Origins of Form
There is still considerable room for doubt that the gradual Neo-Darwinian mechanisms of mutation and selection alone can adequately account for the origin of morphological (form) innovation, particularly in regard to the higher taxonomic species.
Panspermia
Anaxagoras, a Greek philosopher (c500BCE), proposed a hypothesis called “panspermia” (Greek for “all seeds”), which posited that all things including life, originated from the combination of tiny seeds pervading the cosmos.
“Science has more recently posited a modern version of “panspermia” where life could have emerged on another planet or moon billions of years ago and hitched a lift to Earth on a meteorite. The hypothesis describes how life might have arrived on Earth but not how it originated in the first place. No matter where it started, life had to arise from non living matter.”
Did Life come from another planet - D. Warmflash and B. Weiss in Scientific American, pages 40-47; Nov 2005
Geneticists, using DNA sequence comparisons, routinely find genetic programs that are much older than paleontologists, using the fossil record, would predict. This chronology — genetic programs composed before natural selection on Earth could affect them — is a jarring anomaly for darwinism. But it would actually be logical and necessary if genetic programs come from cosmic ancestry.
Abiogenesis
According to the most commonly held views in science, life first emerged billions of years ago as a result of chemical reactions within the earth’s atmosphere, known in scientific terms as abiogenesis.
Oceanic Origins
How did amino acids form in the prebiotic and hence pre-enzymatic world? Huber and Wächtershäuser (p. 630) show that iron and nickel particles can catalyze formation of -amino and -hydroxy acids by hydration of methyl thiolate and/or cyanide in basic aqueous solution with high-pressure CO when heated to 100°C. The authors argue that these conditions could have been provided in underwater volcanic vents on the early Earth. The results are consistent with a model whereby coordination of these and more complex organic reduction products to the metal centers progressively gave rise to Fe and Ni-containing hydrogenase enzymes.
For neo-Darwinism, new functional genes either arise from non-coding sections in the genome or from preexisting genes. Both scenarios are problematic.
LIFE AS INFORMATION
When looked at from an information theoretic perspective, the problem becomes that of the origin of the information (whether genetic or epigenetic) that is necessary to generate morphological novelty at all levels of development, from genes and proteins to cell types, tissue, organs and body plans.
Further, building a new functionally complex animal from a single-celled organism requires not only vast amounts of new genetic information, but must also embody hierarchically organized systems of lower-level parts within a functional whole. Such hierarchical organization itself represents a type of information, since body plans comprise both highly improbable and functionally specified arrangements of lower-level parts.
THE EXPLOSION OF LIFE
Prior to approximately 570 million years ago there existed single celled organisms without a nucleus, known as Prokaryotes. At approximately 570 million years, multi-cellular life (Eukaryotes) began to emerge during the development of what is known as the Ediacaran Biota. This was followed by the Cambrian Explosion approximately 530 million years ago, which represented a dramatic increase (almost 90% of new species) in the level of biological complexity and animal body plans (morphogenesis) within a relatively short period of geological time (only 40 million years).
The key question is this - given the complex and interdependent nature of the processes of Gene, DNA, RNA, amino acid and protein conversion and formation, how did the Darwinian process of evolution allow for such a huge increase in diversity of viable phenotypic structure, in such a relatively short period of time? The answer can be broken down into sections, although it is important to realize that they all overlap.
In his book Climbing Mount Improbable, arch Neo-Darwinian Professor Richard Dawkins states that what random mutation acting through chance alone cannot accomplish, natural selection acting on genetic sequences and their corresponding protein products, can achieve through the cumulative effect of many slight variations. However, difficulties arise when the process of gene origin, development and transfer, as well as the specificity and complexity of protein formation is taken into consideration.
However, as Richard Lewontin points out, "There is no simple relation between the DNA coded messages and the construction of the organism".
1) DNA is not self reproducing
2) It makes nothing
3) Organisms are not determined by it
“DNA does not contain the key to its own interpretation, it is buried in the cytoskeleton of the fertilised egg, the product of history. It took 2 billion years to produce the eukaryotic cell and 1.5 billion years for the rest.”
It Ain't Necessarily So: The Dream of the Human Genome and Other Illusions (2000).It Ain't Necessarily So. Richard Lewontin. Granta Books, 2000.A typical gene contains over one thousand precisely arranged bases. There are four different bases namely Argenine (A) Thymine (T) Cytosine (C) Guanine (G). For any specific arrangement of four nucleotide bases of length n, there is a corresponding number of possible arrangements of bases, 4n. For any protein, there are 20n possible arrangements of protein-forming amino acids. A gene 1000 bases in length represents one of 41000 possible nucleotide sequences; a protein of 400 amino acids is one of 20400 possibilities.
As you can see, the statistics start to look scary very quickly. If the duration of the Cambrian explosion was between 5-10 x 106 and, at most, 7 x 107 years, then this is far smaller than that of the entire universe (1.3-2 x 1010 years).
DNA mutation rates are far too low to generate the novel genes and proteins necessary for building the Cambrian animals.
Evolution of Multicellular Life
In the eighth essay in Science's series in honor of the Year of Darwin, Carl Zimmer describes one of the most important transitions in the history of life: the origin of cells with a nucleus, which gave rise to every multicellular form of life. The fossil record doesn't tell us much: The earliest fossils that have been proposed to be eukaryotes are only about 2 billion years old, and paleontologists have not yet discovered any transitional forms. Fortunately, living eukaryotes and prokaryotes, cells that lack a nucleus, still retain some clues to the transition, both in their cell biology and in their genomes.
By studying both, researchers have made tremendous advances in the past 20 years in understanding how eukaryotes first emerged. A key step in their evolution, for example, was the acquisition of bacterial passengers, which eventually became the mitochondria of eukaryote cells. But some scientists now argue that the genes of these bacteria also helped give rise to other important features of the eukaryote cell, including the nucleus.
The Fall of the Dinosaur
According to the fossil record, the rule of dinosaurs came to an abrupt end 65 million years ago, when all nonavian dinosaurs and flying reptiles disappeared. Several possible mechanisms have been suggested for this mass extinction, including a large asteroid impact and major flood volcanism. Schulte et al. (p. 1214) review how the occurrence and global distribution of a global iridium-rich deposit and impact ejecta support the hypothesis that a single asteroid impact at Chicxulub, Mexico, triggered the extinction event. Such an impact would have instantly caused devastating shock waves, a large heat pulse, and tsunamis around the globe. Moreover, the release of high quantities of dust, debris, and gases would have resulted in a prolonged cooling of Earth's surface, low light levels, and ocean acidification that would have decimated primary producers including phytoplankton and algae, as well as those species reliant upon them.
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