Fossils showing stability over time...............
Many fossils, like this jellyfish fossil, actually show stability of some species over time rather than change and there is a lack of intermediates. Species that are the same as their fossil ancestors are called "Living fossils".
On this page single celled organisms such as bacteria and amoeba are considered as the possible source of all other living organims on the planet. Such cells used to be thought of as "simple cells" but in recent years have been found to be highly complex.
Introduction In Darwin's day, many people swallowed the theory of spontaneous generation - that life arose from non-living matter. It was somewhat easier to believe because the cell's structure was almost unknown.
Ernst Haeckel, Darwin's populariser in Germany, claimed that a cell was a 'simple lump' of aluminous combination of carbon (cited in Behe, 1996). (Above taken from How Simple Can Life Be?). See also at this site "evolution of evolution" which gives more information on earlier thinking of how the first cells arose.
However, nowadays we know that cells are in fact amazingly complex.
"[The instructions within the DNA of a single cell] if written out would fill a thousand 600 page books. Each cell is a world brimming with as many as two hundred trillion tiny groups of atoms called molecules. Our 46 [human] chromosome 'threads' linked together would measure more than six feet. Yet the [cell] nucleus that contains them is less than four ten-thousandths of an inch in diameter." Rick Gore, "The Awesome Worlds within a Cell" in National Geographic, September 1976, pp. 357-358, 360.
"One gram of DNA – the weight of two Tylenol – can store the same amount of digitally encoded information as a hundred billion DVD’s. Yes, you read correctly, I said a hundred billion DVD’s. Every single piece of information that exists on the Earth today; from every single library, from every single data base, from every single computer, could be stored in one beaker of DNA". From - Atheistic Science is Rapidly Sinking in the Quicksand.
According to the theory of evolution, the first living cells were thought to come into being in what is often referred to as the "primordial soup" and this process can be referred to as abiogenesis. This early sea was thought to contain a soup of chemicals that formed themselves into simple single celled organisms.
A recent (2001) Times newspaper headline illustrates the above thinking. The headline stated that "Origin of the species is traced to pond life". The newspaper article comments on a paper (King and Carroll, 2001) in which the organism Monosiga brevicolliswas found to have a protein similar to one found in animals.
Scientists consider the moment at which multi-celled animals, (or metazoa), evolved from the protozoans (e.g. organism such as amoebae and Monosiga brevicollis) to be one of the turning points in the history of life on Earth, and to have occurred about 600 million years ago.
However, as Monosiga brevicollis is a eukaryotic protozoa it is by no means the most simple single celled organism on the planet today. If we are to believe the theory of evolution, this organism itself must have evolved from more simple single celled organisms such as bacteria.
Abiogenesis.Abiogenesis is the theory that life (e.g. simple cells) can arise spontaneously from non-life molecules under proper conditions (click here for some more details). Evidence for a large number of transitional forms to bridge the stages of this process is critical to prove the abiogenesis theory, especially during the early stages of the process. The view of how life originally developed from non-life to an organism capable of independent life and reproduction presented by the mass media is very similar to the following widely publicized account:-
"Four and a half billion years ago the young planet Earth... was almost completely engulfed by the shallow primordial seas. Powerful winds gathered random molecules from the atmosphere. Some were deposited in the seas. Tides and currents swept the molecules together. And somewhere in this ancient ocean the miracle of life began... The first organized form of primitive life was a tiny protozoan [a one-celled animal]. Millions of protozoa populated the ancient seas. These early organisms were completely self-sufficient in their sea-water world. They moved about their aquatic environment feeding on bacteria and other organisms... From these one-celled organisms evolved all life on earth." From the Emmy award winning PBS NOVA film The Miracle of Life quoted in Hanegraaff, 1998, p. 70. To top
Life in a test tube. One of the most famous experiments that has been used to support the emergence of life from the "primeval soup" was published in Science magazine in 1953 and was performed by Dr Stanley Miller (Ankerberg, 1998a) as pictured right. In this experiment water vapour, ammonia, methane and hydrogen was subjected to spark discharges and simple amino acids were formed. After this experiment was performed, a newspaper headline proclaimed that life had been made in a test tube!
However, amino acids, whilst constituents of living cells are no more living cells that iron ore in the ground is a car. The experiment also had lots of shortfalls:-
In brief, some of the shortfalls:-
A methane-ammonium reducing atmosphere would be fatal to life forms (Wysong, 1981).
There is no evidence that the earth's early atmosphere was reducing atmosphere (White, 1978).
In the presence of excess water, polypeptides (chains of amino acids) are broken down into amino acids . "The ocean is practically the last place on this or any other planet where the proteins of life could have formed spontaneously from amino acids" (Wilder- Smith, Dr, 1981).
No experiment has ever been conducted by which living cells can be created in a laboratory from basic ingredients. In later life, Dr Stanley Miller himself conceded in Scientific American that "the problem of the origin of life has turned out to be much more difficult than I, or most other people, envisioned" (Ankerberg, 1998a).
Are simple cells simple. The most simple single celled organism known today are bacteria. Viruses are simpler, but viruses can not replicate outside an existing living cell, so these could not have arisen without more complex living cells for them to replicate in. Protozoa, according to the some versions of the theory of evolution, are thought to be the origin of all other species on Earth, but these are more complex than bacteria.
The information content of a bacteria has been estimated to be around 10,000,000,000,000 bits of information comparable to a hundred million pages of Encyclopaedia Britannica (Sagan, C, Encyclopaedia Britannica).
Escherichia coli is one of the most studied bacteria and has had its complete genome sequenced. There are many different strains of Escherichia coli. Most live in the guts of mammals without causing any disease whilst some strains (such as Escherichia coli O157) can cause disease.
The fact that Escherichia coli is the topic of hundreds of thousands of research papers illustrates the fact that one of the simplest self replicating organisms known to science is in fact incredible complex. Despite the numerous research papers in the past and more current papers, there is still much to learn about this humble bacteria.
Using the most sophisticated laboratories in the World and with the hindsight of about 100 years of research, the most eminent Scientists in the World could not even get near to making this bacteria from raw ingredients. However, such cells or similar or even more complex ones (protozoa) apparently arose by chance without the benefit of years of research and the skills of eminent scientists!
Francis Crick commented below on the chances of making a small specific protein. In view of the of the thousands of proteins in bacteria, the odds must be truly amazing for it to form by chance, because the bacteria would not function as a bacteria unless in the absence of all essential proteins
"To produce this miracle of molecular construction all the cell need do is to string together the amino acids (which make up the polypeptide chain) in the correct order. This is a complicated biochemical process, a molecular assembly line, using instructions in the form of a nucleic acid tape (the so-called messenger RNA). Here we need only ask, how many possible proteins are there? If a particular amino acid sequence was selected by chance, how rare of an event would that be?
This is an easy exercise in combinatorials. Suppose the chain is about two hundred amino acids long; this is, if anything, rather less than the average length of proteins of all types. Since we have just twenty possibilities at each place, the number of possibilities is twenty multiplied by itself some two hundred times. This is conveniently written 20200, that is a one followed by 260 zeros!
This number is quite beyond our everyday comprehension. For comparison, consider the number of fundamental particles (atoms, speaking loosely) in the entire visible universe, not just in our own galaxy with its 1011 stars, but in all the billions of galaxies, out to the limits of observable space. This number, which is estimated to be 1080, is quite paltry by comparison to 10260. Moreover, we have only considered a polypeptide chain of a rather modest length. Had we considered longer ones as well, the figure would have been even more immense." Francis Crick, [Crick received a Nobel Prize for discovering the structure of DNA.]Life Itself, Its Origin and Nature (1981), pp 51-52.
Endosymbiosis - Prokaryotic to eukaryotic organisms? Bacteria are what as known as prokaryotic organisms whereas all higher life forms (such as amoebae, fungi, plants and animals) are what is know as eukaryotic organisms.
The cells of prokaryotic organisms are in many ways very different from the cells of eukaryotic organisms. For example, in prokaryotic organisms there is no true nucleolus, no mitochondria, no chromosomes and no division by mitosis or meiosis, no endoplasmic reticulum, no golgi bodies.
In prokaryotic organisms, the DNA makes an exact (mutations aside) copy of itself before the cell divides into two identical (normally) clones. In eukaryotic organisms, cell division often involves genes from a male organism and a female organism merging to form a new organism which has characteristics of both its parents.
Evolution has led us to believe that early life forms were bacteria (or similar to bacteria). If these were always making clones of themselves (as prokaryotes don't undergo meiosis), how did they ever change to become eukaryotic organisms, let alone all known species of life on Earth?
One theory for this is the endosymbiotic theory. In brief, this theory suggests that one prokaryotic cell was capable of engulfing another, but rather than being digested, the bacteria remained as symbionts. As interdependence between the aerobic bacteria and the host cell grows, the bacterium were thought to become mitochondria or chloroplasts. Furthermore, it suggests that cilia and flagella may have arisen by an endosymbiotic relationship with spirochete bacteria.
The endosymbiotic origin of mitochondria and chloroplasts is an old idea dating back to the early 20th century. However, this theory has its shortfalls.
No procaryotes living today have ever been shown to have another procayote living inside them.
Eukaryotic organisms are much larger and more complex than the sum of two procaryotic organisms.
A eucaryotic cell such as a HeLa cell is large enough to contain hundreds of procaryotic bacteria.
The origins of endoplasmic reticulum, golgi, nuclear membranes and mitosis are unknown.
Monosigna brevicollis. Monosigna brevicollis is a protozoal choanoflagellate (or collar flagellate) that lives at the bottom of puddles and is a eukaryotic organism (see picture left). What has excited scientists is that proteins that were previously only believed to exist in animals and humans (such as receptor tyrosine kinase) have been found in this organism (King and Carroll, 2001).
Scientists consider the moment at which multi-celled animals, (or metazoan), evolved from the protozoan (e.g. organism such as amoebae and Monosiga brevicollis) to be one of the turning points in the history of life on Earth, and this is thought to have occurred about 600 million years ago (King and Carroll, 2001).
However, do the presence of genes found in animals in this protozoa give strong support for animal life arising from this organism? To top
Homology studies have concluded that 75% of human genes or close variants exist in worms, that "we share half our genes with the banana" and that 98.4% of human DNA is similar to that of ape DNA. (New Scientist, 1 July 2000, pp4-5)! So did we also originate from worms and bananas?
Using DNA relatedness (or protein relatedness) as a way of ascertaining ancestral evolutionary lines is making an assumption that evolution definitely did occur and common genes or proteins back this up, rather than suggesting common design.
If evolution did occur and everything evolved by chance mutations, it is indeed surprising that there is so much DNA relatedness across different species. By its very nature, would a process that relied on mutation not lead to less DNA relatedness than that observed? Scientists can't really use the data every way to suit a theory. If DNA relatedness does not point to us evolving from bananas, why should it point to all animals evolving from Monosiga brevicollis?
Another problem with the theory that animal life evolved from Monosiga brevicollis is that several hundred species of these choanoflagellates still exist today. If they really have been around for millions of years with their DNA making accurate copies of itself for all that time, how can their DNA also have mutated into all the animal life forms on earth?
Accuracy of DNA replication and mutation being the origin of all animal species on earth from single celled organism can't both have occurred, can they? To top
Quote from nobel prize biochemist."The development of the metabolic system, which, as the primordial soup thinned, must have "learned" to mobilize chemical potential and to synthesize the cellular components, poses Herculean problems. So also does the emergence of the selectively permeable membrane without which there can be no viable cell. But the major problem is the origin of the genetic code and of its translation mechanism. Indeed, instead of a problem it ought rather to be called a riddle. The code is meaningless unless translated. The modern cell's translating machinery consists of at least fifty macromolecular components which are themselves coded in DNA: the code cannot be translated otherwise than by products of translation. It is the modern expression of omne vivum ex ovo [everything that lives, (comes) from an egg]. When and how did this circle become closed? It is exceedingly difficult to imagine." Jacques Monod (Nobel prize for Medicine in 1965, biochemist, Director, Pasteur Institute, France."Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology", , Transl. Wainhouse A., Penguin Books: London, 1997, reprint, pp.142-143. To top