Biology 1108 1st EditionExam # 1 Study Guide Lectures: 1 - 12Lecture 1 (January 21)Chapter 23- Evolutionary PatternsWhat is evolution? How do phylogenetic trees depict speciation, and how do fossils give furtherthe theory of evolution?- Charles Darwin- “descent with modification” (evolution)- The history of descent with branching is termed phylogeny- A phylogenetic tree depicts the process of speciationo Where a branch splits is termed a node. This represents from which thedescendent species divergedo The length of a branch is significant and can depict branch length proportional totime- Phylogenies are clusters of closely related organismso Invertebrates- chelicerates & insectso Tetrapods- amphibians, reptiles, birds & mammals It is important to note that phylogenies portray EVOLUTIONARYRELATIONSHIPS- or relationships among organisms which reflect theirhistorical origin Phylogenetics compares anatomical & molecular features to depictrelationships, which is displayed in a phylogenetic tree.- Species are arranged into monophyletic groups- groups that contain 2+ taxa, but haveone common ancestoro Examples of monophyletic groups Amphibians- frogs and salamanders Archosaurs- crocodiles and birds Diapsids- crocodiles, lizards & birds Sauropsids- turtles, crocodiles, lizards, & bird- Monophyletic groups include all descendants of a commonancestor and only the descendants of that ancestoro Speciation can be thought of as a process of branchingo Sister groups- (lungfish & tetrapods), groups closely related to each other- Taxonomy- the classification of organisms- 3 different types of “groups”o Monophyletic- common ancestor and all it’s descendantso Paraphyletic- common ancestor and some but not all descendantso Polyphyletic- excludes the common ancestor - Classification hierarchy- domain, kingdom, phylum, class, order, family, genus, species- Synapomorphies: shared derived characteristics- Fossils help create phylogenies by:o Calibrating phylogenies in terms of timeo Providing a record of extinct specieso Placing evolutionary events in context with the Earth’s history- Mass Extinctiono At the end of the cretaceous period eliminated dinosaurs & made way formammals- Being buried soon after death increases an organism’s chance of becoming a fossil Lecture 2 (January 23)Chapter 21- Evolution by Natural SelectionWhat is natural selection? Describe popular genetics and how that leads to different types of genetic variation?- What is a theory?o A pattern observes, produces a hypothesis (that can be tested)- Evolutionary theoryo Built using inductive logico “unprovable but falsifiable”o Model of few partso Makes predictions about future observations- Darwin’s theoryo Natural selection- differential success of surviving and reproducing- Phenotype- an observable trait- Genotype- set of alleles that determines a phenotype- Fruit flies and Adelie penguins are more variable in genetic makeup than humans- Statistical variance- a measure of how far a set of numbers are spread out, when zero, allvalues are the same, and it gives a measure of how the data are distributed around the mean- Causes of genetic variation- Mutation (somatic or germ line & deleterious, neutral, or advantageous)- Recombination’s gives new combinations not present in parent population- Evolution- a change in allele or genotype frequency in a population over time- Genotypeso Homozygous dominant: PPo Homozygous recessive: ppo Heterozygous: Pp- Allele frequency= # of copies of an allele/ total # of alleles in a population- Genotype/Allele frequencies can be measured by observable traits, gel electrophoresis, and DNA sequencingLecture 3 (January 26)Chapter 21- Evolution by Natural SelectionHow do we measure evolution? What is our baseline to compare against?- Hardy-Weinberg Conditions- no differences in the survival and reproductive success of individuals. Populations cannot be added to/subtracted by migration. No mutation. Population must be large enough to prevent sampling errors, and individuals must mate at random (no mate-choice)o Equation- p^2+ 2pq +q^2- Natural selection is a cornerstone of modern evolutionary theoryo Individuals in population vary in traitso Some traits are heritableo More offspring are produces than can survive, and only some of these will survive enough to reproduceo Individuals with certain heritable traits are more likely to survive and reproduce- Natural selection occurs when individuals with certain traits produce more offsprings than do individuals without those traits- these traits become more common in the population over long periods of time- becomes evolution- 3 types of natural selectiono Stabilizing selection- selects AGAINST extremeso Directional selection- selects against one of the 2 extremeso Disruptive selection- selects against the mean- Heterozygote advantage- Artificial selection- selection by a breeder than by competiton- Hardy-Weinberg Equilibrium- no microevolution- population is statico Allele and genotype frequencies do not change over time- Changes in allele frequency are due to natural selection, migration, mutation, or genetic drift- Microevolution in the real world involves relaxing assumptions of the Hardy-Weinberg Equilibrium- Genetic drift- random change in allele frequencyo Dramatically impacts smaller populations- This leads to loss or gain of random alleles and therefore a decrease or increase in genetic variability- Small populations on nature reserves or zoos are especially susceptible to genetic drift- Can be an event or process due to a sampling error, not just sampling of gametes that occurs in fertilization. - Founder effect- when a group starts a new population in a new area- Population bottleneck- a sudden decrease in population sizeo Due to disease outbreak/ natural catastropheso Lead to genetic bottlenecks- a sudden reduction in numbers of alleles in a population- Gene flow- “the great equalizer”, the movement of alleles among and between populations due to immigration/emigration. Results in increased genetic variability and change in allele frequencies potentially- Mutation- a random change in base pairo Increases genetic diversityo Random with respect to fitness of alleleo Most result in deleterious alleles, which lower fitnesso These alleles will be eliminated by sleectionLecture 4 (January 28)Chapter 21-