Theory of Lamarck's Transformism (with Examples)

The Lamarck's theory of transformism Is the set of principles and knowledge formulated by Jean-Baptiste Pierre Antoine de Monet Chevalier de Lamarck in 1802 to explain the evolution of life.

Lamarck was a French naturalist who lived between 1744 and 1829. His Work as a naturalist Consisted of important research on natural sciences and history that led him to formulate the first theory of biological evolution to find answers about living things. He also founded the paleontology Of invertebrates for the study of fossil past.

The Lamarck Theory, also called Lamarckism, argues that the great variety of organisms is not, as previously believed,"always the same"but that living beings are initiated as very simple forms that change with time.

This means that they evolve or are transformed to adapt to the environment in which they live. As changes occur in the physical environment, living beings acquire new needs that generate transferable modifications from one generation to another.

Bases of his investigations

• Living organisms are organized bodies produced on Earth by nature over a large amount of time.

• The simplest forms of life are constantly emerging.

• Life, whether animal or vegetable, in its perpetual evolution, is gradually developing more specialized and diversified organs.

• Each organism has reproductive and regenerative capacity of living beings.

• Over time, conditions caused by changes in the Earth and assimilation of various habits of maintenance of organisms give rise to the diversity of life.

• The product of this diversity are the"species"that materialize the changes in the organization of living bodies. (O'Neil, 2013)

Lamarck argued that by observing nature, the existence of many different forms and habits among animals is undeniable. This diversity allows us to consider innumerable conditions in which beings from each group of organisms (or race) have responded to the changes to meet their needs.

With these premises he formulated two basic laws:

• In every animal the frequent use of its organs fortifies its functions while the constant disuse of them weakens its power until they disappear.

• Genetics is responsible for perpetuating, through future generations, the modifications that organized bodies have had to experience to meet their needs in the face of changes in their environment.

Reasoning for your research

Circumstances create needs, they create habits, habits produce modifications by the use or not of certain organs or functions and genetics is in charge of perpetuating these modifications.

The qualities of each generation come from their own inner effort and their new abilities are inherited to their descendants.

Examples illustrating the principles of this theory

Example 1

Originally, the giraffes had the neck like the horses. They often live in areas where drought is frequent, therefore, the need to acquire water reserves of plants created the habit of feeding on the tender buds of treetops.

Over time, many generations of giraffes needed to meet this need, which led to the modification of the length of their neck.

Longer-necked giraffes transmitted this trait to their offspring and each generation was born with a longer neck than that of their progenitors. This process continued until the neck of the giraffes reached the current length.

EXAMPLE 2

Due to prolonged droughts, low-level rivers do not offer the voluminous elephant the ability to take a bath. Nor is it possible for this huge animal to bend over to reach the mouth of a small well. Therefore, successive generations developed a long trunk to drink and refresh their body.

EXAMPLE 3

Iguanas are usually slow and feed on insects that are very agile, driven by the need to feed, successive generations developed the independent use of each eye to capture their food faster.

EXAMPLE 4

The defense mechanism of many animals to avoid being devoured is another example of evolution. In their struggle to survive, they develop physical changes that scare off their predators. Such is the case of the balloon fish that, in the presence of the enemy, inflates its body. Inherited animal habits, like this one, are infinite in nature.

EXAMPLE 5

Birds adapt, from generation to generation, the size of their beaks and legs to better manipulate the type of branches they need to build their nests according to their habitat. (Www.examplesof.net, 2013)

Zoological philosophy

In 1809, Lamarck published a book called Zoological philosophy Who was well known in France and England, but his principles were not taken into account in his time.

His approach included opponents, such as August Weismann (German evolutionary theorist), who made an experiment to try to rule out the principle of Lamarckism. He cut off the tail of successive generations of mice to prove that their offspring were not born without a tail. In fact, the new generations were born with the tail inherited from their parents. This was a misreading of Lamarck's theory.

First, the tail-cutting action was unnatural (it was not produced by nature). Second, for mice in captivity, it was a circumstance that did not generate a need, did not create habits in those mice to sustain life. Therefore, it did not produce modifications in the gene that was transmitted, in the time, to its descendants. (Beale, 2016)

Despite their detractors, even today, a number of members of the scientific community consider the in-depth study of Lamarck's theory of biological evolution to be important.

The basis of Lamarckism is often summarized as"the inheritance of acquired characters". This means that species descend from one another and that new generations are gradually more complex and better adapted to the environment than the previous generations. (Richard W. Burkhardt, 2013)

References

1. Beale, G.H. (11 of 04 of 2016). Obtained from global.britannica.com.
2. En.wikipedia.org. (Last modified on 12 March 2017, at 00:17). Lamarckism. Obtained from en.wikipedia.org.
3. En.wikipedia.org. (Last modified on 5 April 2017, at 03:11.). Jean-Baptiste_Lamarck. Retrieved from www.wikipedia.org.
4. En.wikipedia.org. (Last modified 04 Apr 2017 at 10:46.). Retrieved from"http://en.wikipedia.org".
5. O'Neil, D. D. (2013). Obtained from anthro.palomar.edu.
6. Richard W. Burkhardt, J. (08 of 2013). Obtained dencbi.nlm.nih.gov.