment. Since evolution is unable to change a species quickly, sudden environmental change can mean the end of a species. Evolution will also build one species without regard to its danger to another. Ebola, polio, and rattlesnakes are examples. It will build one species that serves as food for another. The most outstanding example of the fickleness of evolution lies with the HIV virus. Evolution gave us an insatiable desire for sex, then blessed us with a deadly virus passed by sex. Further to compound this issue, our culture condones both the act and the disease, thus creating a disaster that has not played out yet.
Since evolution supplies a cliff-hanging balance between life and death, almost any accident can cause the annihilation of a species. Since evolution is no more than a series of accidents, eventually such an accident will happen to all.
CONCLUSION 6: Evolution has given us a genome that is a disease ridden pile of genetic garbage.
Evolution has no housekeeping function. It is a lot like our congress that papers over old laws with new ones. DNA changes always reflect what modern engineers call "a quick and dirty fix," when making a needed change. It "patches" over problems. Modern DNA is littered with genetic debris. Over the billions of years since the beginning, DNA in genomes has collected mutation on top of mutation. Whole genes are still being carried, along with mutation after mutation gathered along the way, which eons ago were negated and not used since. Genes that are still needed by the organism have been segmented and scattered. New creations exist alongside old ones while dictating the opposite direction. Genes have been formed inside other genes. The same process that gives variability also provides disaster after disaster. Thousands of genetic diseases and insufficiencies are hidden in our gene pool. Explosive combinations wait for a chance to occur.
A basic modern engineering principle is KISS (keep it simple, stupid). More than 90% of the human genome is considered junk DNA (it must be admitted that we cannot be sure of that figure until we know all of the functions in the genome, which may take decades to learn). The rest, by nature of its patchwork creation, is at best makeshift. Our genome is about three billion base pairs long. That means that it could contain up to 2.7 billion accident prone base pairs too many. And that thing dictates the formation of our bodies and our brains. It is no wonder we have physical and mental problems. The wonder is that we function at all. It becomes obvious why we spend such a huge percentage of our GNP on physical and mental health care.
CONCLUSION 7: The course of life dictated by the laws of nature is toward survival.
Any individual organism that deliberately subjects itself to unnecessary (imprudent) danger or harm is perverted. Since the survival of the species is also vital to the survival of the individual, any individual that deliberately (imprudently) harms the species is perverted. Since the survival of all life is vital to the survival of both the individual and the species, then any individual that deliberately (imprudently) harms life is also perverted.
The keyword is prudence (the application of intelligence). It may be necessary at times to harm in order to help. The end goal of all individual action must be aimed at helping the individual, species and other life to survive.
CONCLUSION 8: Competition is essential in all life.
A universal observation about all mobile living organisms is competition. All healthy organisms wish to survive, and that survival is not always limited to essentials. Competition is not necessarily combat, though combat may be required in some instances in the struggle for survival. Some forms of competition require cooperation, where the competitive aim is group survival (success). Compassion is a form of competition when it adds to the success of group survival. Teaching one's offspring how to compete and survive is a form of competition.
Competition causes an organism to strive, to do its best, to excel. Even when not needed, the healthy organism will practice its competitive skills in preparation for later need.
CONCLUSION 9: The mechanism of competition reacting with an environment produces stress, another essential of life.
The neural firing rates in the human neural system are adjusted chemically. These rates are high in times of danger and slow at times of rest. The chemical balance thus establishes the degree of stress. A moderate stress is essential for organism well being
CONCLUSION 10: Genetic faults are not all inheritable
DNA replication is a complex mechanical process in which there are many opportunities for error. The mechanical propensity for certain mutations will be higher than for others. Some errors will have a higher frequency of occurrence than others. The first time occurrence of a particular mutation is not inherited but is the result of inaccuracies in the replication process. Homosexuality, as an example, is a negative species survival mutation since the mutants do not normally have offspring. Yet it occurs at a relatively fixed rate, indicating a possible mode of replication failure. Note! The individual with the genetic fault may not be the one that is the mutant. It for example, could be in the mother, who then causes the fault in the child even thought the fault itself is not transmitted. Some such faults may not occur in a uniform way but show other factors, such as age or stress. The human homosexual male occurs at higher rates in later births (and older mothers) indicating the possibility that the mutation is a fault in the mother and one that intensifies with age or birth experience.
A mutation, therefore, may not be inherited at all but is instead one that happens frequently
CONCLUSION 11: Survivable mutations are finite in number.
Most mutations are not survivable and the fetus is aborted. This diminishes the range of survivable mutations to a finite number, one which, in a large population, may repeat often. This multiple injection of a given fault into the human gene pool is very damaging to the population, yet would not be solvable with selective breeding.
CONCLUSION 12: The female provides far more genetic function than the male.
The cell of the complex organism contains two sets of DNA. The nuclear DNA provides the organism shape and function, whereas the mitochondrial DNA provides the functioning of the cell itself. In the case of a cell which produces hair, for example, the nuclear DNA supplies the instructions for making the hair, the mitochondrial DNA actually provides the manufacturing function.
Nuclear DNA is supplied by both parents. Only the mother supplies the mitochondrial DNA.
The nuclear DNA, once the organism is mature, rarely replicates. Mitochondrial DNA constantly replicates during the life cycle. The replication stability of the mitochondrial DNA is therefore quite important in the well-being of the organism.
Life is a fact in the universe. Life exists. It exists within the same rules in the universe that everything else must follow. Evolution is a reactive process. Evolution is a requirement of life. The life produced by evolution is a part of the universe, as is a galaxy and a grain of sand. Evolution has no compassion and it has no goals. A given strain of life, while undergoing evolution and enduring a given environment, either survives or does not. The survival of a species rests on the sum total of the individual actions of each member within that species. Action by any member of a species, which is contrary to the survival of that species, is perverse (contrary to nature).
Evolution is obviously no friend of man or his culture. It brought us here, then dumped the whole problem on us. Through sex it has a hammerlock on us that will be painful no matter what we do. It appears that we either return to the tooth and claw so that nature can cleanse and maintain our gene pool, or watch ourselves sink back to the status of the beginning man. The first would allow us to retain our stature at the cost of losing our humanity. The latter is slower, but we lose both our stature and our humanity. Each choice is equally unacceptable. One thing is clear: Slow degeneration is the default condition.
A big hope for the far future lies in the genome project. In time we can clean up our genome, streamline it down to size, and then maintain it free of defects. This would take care of our problems with evolution but it might be way far in the future. Many will say that this is an impossible job. The amount of technical work, alone, is staggering. The mechanics of cleaning up the genome of all humankind all over the world appears impossible. Pre-conception examinations of the haploid DNA may be a possibility and it would fit in with a need for centralized genetic control. This may also turn out to be an impossible job. The only recourse then will be to start a process by which a new super-DNA structure is introduced into the population on a scheduled basis, one that will not mix, thus starting a new species to replace our own. Either technique will provide a great challenge to overcome fears and objections.
READER'S COMMENT: I have read what was written on your webpage. It was very interesting and I accept the "mechanisms of evolution" you present. I can see how they show evolution within a species, but I do not see how they show evolution between species. Please explain how the evidence you present shows this.
In the beginning there was only one very small and very simple biological organism. As it evolved, it's features diverged. Over the past 3.5 billion years or so, all of the various living organisms we see around us developed from this continuing divergence.
Evolution is always working within every species, always changing each species in both form and function. If a desirable mutation should occur in a very large gene pool (such as the human in China) it would be extremely slow to become a standard feature of that gene pool since it must first propagate generation by generation across the entire huge gene pool. A human feature or functional change in China might take hundreds of thousands of years, for example. If a small human gene pool (tribe) should become isolated, by geographical separation perhaps, the pool can change quite rapidly, on the order of a few thousand years. This is how the various human races came to be. If the differentiation continued and the gene pools were not mixed, eventually the different races would become different species. Modern transportation will never allow this to happen, of course.
Homo erectus existed for about 1.9 million years. It was a very successful human species and changed very slowly over that period of time. We don't know for sure where the modern human (Homo sapiens sapiens) developed, but it seemed to be quite sudden and happened about 180,000 years ago. It's a guess, but perhaps a small Homo erectus tribe became completely isolated under severe environmental conditions, one that caused rapid mutation selection so that the differences between erectus and sapiens occurred in a very short time. Such large scale change in a short time could only occur in a very small gene pool.
The idea of a 'species' is a human one, an intellectual approximation that we use to help us categorize various forms (organisms) of life. It is also a hazy concept, because every 'species' we define is actually in transition from one species to another and in most cases there is at least one other organism which is quite similar to the one being categorized, so similar that it is hard to call it a separate species. Even our categorization of the fossil history of man is highly controversial. Who can say exactly when Australopithecus africanus ceased to exist and Homo habilis began? Or were they merely variations in time within the same species?
So, the concept of 'species' is archaic. We thought that the forms of life were stable and that they could be categorized in a fixed fashion. We find, instead, that what we now see as the current set of 'species' around us is actually a current snapshot and that all of these 'species' are in transition.
READER'S COMMENT: Thank you for your explanation, but I see no proof of what you claim. I know of no transitional links and intermediate forms in either the fossil record or the modern world. From what I have read: Nine of the twelve popularly supposed hominids are actually extinct apes/ monkeys and not part human at all. The final three supposed hominids put forth by evolutionists are actually modern human beings and not part monkey/ ape at all. Therefore, all twelve of the supposed hominids can be explained as being either fully monkey/ ape or fully modern human but not as something in between.
The determination of a species is highly a matter of opinion. One may, based on opinion alone, categorize a particular hominid skeletal fossil as ape or man (or cat for that matter). There will even be disagreements among those who are well versed in skeletal structure and corresponding function. One thing we can be sure of is that all these hominid fossil examples consistently walked upright, a feature that is not ape-like, and that in time there was a transition between the physical characteristics of the ancient ape and modern man. To say that prior to a particular point along this lineage that they were all ape and after that point in time they were all human would indicate that there is some form of natural function at work that has not been observed and can't be logically developed from the abundant available real knowledge.
There are other considerations: notably the element of time. Through various means these fossils may be dated. The chronology of the fossils corresponds with the order in the development of the hominid from the ancient ape to the modern man. These methods of time determination are proven. Time and again they have been challenged, but never disproved. Those fossils existed in the time frame we can measure.
The fossil record of the hominid shows a steady progression from the ancient primate to the modern human. Each fossil 'species' is a 'link' between the one before and the one after. Only with great effort can one view this evidence and refuse to see this transition. Similar transitions are visible in all other species.
Evolution as a process is a matter of fact. It can be and has been proven time and again in the laboratory. Observations in the laboratory correlate with observations in the outside world. The evidence is overwhelming if taken in total. If man is real, the universe is real, and there is no perverse deity making fools of us all then evolution as a natural process does exist and modern man is an evolved descendent from an ancient primate.
READER'S COMMENT: I wonder how a single cell could have evolved, since a cell cannot function or survive without all of its parts.
Evolution is a demonstrable, provable, measurable process involving DNA with associated non-living biological chemicals. In the beginning this DNA was in a sea of such chemicals. It did not require the protection of the cell. Evolution produced the cell. It is the DNA that evolves. It doesn't matter whether it is in a single cell or not. It doesn't matter whether it is in cooperation with other cells. It doesn't matter whether it is alone in a soup, in a cell, in a tree or in a human. It is the DNA which evolves. The form of the biological organism (species) follows from the DNA.
The process of the evolution which brought about the development of the cell is extremely complex, far more complex than the development of the human from the ancient primate. There are many good college texts that cover this topic quite well. My favorite is MOLECULAR BIOLOGY OF THE CELL by Alberts, Bray, Lewis, Raff, Roberts and Watson, Garland Publishing - ISBN 0-8153-1619-4. If you are serious about the subject you will find this text fascinating, all 1200 pages of it.