Bio 105 1st Edition Lecture 12 Current Lecture Outline I II Know the characteristics of the early beliefs Be able to identify the different confounding evidence III Know the Theory of Uniformity IV Be able to identify Charles Darwin along with his characteristics V VI VII VIII Be able to identify Reproductive Capacity and Competition Be able to identify the characteristics of the term Survival of the Fittest Know the three different terms of Natural Selection Know about the different types of alleles Current Lecture Evolution Natural Selection Early Beliefs Single Creation Chain of Being Theory o The world came into existence at once and has remained the same ever since o We extend from the lowest forms of life to the highest humans and on to spiritual beings o Each kind of being species a separate link Confounding Evidence Disputes Single Creation Theory 1 Biogeography we have discovered new organisms in previously unknown places that are very similar 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 2 Comparative morphology studies of the similarities and differences in body plans of major groups showed puzzling patterns 3 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 resourcesand 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 resistance o Antibiotic Resistance directional shift toward resistant strain 2 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 worse 3 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 phenotype seen What Determines Causes Alleles in a New Individual 1 Mutations in meiosis produce new alleles 2 Crossing over in Meiosis I creates new combinations of alleles 3 Independent assortment mix maternal and paternal genes 4 Fertilization combine sperm and egg 5 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 population Ex Amish populations Inbreeding Nonrandom mating between related individuals Lecture Outline I II Know what the discovery of a fossil depends upon Be able to identify Absolute and Relative dating III Know the difference between Morphological Convergence and Morphological Divergence IV Be able to identify characterize and provide an example of Prezygotic Isolation and Postzygotic Mechanisms V Know the chronological order of higher taxa Lecture 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 events1 Organism must die a the right place and time to be buried in sediments favoring fossilization 2 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 rock 4 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 absolute ages 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 dies the proportion of carbon 14 to the total carbon declines as carbon 14 decays to nitrogen 14 Measure half life which is the time it takes for 50 of the original sample to decay is unaffected by temperature pressure or other