Main Difference – Microevolution vs. Macroevolution
Microevolution and macroevolution are two terms that describe the two scales of evolutionary changes in organisms. Microevolution refers to the small scale changes, particularly at gene level that cause the evolution of the species. On the other hand, macroevolution refers to the changes occurring above species level that contribute to the large-scale evolutionary process. This can be considered as the main difference between Microevolution and Macroevolution. Microevolution happens through processes such as mutation, selection, gene flow, and genetic drift. However, macroevolution is the final result of such microevolutionary changes.
What is Microevolution
Microevolution refers to the small scale changes that is happening in gene frequency in a group of organisms that share a common gene pool. This type of changes occurs due to recombining of genetic material within a group of organisms. Thus, this type of changes occurs due to four processes: mutation, selection, gene flow, and genetic drift.
Mutation
Mutation refers to the changes in the DNA sequence of a genome of the cell. This type of changes can have an effect on the phenotype when the change happens in protein coding sequence/gene. DNA sequence or nucleotide can be altered due to radiation, viruses, transposons, and mutagenic chemicals; they can be also due to errors that occur in DNA replication process. Mutation can cause alteration of the function of a gene or can create new genes (through duplication).
Selection
There are two types of selection: natural selection and artificial selection. Natural selection occurs when favorable mutations pass through generations; here, the unfavorable phenotypes of the population diminish with time. Reproductive success of mutated traits keeps them in the population. Natural selection is the primary process of evolution. Artificial selection is the process of selecting phenotypes using animal or plant breeding systems. Artificial selection produces hybrids of good characters.
Gene Flow
Gene flow is the exchange genes between populations, between same species. Migration into and out of the population change the allele frequencies and induce variations.
Genetic Drift/ Allelic Drift
Genetic drift is the change in frequency of an allele due to random sampling. Offspring allele frequency is determined by the parents’ allele present at that time. This process happens purely due to chance and individuals who survive to become parents are determined by chance.
What is Macroevolution
Macroevolution refers to the evolution above the species level. It considers the large scale transformations in the evolution, such as the origin of mammals and evolution of flowering plants. Macroevolutionary studies basically depend on fossil study data. Understanding of macroevolutionary changes helps to understand the diversity of organisms and speed of evolutionary changes over time.
There are many ways to view macroevolution such as molecular evolution, taxonomic evolution, morphological evolution, ecological evolution.
Molecular Evolution
Changes that occur at a molecular level or gene level cause conspicuous differences in genetic level.
Taxonomic Evolution
Gene level changes can cause effects on species. Over time, changes in species can give rise to new clades.
Morphological Evolution
Morphological changes in phenotype can cause big effects on major clades over time.
Ecological Evolution
Ecological changes over time can cause ecological landscape variations. For instance organism’s behavior can change according to the environment they live. Therefore, the distribution of species varies according to the resources they have such as predators, food availability.
Difference Between Microevolution and Macroevolution
Definition
Microevolution is concerned with gene level changes that contribute to evolution.
Macroevolution is concerned with studies large-scale differences that contribute to evolution.
Species Level
Microevolution occurs at the species level.
Macroevolution occurs above the species level.
Changes
Microevolution studies the changes occur within species.
Macroevolution studies the changes occur between species.
Time
Microevolution occurs through several generations.
Macroevolution occurs through a longer time period.
Cause
Microevolution occurs due to mutation, selection, gene flow, genetic drift.
Macroevolution occurs due to extended microevolution.
Base of Studies
Microevolutionary studies are based on molecular experiments.
Macroevolutionary studies usually based on fossil data.
References:
. (2016). Berkeleyedu. Retrieved 8 January, 2016, from here
John D. Morris, Ph.D. 1996. What Is The Difference Between Macroevolution And Microevolution?. Acts & Facts. 25 (10).
Sesink Clee, P. & Gonder, M. K. (2012) Macroevolution: Examples from the Primate World. Nature Education Knowledge 3(12):2 from here
Image Courtesy:
“Horse evolution” by Mcy jerry at the English language Wikipedia. (CC BY-SA 3.0) via Commons
“Fishapods” by Graphic by dave souza, incorporating images by others, as description – Own work by uploader using commons sources. (GFDL) via Commons
