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Carolus Linnaeus
In 1735, Carolus Linnaeus made his own classification system for the types of organisms that were known at the time. Even though he used the system to group organisms by similarites, the system also reflects relationships in evolution. This system is still in use today and has guided and influenced the many scientists after him. -
Georges-Louis Leclerc de Buffon
Buffon proposed the idea that species shared common ancestors instead of arising separately. With this idea, he inspired Erasmus Darwin. Buffon also rejected the idea that Earth was 6,000 years old. He thought that it was older. His belief that the Earth was older than 6,000 years, inspired Charles Lyell. -
James Hutton
James Hutton, a Scottish geologist, proposed that the changes he observed in landforms resulted in slow changes over a long period of time. This became known as gradualism. He thought that the creation of canyons by rivers cutting through rock was not because of a large scale event, but by slow processes that happened in the past. This idea has become very important to evolution and the term gradualism is used often in science. Gradualism also helped Charles Lyell develop uniformitarianism. -
Erasmus Darwin
Erasmus Darwin, the grandfather of Charles Darwin, proposed that all living things descended from a common ancestor and that more-complex lifeforms arose from less-complex life forms. This idea inspired and was expanded by Charles Darwin. -
Thomas Malthus
English economist Thomas Malthus proposed that resources like food, water, and shelter were natural limits to population growth. Meaning that human populations would grow geometrically if there were an unlimited amount of resources. But, because disease and a limited food supply exist, the population has been smaller. This idea affected Charles Darwin and helped him build his own theory. -
Jean-Baptiste Lamarck
Lamarck, a French naturalist, proposed that all organisms evolved toward perfection and complexity. He also proposed that changes in an environment can cause an organism's behaviour to change, which leads to a greater use or disuse of an organ or structure. The structure would then grow larger or smaller and the organisms would pass this on to their offspring. This is known as the inheritence of acquired characteristics. Lamarck's idea about physical characteristics influenced Charles Darwin. -
Georges Cuvier
Georges Cuvier, a French zoologist, did not believe that species could change, but did believe that organisms could become extinct. To prove this, he looked at fossils in different rock layers and found that the types of fossils differed at each rock layer. He explained this using catasrophism, which states that natural disasters have caused species to go extinct and that species moved after disasters and died in new layers. Cuvier's research affected Charles Lyell and his research on geology. -
Charles Lyell
English geologist Charles Lyell expanded the idea of gradualism into the idea of uniformitarianism. Uniformitarianism states that the geological processes that shape Earth are uniform through time. Lyell observed small processes that made small changes in the Earth's features and inferred that similar changes happened in the past. Uniformitarianism combines Hutton's idea with Lyell's observations. Uniformitarianism became the favored theory of geologic change.This theory affected Charles Darwin. -
Charles Darwin
Charles Darwin was a naturalist known for his work on the Theory of Evolution and Natural Selection. He visited the Galapagos Island and noticed variations in finches animals that were well suited to their environments. He concluded that species have evolved to suit their environment, and these changes are passed down to offspring. Darwin also discovered artificial selection and natural selection. His discoveries are the basis for evolution. He affected all scientists that study evolution. -
Alfred Russel Wallace
Alfred Wallace was a English naturalist who proposed that natural selection could drive the reproductive isolation of two varieties by encouraging the development of barriers against hybridisation. By studying bird and insect specimens he also came to the conclusion that living things evolve. After all of his studies, he mailed his research to Charles Darwin. Together, they co-developed the theory of natural selection and evolution, which is still used today, and has affected many scientists. -
Earnest Haeckel
Earnest Haeckel was a German scientist who believed that the stages of development found in vertebrate embryos reflected the stages of evolution for each of those organisms. This is known as the recapitulation theory. In 1868, he wrote a book on this theory that was accompanied by pictures. The pictures were used in textbooks, but then scientists saw flaws in the images. Earnest admitted to his mistakes and tried to fix them, but his reputation never recovered. His theory is no longer used. -
E.J. Steele
E.J. Steele is an Australian molecular immunologist. Steele hypothesized the RNA/RT-based mechanism of somatic hypermutation. This is known as neo-Lamarckism and Steele's hypothesis provided the first mechanism to explain Lamarckian evolution. Through his work and research on somatic hypermutation, he has recombined Darwin and Lamarck. This recombination is called meta-Lamarckism. E.J. Steele's work and research was inspired and influenced by Lamarck's controversial theories.
