BIO3400 1nd Edition Lecture 2 Outline of Last Lecture II Evolutionary Biology III Major Questions IV Levels of Evolutionary Biology V Ecology VI Levels of Ecology VII Evolution and Ecology are Closely Linked Outline of Current Lecture I Assumptions of the Scientific Process II Science Terminology III Doubt and Uncertainty in Science IV The Scientific Process Peptic Ulcers V What is Evolution VI History of Evolutionary Thought VII Charles Darwin Current Lecture Unit 1 Introduction to Evolution Assumptions of the Scientific Process Observations reflect real phenomena These phenomena are governed by natural causes Natural causes can be discovered by observation and experimentation There is consistency in the causes that operate in the natural world These assumptions are the we aren t living in the matrix assumptions Science as a Way of Knowing Guess compute consequences of the guess compare to experimentation or observation of the natural world if disagrees wrong Scientific Terminology These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Fact an objective and verifiable observation Hypothesis educated guess Theory law an explanation of a natural phenomenon based on a weather of well documented evidence Hypotheses and theories explain interpret facts Doubt and Uncertainty in Science Theories and hypotheses are never proved right they can only be proved wrong Theories and hypotheses are always subject to revision or rejection A single experiment doesn t disprove a well established theory we have to check to make sure Example of the Scientific Process Peptic Ulcers Hyperacidity Theory 1950s Excess stomach acid is the primary cause of peptic ulcers reduction in stomach acid will successfully treat peptic ulcers acid reduction is a successful treatment in some patients o Inconsistent observations Acid reduction is ineffective for some patients Antibiotics successfully treat peptic ulcers Bacteria are observed in gastric biopsies SOO Helocobacter pylori Theory 1982 The bacteria H pylori is the primary cause of peptic ulcers 1 Antibiotics will be a successful treatment 2 Infection with the bacteria will cause peptic ulcer Both 1 and 2 were confirmed Robin Warren and Barry J Marshall received the Nobel prize in medicine in 2005 Major Benefits from Science Electricity All plastics Modern ag Modern medicine Weather forecasting New sources of energy Computing What is evolution Change over time What is biological evolution Change in allele frequencies over time Evolution is not change within an individual s lifetime Evolution is not ontogenetic changes from training learning or acclimation Individuals do not evolve populations evolve Evolution is change in the genetic constitution of a population over time Evolution is happening all the time It is the natural state for populations It cannot be stopped History of Evolutionary Thought Before the 18th century the traditional view was o The earth was 6 000 years old o All species came into being at once in their present forms o Species were fixed over time and did not change Before Darwin Early Evolutionary Thinking Hierarchical classification of life on Earth Carl Linnaeus 1707 1778 Published Systema Naturae in 1735 Classified thousands of plants and animals Created the binomial classification of species ex Homo sapiens KEY IDEA all species can be classified into hierarchical groups based on similarities to one another Early explanations for why species change Jean Baptiste Lamarck and Erasmus Darwin Erasmus Darwin Charles grandfather published philosophie zoologique in 1809 Internal forces cause organisms to change within their lifetime These acquired characteristics are inherited crane with long legs WRONG KEY IDEAS inheritance species change over time by accumulating small changes Population Growth and Regulation Thomas Malthus 1766 1834 Published An Essay on the Principle of Populaion 1798 All populations have the potential to grow exponentially Most natural populations are not growing Populations are held in check by limited resources diseases predation etc KEY IDEA NOT ALL INDIVIDUALS WILL BE ABLE TO REPRODUCE TO THEIR FULL POTENTIAL Uniformitarianism Charles Lyell 797 1875 Catastrophism vs uniformitarianism Published Principles of Geoloy in 1830 The earth has been shaped by gradual forces and these forces are still acting today The earth must be very old Requires a very very long timescale KEY IDEA very slight changes over very long time periods can produce enormous change Darwin and Wallace the development of a theory to explain how and why species change Charles Darwin 1809 1882 developed an interest in natural history at a young age attended med school in Edinburgh 1825 o ignored med studies in favor of geology and biology o attended Cambridge to train to be a clergyman 1827 1831 again favored natural history Voyage of the Beagle 1831 1836 Variation among very similar species on the different islands Galapagos tortoise Saddleback vs domed shell Long vs short neck Darwin s mechanism to explain evolution natural selection Organisms leave many more offspring than survive to the next generation but populations are not usually increasing This a struggle for existence is always occurring individuals are competing for limited resources Individual organisms differ from each other in many aspects of what we would not call the phenotype eg Body size coloration behavior These difference can affect how good individuals are at obtaining food avoiding predators or mating Therefore some will leave more offspring have higher fitness than others If the differences in phenotype tend to be passed on to offspring inherited then the average phenotype of the species will change over time becoming better adapted spent 20 years gathering evidence Alfred Russel Wallace in 1858 Wallace sent Darwin a letter describing the same idea abot natural selection as a mechanism for evolutionary change Darwin and Wallace made a joint presentation in 1858 in London The Origin of Species Darwin then rushed to publish an abstract of his full findings November 24 1859 The Origin of Species had 2 main points 1 Evolution had occurred o Organisms descended from common ancestors o Evidence from fossils geographical distribution of species artificial selection comparative anatomy and embryology o Widely accepted within 20 years 2 Primary mechanism was natural selection o o o Theory