What Is Divergent Evolution? - Definition, Causes, Examples
Evolution is the process by which living organisms change and adapt over time in response to their environment, leading to the diversity of life that we see on Earth today. Divergent evolution is a type of evolution that describes how related species become more different over time due to different environmental pressures, leading to the formation of new species.
This article from thedailyECO will explore the concept of divergent evolution in detail, including its definition, examples from the animal and plant kingdoms, and the mechanisms that drive this process.
What is divergent evolution?
Divergent evolution is a biological process in which one species diverges into two or more distinct species due to different environmental pressures. This results in the development of different physical, behavioral, or genetic traits over time, leading to the formation of new species.
The key characteristic of divergent evolution is the increasing divergence between related species as they adapt to different environments. These modifications can be caused by genetic mutations or natural selection, where certain traits provide greater survival advantages.
Divergent evolution often occurs in response to geographic isolation, where populations of a species are separated by physical barriers such as mountains or oceans. This isolation can occur in a small group or a fragment of the population, but there must always be a common ancestor from which the other populations originate.
The development of these unique traits can eventually result in the formation of new species that are unable to interbreed and produce fertile offspring with their ancestral population. This process is known as speciation, and it plays a significant role in the evolution of life on Earth, as it has led to the vast array of species and ecosystems that exist today.
You might be interested in this other article on what rapid evolution is.
Causes of divergent evolution
Divergent evolution can occur due to a variety of factors, including changes in the environment, genetic drift, and natural selection. Let us take a closer look at the most common reasons for divergent evolution:
- Environmental changes: can create selective pressures that favor different traits in different populations of the same species. Over time, these differences in adaptation can lead to the development of unique physical, behavioral, or genetic traits, resulting in the formation of new species.
- Genetic drift: which is the random fluctuation of gene frequencies in a population, can also contribute to divergent evolution. Small populations that become isolated from each other may experience random changes in gene frequencies due to chance events, leading to the development of different traits over time.
- Natural selection: is another important factor in divergent evolution. If different populations of the same species are exposed to different selective pressures, they may develop unique traits that increase their fitness in their respective environments. Over time, these differences in adaptation can lead to the formation of new species.
Continue reading this other article, where we explain what parallel evolution is.
Examples of divergent evolution
To further illustrate divergent evolution, here are some examples:
Polar bears and brown bears
Polar bears and brown bears are closely related species that evolved from a common ancestor. Over time, they diverged and developed distinct adaptations that are specific to their respective environments.
For example, polar bears have adapted to the Arctic environment, with their white fur providing camouflage against the snow and ice. They also have large paws that help them move over the ice and catch prey such as seals.
In contrast, brown bears have adapted to live in forested areas and have a darker coat that provides camouflage in these habitats. They have longer claws that are adapted for digging and climbing, as well as a more varied diet that includes nuts, berries, and fish.
These adaptations have led to the formation of two distinct species that are well-suited to their respective environments. While polar bears and brown bears can interbreed, they are usually found in different habitats and have evolved to have different physical and behavioral traits that make them better suited to their unique environments.
Kangaroos, wombats, and koalas
Australian marsupials are a prime example of divergent evolution. When Australia separated from other land masses, marsupials already present on the continent diversified and adapted to fill ecological niches that were previously occupied by placental mammals in other parts of the world.
The kangaroo has evolved to hop, which allows them to move quickly across vast distances in the dry, open environment. Other marsupials such as the wombat and koala have adapted to eat eucalyptus leaves, which are toxic to most other animals.
The evolution of these unique adaptations in Australian marsupials is due to the lack of competition from placental mammals, which dominated other land masses. As a result, marsupials evolved in isolation and diversified to fill ecological niches that were previously unavailable to them.
Although Australian marsupials share many characteristics with placental mammals, such as fur and mammary glands, they have evolved unique anatomical and physiological adaptations that have allowed them to survive and thrive in a distinct ecosystem.
Cauliflower and cabbage
Cauliflower and cabbage are both members of the same species, Brassica oleracea. However, they have evolved to have different physical characteristics due to divergent evolution.
Cauliflower is the result of artificial selection by humans, who selectively bred B. oleracea plants with thickened, undeveloped flower buds, resulting in the formation of the edible cauliflower head.
Cabbage, on the other hand, is the result of natural selection, with the ancestors of B. oleracea evolving to have leaves that were more tightly packed and better adapted to colder, drier climates. Over time, these traits were selected for, resulting in the formation of the dense, compact head that we know as cabbage.
What is the difference between divergent and convergent evolution?
Divergent evolution and convergent evolution are two types of evolutionary processes that can result in the emergence of new species. However, they differ in several important ways.
As mentioned before, divergent evolution occurs when a single species evolves into two or more different species over time due to different selective pressures. As a result, the different species become increasingly different from each other in terms of their physical, behavioral, or genetic traits.
On the other hand, convergent evolution occurs when two or more different species evolve similar adaptations in response to similar selective pressures. This process results in different species that appear similar in terms of their physical, behavioral, or genetic traits, despite having evolved independently of each other.
For example, both bats and birds have wings that allow them to fly, but their wings have evolved through different mechanisms, with birds having feathers and bats having membrane-like wings.
You might also be interested in this other article, where we explain what biological adaptations are.
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