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Many of these new theories owed their existence to new technologies, especially the microscope. The compound microscope was invented in 1590, but only in 1683 did Anton von Leeuwenhoek improve the design to the point where he could use it to explore microscopic life, thus opening a whole new world to the study of biologists.
Other advances came not from new instruments but new lands. The journeys of sea-exploration beginning in the Renaissance continued into the nineteenth century, and the entire age therefore saw important discoveries in the biological sciences. One of the most important botanists of eighteenth- and nineteenth-century England, for instance, was Sir Joseph Banks, who traveled around the world with Captain Cook and collected a great many botanical samples, later collecting them in the new botanical repository at Kew Gardens.
Vast collections of new data required new means of organizing biological knowledge. One of the most important came from Carl Linnaeus (1707-1778), who established his taxonomic system of plant species based on sexual characteristics, a system which superseded John Ray's late seventeenth-century system and which, with modifications, is the basis of modern taxonomy. Erasmus Darwin, grandfather of the more famous Charles Darwin, expounded the Linnaean system in his Botanic Garden.
The eighteenth century also saw significant advances in the understanding of the reproductive process. As late as 1748, John Turberville Needham argued for the spontaneous generation of life in his Observations upon the Generation, Composition, and Decomposition of Animal and Vegetable Substances. He was challenged in 1751 by Pierre de Maupertuis, and in 1768 Lazzaro Spallanzani conclusively disproved the theory. In 1779 Spallanzani demonstrated that sperm is necessary for fertilization, and in 1780 developed the techniques of the artificial insemination, using dogs for his experiments.
Greater understanding of reproduction led to greater understanding of the inheritance of genetic traits. The theory of evolution in fact predates Charles Darwin; the Chevalier de Lamarck, for instance, developed an evolutionary theory in his Système des animaux sans vertèbres (1801). Darwin's most important contribution was giving a more solid basis to the theory of natural selection (or "survival of the fittest") first proposed by P. L. M. de Maupertuis in 1741. Darwin first announced his theory in a lecture in 1858, and expanded it in his 1859 On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Species in the Struggle for Life (1859).