History of Evolutionary Biology PDF

History of Evolutionary Biology Historical Background Anaxiamander (611-547 BC): the Roman philosopher. He said evolution affected all living beings, including humans Socrates, (470 – 399 BC): He was teacher of Plato and was a Greek philosopher. He was poisoned to death with hemlok Plato (427-347 BC...

History of Evolutionary Biology Historical Background Anaxiamander (611-547 BC): the Roman philosopher. He said evolution affected all living beings, including humans Socrates, (470 – 399 BC): He was teacher of Plato and was a Greek philosopher. He was poisoned to death with hemlok Plato (427-347 BC) – Believed in 2 worlds: the real world (ideal and eternal), and an illusionary world (imperfect and perceived through the senses). Typological view of nature – individual variation as the imperfect manifestation of ethos. Aristotle (384-322 BC) – Believed that all living organisms could be arranged in a “scale of nature” or Great Chain of Being. The ladder of life consists of graduation from inanimate material through plants, through lower animals and humans to other spiritual beings.  History of Evolutionary Biology Ancient Philosophers Anaximander (611-547 B.C.) The Roman philosopher Gave notion of apeiron (Gr. infinite), a non- perceivable substance which he regarded as the primary source material of the natural world Plato (428-348 BC ): Life was unchanging eternal, perfect world we can’t see any imperfectness  History of Evolutionary Biology The Ancient Greeks Aristotle (384-322 BC): – Organisms don’t change – He gave the concept of Great Chain of Being (Scala Naturae) Lucretius (99-55 B.C.) – He conceived the idea that all living things were related and that they had changed over time The Great Chain of Being  History of Evolutionary Biology Great Chain of Being (Scala Naturae) In Latin, scala means “ladder” or “flight of steps” and naturae means “of nature” or “of the universe”. It shows humans at the top of the ladder; i.e., at the pinnacle of perfection. Below them are progressively less perfect animals: apes and monkeys and then cats and dogs. It is now believed that the Scala Naturae was wrongly used to interpret the evolution of vertebrates  History of Evolutionary Biology Natural theology and Scholasticism (tradition and dogma) The philosophy of middle ages and revival in Europe Synthesis of Aristotle’s teaching with scriptures Provides justification for social and political system of the time Challenges to any part of this doctrine were very dangerous Attempts made to justify natural science on theological grounds  History of Evolutionary Biology Carolus Linnaeus (1707-1778) – Established the modern system of taxonomy in an attempt to discover order in the diversity of life “for the greater glory of God”.  Groupings based on similarity  Hierarchal relationships of organisms  History of Evolutionary Biology Early Ideas about Evolution  Earth formed according to laws of physics and chemistry  Older than previously thought  Life emerged as distinct types  Transformed when environment changed Georges Buffon (1707-1788)  History of Evolutionary Biology Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck 1809 Philosophie Zoologique First articulated theory of evolution  Organisms continually arise by spontaneous generation.  “Nervous fluid” acts to move each species up the “great chain of being”.  Organisms develop adaptations to changing environment through the use and disuse of organs. (Heavy use attracts more “nervous fluid”.)  Acquired characteristics are inherited.  History of Evolutionary Biology Problems with Lamarck’s ideas: 1) There is no evidence of spontaneous generation 2) There is no evidence of an innate drive toward complexity - E. coli - Parasites - Cave dwelling organisms 3) There is no evidence of inheritance of acquired characteristics. (BUT…..epigenetics???)  History of Evolutionary Biology How Old is the World? Calculated in 1664 that the Earth was precisely 5,668 years old. “Heaven and Earth, Centre and substance were made in the same instant of time and clouds full of water and man were created by the Trinity on the 26th of October 4004 B.C., at 9:00 in the Morning.” Archbishop James Ussher  History of Evolutionary Biology Record of Historical Change Nicolas Steno (1638-86): Father of geology and stratigraphy  History of Evolutionary Biology Geologists recognized that change was gradual James Hutton – Observable processes produce small changes that accumulate over time – The earth must be old William Smith – Different rock layers contain distinct fossils Smith’s first William Smith Geological Map (1769-1839)  History of Evolutionary Biology Emerging field of GEOLOGY lead to a new concept of the age of the Earth  The history of the earth extends back through vast time periods  The processes at work today are the same as those that have been operating throughout the entire history of Earth Charles Lyell Principles of Geology These concepts became known as UNIFORMITARIANISM or ACTUALISM  History of Evolutionary Biology Paleontology provided evidence that life changed Georges Cuvier (1769-1832)  Fossils resemble but are not exactly the same as modern species  Many past species are extinct Mary Anning discovered several species of extinct marine reptiles  History of Evolutionary Biology Essay on the Principle of Populations 1798  Populations reproduce exponentially.  Natural populations have a large capacity to reproduce and if left unchecked they will increase at a rapid rate.  many more organisms are born Thomas Malthus than can possibly survive 1766-1834  History of Evolutionary Biology Charles Robert Darwin (1809-1882)  Briefly studied medicine at Edinburgh.  Studied for the clergy at Christ’s College, Cambridge University.  Interacted with some natural scientists (John Henslow and Adam Sedgwick) at Cambridge.  Offered a position (in 1831) as the ship’s naturalist on the H.M.S. Beagle, which was going on an expedition to chart the waters of South America.  History of Evolutionary Biology The Voyage of the Beagle (27/12/1831 to 02/10/1836) History of Evolutionary Biology VARIATION IN BILL SHAPE AMONG GALAPAGOS FINCHES  Closely related species that occupy different ecological settings tend to have different characteristics.  Populations that are physically isolated tend to differ. History of Evolutionary Biology OBSERVATIONS FROM DOMESTIC ANIMALS  High levels of variability within a species.  Variants can pass these characteristics to offspring.  Artificial selection can rapidly alter the characteristics of a breed.  History of Evolutionary Biology As more individuals …are born than can possibly survive, and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in a manner profitable to itself, will have a better chance of surviving, and thus be naturally selected. – The Origin of Species 1859 Charles Darwin  History of Evolutionary Biology SEPTEMBER 28, 1838 “… it at once struck me that under these circumstances favorable variations would tend to be preserved and unfavorable ones to be destroyed.”  History of Evolutionary Biology “Then it suddenly flashed upon me that this self-acting process would necessarily improve the race, because in every generation the inferior would inevitably be killed off and the superior would remain – that is, the fittest would Alfred Russell Wallace survive” (1823-1913)  History of Evolutionary Biology Darwin’s Four Elements of “Theory” of Evolution 1. Evolution has occurred. Species are not unchanging entities but evolve over time. All species derive from very different species living in the past. This theory was not entirely new, but Darwin provided convincing evidence for it. 2. The primary cause of evolutionary change is natural selection. Species change over time because bearers of different traits have different probabilities of contributing offspring to the next generation.  History of Evolutionary Biology DARWIN’S FOUR “THEORIES” OF EVOLUTION 3. Splitting of single species into two or more species has occurred. Darwin postulated that all life originated with one or a few species. Because many species exist today, there must have been a process whereby one species can split into at least two species. The necessary conclusion from this view is: All species share common ancestors. 4. Evolutionary change is gradual. Evolution occurs by the gradual transformation of populations over long periods of time (hundreds to millions of years) rather than by a species changing nearly instantaneously into something different.  History of Evolutionary Biology Elements of Evolution by Natural Selection? COMPETITION: Many more individuals are born than survive VARIATION: Individuals vary in traits directly related to their ability to survive and reproduce HERITABILITY: These advantageous traits are passed on to offspring ITERATION: This process is repeated generation after generation over long periods of time  History of Evolutionary Biology “If I were to give a prize for the single best idea anybody ever had, I’d give it to Darwin for the idea of natural selection. Ahead of Newton, ahead of Einstein, because his idea unites the two most disparate features of our universe: the world of purposeless, meaningless matter in motion on the one side, and the world of meaning and purpose and design on the other. He understood that what he was proposing was a truly revolutionary idea.” Daniel Dennett, Philosopher, 2001  History of Evolutionary Biology BIOLOGY’S LAW EVOLUTION BY NATURAL SELECTION – a necessary outcome of differential survival and reproduction, provided the characteristics that caused those differences are heritable.  A mechanism, as mechanical as any physical law.  Acts on individuals, but only populations evolve.  Opportunistic, not goal seeking – backward-looking, not anticipatory.  Not the only mechanism of evolution.  History of Evolutionary Biology Modern Evolutionary Theory The modern evolutionary theory is an elaboration of the classical Darwinian theory. The Modern Synthetic Theory of Evolution (also called Modern Synthesis) merges the concept of Darwinian evolution with Mendelian genetics, resulting in a unified theory of evolution. This theory is also referred to as the Neo-Darwinian theory and was introduced by a number of evolutionary biologists such as Dobzhansky, Haldane, Fisher, Sewall Wright, Stebbins, Ernst Mayr.