EBIO 1220 1st Edition Lecture 6 Outline of Last Lecture I. The Geologic RecordII. Three Major Eonsa. Archaeanb. Proterozoicc. Phanerozoici. Overviewii. Paleozoiciii. Mesozoiciv. CenozoicIII. Three Major Extinctionsa. Permianb. Cretaceousc. Current IV. Naming and Classifying OrganismsV. PhylogenyOutline of Current Lecture II. Reading a PhylogenyIII. Constructing PhylogeniesIV. Identifying Groups in Phylogenetic Treesa. Monophyleticb. Non-monophyleticc. Homologyd. Analogye. Derivedi. Homologous Structuresii. Analogous Structuresf. Convergent EvolutionV. ArchaeaVI. BacteriaVII. Prokaryotes vs. EukaryotesCurrent LectureII. Reading a Phylogenya. Phylogeny: evolutionary history of a groupThese 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.b. Phylogenetic Tree: a visual representation of a phylogenetic hypothesisc. Groups being studied are on the tips of the branchesd. Relatedness is shown in branching pointse. Relative time shown by length of branchesf. Point of divergence of a taxa shows common ancestryg. Ancestors may no longer existIII. Constructing Phylogeniesa. Use many different kinds of data to understand relationshipsi. Fossilsii. Morphologyiii. Developmentiv. Behaviorv. DNA/protein sequences (most important and reliable)b. Strength in agreement between two types of datac. Different sets of data could lead to different phylogenetic treesIV. Identifying Groups in Phylogenetic Treesa. Monophyletic clade: consist of the ancestor and ALL of its descendantsb. Non-monophyletic clade: consist of ancestral species and SOME but not all of its descendantsc. Homology: similarities that are attributable to common ancestry (homologies)d. Analogy: similarities that are attributable to convergence, not common ancestry (homoplasies)e. Derived: inherited from/ originated fromi. Homologous Structures: example- human arm and seal flipper1. Derived from common ancestral structureii. Analogous Structures: example- bee wing and bird wing1. Derived independently (possible due to similar environmental challenges) not common ancestral structuref. Convergent Evolution: similar environmental pressures and natural selection produce similar (analogous) adaptionsi. Organisms are from very different evolutionary lineagesii. Creates analogous traitsV. Archaeaa. Extremophilesi. Extreme Themophiles1. Thrive in very hot environments2. Sources of heat-stable molecules useful in biotechnology3. Sulfobus: live in sulfur rich volcanic springs4. Pyrolobus fumarii: live in deep sea hydrothermal ventsii. Extreme halophiles (“salt lovers”)1. Tolerate and thrive in extremely salty wateriii. Methanogens1. Anaerobic, chemoautotrophs that obtain energy by oxidizing hydrogen w/ CO2VI. Bacteriaa. Important!i. Cause half of all known human diseasesii. Body harbors more bacterial cells than cells of its ownb. Human Microbiome (good bacteria living inside us)i. Functions: digestion, immunity, disease regulationii. Manages human ecosystemiii. Physical health depends on maintaining particular balance of bacteriac. Evolution of sex (genetic recombination:i. Specialized Pilus1. Horizontal gene transfer = microbiome “sex”2. Mostly binary fissionVII. Prokaryotes vs. Eukaryotesa. Prokaryotesi. No membrane-bound nucleusii. No organellesiii. Smaller in sizeiv. Unicellular: often form coloniesv. 3.5 billion years oldvi. Archaea and Bacteria1. Non-monophyletic group2. Differences: a. Archaea tolerant of extreme conditions b. Bacteria responsive to antibioticsc. Bacteria are pathogenic, this is rare for Archaea3. Archaea and Eukarya actually more closely related than either is to Bacteria (more recent common ancestor)b. Eukaryotesi. Membrane-bound nucleusii. Organelles enclosed by membranesiii. Larger in sizeiv. Unicellular or multicellularv. 2.1 billion years oldvi. Organelles and multicellularity unify