What is evolution and Mechanisms of evolution

Evolution is a series of changes that accumulate in a population of organisms over time, which gives rise to offspring with genetic modifications. It is a slow and gradual biological process whose cardinal points are that all living beings share an ancestor in common and that every way of life has changed over the years.

A simple and well-known example is that of the evolution of the human being. Scientists, based on genetic studies and morphology, among others, believe that the current Homo sapiens descends from sipery ancestors and therefore shares many characteristics with chimpanzees and other primates. If you want to know more, don’t miss this article about evolution.

What is evolution

Evolution is more complex than you think. It is not simply the adaptations that an organism experiences according to its environment, but combines several mechanisms that make possible the different characteristics between the millions of species on the planet.

All changes have occurred through genetic inheritance, which means individuals transmit adaptive genetic changes to their descendants and, at some point, modifications become common in a population of living beings.

Modern science indicates that a common ancestor gave rise to the enormous diversity of living beings that exist, so, although it seems unbelievable, all organisms are related. It is believed that about 3.5 billion years ago the first procariota bacteria appeared and about 2 billion years ago the first eukaryote cells were created with real organelles.

The first living things made up of more than one cell could have originated about 1 billion years ago. The Proterozoic era saw the birth of the first fish and the Paleozoica to the plants and the fungi. Mammals have existed since the Mesozoic era. Over time the organisms became more complex.

Theory of evolution

The English naturalist Charles Darwin is renowned for formally enunciating the theory of evolution. Evolution had already been thought and proposed by philosophers such as Anaximandro, Emp├ędocles and Aristotle, but it did not attract particular attention until Darwin published his book “The Origin of Species” (1859), where he introduced his evolutionary theory.

According to this theory, all the species that exist have evolved from very simple ways of life that developed more than 3 billion years ago. It is believed that before life existed, the chemical elements were scattered on Earth and that they subsequently joined and formed increasingly complex beings.

Probably, the first organisms developed in an aquatic environment. Then, life may have started from single-celled organisms. Some of them were transformed into multicellular organisms and, through various mechanisms, ways of life were diversified. Today the theory of evolution has been expanded and studied to the point of being practically accepted by the scientific community.

Theory of Lamarck’s evaluation

On the other hand, the French naturalist Jean-Baptiste Lamarck also developed a theory of evolution with two main points:

  • A characteristic of a living being that is improved passes this improvement to its descendants.
  • A feature widely used by an organism develops and becomes bigger and stronger. On the contrary, a poorly used characteristic tends to disappear.

 

This theory was formulated before Darwin’s, although its postulates currently lack scientific acceptance, as the characters acquired by the influence of the environment cannot be genetically inherited.

Mechanisms of evolution

All living beings are constantly evolving and this is due to mechanisms through which individuals inherit certain characteristics. The basic mechanisms of evolution are:

  • Natural selection
  • Generic Derivative
  • Mutation
  • Migration or gene flow.

Such mechanisms do not occur at the same time, but can be presented in specific cases. However, natural selection is the main mechanism by which living beings from a population evolve.

Controversies on evolution

Before the exposition of Darwin’s theory of evolution, the widespread belief in the nature of living beings consisted of what the Bible and other religious books or doctrines indicated. However, the belief based on scientific research about the possibility of the origin of life without divine intervention (from a god or Creator)

At that time Darwin could not explain the reasons for the differences between individuals of the same species and therefore had no evidence to justify his theory. About 50 years after the publication of his work, science helped clarify the issue, with the help of emerging studies on inheritance and variability. The 20th century and the development of genetics made it possible to show more accurately that species are constantly changing.

The scientific community and much of today’s society accept the theory of evolution due to multiple evidence that supports it. Let’s see some:

  • Fossil records of species other than current ones that are or are not extinct.
  • Undeniable changes in species in relation to their eating or reproductive habits, among others, linked to adaptation to their environment.

Of course, scientists are required to conduct the genetic studies necessary to test evolutionary changes. However, even today, so-called creationists keep valid only the biblical version of the origin of life and oppose any idea about evolution.

It should be considered that the theory of evolution is not simply a theory that indicates the origin of life, but focuses on the processes of change that lead to evolution. The theory allows us to understand the history of life and the way it is naturally modified.

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