Proponents of replicators point out that metabolic pathways are way too complex to have arisen spontaneously. Proponents of metabolism-first theories point out that replicators larger than mer cannot spontaneously form. The first experiments done by Stanley Miller in demonstrated that mixtures of reducing gases, thought to be present in the primordial earth, when subjected to electrical discharges, produced many organic compounds, including several amino acids.
Rigid linkage means that the evolution process cannot work out a way to achieve the benefit without incurring the adverse side-effect aging. See Evolutionary Value of Life. Problems with the Disposable Soma Theory It is widely accepted that indeed many deteriorative processes exist in nature and that organisms do expend much energy and material resources in combating these processes.
Dead cells are replaced, hair and nails grow, infections are combated, and wounds are healed. However, disposable soma requires a subtle assumption: The energy and resources associated with organism Theories and hypotheses seem to be largely very short-term in nature.
For example, in humans, hair, nails, epithelial cells, and red blood cells are frequently replaced weeks. If we added up the weight of all of these items produced during an average human life span it would likely exceed the weight of the person. On the other hand, nerve and brain cells are very infrequently replaced.
The total mass of material and associated energy associated with replacing these cells or other long-term maintenance is therefore negligible by comparison. Our need for sleep widely seen as associated with maintenance is very short-term.
These observations make it extremely difficult to see how there could be a tradeoff between the major maintenance and repair effort short-term and aging long-term. A young animal cannot afford to cease short-term maintenance and repair because doing so would damage its ability to reproduce.
Ceasing long-term maintenance and repair to the extent that it exists would not save significant resources. The disposable soma concept works best in cases where the beneficial reproductive effect is immediately prior to mortality such as in the case of the semelparous male marsupial mouse that is said to fatally exhaust itself in extremely extended copulation.
Some organisms are not observed to age and yet are able to continue reproducing. Some display increased reproductive capacity with age. These observations obviously conflict with the idea that there is some unavoidable biological tradeoff between reproduction and aging.
Beginning in the s modern programmed aging theories reemerged with a substantial theoretical basis. This basis was in turn the result of many intervening discoveries mainly in genetics that altered the way we think about the evolution process.
Limiting the lifespans of individual members of a population increases the probability that the population will avoid extinction. Kirkwood is still a vocal proponent of non-programmed aging and his own disposable soma theory and published a paper in attacking programmed aging theories and other non-programmed theories .
Programmed aging proponents were surprised to see that this article essentially concedes the evolutionary basis for programmed aging by conceding that non-individual benefit can influence the evolution process.
It also concedes that "circumstances could exist" in which aging could be programmed and further, does not argue against the specific circumstances proposed by specific programmed aging theories.
Programmed Disposable Soma Theory The disposable soma theory essentially requires a program or a biological mechanism that would cease or down-regulate myriad different maintenance and repair mechanisms at the appropriate age for a particular species living in particular circumstances.
This article  explains why such a program would be very similar to the programs suggested by programmed aging theories. The "programmed disposable soma theory" leads researchers in the same directions as "programmed aging" theories!
Nature 2. The evolution of ageing and longevity. Proceedings of the Royal Society of London B Kirkwood T, Melov S. Biochemistry Moscow Phenoptosis A programmed aging response to Kirkwood article above.Two-Source Hypothesis [Mark-Q model] The dominant source theory among scholars today, the Two-Source Hypothesis (2SH) holds that Mark was the first gospel to be composed and became the primary narrative source for Matthew and Luke (Markan priority).In addition, Matthew and Luke independently supplemented their Markan .
The Acquisition-Learning distinction is the most important of all the hypotheses in Krashen's theory and the most widely known and influential among linguists and language practitioners..
According to Krashen there are two independent systems of second language performance: 'the acquired system' and 'the learned system'. The . A hypothesis (plural hypotheses) is a proposed explanation for a leslutinsduphoenix.com a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it.
Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories.
Even though the words "hypothesis" and "theory" are often used.
In , a statistician named Thomas Kirkwood (now a biologist and professor of medicine at the University of Newcastle) published his disposable soma theory of aging [1, 2].Kirkwood’s idea was that organisms only have a limited amount of energy that has to be divided between reproductive activities and the maintenance of the non-reproductive aspects of the organism (soma).
EC: Ellie Crystal: One of the theories about End Times is sudden pole shifts - these theories surfacing more often in As I see it - tectonic plates breaking, sudden poles shifts, other Earth Changes all manifest simultaneously at the end of the experiment.
Origin of life researchers have been refuting each other's theories, saying why each is impossible. Proponents of replicators point out that metabolic pathways are way too complex to .