2) One point was that many species of organisms presently inhabiting Earth are descendents of ancestral species that were different from modern species. Another point was natural selection, which is the idea that a population can change over generations if the individuals that possess certain heritable traits leave more offspring than other individuals.
3) Larmarck's theory of evolution and Lyell's idea of uniformitarianism.
4) Linnaeus contributed taxonomy. Taxonomy, which categorized life on morphological similarities. These were usually evolutionarily related, so a system was already in place by the time evolution was accepted.
5) The fossil record shows a progression of life forms from simpler ones in the older rocks, to more complex ones in the younger rocks. Since Hutton and Lyell, the geologists, had shown the great age of the earth, the progression of life complexity shown in the fossil record enabled Darwin to reason that the fossil record was evidence that species had evolved over time.
6) Hutton's and Lyell's ideas exerted a strong influence on Darwin. Darwin agreed that if geology change results from slow, continuous actions rather than the sudden events, then Earth must be much older than the 6.000 years that theologians estimated. He then reasoned that maybe the same slow and subtle processes could also act on living organisms.