Originally posted by twhitehead
I have noticed that some theists seem to think that life has some magical property that can only come from God. There have been a number of comments suggesting that 'life from non-life' is not only impossible but somehow self evidently ludicrous.
I think such thinking has some major flaws, not least of which is a lack of understanding of grey definitio ...[text shortened]... iving human cells 'life'? At what point can it be declared 'dead' or 'non-life'?
The following is what the evolutionary scientists say about viruses and prions:
Viruses are found wherever there is life and have probably existed since living
cells first evolved. The origin of viruses is unclear because they do not form
fossils, so molecular techniques have been used to compare the DNA or RNA of
viruses and are a useful means of investigating how they arose.
There are three main hypotheses that try to explain the origins of viruses:
1. Viruses may have once been small cells that parasitised larger cells. Over
time, genes not required by their parasitism were lost.
2. Some viruses may have evolved from bits of DNA or RNA that "escaped" from
the genes of a larger organism. The escaped DNA could have come from plasmids
(pieces of naked DNA that can move between cells) or transposons (molecules of
DNA that replicate and move around to different positions within the genes of
the cell).
3. Viruses may have evolved from complex molecules of protein and nucleic acid
at the same time as cells first appeared on earth and would have been dependent
on cellular life for billions of years.
Viroids are molecules of RNA that are not classified as viruses because they
lack a protein coat. However, they have characteristics that are common to
several viruses and are often called subviral agents. Viroids are important
pathogens of plants.
Viruses that are dependent on the presence of other virus species in the host
cell are called satellites and may represent evolutionary intermediates of
viroids and viruses.
Viruses are now recognised as ancient and to have origins that pre-date the
divergence of life into the three domains. This discovery has led modern
virologists to reconsider and re-evaluate these three classical hypotheses.
It seems unlikely that all currently known viruses have a common ancestor, and
viruses have probably arisen numerous times in the past by one or more mechanisms.
Prions are infectious protein molecules that do not contain DNA or RNA. They can
cause infections such as scrapie in sheep, ("mad cow" disease) in cattle, and
chronic wasting disease in deer; in humans prionic diseases include Kuru,
Creutzfeldt–Jakob disease, and Gerstmann–Sträussler–Scheinker syndrome. They are
able to replicate because some proteins can exist in two different shapes and the
prion changes the normal shape of a host protein into the prion shape. This
starts a chain reaction where each prion protein converts many host proteins
into more prions, and these new prions then go on to convert even more protein
into prions; all known prion diseases are fatal. Although prions are fundamentally
different from viruses and viroids, their discovery gives credence to the theory
that viruses could have evolved from self-replicating molecules.
The evolutionists still cling to the possiblility of a common ancestor with every
little hint that their "fairy tale" may be true.
Life
18 Jan '12 20:35
Back to Top