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Difference Between Homology and Homoplasy

Main Difference

The main difference between Homology and Homoplasy is that Homology is a product that results from divergent evolution, whereas Homoplasy is a result of convergent evolution.

Homology vs. Homoplasy

Homology is defined as the similarity between the characters that come from the same ancestor. Homoplasy is defined as similar characters but is not derived from the same ancestor. Homology is any common element that comes due to evolutionary change in the structure and parts of different organisms from the common ancestor. Homoplasy is when the organ of the two organisms works with similar features and functions due to similarity in the environment rather than any ancestral link.

Characters in the process of homology show a high degree of genetic similarity. Characters in the process of homoplasy don’t share a high degree of genetic or ancestral similarity. Homology shows different developmental pathways. Homoplasy shows similar developmental pathways. Characters of homology perform different functions. However, the characters of homoplasy show the same function. Term homology is used to describe the evolutionary relationship of species. Homoplasy is not used to describe any evolutionary relationship. Homology is related to dependant evolution. Homoplasy is related to independent evolution.

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Term homology has related the species that come out from the same ancestor. Term homoplasy is related to the species that share special character but don’t come out from the same ancestor. As the bird’s wing, the bones in the wings are homologous organs and represent homology. But the wings itself are homoplasies structure and represent homoplasy. Homology is also known as structural homology. Homoplasy is also known as functional homoplasy. Homology reflects common ascendant as well as common descendent. Homoplasy doesn’t reflect common ascendant or descendant.

Comparison Chart

HomologyHomoplasy
Similar traits from a similar ancestor are homologySimilar traits from a different ancestor are homoplasy
Basic Structure
SimilarDifferent
Perform
Different functionsSame functions
Depend Upon
Evolutionary relationshipEnvironmental conditions
Examples
Limbs of vertebrateWings of bats, birds and insects, etc
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What is Homology?

Word homology is related to the same biological structures and similar characters. When these similar characters study, it is noticed that these characters come from the same origin or common ancestor. The best examples of homology are seen on the limbs of birds and different organisms like rabbits, lizards, and rabbits, etc. It is noted that the appearance of these limbs is different in all these species, but they share a similar set of bones. Homology deals with the similarity between the species which arise from the same ancestor, and it results from divergent evolution.

After research on homologous organs, it is claimed that fossils of old species that become extinct like Eusthenopteron from where the birds, frogs, lizards, and rabbits are originated possess the same set and same arrangement of bones. It is noted that two species that show homology were the same specie at once but now diverge and known as the most recent ancestor. With time two species from the same ancestors diverge due to the adaptation of other environmental factors.

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After divergence, these species still possess the same characters that come from the same ancestor. The anatomy of different limbs of vertebrates is taken as an example of homology—for instance, limb homology of vertebrates. The number of bones, form, and construction all are identical in the limbs of vertebrate, while it represents some adaptive modifications. It means that modified limbs perform different functions according to the requirement of the environment in which the organism lives. These limbs either adapted for the purpose.

What is Homoplasy?

Word homoplasy is referred to as the structure and biological characters of different species that do not share the same ancestor and not similar inherited. Homoplasy arises due to natural selection; it is usually evolved independently in the same environment or same niches with other species, which also have the same trait but belongs to different genera. For instance, an organ-like eye developed differently in different organisms but performed similar functions. Homoplasy involves organs that are different in structures but are similar in function.

Homoplasy is an opposite term of homology which comes out with similar character or function but not from the same lineage. That’s why it is related to independent convergent evolution. As homoplasy doesn’t occur in the same specie or specie from the same ancestors, it basically occurs in the species live in a similar environment. Homology is all about similar characters e.g., wings of birds of different species show similar functionality. Some examples of homoplasy are also shown in sharks, flying squirrels, sugar gliders, and dolphins.

For instance, wings of birds and bats are structurally different, but they always perform the same function. Due to the reason for natural selection and other environmental factors, species tend to evolve in their life according to their need. The characters that evolved by the organism due to natural selection or other environmental factors don’t match with the characters of their ancestors. It is also said that homoplasy is a type of phylogenetics in which some traits or characters are picked independently by evolution except the ancestral lineage.

Key Differences

  1. In homology, homologies perform different functions whereas, in homoplasy, homoplasies perform the same function.
  2. Homology possesses a common ancestral region. On the other hand, homoplasy possesses a different ancestral region.
  3. Homology refers to divergent evolution; conversely, homoplasy is related to convergent evolution.
  4. The main homology structure of homologies is the same, although in homoplasy main structure of homoplasies is different.
  5. Homology is related to the evolutionary relationship on the flip side homoplasy isn’t refers to any evolutionary relationship.
  6. The main example of homology is shown in the limbs of the vertebrates. However, the example of homoplasy is noted in the wings of the birds.
  7. Homology deals with the structure; on the other side, homoplasy deals with the function.
  8. Homology shows a high degree of genetic similarity as compared to homoplasy, and it doesn’t show any genetic similarity.

Conclusion

It is concluded that homology is about the species of the same genetic lineage, and homoplasy is about the specie of different genetic lineage.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White