Lamarck (1744-1829) was a French naturalist, soldier, biologist, academic and early advocate of the idea that characters acquired from living beings can be inherited.
The Lamarckism or theories of Lamarck defend the idea that an organism can transmit characteristics that it has acquired during his life to his descendants. It is also known as inheritance of acquired characteristics or soft inheritance.
The Postulates of Lamarck Are the theories of the evolution of the species, formulated by the famous French naturalist Jean Baptiste Lamarck.
These theories emerged as a result of the constant observation of nature, the processes of adaptation of living beings and the paleontology , Especially in invertebrates. Their scientific positions constitute for many as pioneers in the field of evolutionary studies.
Concept of evolution of Lamarck
The main hypothesis of Lamarck has its starting point in the creation of the world, where nature and species were designed in a perfect balance.
Thus, as the characteristics of the environment change, species develop new properties that allow them to survive and continue. These transformations happen both gradually and through what is known as the transmission of acquired characters.
The transmission of acquired characters refers to the process of hereditary transference of certain adaptations that the living beings develop during their life cycle.
Jean-Baptiste de Lamarck
A good example may be of the ancestors of the dolphins. Millions of years ago these mammals walked on the earth, however, fifty million years ago the conditions of the environment were transformed, forcing them to spend more and more time in the water. Finally, the new generations were changing their anatomy to become the animals we now know.
Although Lamarck contributed to the construction of the premise of the transmission of hereditary characters, it has already been raised by other scholars of the subject.
The true merit of the biologist was to shed the idea that the genetically modified modifications widened the evolutionary spectrum, thus excluding natural phenomena such as extinction.
The compilation of his scientific findings is in his main work called Philosophie Zoologique ( Zoological Philosophy ). This was first published in 1809.
Postulates or theories of biological evolution according to Lamarck
1- Use and disuse of organs
For every living being, the frequent or constant use of any organ, causes that little by little it becomes more skillful, strong and resistant, it fortifies it little by little.
On the contrary, the lack of use of the same organ or another, results in it becoming useless, until finally it is suppressed.
Also, the change of activities or purposes executed by an organ can be presented. Over time, this will be reflected in a series of modifications in its anatomy making it more suitable for daily activities.
In 1876 Friedrich Engels public The part played by labor in the transition from apen to man ( The role of work in the transformation of the monkey into a man ). In this paper Engels argues that the evolution of the human being as we know it was presented due to a number of factors, such as the environment, the climate, the need to hunt and build tools.
These events forced primitive man to become bipedal, freeing his hands from the burden of facilitating mobility and giving rise to new activities that required more precision and dexterity. In short, the need to work, build and create was the key to success in this evolutionary process.
Another interesting example may be the one Lamarck Philosophie Zoologique. Giraffes inhabit the African continent in rough terrain, where survival conditions are extreme.
This curious specimen has developed a longer neck and forelegs compared to its hind legs. Thus, it manages to reach six meters in height and can obtain food from the leaves of the trees with all facility.
Always committed to field work, Lamarck also observed several species of birds from which he also drew some conclusions.
There are birds that spend most of their lives on the trees, they have obtained special hook-shaped claws. Those who hunt insects or fish but do not usually wet their body have developed long limbs and devoid of plumage. In the case of swans, there is evidence of long necks and short legs, adapted to the water.
At present, it has been analyzed how the use of mobile devices has modified the habits and even the mental structure of the human being.
Today, most people have access to a wide variety of technological devices, where large amounts of information are exchanged.
In this regard, many dare to assert, that man has changed his dynamics of data processing, he has even developed a great skill with his fingers, especially in the thumb. Is this the new change in the environment that will push new evolutionary processes?
2- The transmission of acquired characters
Lamarck considered that the creation of nature was done by divine work. From there emerged the first simplest living forms.
Climate change and the presence of new species is a constant reality, forcing these creatures to change their behavior.
To guarantee continuity, new individuals that arise from reproduction, bring with it that information evidenced in characteristics such as the strengthening or disappearance of organs, presence or absence of fur, sharpness or disappearance of some senses, among others.
In 1802 Lamarck sets an example with two newborns of the same species but different sex. One of them will have his left eye bandaged for the rest of his life.
Upon reaching the stage of reproductive maturity, these two mates bringing new offspring to those who will also be blindfolded. It can be said that if the same is done for many generations, the left eye will probably disappear and the right will change its location.
Extinction or evolution of the species?
Lamarck never refuted the idea of God's creation of the world. This belief served as a reference of what is considered one of his most controversial theories. A postulate that during the 20th century was in the mouth of both sympathizers and detractors.
For him, if the creation of the world was perfect, why should we think about the extinction of species? Based on his numerous studies, Lamarck argued that species that were considered extinct would, in fact, have undergone a series of modifications in their anatomy, resulting in other species.
Many of these beings had evolved into new species, others would not have been discovered because they would probably find themselves inhabiting lands unexplored by humans or under the depths of the sea.
Lamarck asserted that if he made a recognition of all the species of animals on the planet, a linear series could be created. Each one of them would differ from the others by slight differences in their anatomy.
He also claimed that there were very abrupt differences between them, which was due to the fact that at that time there were species to be discovered.
The discovery of the platypus and equidna in the late eighteenth century, mammals with certain reptilian characteristics such as oviparous reproduction, contributed positively to Lamarck's claims.
According to him, the condition that the characteristics of a living being should not be altered, it was precisely that the environment that inhabits it did not undergo any modification either.
Once upon a time Étienne Geoffroy Saint-Hilaire Brought a large collection of bodies of mummified animals. Curiously, these did not show modifications with respect to the species of that moment, fact that reinforced the theories of Lamarck.
Lamarck's contributions to biology
In a nutshell, Lamarck's legacy in the field of science and biology can be summarized as:
- Living beings have the ability to adapt to an ever-changing environment. This foundation, regarded as the first evolutionary theory, was the basis for further research throughout the twentieth century.
- Lamarck first used the word"Biology"to refer to the science that studies living beings.
- Although his contributions were controversial and questionable at that time, his interest from university teaching by the study of the Invertebrate beings Both living and fossil, earned him the title many years after founding the paleontology of invertebrates.
- He was the first scientist to separate crustaceans, arachnids and Annelids Of insects.
- It had important approaches in the cellular theory, affirming that no body can have life but is conformed by cellular tissues.
- Lamarck denied the processes of extinction of some species, arguing that what really happened could be interpreted as a series of modifications in the anatomical structure of the animals. Something that made them more apt to move in their own environment.
- Lamarck separated the organic world from the inorganic.
- He affirmed, like Darwin, that the earth was extremely ancient, organisms evolve without being fully aware of it and can not be as old as nature. To do this, he took into account that after several million years of land was created, the first forms of life arose, basically single-celled beings.
- He put forward the concept of geological catastrophism, which refers to the theory that the origin of the earth occurred in a catastrophic way.
- He emphasized that the nature of species was always inclined to evolve from the simple to the complex. It is possible to emphasize the evolution of the ape to the contemporary man.
Differences and similarities between Lamarck and Darwin
- The most important similarity between Lamarck and Darwin's theories is the assertion that biological mechanisms are based on the adaptation of organisms within their environments, over the years and from generation to generation.
- For Lamarck, the adaptation of biological mechanisms occurs in a single stage called directed variation. For example, an animal suffers the inclemency of the cold, it will react immediately, but not consciously to this stimulus, perhaps becoming more agile, adapting or changing its home.
- For Darwin, in the first stage, if an animal suffers extreme cold conditions, it is possible that future generations bring with them a thicker layer of hair, but others may be born with less hair.
- In the second stage of Darwin, better known as"natural selection", presents a series of deaths for those who were born with less hair, giving way to the survival of the fittest.
Some biographical information about Lamarck
Jean Baptiste Lamarck was born in Bazentin-le-Petit a small town located in the north of France in 1744. He had a promising military career that ended because of an injury.
He completed studies in Medicine and Biology that gave him his first job as an assistant in the Garden of Plants, which later became the National Museum of Natural History. There Lamarck specialized as a teacher in the natural history of insects and worms.
One of the first contributions of the biologist was to try to organize the first collections of invertebrates of the museum. It is worth noting that this work gave the possibility to carry out important analyzes that materialize with the publication of Zoological Philosophy and Natural History of Animals Invertebrates you.
In this work he condenses the studies carried out, thus revealing what is considered the first theory of evolution of the species. It includes the premises of the constant transformation of the species in synchrony with nature, the transmission of these new characteristics through inheritance and the denial to the extinction of living beings.
Unfortunately, Lamarck's works were not considered important in his day. On the contrary, they were a center of criticism and discredit on the part of the academic community.
His years passed in an unsuccessful struggle against the precariousness of his living conditions. He lost his sight and was confined to the care of his relatives. He died on December 28, 1829.
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