Adaptive radiation: What is and examples

Adaptive radiation is an evolutionary process that corresponds to The diversification of a group of organisms and that leads to the formation of morphological varieties from a common ancestor. In other words, this phenomenon describes the speciation of one or more species in a short period of time.

But what is the speciation? It is defined as a speciation to the process by which A set of individuals of a certain species results in one or more species. These new species have adaptations whose changes in multiple directions allowed him to fill numerous ecological niches, and it is believed that some factors influence the explosive speciation process.

Therefore, if we ask ourselves what factors induce adaptive radiation, we can say that they are:

• Geographic isolation
• Environmental heterogeneity
• The absence of natural predators

There are two tools that influence the adaptive radiation process: Mutations and natural selection. Regardless of the fact that there are mutations that are harmful, some of them have a favorable effect and allow their carriers to survive for a longer time and reproduce: their descendants will be more numerous and inherit these favorable genetic varieties.

This differential survival of favorable and unfavorable mutations is what constitutes natural selection. It is due to this, according to synthetic theory, that populations will be adapted to their environment and can then be inserted into the ecological niche that is conducive to them.

Now that we know the definition of adaptive radiation and the factors that induce it, we will see some of its characteristics. If you are interested, you can also take a look at the next article of genetic mutations: examples and definition.

Below we present a series of characteristics that distinguish adaptive radiation:

• Ancestor in common: One of the main characteristics of adaptive radiation is that all species derive from a single ancestor in common.
• Phenotype-environment correlation: The relationship between the characteristics that are manifested in an organism (phenotype) and the environment, is essential to speak of adaptive radiation.
• Usefulness of phenotypic characters: That these phenotypic characteristics are “useful” to the organism to survive in the environment from which it is part.
• Quick speciation events: Appearance of new species in a relatively short period of time.

According to some authors we can classify three types of adaptive radiation:

• For changes in the environment: A species that can survive in a changing environment, will possibly derive in new species that are able to occupy the ecological niches resulting from change. A clear example of this type is the great mammals, who after the mass extinction of the dinosaurs generated by catastrophic events that involved the massive destruction of habitats, managed to expand and conquer new environments.
• By general adaptations: A species that unlike others develops a new character or ability can move towards new sites. An example is the development of the flight of some birds that facilitates its arrival in new spaces. Perhaps this other post may be interested in the origin and evolution of animals: summary.
• For the formation of archipelagos: In this case, certain sites that are isolated from the continent such as the islands, can be colonized by new species and follow an adaptive radiation process. Darwin’s pinzones are an example of this type of radiation.

Now that we have seen the types of adaptive radiation that exist, we will present some of the examples that exist.

• Pinches: One of the most famous examples is the pinzones that Darwin was able to observe in the Galapagos Islands, who would later be fundamental to support his theory of offspring with modification. Differences in peaks are considered to obey the adaptive radiation phenomenon, that is, their evolutionary diversification, led to wide morphological diversity in a relatively short period of time. Therefore, variations in the shape and size of the peak correspond to adaptations that allowed them to feed on grains, seeds, shoots, leaves and worms in different environments.
• Mammals: In less than 30 million years, all the current orders of mammals had emerged, colonizing very diverse environments: for example, air, in the case of bats; The oceans with the example of the cetaceans and extreme environments such as the poles conquered by polar bears. Do not hesitate to consult this article with the types of mammals, their characteristics and examples.
• Fish cyclic: Original from the East Africa lakes, they have diversified in thousands of species and this fact has been possible because the different evolutionary lineages have been able to exploit new trophic niches. These species have varied specializations in their diets ranging from piscivores, insectivores, filters, to algae scrapers.
• Marsupial mammals: The radiation of the marsupials has generated a South American group and another belonging to Australia and New Zealand, whose ancestor in common dates from 130 million years ago. This process included groups with different eating habits: strict, omnivorous, insectivorous-frugivorous carnivores. We leave you this other article about what the marsupial animals and examples are.
• Tuco-Tucos: On the other hand, the evolution of the “tuco-tucos” rodents, belonging to the genre Ctenomys, It has generated an explosive diversification that resulted in about 60 species currently distributed in South America.
• Angiosperms: Flower plants constitute the largest group of land plants and their first fossils have dated for 130 million years. In the fossil registry a great diversity of flowers and sizes that indicate an early evolutionary radiation have been found. At present, angiosperms are extremely diversified and the diversity of environments that occupy any other types of vegetables since they have adapted to very varied environments. Do not hesitate to take a look at the next post of Ecology Verde on angiosperm plants: what are, characteristics and examples.

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