About natural selection One subtle but important point is th

About natural selection

One subtle but important point is that although natural selection occurs through interactions between individua lorganisms and

their environment, individuals do not evolve. Rather, it is the population that evolves over time. A second key point is that

natural selection can amplify or diminish only those heritable traits that differ among the individuals in a population. Thus, even if

a trait is heritable, if all the individuals in a population are genetically identical for that trait, evolution by natural selection cannot occur.

Third, remember that environmental factors vary from place to place and over time. A trait that is favorable in one place or time may be useless—or even detrimental—in other

places or times. Natural selection is always operating, but which traits are favored depends on the context in which a species lives and mates.

someone can explain what that means? with easy example..bio is too hard....

Solution

Natural selection occurs through interactions between individual organisms and their environment, individuals do not evolve. Rather, it is the population that evolves over time.

The statement is very simple and easily understood. By natural selection we understand that it is the forces of the nature including both biotic and abiotic factors that influence the growth , development and perpetuation of an organism .Which means according to Darwin\'s theory the survival of the fittest is operative. Only organisms that can adapt and change will survive and are established in population.

For ex In Asian lady bird beetles there is a variation in the spot pattern and color if one of the color is favored in nature by helping the organism to survive the predators will establish itself among the population and if successfully reproduces over a period of time it establishes itself as successful variant.

This can alos be understood with another example : Darwin\'s finches are a type of finches native to galapagos island . Much study is done regarding the evolution of the birds beak.This bird are medium in size and feeds on nuts when birds of bigger size entered the island and competed with the native birds for the nuts the larger bids drove the smaller native birds and ate all the large nuts to withstand the competetion the smaller birds evolved smaller beaks to enable them to feed on smaller nuts and this evolution has happened over a period of time and in the population of native finches and established itself as a new trait.

Natural selection can amplify or diminish only those heritable traits that differ among the individuals in a population. Thus, even ifa trait is heritable, if all the individuals in a population are genetically identical for that trait, evolution by natural selection cannot occur.

This means that in any group of organisms having similar traits the chances of evolution is less however if the same species migrates to a different environment in order to establish itself in that environment it evolves a new character to adjust to that environment and establishes itself as a new trait in course of time.

for ex:classic example to explain is the evolution of peppered moth Biston betularia. Orginally the moth was light and mottled colored as a camouflage against the predators but with industrial revolution the dark colored moths which were of less density established themselves as a major population.

Environmental factors vary from place to place and over time. A trait that is favorable in one place or time may be useless—or even detrimental—in other places or times. Natural selection is always operating, but which traits are favored depends on the context in which a species lives and mates.

Mantids are classic examples for the evolution there are three different types of mantids which have evolved according to the environmental conditions in which they survive. The flower mantid of Malayasia resembles the flower of orchid and uses it as a camouflage that is not suitable else where as these flowers are not seen in other parts like wise the leaf mantid of Borneo resembles the dried vegetation that is locally seen . This mantid has no advantage else where thus among the same genus different species have evolved to suit the conditions in which they thrive.