Middle School Life Science: Darwin's Theory of Evolution — Flashcards

Evolution is the change in heritable characteristics of biological populations over successive generations. Evolution is the process of continuous change from a lower, simpler, or worse to a higher, more complex, or better state : growth.

There were three scientists in particular that influenced Darwin. Their names are Lamarck, Lyell, and Malthus. All three were somewhat older than Darwin, and he was familiar with their writings.    
Jean Baptiste Lamarck was a French naturalist. He was one of the first scientists to propose that species change over time. In other words, he proposed that evolution occurs. Lamarck also tried to explain how it happens, but he got that part wrong. Lamarck thought that the traits an organism developed during its life time could be passed on to its offspring. He called this the inheritance of acquired characteristics. Like Lamarck, Darwin assumed that species evolve, or change their traits over time. However, Darwin came up with a different explanation for how this occurs: natural selection.    
Charles Lyell was an English geologist. He wrote a famous book called Principles of Geology. Darwin took the book with him on the Beagle. Lyell argued that geological processes such as erosion change Earth's surface very gradually. To account for all the changes that had occurred on the planet, Earth must be a lot older than most people believed. From Lyell, Darwin realized that living things had had a long time to evolve. There was enough time for evolution to produce the great diversity of organisms that Darwin had observed.    
Thomas Malthus was an English economist. He wrote a popular essay called “On Population.” He argued that human populations have the potential to grow more quickly than the resources they need. When populations grow too large, disease and famine occur. These calamities control population size by killing off the weakest people. From Malthus, Darwin saw that populations could become too large for their resources. This overproduction of offspring could lead to a struggle for existence in which the fittest would survive.