BZ220 1st Edition Lecture 3Outline of Last Lecture I. Strong Inference and Multiple HypothesesII. Evidence of EvolutionA. Fossil RecordB. Homology C. Vestigial TraitsD. Age of EarthE. Direct Observation of ChangeIII. Pre-Darwin Evolution IdeasA. Scale of NatureB. Carl LinnaeusC. Baron Georges CuvierD. Jean-Baptiste LamarckE. Charles Lyell Outline of Current LectureI. DarwinA. Voyage of H.M.S. BeagleB. Origin of SpeciesII. Thomas MalthusIII. Alfred Russel Wallace IV. Natural SelectionV. FitnessVI. Evolution of beak shape in Galapagos finchesThese 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.Current LectureCharles Darwin is named as the father of evolution; however, his journey to get this title as well as other individuals were very important in his discovery. Darwin lived form 1808-1882 and had difficulties in school where led him to, at the age of 19, dropping out of school and going on a five year long voyage of the H.M.S. Beagle. On his journey, he travel various place around the world, but the Galapagos Islands findings were his most famous discoveries. When first traveling, Darwin noticed not only 14 endemic species of finches but also 4 endemic species of mockingbirds on the various islands of the Galapagos. While looking at these species, Darwin noticed that although the finches and mockingbirds seemed to be very similar, each of the species had varying lengths and shapes of beaks based on the food sources found in their living areas of the islands. After visiting the Galapagos, Darwin visited Australia and began to compare the strange creatures in Australia likethe Australian numbat and Australian marsupial mole to other animals in the rest of the world. After his voyage, investigations of artificial selection on pigeons, and several years of conversing with fellow colleagues, Darwin (22 years after his discovery) published The Origin of Species. Darwin’s book had five main points: evidence of evolution does exist (lineages change), all species diverged from a common ancestor (common descent), evolution is done through a process of small steps, evolution occurs when changes in the proportions of variation occurs within a population, and natural selection is the mechanism of evolution. Some of the individuals who helped Darwin with his theories directly and indirectly wereThomas Malthus and Alfred Russel Wallace. Thomas Malthus wrote an essay on the Principle of Population that would help give Darwin the idea of natural selection. In this essay, Malthus showed that the rate of population growth in humans was greater than the rate of increase in food which if unchecked would lead to famine and struggle for survival.Alfred Russel Wallace also in the same time frame as Darwin discovered the idea of natural selection while collecting insects in Malaysia. Due to this coincidence, Darwin was more confident on his theory of evolution through natural selection and was pushed to publish his book. Origin of Species along with Wallace’s essay on natural selection were presented togetherin 1858. This idea of natural selection has four postulates that must be met in order for evolution via natural selection to occur. These postulates are: Individuals within populations are variable for a specific trait, Some of this variation is passed onto the offspring, Individuals vary in survivaland reproductive success, and Survival and reproduction are not random with respect to the specific trait (i.e. individuals that survive and reproduce have the most favorable variations).When these postulates are met, populations will gradually change across generations to have a higher frequency of favorable variations. Some important points about natural selection are selection is not the only mechanism of evolution, selection acts on individuals but changes characteristics of populations, selection acts on phenotypes but can change allele frequencies via evolution, selection does not adapt populations to future conditions, and selection favors traits that increase an individual’s fitness (it does not act “for the greater good of the species”). There are 4 mechanisms that act on evolution, natural selection is just the most well-known. If natural selection changed the characteristics of individuals it would be more closely resembling Lamarckian evolution which we know is not true. Natural selection acts on phenotypes like a bird’s beak but will eventually change the allele frequencies that code for a bird beak in the population. Natural selection adapts individuals to current conditions, but cannot predict the future and adapt an individual for what is coming (natural selection is always one step behind environmental changes). Selection will help an individual out to make it survive and reproduce more; however, just because it reproduces more doesn’t mean its aim is to help expand the entire species (biology including natural selection is selfish and relies on an individual’s success to do better than others in the same species when it comes to reproduction and survival).This idea of the ability of an individual to survive and reproduce in its environment is known as Darwinian fitness. Absolute fitness is the number of offspring contributed by an individual to the next generation. Relative fitness is the number of offspring contributed by an individual, divided by the number of offspring of the fittest individual in the population. Relativefitness is the most commonly used of these terms, for it is the easiest to apply and understand. All relative fitness numbers will be on a 0 to 1 scale and in fraction or decimal form (if 5 is the number of offspring for the fittest individual and 3 is the number of offspring from the contribution individual, the relative fitness of the contributing individual would be 3/5). These ideas of fitness and natural selection have been successfully tested by scientists. The Grants in the 1970s started testing these ideas on the Galapagos finches on island Daphne Major. The trait that they tested was beak size. By observation and data collection, it was clear that postulate 1 (is there variation in the trait) was met. On average the beak size was 9.5 mm but some beaks in the population were up to 12.5 mm or down to 6 mm in size. Postulate 2 can be seen that the variation in beak size is heritable by using data to show a strong relationship between