Bio 105 1st Edition Lecture 12Current Lecture Outline:I. Know the characteristics of the early beliefsII. Be able to identify the different confounding evidenceIII. Know the Theory of UniformityIV. Be able to identify Charles Darwin along with his characteristicsV. Be able to identify Reproductive Capacity and CompetitionVI. Be able to identify the characteristics of the term “Survival of the Fittest”VII. Know the three different terms of Natural SelectionVIII. Know about the different types of allelesCurrent LectureEvolution & Natural Selection Early Beliefs- Single Creation- Chain of Being Theoryo The world came into existence at once and has remained the same ever sinceo We extend from the “lowest” forms of life to the “highest” humans and on to spiritual beingso Each kind of being (species) a separate link Confounding Evidence- Disputes Single Creation Theory1. Biogeography- we have discovered new organisms in previously unknownplaces that are very similarThese 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.2. Comparative morphology- studies of the similarities and differences in body plans of major groups showed puzzling patterns3. Geologic discoveries-fossils The Theory of Uniformity- Lyell’s Principles of Geology- Stated that subtle, repetitive processes of change had shaped Earth and that the Earth is actually much older than thought Charles Darwin- Charles Darwin began a five year round the world voyage aboard the HMS Beagle, in his role as ship’s naturalist he collected and examined the species that inhabited the regions the ship visited Galapagos Islands- Formed from under water volcanoes Darwin & Galapagos Finches- He attempted to correlate variations in their traits with environmental challenges (such as beak/bill size & diets Reproductive Capacity & Competition- All populations have the capacity to increase in numbers- No population can increase indefinitely- Eventually the individuals of a population will end up competing for resources- and “something & someone has to give” Changes in Alleles Over Time- Over time, the alleles that produce the most successful phenotypes will increase in the population- Less successful alleles will become less common- Change leads to increased fitness and adaptation to environment Adaptation- An aspect of form, function, or behavior that improves the odds for surviving and reproduce Thomas- First ideas of “Survival of Fittest”- Argued that as a population size increases resource will begin to dwindle and the struggle to live will intensify and conflict will increase Natural Selection- Outcome of variation in traits that affect which individuals survive and reproduce in each generation Populations Evolve not individuals Microevolution- small scale changes in the gene frequency (alleles) in the gene pool- Changes brought about by: -Natural selection –Gene flow –Genetic drift Results of Natural Selection- three possible microevolutionary outcomes and population shifts:1. Directional Selection- a shift in the range of values for a given trait in some direction (pesticide and antibiotic resistance)o Pesticide Resistance- directional shift toward resistanceo Antibiotic Resistance- directional shift toward resistant strain2. Stabilizing Selection- stabilization of an existing range of values (human birth weight)o Intermediate forms are favored-extremes are eliminated i.e. Human Birth Weight – greater survival between 5-8 pounds below and above do worse3. Disruptive Selection- disruption of an existing range of values (beak sizes in finches)o When forms at both ends/ extremes of are favored intermediate forms are selected against Variation in Phenotype- Offspring inherit genes, not phenotypes- the genes inherited lead to the phenotypeseen What Determines/ Causes Alleles in a New Individual?1. Mutations-in meiosis produce new alleles2. Crossing over in Meiosis I- creates new combinations of alleles3. Independent assortment- mix maternal and paternal genes4. Fertilization- combine sperm and egg5. Change in chromosome number or structure- loss, duplication, etc. Hardy- Weinberg Theory- States that the shuffling of genes during sexual reproduction does not alter the proportions of different alleles in a gene pool and that the combinations of the alleles will always add to ONE (1) Founder Effect- Small number of individuals starts a new populationEx: Amish populations Inbreeding- Nonrandom mating between related individualsLecture Outline:I. Know what the discovery of a fossil depends uponII. Be able to identify Absolute and Relative datingIII. Know the difference between Morphological Convergence and Morphological DivergenceIV. Be able to identify, characterize, and provide an example of Prezygotic Isolation and Postzygotic MechanismsV. Know the chronological order of higher taxaLecture 16- Evolution and Natural Selection- Macroevolution Fossils- preserved remnants or impressions left by organisms that lived in the past. Sedimentary rocks- form from layers of sand and silt that settle to the bottom of seas and swamps-richest source of fossils The discovery of a fossil depends on a sequence of improbable events- 1. Organism must die a the right place and time to be buried in sediments favoring fossilization2. Rock layer with the fossil must escape processes that destroy or distort rock (i.e. heat, erosion)3. Fossil then has only a slight chance that it will be exposed by erosion of overlying rock4. Finally, only a slim chance that someone will find the fossil on or near the surface before it is destroyed by erosion too Sometimes- Entire Organism Preserved-If an organism dies in a place where decomposition cannot occur, then the entire body, including soft parts may be preserved as a fossil Dating Fossil Age: Relative VS. Absolute- Relative Dating- Estimates fossil age by comparing fossil with ages of similar fossils found in similar areas and locations- provide relative ages, but not absoluteages, the actual time when the organism died.- Absolute Dating- uses Radiometric Dating by looking a radioactive isotopes in organism to determine absolute ages for fossils Carbon Dating (C14)- Young Fossils- The radioactive isotope, Carbon-14, is present in living organisms in the same proportion as it occurs in the atmosphere- After an organism