While it is hard to expound on life’s origin, in biology, we have learned that evolution occurs when the original species of life forms or living organisms develop and experience changes and alterations as they adapt to their environment. Thus, life constantly transforms and results in variety or variation among species and population.
Species, Population and Variation (between populations)
Species is a group of living organisms of the same features that can reproduce and whose fertile offsprings can likewise reproduce and so on within and among that particular species; while population is a closely associated group of the same species living at a certain period in the same place. On the other hand, genetic variations between populations usually occur with those that are geographically dispersed and may be caused by genetic drift.
Four Forces of Evolution
Natural Selection –is popularly known as the adaptive evolution wherein life forms with features or traits which are more adaptable to their environment are most likely to survive and therefore are able to continuously reproduce than those with less advantageous traits. Thus, the surviving life form is the one with the strongest features
Mutation – is an abrupt change in genetic elements that may result in alteration through deletion, insertion or sometimes replacement in the gene sequence in the DNA. This change during the copying of the DNA may alter the physical and even behavioral characteristic of the mutant form regardless, if that change is visible or not. While mutation is common and mostly has neutral effect on the organism, sometimes the change can be harmful and may destroy the DNA completely.
Gene Flow – occurs during interbreeding and migration and results in the exchange of genetic factors of populations wherein characteristics of one population integrate with those of the other population and thus the variation between the two are decreased.
Gene drift – is also a random or chance change in the gene form that happens from one generation to the next in a particular population. If a portion of one population is isolated from its bigger, original group, this portion reproduces within its smaller group and thus results in genetic drift.
Isolating Mechanisms and Speciation
Isolating mechanisms are characteristics of species that prevent the successful reproduction with members of other species such that they act as barriers to the exchange of genes between populations. Individual species are unable to fuse and therefore cannot procreate.
Relatively, speciation is the formation of new biological species through the division of a particular species or line-age into two or more species with distinct genes. An example is when geographic isolation of the same species results in speciation when after a considerable period the isolated species meet again they are unable to mate with the original species due to acquired characteristics during adaptation to the new environment.
In biological evolution, the existing life forms today while different from those that have inhabited the earth in the past, are the results of change and variation of the original species and that is how life continues to exist. Additionally the theories, concepts and other experimentations on evolution are essentially significant to mankind and have been used to improve life to understand sickness and discover cures through various evolutionary and revolutionary undertakings.