The Four Forces Evolution (Essay Sample)

The Four Forces Evolution
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The Four Forces Evolution
Summary
Microevolution refers to the vertical variation of genes over a period. This results in slight observable changes. On the other hand, Macroevolution refers to the major evaluation changes that happen over long time leading in the formation of entirely new species.
Species refers to the basic unit of classification that can reproduce.
A population refers to the total number of organisms that are found in a given geographical location
The four forces refer to the forces that keep the species in check to ensure survival. They include mutation, gene drift, gene flow and the natural selection.
Variations refer to the differences that are found in the organisms while isolation refers to reproductive characteristics that prevent different species from mating and fusing.
Microevolution
Microevolution refers to the variations of the genes within a given type over a period. It is defined as the change in gene frequency in a population. The changes occur on a short period scales and thus are observable. An example is the changes in the sparrow. In North America, sparrows were domesticated in 1852 and since then, the bird has seen specific changes over time. For instance, sparrows on the Northern part have larger body sizes than those that are in the south. This is a result of a larger selection and the northern part being colder as compared to the south, thus favouring larger bodies. Another example is the changes brought about by the global warming. For example, there are longer summer these days and slightly higher temperatures. Considering the impacts to species that are dominant during the winter period, increased summer days and higher temperatures will force them to undergo an evolutionary change in order to fit in the new order. Data collected over time suggest that the insect has evolved in order to fit into the new environment. Other typical examples of microevolution are the resistance to the antibiotics, pesticides and herbicides among various organisms. Others include changes of physical appearances including the colours and body shapes (Morris, 1996).
Macroevolution
Macroevolution, on the other hand, refers to major evolution changes over a period that is the evolution of new species from the already existing ones even though they have different ancestral origins. The changes that occur can be as horizontal in nature and occurs due to the natural selection that means that nature allows such a variety given the available sets of conditions. It can as well be triggered artificially, for instance, when an animal is crossbred with another species to produce an entirely new one. Owing to the geological time frames involved in the evolution, it is almost impossible to observe. Examples include major changes that occurred in the evolution including the transitions from vertebrates to invertebrates or transition to life in water to dry land or birds growing feathers during their evolution (Morris, 1996).
Species
This refers to the fundamental unit of classification. It is as the largest group of organisms that can reproduce. There are usually challenges in coming up with a definite classification owing to the slight changes in the animals. Various similarity factors such as the DNA, ecological niche and morphology are usually employed in defining the species. Owingthesevariations, species are at into subspecies. They are believed to have originated from a common ancestor (genus), and thus they are given a common name to identify the common origin. This name is then combined with the specific name to identify them.
Population
Population refers to the total number of organisms that are of similar species in a given geographical area and are in a position to interbreed. The population is usually estimated using Lincoln index. This is a statistical tool that is used to give estimates of organisms that have not beenobserved.
The Four Forces
These are the natural forces that kee