State Lamark and Darwin's Theory

The theory of ‘Lamarckism’ centers around two main ideas, the concept of use and disuse and the law of inheritance of acquired characteristics. The concept of use and disuse, concentrated on the idea that if an organ were to be used frequently enough it would become enhanced and if an organ was not used it would essentially become ‘lost’. His law of inheritance then continued to state that these enhanced organs/characteristics would be passed down through the organism’s offspring, therefore over time, altering the standard of a species. Lamarck applied this theory as an explanation for the disproportionate length of modern giraffes’ necks. He believed that due to the height of tree branches in Africa, the early ancestors of giraffes must have been forced to stretch their necks in order to feed. During their lifetime, this excessive stretching would have resulted in the lengthening of their necks, an acquired characteristic which would then be inherited by their offspring. As time progressed however, Lamarck’s two-part theory was eventually discredited. This was largely due to our understanding of genetics. More recent studies have confirmed that the only way a trait can be inherited is through genes, segments of DNA that are unaltered by the

What this seemed to mean to Darwin was biological evolution. Organisms better suited to their environment gained some survival advantage and passed their genetically transmitted advantages to their offsprings. Darwin thought that this process was extremely slow and even. In fact, we became aware that it is neither slow nor even: there are examples of a good deal of change in a short period of time; and there are examples of very little change over a long period of time. Nor did Darwin understand the mechanism by which the transmission took place. This was to be figured out by Gregor Mendel, Thomas Hunt Morgan, DeVries and in our own time, Watson and Crick who deduced the spiral shape of the DNA molecule.

comes from and how they evolved in the manner that they did. This type of

Evolution is the process of biological change by which descendants come to differ from their ancestors. Natural Selection is when an individual with the best trait survive and breed in more population. Larger populations of organisms with the desired traits will then occur and organisms will evolve. The four principles of Natural Selection are variation, over production, adaptation, and descent with modification. Charles Darwin, an English naturalist and geologist saw two major trends within organisms which were variation and adaptation. Variations are differences in individuals’ physical traits compared to other individuals. In the Galapagos Islands Darwin noticed that finches had different beak sizes and shapes. Darwin then concluded that finches with thicker beaks lived in areas where nuts were the main food source and finches with smaller beaks tended to live in areas where insects were the main food source. Adaptation are features that allow an organism to better survive in their environment. There has been many adaptations in animals but one of the best has been living in groups because animals can then “help each other find food, defend against predators and care for their young” (animalpanet, n.d.). Overproduction is when organisms produce more offspring than the environment can support. Darwin stated that all animals over produce since offspring can reach reproduction age and have offspring of their own. For example, “even a slow breeder

Evolution is the idea of a living organism adapting or mutating to gain beneficial physiological, psychological and structural features. The genetic makeup of all living things is constantly changing, due to DNA replication errors or outside factors, some of these changes impact drastically on the organism changing it for the better or worse. Typically when an organisms genetic code is changed for the better and it reproduces and outlives its unchanged counterparts this process is called evolution.

Evolution has been a very debatable topic since the theory of evolution first evolved. By definition, evolution is “the process by which different kinds of living organism are believed to have developed from earlier forms during the history of the earth”, but there are many different types of “evolution” such as coevolution, divergent, parallel and convergent – all with different theories. Jean Baptiste Lamarck was a French naturalist who invented the theory of inheritance of acquired characteristics (aka. “soft inheritance”). This evolutionary theory described how the natural environment affected the way an animal used their body parts. The features used regularly or for survival are passed onto the creatures offspring, and the parts that weren’t used, weren’t. On the other hand, another English naturalist Charles Darwin established a theory of “natural selection”. A process in which creatures that survived in their environment would pass their genes through the generations, compared to the weaker species with a lower survival rate, who reproduce less offspring or none.

On the other hand, natural selection by inheritance is characterized by the passing on of the beneficial gene to their offspring through meiosis. Charles Darwin gives an example of giraffes whereby in their original nature, they had variations in the length of their necks, and natural selection favored the ones with longer necks. As a consequence, the favored characteristic is passed on to the newer

comes from and how they evolved in the manner that they did. This type of

Unfortunately, an injury forced him to resign in 1768 but his fascination for botany endured. According to BBC UK, Lamarck believed that a characteristic which is used more and more by an organism becomes bigger and stronger; therefore one that is not used eventually disappears. Any characteristic of an organism that is improved through use is passed to its offspring. For example, a giraffe stretches its neck to reach food. This means that the neck gets longer because it is used a lot and that the offspring inherit its long neck. Lamarck was the first biologist to propose a mechanism for evolution – he proposed that organisms acquired features as they needed them (amazingdiscoveries.org). Additionally, other animals, such as kangaroos, have forelimbs that are short because they don’t use them as much as their legs or tail. The transformation theory suggests that the current generation can possess certain traits

Charles Darwin's theory of evolution centres on the idea that species compete to survive, and favorable characteristics are passed on from one generation to the next. Darwin said that evolution took place by a process of natural selection or survival of the fittest. This meant that the animals and plants best suited to their surroundings survived and were able to pass on their genes to their offspring. The ones that weren't best suited died off and didn't get the chance to reproduce.

One of the first and central mechanisms proposed by Darwin during his life was that of "natural selection." Some may refer to this as "survival of the fittest," whereby species that produce offspring have been successful in doing so because they have produced random individual features which have lead them to live longer and pro-create offspring with the same inheritable desired features. Not all individuals will be able to reproduce, therefore only the fittest will…"multiply, vary, let the strongest live and the weakest die," (Darwin, Charles (1968, 1859)) Origin of the Species.

Darwin believed that the struggle for natural resources allowed for individuals with certain physical and mental traits to succeed more than those who did not possess the traits, and that the traits accumulated in the population over time. Darwin said that under certain conditions could lead to the descendants being so different from its ancestors that they would then be defined as a new species. However, Darwin felt that social instincts like sympathy and moral sentiments also evolved through natural selection, and that these resulted in the strengthening of societies in which they

Furthermore, in “Origin of the species,” Darwin argues that different environment encouraged the reproduction of those species whose traits suited them to survive and any of their

Many scientists believe variations are caused by environmental factors, such as food availability, weather and more; and that species evolve when environmental conditions change to increase the species survival. Darwin censures this idea; he believed that the main cause of variation is due to reproduction (Chapter I). Darwin suggested that parents pass down specific characteristics to their offspring, and those variations are continued on in the following generations. The problem with Darwin’s theory of reproduction is that Darwin did not comprehend how or why some characteristics are perennial and how others are not. Darwin’s inferences on variations also conflict with the idea that God created species independently, which was widely understood by many people in a time where religion was prominent (Chapter II).

French naturalist Jean Baptiste Lamarck was the first to propose the idea that plants and animals changed over time to adapt to the environment and increase survival. He believed that the changes in form of plans and animals passed down to their offspring, this idea he called Lamarckian inheritance of acquired characteristics (Lamarckism). A well-known example for Lamarckism is the giraffe and their long necks. According to Lamarck, giraffes stretched their neck to reach high branches to get food over a long period of time which resulted to the development of elongated necks, then they passed the elongated necks to their offspring.