Before the theory of evolution was proposed, the dominant view was the story of Genesis from the Bible. According to this view, God created the sun, the earth, and plants and animals from the first day to the fifth day. On the sixth day, God created humankind, both male and female, in his own image, giving them dominion over the earth and all living things. On the seventh day, God rested, setting it apart as a day of rest and worship, known as the Sabbath. Species were created thousands of years ago, and they have remained unchanged until today.
Fossil record contrary to the creationism
During ancient times, sand and gravel would sink to the bottom of the sea or lake, eventually forming sedimentary rocks through millions of years of transformation. These rocks often contain fossilized remains of ancient organisms. By examining the characteristic of the rocks, paleontologists divided them into different stratifications. They have found that fossils in upper layers of sedimentary rock (younger rocks) are more similar to modern organisms. Some organisms only exist in older rock layers and disappear in upper layers. These fossils indicate that life existed on Earth long ago, which is contrary to the belief in the Bible that life has only been present for a few thousand years. Fossils from different layers can be arranged to form an line of descent that ranged from ancient to contemporary organisms. Many scientists have begun to question the notion of creationism and instead embrace the idea that current organisms have gradually evolved from more ancient lives.
Lamark: use and disuse, inheritance of acquired characteristics
However, with the advent of the Age of Exploration, explorers sailed to other continents and discovered a vast number of unknown plants and animals. How these species diversified became a question frequently pondered by explorers. They were beginning to doubt whether living beings were fixed forms made by God.
Although some naturalists already believed that species could change in response to environmental variations, it was Lamarck who first explained how these changes occurred.
He proposed that the differences in organisms arise from the combined effects of intrinsic trend and external factors. The nature had a intrinsic trend that continuously drove life towards increasing complexity.The external environment also influences the characteristics of organisms. Organisms would use certain organs more frequently to adapt to the environment, leading to the stronger organs. Conversely, organs that were rarely used would become weaker and eventually deteriorate. These newly acquired characteristics could be inherited by offspring. Lamarck used the example of giraffes to illustrate his point. Long ago, the neck of giraffes was short. Giraffes stretched their necks in order to reach the tender leaves at the top of trees. Their necks gradually lengthened through repeated use. The long necks were then inherited by their descendants, who repeated the process until today's giraffes evolved.
Due to the contradiction between his idea and the deeply entrenched doctrine of divine creation, Lamarck was fiercely ridiculed and vilified by scholars and society when his ideas were first proposed. His views are now recognized as incorrect, but he took the first step to become an early contributor of the evolution theory. His ideas also profoundly influenced Darwin.