Ever wondered why dolphins and sharks are relatively similar but they are completely unrelated. Sharks lay eggs while dolphin is a mammal. Even then, there are common traits between these two species.
This is because of the fact that they share one common ancestor around 300 million years ago. From that particular ancient ancestor, many animals evolved into different beings. That’s how some ended up having common features.
According to biologists, this phenomenon of organisms not being closely related but still independently evolve into having similar traits is called Convergent Evolution. This occurs as an end result of having to adapt to a similar environment.
What Is Convergent Evolution?
As stated in the Wikipedia, convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. It creates analogous structures, which are similar in forms or functions between unrelated species, but these structures weren’t present in the common ancestor of the two species.
There are many circumstances that can result in this long process called convergent evolution. This ultimately occurs when organisms are required to adapt to similar ecological niches.
The opposite of convergence is divergent evolution, where the related species with a common ancestor evolve to possess different traits. It is seen that the convergent evolution is quite similar to parallel evolution, which occurs when two independent species evolve in a similar way and independently acquire similar features.
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Examples of Convergent Evolution
Convergent evolution is very much prevalent in many species. It is quite provable because of the many existent examples.
The most common example of convergent evolution would be the evolution of wings in birds, bats, and pterosaurs (extinct), each of which belongs to different classes of organisms and therefore not having a common ancestor.
One such example found in plant species would be Euphorbia species that are able to tolerate harsh conditions of drought but are native to continents of moderate climatic conditions.
Convergent evolution may also occur when two completely different and unrelated organisms inhabit in a similar ecological niche. One example would be the green coloration of Emerald Tree Boa from South America and Green Tree Pythons from Australia;
Both of which live high up in the trees of the rainforests and predate upon small birds. Both humans and octopuses have eyes with an iris, a lens, and a retina. And even though bats are a mammal and birds are oviparous, they both have wings.
These traits may appear to be similar but they have independent origins. If we notice the bird wings, they are more similar to “arms”, whereas bat wings look like “hands” with digits. These features are actually called analogous structures.
There is a similar colony structure between naked mole-rats and multiple species of bees and ants. This can actually take place in order to maximize the success of breeding within colonies.
Convergent evolution hasn’t occurred only at the surface level i.e. the physical traits but also on a molecular level such as the proteins and toxins. For example, snakes (Vertebrates), scorpions (Arthropods), and snails (Molluscs) all produce neurotoxins that act quite similarly upon their prey.
The basis of convergent evolution is actually the roles provided by the environment to survive. The Oceans need swimming predators, like sharks or dolphins. The skies need creatures that can fly and inhabit the trees, which makes them evolve into species possessing traits that could allow them to be able to grab branches with a tail, hands, or claws.
One of the most common modern-day examples is these two groups of animals: Marsupial mammals, which develop in pouches after birth, and mammals that are born from placentas, like humans.
These particular two groups have similarities since they originated from a common ancestor around 100 million years ago. They developed analogous structures due to their similar habitat, feeding habits, etc.
Some of the small examples pertaining to convergent evolution would be the silk-producing ability of spiders, silkworms, and silk moths. And also the long structures like beaks evolved to help collect nectar in hummingbirds, bees, moths, and butterflies.
Is Convergent Evolution Inevitable?
The fossil record shows us that the same patterns have repeated across millions of years. It involves fins, legs, shells, claws, etc. appearing as similar structures in a quite similar environment.
The phenomenon has led scientists and biologists to think if this process is inevitable and if the earth is re-set to the beginning; will it follow the same route as it did now? However, it is hard to answer as convergent evolution is closely similar to parallel evolution, in which a species inhabit two different environments and still evolves into having similar traits.
Some scientists consider the evolution of marsupials to be parallel with that of placental mammals, while others argue that parallel evolution is just a lesser extreme form of convergent evolution.
With this, it can be proved that species can diverge, converge and follow the path of the circle again. Evolution shows that only the species can adapt tactics to survive in a competitive environment, which could either come from an ancestor or simply evolved.
The Basics of Convergent Evolution:
Convergent evolution occurs when distinct species, devoid of shared ancestry, develop analogous traits, structures, or behaviors in response to comparable environmental pressures.
These similarities are not the result of common genes or inherited characteristics but rather the outcome of natural selection favoring traits that enhance survival and reproduction within specific ecological niches.
Mechanisms of Convergent Evolution:
Several mechanisms drive convergent evolution, with environmental selective pressures being the primary catalyst. In response to these pressures, species may independently develop similar adaptations through mutation, genetic variation, and selection.
Phenomena like parallel evolution and adaptive radiation are manifestations of convergent evolution, highlighting the versatile ways in which species can adapt to their surroundings.
Examples of Convergent Evolutions:
- Wings in Birds and Bats: Birds and bats are two distinct groups of vertebrates that have independently evolved wings to facilitate flight. While their wing structures vary significantly in terms of composition and mechanics, the analogous function of powered flight is a classic example of convergent evolution.
- Echolocation in Dolphins and Bats: Dolphins and certain species of bats possess the remarkable ability of echolocation. They emit high-frequency sounds and use the echoes to navigate and locate prey. Despite their evolutionary divergence, these animals have developed convergent adaptations for this extraordinary sensory capability.
- Thorns in Plants: Many plant species across different families have evolved thorns as a defense mechanism against herbivores. While the genetic makeup and evolutionary history of these plants differ, the development of thorns serves a shared ecological purpose.
- Streamlined Body Shapes in Aquatic Animals: The streamlined body shapes of aquatic animals like dolphins, sharks, and ichthyosaurs enable efficient movement through water. These diverse species have independently evolved similar body forms to thrive in their aquatic environments.
Implications and Significance:
Convergent evolution highlights the remarkable adaptability of life forms in response to environmental challenges. It underscores that nature often finds optimal solutions to common problems, even among unrelated organisms.
Moreover, understanding convergent evolution aids in deciphering the history of life on Earth and provides insights into the selective pressures that have shaped biodiversity.
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Conclusion
This theory has lots of upvotes and established throughout the world. Convergent evolution is studied extensively as it possesses multiple examples and proofs. It is one of the most important topics in the history of evolution, which scientists still work upon.
This article provided you the necessary information about convergent evolution, its examples, and its relation to parallel evolution and analogous structures.
