Prelim

• the word evolutions comes from the Latin word 'evolvere' meaning 'to unfold or unroll', to reveal or manifest hidden potentialities
• today, evolutions has come to simply mean, 'change'
• biological evolution is change in the properties of groups of organisms over the course of generations
• the development, or ontogeny, of an individual organism is not considered evolution: individual organisms do not evolve
• groups of organisms (populations) undergo 'descent with modification'
• populations may become subdivided , so that several populations are derived from a common ancestral population
• if different changes transpire in the several populations, the populations diverge
• in plato's philosophy was his concept of the eidos, the 'form' or 'idea', a transcendent ideal form imperfectly imitated by its earthly repesentations. in this philosophy of essentialism, variation s accidental imperfection
• Plato's essentialism became incorporated into the western philosophy largely through Aristotle who developed plato's concept of immunitable essences into the notion that species have fixed properties
• special creation - a belief in Christians wherein each species had been created individually by God in the same form it has today
• Carolus Linnaeus, established the framework of modern classification in his Systema Naturae (1735)
• Linnaeus classified related species into genera, related genera into orders, and so on
• geologists James Hutton and Charles Lyell expounded the principle of uniformitarianism, holding that the same processes operated in the past as in the present, and that the observations of geology should therefore be explained by causes that we can now observe
• Darwin was greatly influenced by lyell's teachings, and he adopted uniformitarianism in his thinking about evolution
• Chevalier de Lamarck - in his Philosophie Zoologique (1809), proposed that each species originated individually by spontaneous generation from non-living matter, starting at the bottom of the chain of being
• Lamarck proposed that a 'nervous fluid' acts within each species causing it to progress up the chain
• inheritance of acquired characteristics - alterations acquired during an individual's lifetime are inherited
• H.M.S Beagle - darwin's ship where he was invited to serve as a naturalist; a ship the British navy was sending to chart the waters of South america
• H.M.S Beagle voyage lasted from December 27, 1831 to October 2, 1836
• thomas malthus argued that the rate of human population growth is greater than the rate of increase in the food supply, so that unchecked growth must lead to famine
• thomas malthus was the inspiration to darwin's natural selection
• descent with modification - all species, living and extinct, have descended, without interruption, from one or a few original forms of life
• "evolution as such" - characteristic of lineages of organisms change over time.
• common descent - species had diverged from common ancestors and that all of life could be portrayed as one great family tree
• gradualism - differences between even radically different organisms have evolved incrementally, by small steps through intermediate forms
• populational change - evolution occurs by changes in the propositions of individual within a population that have different inherited characteristics
• natural selection - changes in the proportions of different types of individuals are caused by differences in their ability to survive and reproduce and that such changes result in the evolution of adaptations
• adaptations - features that appear designed to fit organisms to their environment
• particulate inheritance - proposed that inheritance is based not on blending fluids, but on particles that pass unaltered from generation to generation so that variation persist
• Neo-Lamarckian –based on the old idea of inheritance of modifications acquired by organism’s lifetime
• Orthogenetic – or straight line evolution, held that variation that arises is directed toward fixed goals. None of the proponents ever proposed a

  mechanism for it.
• mutationist - discretely different new phenotype can arise by a process of mutation
• Ronald A. Fisher, John B. S. Haldane, Sewall Wright - developed a mathematical theory of populations genetics
• theory of population genetics - mutation and natural selection together causes adaptive evolution: mutation is not an alternative to natural selection, but is rather its raw material
• neutral theory of Molecular evolution - developed by Motoo Kimura; holds that most of the evolution of DNA sequences occurs by genetic drift rather than by natural selection
• evolutionary genomics - concerned with variation and evolution in multiple genes or even entire genomes
• evolution is the unifying theory of the biological sciences; it aims to discover the history of life and the causes of the diversity and characteristics of organisms
• Ernst mayr - systematics aand origin of species
• Bernhard rensch - evolution above the species level
• g. Ledyard Stebbins - variation and evolution in plants