Darwin's Theory example essay topic

Comparison of the evolution theories of Charles Darwin and Jean-Baptiste Lamarck In this essay I am going to compare the theories of Charles Darwin and Jean-Baptiste Lamarck. Charles Darwin was a British Scientist who lived between 1809-1882. He laid down the foundation of modern evolutionary theory with his concept of the development of life through the slow working process of natural selection. Darwin started to make notes about this theory in 1836 and in 1838 he had arrived at a sketch of a theory of evolution through natural selection. It was not until 1858 that his theory was first published in a paper.

Darwin's theory is that as plants or animals spread to new areas, or as the conditions change different variations would be favoured in different places. This would mean these variations would spread through the populations of the plants or animals. Over time this would finally lead to a development of new species. This theory was explained in the book 'The Origin of Species', which describes his studies on the Galapagos Islands in the Pacific Ocean.

He noticed that the species on the islands varied slightly from each island and were adapted to local conditions. The reaction to this theory was immediate. Biologists argued that Darwin could not prove his hypothesis. Other criticised his ideas of variation and how he could not prove how these variations came about or how they were passed on. This part of his theory was not answered until the birth of modern genetics in the early 20th century. In fact many scientists had doubts about this theory for 50-80 years.

The most publicized attacks came from religious opponents who believed it was impossible for humans to be on the same level as animals. Jean-Baptiste Lamarck was a Frenchman who lived between 1744 and 1829. He claimed that changes in a species are brought about by environmental pressures-such as changes in the food or weather patterns. The changes that take place in an individual over a lifetime are passed down to its offspring. This is called inheritance of acquired characteristics. An example of this idea is the way in which tortoises found on different islands gained their differently shaped shells.

Lamarck's theory suggests that on islands with short grass and leafy bushes, tortoises stretched up to eat the leaves on the lower branches. This action gradually wore away their shells this characteristic was passed on to their offspring. The islands where tortoises ate only grass, their shells remained rounded. When Lamarck died he received little scientific recognition for his work. It was not until the second half of the 19th century that his ideas were considered again.

These two theories are similar to one another in that both of them suggest that the characteristics be passed on to the species offspring. The differences are that Darwin suggests that it is the species best suited for the conditions, which would survive and spread among the islands. Lamarck on the other hand thought that the species adapted to suit the conditions that they lived in. In conclusion I think that Darwin theory at first was not popular, but then as his theory could be proven it was the more accepted one out of the two.