“The theory suggests that traits or characteristics of an organism are produced or inherited by direct influence of the physical environment, by effort, or by use or disuse of body parts”
Lamarckism is now often used to refer to the theory that acquired traits could be inherited. Although, what Lamarck believed was far more complex. Lamarck believed that organisms were not altered by their environment, but that a change in the environment would cause changes to the organisms needs and behaviour. When the needs of the organism were change, it also cause changes in its behaviour. The altered behaviour influences whether the given structure or organ would have greater or lesser use. These behaviours would cause the organ or structure to increase in size over several generations, despite disuse would lead to shrinking or disappearing. The rule; that use or disuse causes structures to enlarge or shrink, was Lamarck’s first law.
Lamarck’s second law was that those acquired traits were inheritable by the offspring. This law states that all of the traits are passed on by reproduction to the new individual, as long as the traits are common to both offspring, or at least to the organisms that produces the young.
Giraffe 1 has a short neck, and stretches to reach leaves. The offspring of giraffe 1 (giraffe 2) is born with a longer neck. Giraffe 2 stretches its neck to reach higher leaves which leads to its offspring having an even longer neck.
Part A – Section 2 (a)
Biography of Lamarck
Jean-Baptiste Lamarck, the youngest of 11 children, was born on August 1st, 1744. Born in the village of Bazentin-Le-Petit in north of France, he attended the Jesuit school until his father died in 1759.
Lamarck soon after joined the army and was declared officer for his bravery. After peace was declared in 1763, he spent 5 years on garrison duty. Lamarck was forced to leave the army due to an accidental injury.
After this, he worked as a bank clerk. He also began studying medicine and botany, at which he rapidly became an expert at. Lamarck studied at the French Academy of sciences and was then appointed to an assistant botanist at Jardin des Plantes, which was the royal botanical garden. Later on, Jardin du Roi was changed to the ‘Muśee National d’Histoire Naturelle’ (National Museum of Natural History). The museum was run by twelve different professors, who all belonged to different scientific fields. Lamarck was appointed the professor of the natural history of insects and worms. Although, this was a subject he knew nothing about. Lamarck took on the tremendous challenge of learning and creating a new field of biology. He then published a series of books on invertebrate zoology and palaeontology. He was also the first to separate the Crustacea, Arachnida, and Annelida from the ‘Insecta’.
Unfortunately, Lamarck’s work never became popular during his lifetime, and never got the credit he deserved. On the 28th of December, 1829, Lamarck died due to reasons unknown.
Part A – Section 2 (b)
August Weismann was a German evolutionary