Difference Between Convergent and Divergent Evolution

 Main Difference – Convergent vs Divergent Evolution

Evolution is the process by which modern organisms such as plants and animals have developed from past organisms. There are three mechanisms of evolution known as convergent evolution, divergent evolution, and parallel evolution. The main difference between convergent evolution and divergent evolution is that convergent evolution is the development of similar features in two species with different ancestral origins whereas divergent evolution is a process where two different species share a common ancestor.

Key Areas Covered

1. What is Convergent Evolution
      – Definition, Features, Examples
2. What is Divergent Evolution
      – Definition, Features, Examples
3. What are the Similarities Between Convergent and Divergent Evolution
      – Outline of Common Features
4. What is the Difference Bbetween Convergent and Divergent Evolution
      – Comparison of Key Differences

Key Terms: Analogous Structures, Common Ancestor, Convergent Evolution, Divergent Evolution, Evolution, Forelimb Structure, Homologous Structures, Parallel Evolution

What is Convergent Evolution

The development of similar structures within different species that live in the same environment is known as the convergent evolution. For example, the wing is an adaptation to flight. Wings can be found in bats as well as insects. The wings of bats and the wings of insects are evolved from completely different original structures. Thus, the convergent evolution causes similar structures in different lineages of organisms. These similar structures are called analogous structures. Another example of convergent evolution is the body shape of dolphins and sharks. Though dolphins and sharks are distantly related animals, their body shapes are adapted for fast swimming. Thus, the environment forces the phenotype of distantly related organisms to become analogous.

Figure 1: Convergent evolution of the body shape of the shark and dolphin

 The development of the eye of vertebrates, cephalopods, and cnidarian is another example of convergent evolution.

What is Divergent Evolution

Divergent evolution is a process of developing two or more species from a common ancestor. The branching begins with the selective breeding of naturally or artificially chosen traits, which occurs over time. Thus, divergent evolution is a process of macroevolution, creating more diversity of species in the biosphere. Divergent evolution produces important changes within individuals for their survival within a changing environment. Natural disasters such as volcanos, changings of the climate, and spread of diseases may cause the divergent evolution. The most beneficial traits will be selected through natural selection. Adaptive radiation is a type of microevolution, which leads to the divergent evolution. The production of new species by divergent evolution is referred to as speciation. Physical barriers, as well as biological or reproductive differences within a population, will keep the population from reproducing with each other. This will increase the rate of the divergent evolution.

Figure 2: Forelimb structures of vertebrates

Darwin’s finches, who live in Galapagos Islands, are an example of divergent evolution. These finches diverge from a common ancestor and at present, they are adapted to different diets, which cause variations in their size and shape of the body. The evolution of forelimbs of mammals is one of the most common examples of divergent evolution. The similar bone structure of the forelimbs of humans, cats, bats, and whales indicates that they are evolved from a common ancestor. The forelimb structures of several vertebrates are shown in figure 2. 

Similarities Between Convergent and Divergent Evolution

• Both convergent and divergent evolution have contributed to the development of present organisms from the past organisms.

• Both convergent and divergent evolution generate variation, aiding species to perform their niche in the environment.

Difference Between Convergent and Divergent Evolution

Definition

Convergent Evolution: Convergent evolution is a process by which distantly related species develop similar structures as adaptations to the environment.

Divergent Evolution: Divergent evolution is a process by which an interbreeding species diverges into two or more descendant species.  

Environment

Convergent Evolution: Both species live within the same environment.

Divergent Evolution: The two species live in different environments than their ancestor.

Significance

Convergent Evolution: Unrelated organisms evolve similarities while adapting to a common environment.

Divergent Evolution: The divergence of two different species results in two species becoming less like the common ancestor.

Developing Structures

Convergent Evolution: Convergent evolution occurs through developing analogous structures.

Divergent Evolution: Divergent evolution occurs through developing homologous structures.

Examples

Convergent Evolution: Ostriches, rheas, and emus are examples of convergent evolution.

Divergent Evolution: Dinosaurs, Darwin’s finches, and forelimb structures of vertebrates are examples of divergent evolution.

Conclusion

Convergent evolution and divergent evolution are two types of processes that bring changes to organisms, allowing the organism to adapt to their environment. In convergent evolution, analogous structures are developed in distantly related species, which live in the same environment. In divergent evolution, two or more new species are given rise from a common ancestor through the development of homologous structures. This is the main difference between convergent and divergent evolution.

Reference:

1.” Convergent Evolution.” Boundless. N.p., 08 Aug. 2016. Web. Available here. 18 July 2017. 
2. Scoville, Heather. “More Diversity: What is Divergent Evolution?” ThoughtCo. N.p., n.d. Web. Available here. 18 July 2017. 

Image Courtesy:

1. “illustration of convergent evolution” by Craig Pemberton (CC BY-SA 2.0) via Flickr
2. “Illustration of convergent evolution” By The original uploader was Sunshineconnelly at English Wikibooks – Transferred from en.wikibooks to Commons by Adrignola  (CC BY 3.0) via Commons Wikimedia