Convergent Evolution- Definition, Causes, Examples, vs. Divergent

Evolution gives the meaning of gradual changes observed in an organism over a while which gives diagnostic characteristics to them resulting in their proper adaptation to the environment they live in. These changes can be genetic and phenotypic as well.

Evolution leads to different genera within a class of organisms and different species within a genus. So the organisms can have similar origins or similar characteristics based on the structure and function of their body parts.

Based on the pattern of how organisms evolved to have similar characters structurally and functionally although belonging to different classes or having different characters although belonging to the same class evolution can be divided into three types:

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What is Convergent Evolution?

Convergent evolution is the type of evolution in which organisms belonging to different origins (distantly related or organism with different phylogeny) evolve independently to have similar kinds of traits. These different traits will have the following characteristics:

  • Body structures that are anatomically different.
  • Different embryological origins
  • The traits will have similar functions.

The structures which possess different origins but are superficially similar due to similar functions are called analogous. Convergent evolution develops analogous structures hence this kind of evolution can also be called analogous evolution.

(Pneumonics: AC- Analogous Convergent)

Structural, anatomical, and palaeontological evidence are studied and compared to determine analogous organs.

Causes of Convergent Evolution

  • Exposure to the same environmental conditions.
  • Similar adaptive mechanism to the conditions they need for survival.
  • Genetic changes due to mutation occur simultaneously in the different classes of organisms.
Convergent Evolution
Figure- Convergent Evolution.

Examples of Convergent Evolution

There are various examples of convergent evolution.

  • Wings of birds (Aves), Bats (Mammals), and pterosaurs (extinct reptiles) are modified limbs that have similar functions i.e. flight but they all belong to different origins (i.e. all three don’t have common close ancestors), and their wings developed about 150 million years ago, 50-60 million years ago, and 225 million years ago respectively.
  • Dolphins (mammal) and sharks (Pisces) are not closely related but have streamlined bodies, dorsal fins, and flippers similar in function which help them to adapt to the oceanic environment.
  • Development of complex eye in vertebrates, cephalopods, and arthropods.
  • Presence of eyespots on the tail of fish (Pisces) and wings of the butterfly (Arthropod).
  • Thick skin to prevent external harm and round shape to conserve water present in desert plants such as cactus and poinsettia. 
  • Presence of bills in Duck (Aves) and Platypus (Mammal).

Convergent vs Parallel Evolution

Convergent EvolutionParallel Evolution
It occurs among distantly related or unrelated organisms.

Changes occur in non-homologous genes in different organisms.

Analogous traits are developed among different species.

Convergent refers to merging toward a point of similarity of structure and function between the unrelated origin of organisms.

It occurs within the same type or particular habitat.

Examples: Wings of insects, birds, and bats,  fins of penguins and fishes, etc.
It occurs between close or related organisms.

Changes occur in orthologous genes of different organisms diverged by a speciation event.

The same traits are evolved simultaneously within the species from common ancestors.

It refers to the gradual similar changes occurring parallel between related species.

It can occur between different but equivalent habitats.

Examples: Evolution of the old world and new world monkeys, Thoatherium (Earlier Horse) and Equus (Modern horse) developing one-toed foot for running.

Convergent vs Divergent Evolution

Convergent EvolutionDivergent Evolution
Similar functional structures are developed in different organisms.

It occurs between species with different origins.

The structures developed in the organisms during this type of evolution are called analogous.

It is also called analogous evolution.

It converges towards a point of similarity.

The species are different in genes.

Examples: Wings of insects, birds, and bats,  fins of penguins and fishes, etc.
Different functional structures are developed in similar organisms.

It occurs between species with a common origin.

The organs or structures developed in the organisms during this type of evolution are called homologous.

It is also called homologous evolution.

It diverges towards dissimilarity.

The species share similar genes or homologous genes.

Examples: Darwin’s finches, limbs of bat, whale, horse, humans, etc.

References and Further Readings

  1. Stern DL. The genetic causes of convergent evolution. Nat Rev Genet. 2013 Nov;14(11):751-64. DOI: 10.1038/nrg3483. Epub 2013 Oct 9. PMID: 24105273.
  2. DOUGLAS J. FUTUYMA, Evolutionary Biology, 3rd ed. (1998).
  3. MONROE W. STRICKBERGER, Evolution, 3rd ed. (2000).
  4. Stayton CT. What does convergent evolution mean? The interpretation of convergence and its implications in the search for limits to evolution. Interface Focus. 2015;5(6):20150039. doi:10.1098/rsfs.2015.0039.
  5. Sackton TB, Clark N. Convergent evolution in the genomics era: new insights and directions. Philos Trans R Soc Lond B Biol Sci. 2019;374(1777):20190102. doi:10.1098/rstb.2019.0102.
  6. Hao Y, Qu Y, Song G, Lei F. Genomic Insights into the Adaptive Convergent Evolution. Curr Genomics. 2019;20(2):81-89. doi:10.2174/1389202920666190313162702.
  7. Stern DL. The genetic causes of convergent evolution. Nat Rev Genet. 2013 Nov;14(11):751-64. doi: 10.1038/nrg3483. Epub 2013 Oct 9. PMID: 24105273.
  8. Mitchell JD, Sumner JG, Holland BR. Distinguishing Between Convergent Evolution and Violation of the Molecular Clock for Three Taxa. Syst Biol. 2018;67(5):905-915. doi:10.1093/sysbio/syy038.
  9. Larter M, Dunbar-Wallis A, Berardi AE, Smith SD. Convergent Evolution at the Pathway Level: Predictable Regulatory Changes during Flower Color Transitions. Mol Biol Evol. 2018 Sep 1;35(9):2159-2169. doi: 10.1093/molbev/msy117. PMID: 29878153.

About Author

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Bikash Dwivedi

Bikash Kumar Dwivedi completed his undergraduate degree (B.Sc.) in Microbiology from St. Xavier's College, Kathmandu, Nepal. He works in molecular biology and medical microbiology for the betterment of mankind. He is interested in the field of antibiotic resistance, immunology, and disease epidemiology.

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