16 Jan 2017
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Ecology Selfish Gene Reading Chapter 2
The Replicators
- The universe is populated by stable things: collections of atoms that are permanent
enough or common enough to deserve a name
- Atoms within entities are organized in a manner that makes them most stable
The earliest form of natural selection was simply a selection of stable forms and
a rejection of unstable ones
- Coiatio of gases hypothesized to e preset i Earth’s early atosphere (water,
carbon dioxide, methane, and ammonia) and chemical/energy conditions of the young
Earth allows formation of a primordial soup, containing amino acids.
Organic substances become locally concentrated and energy from the sun causes
combination into larger molecules
- Replicator: the original molecule that had the ability to create copies of itself
- The replication process is not perfect, leading to mutation in daughter molecules that
makes evolution possible
- As mistakes in the replication of the original Replicator arose, the primeval soup became
filled by a population of several varieties of replicating molecules all sharing a common
ancestor
- Positive selection of replicators would occur based on:
Longevity: Replicators of high longevity would tend to become more numerous,
ad would therefore e seleted for
Fecundity: A stronger ability to create copies of oneself more quickly would
allow survival and selection for these replicators
Accuracy: A higher frequency of mistakes encourages diversity, thus producing
molecules that are not identical to the original replicator and decreasing the
population frequency of the original relative to more accurate replicators
- Competition for resources limits the extent to which survival of all individuals can occur
- Building blocks would have been a resource for which replicators would have had to
compete.
- Miscopies that led to higher stability of individual or decreased stability of other
individuals (in the form of building block resources) would automatically be favoured.
- Replicators may have evolved to protect themselves within containers, which could
have led to evolution of individual cells.
- Nowadays, those successful replicators (genes) are preserved within all living organisms.
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