2 March 2024

This theory is also known as neodarwinism or modern evolutionary synthesis, and this is a widely accepted scientific approach that seeks to understand how species change and develop in an adaptive way over time.

It is based on the combination of the ideas of Charles Darwin and the principles of Mendelian genetics, offering a comprehensive explanation of the mechanisms that occur in biological diversity and the development of new characteristics in organisms.

What ideas does the synthetic theory of evolution contribute regarding Darwin’s theory?

This theory is also known as neo-Darwinism or modern evolutionary synthesis. The synthetic theory is the representation of an update and expansion of the ideas proposed by Charles Darwin in his theory of evolution. Although the theory of said scientist establishes the foundations of evolution by natural selection, this other theory adds new discoveries and conceptswhich come to broaden the understanding of the evolutionary process.

Next 5 key ideas will be described that this theory contributes in relation to what was established by Darwin:

  1. Genetics and heredity: Mendelian genetics is integrated into the evolutionary framework. Darwin, in his time, did not have knowledge about the genetic mechanisms that transmit characteristics from generation to generation. That is why the synthetic theory establishes that genes are the carriers of heredityand that mutations and genetic recombination are the main drivers of these changes.
  2. Genetic variability: establishes the importance of this point within a population, since it genetic diversity is the fuel so that evolution can exist, that is, it is the raw material on which natural selection acts. The greater the genetic variability, the greater the capacity of a population to adapt to environmental changes.
  3. Gradualism: Darwin proposed this idea in his theory, and the synthetic theory supports it. He maintains that evolution occurs graduallythrough small changes, which in turn are cumulative over time, and those that are benefits will be the ones that will be maintained and propagated.
  4. Natural selection as the main mechanism: In the same way as the previous one, it was also raised by Darwin and supported by the synthetic one, where it is considered that natural selection is what drives the evolutionary process. Individuals favor the characteristics that provide the most advantages for survival in their environment, which makes them prone to pass on their genes, thus propagating favorable traits.
  5. Integration of other evolutionary mechanisms: In addition to natural selection, new mechanisms such as genetic drift and migration are added. The first refers to random changes in the frequency of genes according to the population, due to reproductive variations. On the other hand, migration implies the movement of individuals, thus mixing and introducing new genetic variables.

principle of causality

This is a philosophical and scientific principle which states that Every event has a cause, or a set of causes., which precede and explain it. According to this principle, every effect that can be observed in nature has one or several causes that produce it.

In the context of the theory of evolution, both Charles Darwin’s and the synthetic theory of evolution are based on this principle, since They maintain that evolutionary changes in species are produced by natural processes. and specific mechanisms that may be observable.

In Darwin’s theory, the main mechanism is natural selectionAccording to this scientist, organisms with characteristics that are advantageous are more likely to survive and reproduce. This leads to the spread of said traits in future generations.

In synthetic theory, Darwin’s ideas are combined with Mendelian genetics. In it, evolutionary changes are the product of natural selection, through genetic variations caused by mutations that occur randomly, together with the genetic recombination of sexual reproduction.

principle of effectiveness

It is the ability of an organism to survive and reproduce in a given environment. In this context, natural selection acts on individualsthose with the highest fitness have a high chance of surviving and passing their genes on to offspring.

Over time the fittest and most beneficial traits are those common in the population, in this way the adaptive efficiency is reflected. It is important to note that it does not always refer to the strength or superiority of an organism, but also to its ability to adapt and successfully reproduce.

scope principle

It is the range of adaptability, that is, the ability of a species to adapt to different environmental conditions, thus managing to occupy the various areas. Some species are recognized as having certain limits and ranges in which they can survive and then reproduce successfully.

These limits are determined through a combination of factors, including emphasize the genetic, phenotypic characteristics and the environment. That is why some species have a very broad evolutionary scope and can easily adapt to different environments.

Said characteristic it grants them the ability to colonize different habitats and the use of resources. For example, humans have an exceptional evolutionary scope, thanks to which we can adapt to various environments around the world. On the contrary, there are other more limited species that can only survive in certain specific conditions.

Through evolution, other species that were not capable of this ability they can acquire it and expand their reachand even the opposite can happen, since evolution also causes them to lose certain abilities.

What are the types of synthetic theory of evolution?

Within this theory several approaches and areas of study stand out, some of the types will be developed below:

Neo-Darwinism: was the theoretical framework developed by a group of leading scholars of evolutionary biology. They were Theodosius Dobzhansky, Ernst Mayr, and George Gaylord Simpson. These scientists integrated concepts of Mendelian genetics and Darwin’s natural selectionin order to create a unified vision of how evolution occurs.

Dobzhansky emphasized the importance of genetic variation and speciation in the evolutionary process, he worked on natural populations of fruit flies, and was able to demonstrate how natural selection acts on a population of organisms.

Ernst Mayr, focused his research on the speciation and population biology, emphasizing reproductive barriers, using geographic isolation or genetic divergence as an example, which are essential for the formation of new species. Likewise, he introduced the concept of ‘allopatric speciation’, which refers to this geographic isolation of populations.

George Gaylord Simpson, American paleontologist, this scientist used fossil evidence to understand evolution of groups of organisms through geological time. It establishes the idea that the evolutionary processes observed in the present, such as natural selection and genetic drift, also acted in the past and from this signature life today originated.

The renewed synthetic theory: Lewontin and Gould were two biologists who made important contributions to evolutionary theory. Both raised criticisms that have enriched the field of evolutionary biology, thereby improving our understanding of evolution.

Richard Lewontin criticizes the simplicity of the approach to population geneticsand establishes that the variability is much greater than what is recognized, in addition to considering the importance of environmental and ecological factors.

stephen jay gould refutes of the synthetic theory, saying that it is not a gradual and constant process, but can occur even in periods of rapid change. It also establishes the importance of historical factors, where random events can influence the results of the evolution.

Both scientists agree that evolution is more complex than we thinkand emphasize the need to consider many factors, which go beyond just natural selection.

What role does the environment play in the synthetic theory of evolution?

In this theory the environment plays a key roleAlthough natural selection is considered to be the key mechanism, other authors highlight the importance of the environment, since it is here where the context in which selection will act is established.

This factor influences the survival and reproduction of organisms, since it represents challenges and opportunities. This happens by being exposed to different environmental conditions, such as climate changes, resources, predators, and competition with other species.

These environmental conditions make the selection of certain traits and behaviors to best suit them. That is why genetic variability and genetic mutation in populations are random. but directly anchored to the environment, which will be the determinant to establish which ones will be selected.

Organisms that have characteristics that allow them to survive and reproduce in a particular environment, are more likely to pass on their genes to the following generations, which is known as ‘adaptation to the environment’.

The interaction between the two is continuous, since the environment can change over time, this as a consequence of climate change, alterations in the different ecosystems and even interactions between other species. These changes exert selective pressure, favoring certain traits, even affecting the physiology of some species, and the birth of new adaptations.

In addition to natural selection, there are other evolutionary mechanisms, among which are migration and genetic recombination, which in turn interact with the environment. These mechanisms can influence the genetic diversity of populations.

The synthetic theory of evolution is very important in the science of biology, since it provides a unified theoretical framework, which helps to understand the evolutionary processes that have shaped the biodiversity of life on earth, and man himself. It has made it possible to integrate genetics, natural selection and other evolutionary mechanisms in a coherent way in order to explain how changes in populations and species occur over time.

One of the main contributions of synthetic theory is its ability to make predictions about evolution and provide a foundation for scientific inquiry.

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