Evolutionary Biology

Terminology definition

Evolutionary biology is a branch of biology that unites various cornerstones of modern biology under one umbrella. Species are arranged based on the evolutionary basis right from lower to higher animals. This branch of study mainly concerns with species origin and evolutionary changes. The one who performs the evolutionary study is referred as evolutionary biologists.

Evolution

Change in genes of an individual over a period of time is referred as evolution. Genes can be transmitted for any number of generations. Single organism can never set an example for evolutionary changes as they remain intact with the same genes through out the life span. However, evolutionary changes are predictable only in populations. The reason for this evolutionary opaqueness is genotype changes during evolution of population. Evolutionary processes are simply defined when selected individual genes mutate and result in population evolution. There are two types of evolution, namely, microevolution and macroevolution. This shows that all organisms are originated from common intimates.

For instance, an English moth named Biston Betularia with two color morphology, namely, light and dark sets best example of evolutionary changes. Colors of the moths are determined by a hereditary unit called gene.

History of evolutionary biology

Modern evolutionary system that took place during 1930s and 1940s resulted in development of evolutionary biology. Till 1970s and 1980s there were no significant changes in this field. After this, molecular biology and cellular biology ignited the spark in the academic disciplines. At present, microbiology is seen with evolutionary aspects.

Misconceptions of genetic variation

• A morphological change is possible without evolution and vice versa.
• Phenotypic changes caused by environmental factors are not evolution as they are heritable.
• Evolutionary changes are not continuous or in progress.
• Every single species of population alter its environmental conditions.
• As environment changes, organisms find its own microenvironment for its survival of the fittest.

Genetic variation

Genetic variation is responsible for evolutionary changes. The way by which evolutionary changes occur is mutation. Mutation leads to change in gene type. New genetic variations are favored by such changes.  The two components that are involved in genetic variations are      diversity in alleles and allele’s non random association. There are three types of Alleles, namely, A, B and O in human blood. Every organism has two alleles, that is, one from his mother and the other from his father. If an individual has the same type of allele in its locus, then, it is referred as homozygous and the one with different alleles in its locus is referred as heterozygous. When alleles of different genes associate, it can be measured by linkage disequilibrium. Natural selection helps in proper maintenance of association between linkage disequilibrium and alleles pattern.

Evolutionary theory

Lamarck proposed evolutionary theory in the year 1809. According to Lamarck, species are derived form non living resources, and are primitive. Species developed complexity because of inheritance referred as orthogenesis. However, it is proved to be wrong by Darwin’s theory on the origin of species. Darwin’s theory proved that species are originated from common ancestors by natural selection. He developed a theory with wrong concept called ‘theory of blending inheritance’. Later Gregor Mendel developed genetic traits without any blending. Many evolutionary biologists incorporated Mendelian genetics to develop evolutionary theory.

Importance of evolution in biology

Evolutionary biology helps in proper understanding of evolution of aging. This study aids in artificial life, a sub specialty of bioinformatics to model and recreate the organisms. Computation is through computer, statistical and mathematical models. It helps in better understanding of organism structure, morphology, behavior and socio cultural evolution. Evolutionary biology helps in diagnosis, treatment with evolutionary medicine.