WHAT IS NATURAL SELECTION AND WHAT DOES IT PROPOSE?
Natural selection is the mechanism of evolution, the process in nature where the species that have adapted the best to their environment are inclined to survive and transfer their genetic traits/material to the next generation in larger numbers. Specimens less well-adapted to their habitat are usually be eliminated. The environment are both the physical and biological influences.
If a habitat cannot supply an increasing population (not enough resources), then not everyone will be able to pass on their genetic material. Competition among individuals is the result of this. Specimens will have to fight for resources and breeding partners, therefore, only the healthiest and best adapted individuals will ‘win’. The ones that can’t adapt to the environment well enough will not to pass on their genes, which means less of the ‘weaker’ genetic material in the population. The individuals who have the upper hand against the environment, competitors and predators have it because of a genetic mutation or variation. This may be because of mutated genes or a particular combination of gametes (reproductive cells). Those that have the variation are better suited to live in the environment which will lead to the next generation of offspring to have more individuals with the trait that gives them the greater chance of survival. As time progresses, the variation will be common throughout the species and lead to evolution of the species.
KEY COMPONENTS OF NATURAL SELECTION
Charles Darwin’s process for natural selection had four parts (or components):
- Variation: Organisms (within populations) display individual variation in behaviour and appearance. These variations could include hair colour, body size, body/facial markings, or the number of offspring. Conversely, some characteristics show little or no variation among specimens—for example, the number of eyes in animals.
- Inheritance: Some characteristics are consistently passed on from parent to the offspring. Such characteristics are inheritable, however some other traits are influenced mostly by environmental circumstances and show weaker inheritability.
- High rate of population growth: Most populations have more children every year than the local environments’ resources can maintain. This usually leads to a struggle for resources among the species in that environment. Each generation experiences a higher mortality rate since that with each generation, there are more offspring, leading to an unhealthy standard among the species.
- Differential survival and reproduction: Specimens having characteristics/traits that well-adapted and suitable for the challenge for local resources will supply more offspring to the next generation of the population.
In each generation, the challenge for resources (or the ‘struggle for existence’) will favor individuals with some variations over the individuals that do not have variation. By doing this, it will alter the frequency of different traits within a population; an increase in variation. This process is referred to as ‘natural selection’. The characteristics that offer an advantage to those individuals who leave more offspring are called adaptations.
For natural selection to work on a trait, the trait must have inheritable variation and must offer an advantage over other individuals in the competition for resources. Both must occur for natural selection to be experienced in a trait. If either does not occur in an individual, natural selection is not experienced. Today, scientists understand that such traits may change due to other evolutionary mechanisms that have been discovered since Darwin formulized the theory.
Natural selection functions by comparative advantage, and not a complete standard of design. “…as natural selection acts by competition for resources, it adapts the inhabitants of each country only in relation to the degree of perfection of their associates” (Charles Darwin, On the Origin of Species, 1859).
During the 20th century, genetics was joined with Darwin’s mechanism, allowing scientists to assess natural selection as the differential survival and reproduction of genotypes, corresponding to particular phenotypes. (University of Michigan, 2010).
Natural selection only works on existing gene variations inside a population. Such variations arise due to cell mutation. Mutations occur by chance and do not account for the possible advantage or disadvantage of the mutation in the individual. Essentially, variations do not occur because they are needed by the individual.
Natural selection is the mechanism of evolution, the process in nature where the species that have adapted the best to their environment are inclined to survive and transfer their genetic traits/material to the next generation in larger numbers. Specimens less well-adapted to their habitat are usually be eliminated. The environment are both the physical and biological influences.
If a habitat cannot supply an increasing population (not enough resources), then not everyone will be able to pass on their genetic material. Competition among individuals is the result of this. Specimens will have to fight for resources and breeding partners, therefore, only the healthiest and best adapted individuals will ‘win’. The ones that can’t adapt to the environment well enough will not to pass on their genes, which means less of the ‘weaker’ genetic material in the population. The individuals who have the upper hand against the environment, competitors and predators have it because of a genetic mutation or variation. This may be because of mutated genes or a particular combination of gametes (reproductive cells). Those that have the variation are better suited to live in the environment which will lead to the next generation of offspring to have more individuals with the trait that gives them the greater chance of survival. As time progresses, the variation will be common throughout the species and lead to evolution of the species.
KEY COMPONENTS OF NATURAL SELECTION
Charles Darwin’s process for natural selection had four parts (or components):
- Variation: Organisms (within populations) display individual variation in behaviour and appearance. These variations could include hair colour, body size, body/facial markings, or the number of offspring. Conversely, some characteristics show little or no variation among specimens—for example, the number of eyes in animals.
- Inheritance: Some characteristics are consistently passed on from parent to the offspring. Such characteristics are inheritable, however some other traits are influenced mostly by environmental circumstances and show weaker inheritability.
- High rate of population growth: Most populations have more children every year than the local environments’ resources can maintain. This usually leads to a struggle for resources among the species in that environment. Each generation experiences a higher mortality rate since that with each generation, there are more offspring, leading to an unhealthy standard among the species.
- Differential survival and reproduction: Specimens having characteristics/traits that well-adapted and suitable for the challenge for local resources will supply more offspring to the next generation of the population.
In each generation, the challenge for resources (or the ‘struggle for existence’) will favor individuals with some variations over the individuals that do not have variation. By doing this, it will alter the frequency of different traits within a population; an increase in variation. This process is referred to as ‘natural selection’. The characteristics that offer an advantage to those individuals who leave more offspring are called adaptations.
For natural selection to work on a trait, the trait must have inheritable variation and must offer an advantage over other individuals in the competition for resources. Both must occur for natural selection to be experienced in a trait. If either does not occur in an individual, natural selection is not experienced. Today, scientists understand that such traits may change due to other evolutionary mechanisms that have been discovered since Darwin formulized the theory.
Natural selection functions by comparative advantage, and not a complete standard of design. “…as natural selection acts by competition for resources, it adapts the inhabitants of each country only in relation to the degree of perfection of their associates” (Charles Darwin, On the Origin of Species, 1859).
During the 20th century, genetics was joined with Darwin’s mechanism, allowing scientists to assess natural selection as the differential survival and reproduction of genotypes, corresponding to particular phenotypes. (University of Michigan, 2010).
Natural selection only works on existing gene variations inside a population. Such variations arise due to cell mutation. Mutations occur by chance and do not account for the possible advantage or disadvantage of the mutation in the individual. Essentially, variations do not occur because they are needed by the individual.