Ch 20

• Early 1850s: Louis Pasteur crystallizes galactose
• 1856: Tinsmith Ralph Collier of Baltimore, Maryland, patents the first egg beater with rotating parts
• 1856: Buchanan is elected president and Lincoln joins newly formed Republican party
• Sigmund Freud and Nikola Tesla were born in the early 1850s
• Solar eclipse of July 28, 1851: Total solar eclipse. The first correctly exposed photograph, a daguerrotype, of the solar corona is made during the total phase of the eclipse by Berkowski at Koenigsberg Observatory in Prussia.
• Napoleon III rules France, Queen Victoria rules United Kingdom of Great Britain and Ireland in 1850s
• 1855: 1st train crosses Mississippi River's 1st bridge, Rock Island, Illinois to Davenport Iowa
• In 1858 Charles Darwin and Alfred Russel Wallace each presented papers to the Linnean Society of London describing a mechanism for biological evolution
• In 1859 Darwin published his book, On the Origin of Species by Means of Natural Selection, which proposed that natural mechanisms produced the diversity of life on Earth
• Darwin's concept of evolution forms the unifying paradigm within which all biological research is undertaken
• Biological evolution

  Occurs in populations when specific processes cause the genomes of organisms to differ from those of their ancestors
• The genetic changes, and the phenotypic modifications they cause, are the products of evolution
• By studying the products of evolution, biologists learn about the processes that cause evolutionary change
• Natural history


  A branch of biology that examines the form and variety of organisms in their natural environments
• Aristotle's Great Chain of Being


  Each species is formed individually with its own purpose and place in nature and where no species evolves into a new species
• Aristotle: 'In all the things of nature there is, you see, something amazing.'
• Natural theology


  By the fourteenth century, Europeans had merged Aristotle's classification system with biblical creation
• Beginning in the 14th century, scientists proposed mechanistic theories to explain physical events: Nicolaus Copernicus (1473–1543); Galileo Galilei (1564–1642), René Descartes (1596–1650), Isaac Newton (1643–1727)
• Sir Francis Bacon (1561–1626) established the importance of observation, experimentation, and inductive reasoning
• Taxonomy


  Swedish botanist Karl von Linné (Carolus Linnaeus) created a logical classification system for all living things which he proposed in his book Systema Naturae, first published in 1735
• Linnaeus used a binomial nomenclature: genus and species
• Three new disciplines that promoted a growing awareness of change

  • Biogeography
  • Comparative Morphology
  • Paleobiology
• Biogeography


  Studies the world distribution of plants and animals
• Homologous structures


  When biologists began to compare the morphology (anatomical structure) of organisms, they discovered interesting similarities and differences
• Vestigial structures


  The useless parts we observe today must have functioned in ancestral organisms
• By the mid-18th century, geologists observed different fossils in younger and older layers of sedimentary rocks
• Georges Cuvier's theory of catastrophism


  Each layer of fossils had died in a local catastrophe
• Jean Baptiste de Lamarck's theory of biological evolution


  Based on specific mechanisms (principle of use and disuse and inheritance of acquired characteristics)
• Lamarck had four important ideas that were used by Darwin: all species change through time, new characteristics are passed from one generation to the next, organisms change in response to their environments, and specific mechanisms cause evolutionary change
• According to Lamarck, short-legged ancestors of herons stretched their legs to stay dry while feeding in shallow water
• In 1831 Charles Darwin embarked on a voyage around the world on the naval surveying ship H.M.S. Beagle
• Darwin noticed great variability in bill shapes among 13 species of finches from the Galápagos Islands
• Darwin realized that changes in species over time provided the only plausible explanation for his observations
• Darwin knew that selective breeding of plants or animals enhanced desired characteristics in future generations – a process he called artificial selection
• Darwin read Thomas Malthus' Essay on the Principles of Population, which discussed the effects of individuals competing for limited food resources
• Darwin realized that species typically produce many more offspring than are needed – some survive and reproduce, others die without reproducing
• Darwin called the process of natural selection, where certain heritable traits enable some individuals to survive and reproduce more than others, leading to changes in populations over generations
• Selective breeding


  Process of enhancing desired characteristics in future generations
• Darwin knew that selective breeding of plants or animals enhanced desired characteristics in future generations
• Artificial selection

  The process Darwin called selective breeding