Evolution of Animals - Zoology - Lecture Slides, Slides of Zoology

Download Evolution of Animals - Zoology - Lecture Slides and more Slides Zoology in PDF only on Docsity! The Evolution of Animals A Brief History of Evolutionary Thinking Docsity.com Early Viewpoints about Diversity The prevailing view for most of history in the "educated civilized world" was that all species were created, perfect, & immutable. What is immutable? The concept is traceable to the Greek philosopher Aristotle & has been kept alive by judeo-christian teachings. Docsity.com Fossils from the Burgess Shale Docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. SF =e Docsity.com France was a hotspot of research and thought about animals and their diversity: Buffon Lamarck Cuvier English scientists were also important: Malthus Lyell Wallace Darwin Docsity.com Jean-Baptiste Lamarck (1744-1829) "Do we not therefore perceive that by the action of the laws of organization . . . nature has in favorable times, places, and climates multiplied her first germs of animality, given place to developments of their organizations, . . . and increased and diversified their organs? Then. . . aided by much time and by a slow but constant diversity of circumstances, she has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote is it from all that is generally thought on this subject!" Text of a lecture given by Lamarck at the Musée National d'Histoire Naturelle, Paris, May 1803 Docsity.com Lamarck proposed an evolutionary mechanism: “Inheritance of Acquired Characteristics” Lamarck’s First Law: use or disuse causes structures to enlarge or shrink. Lamarck's "Second Law" stated that all such changes were heritable. Results of Laws 1 & 2 -- continuous, gradual change of all organisms, as they became adapted to their environments. Docsity.com MYTH Darwin Discovered Evolution Docsity.com Darwin’s Contribution: EVOLUTION ...by ... NATURAL SELECTION Docsity.com CLASS: Take 5 min & summarize Darwin’s concept of Evolution by Natural Selection Docsity.com Essence of Malthus: Population increases geometrically while the means of subsistence increases arithmetically. Geometric Increase of People dN = rN N = population size dt r = rate of increase (= births – deaths) Nt = Noe rt No = beginning pop size Docsity.com Arithmetic Increase of Food dF = k dt Ft = Fo + kt Docsity.com geometric increase population Point of Crisis -- resources Malthus’ Basic Theory 7 arithmetic increase Docsity.com Number of persons (billions) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2001 f World population growth curve Black death 1348 L l T l l l 500 1000 1500 1750 2000 Date (A.D.) Docsity.com Great Book: The Voyage of the Beagle Docsity.com Darwin Characteristics Ultra-cautious Deliberate Thorough Systematic Sickly Fearful of public & church reaction Docsity.com Evolution by Natural Selection ... Know This!! Darwin's Explanatory Model of Evolution by Natural Selection Observation 1 Organisms have great potential fertility, which permits exponential growth of populations. (Source: Thomas Malthus) Observation 2 Natural populations normally do not increase exponentially but remain fairly constant in size. (Source: Charles Darwin and many others) Inference 1 A struggle for existence ?— > occurs among organisms in a population. (Source: Thomas Malthus) Inference 2 Inference 3 Ob: tion 3 Observation 4 Varying organisms show Natural selection, acting worvellon eos Variation occurs among | differential survival and | over many generations, Natural resources are limited. i ithi i reproduction, favorin >") gradual produces new Source: Thomas Malthus) organisms within populations. i, ring g ly ( . (Source: Animal breeding advantageous traits adaptations and new ————————— and systematics) (= natural selection). species. L (Source: Charles Darwin) (Source: Charles Darwin) Observation 5 Variation is heritable. (Source: Animal breeding) Docsity.com “I hardly know whether I at first felt more vexed at the solution not having occurred to me, than pleased that it had been found at all … “ Alfred Newton “How extremely stupid not to have thought of that”. T.H. Huxley “I coulda dunnit easy … piece a cake!” B. Rehnberg Docsity.com All Animals Have Excessive Reproductive Capacity 750 years 2 elephants 19,000,000 elephants 5 months 2 houseflies 191 x 1018 houseflies 48 hours 1 bacterium bacteria cover the earth to a depth of 7 feet 2 humans?? FROM MALTHUS! Docsity.com Survival Advantage?? Docsity.com Wallace was 14 years younger than Darwin. Grew up relatively poor and could not go to college. While working as a surveyor, he began to develop an interest in natural history. Few jobs in England ….. few career options … he became a collector. Docsity.com He launched two large-scale collecting expeditions: 1) Amazon River basin -- set sail at age 25! 2) South Pacific (Malay Archipelago). Animal diversity shocked him! Started thinking. Docsity.com Darwin Characteristics Ultra-cautious Deliberate Thorough Systematic Sickly Fearful of public & church reaction Docsity.com Fast forward 146 years Kent, England York County, Pennsylvania Dover school board rejects a popular high school biology text because it is … “laced with Darwinism” Docsity.com The Evolution of an Idea Creationism Scientific Creationism Intelligent Design ?? “Fair and Balanced” Treatment in Public Schools Docsity.com