The Origin Of Species By Charles Darwin

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Natural selection today is considered one of the main processes of evolution, and also thought to be one of the reasons that there is such great diversity between all of the organisms on the earth today (6). The Origin of Species written by Charles Darwin helps explain that for natural selection to occur there must be optimal conditions satisfied; the units must vary, the units must be able to be passed on from generation to generation, and also there must be competition for resources (6). Since all organisms differ and have different traits and genes some organisms will have an advantage over the others and also tend to produce more offspring (6). Lewontin believed that natural selection could be applied to genes, organisms, populations, and also species levels, while Brandon and Burian are the ones who came to distinguish the ‘units of selection’ (6). Since life evolved from a hierarchy we can also assume that natural selection will occur at all of these levels that have evolved. Life started just at the molecular level and then evolved into more complex multicellular organism like humans, hierarchy of levels (6). Sometimes adaptions will benefit all of the levels of this hierarchy, for example if it benefits the individual then it may also benefit the species as a whole which is a higher level or it may also benefit the genes that make up the individual which is a lower level of this hierarchy (1). Occasionally this is not the case though, sometimes an adaption that benefits the individual will have a negative effect on the group or vise versa this is when we have to look at why the adaption evolved and at which level the adaptation was generated (1). Natural selection works at the genomic level, the selective force ... ... middle of paper ... ...s means that whenever an individual mutates and produces more offspring they will become favored by natural selection. Even though there were no selfish genes in this population, selfish genes mutate and then will be spread throughout this population (1). Groups have much slower life cycles than individuals so natural selection does not work as strongly (1). Wades did an experimental study on flour beetles and tested individual and group selection in a lab. He found that natural selection occurred on both levels, but this does not show the kind of adaptations that would of occurred in nature (2). In individual selection the individuals show selfish traits, while group selection demonstrates that individuals will show cooperative behaviors (2). Both individual and group selection demonstrate multilevel selection processes that work on traits or behaviors (2).
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