Introduction to Organismal Biology Lecture 8

Living organisms must have these 7 properties: cellular organization (unicellular/multicellular) energy metabolism (ability to acquire energy from environment) reproduction Gexual/ asexual) - - heredity evolution (transmission of genetic info) growth development regulation homeostasis response to stimuli (interaction with environment) Carbon is used by all living things so it can be used as endence of life From organic molecules to pratos cells: 1. abiotic synthesis of organic molecules 2 (monomers) polymerization into macromolecules (polymers) 3. package them into protocells (precursors of cells, they're not living. organisms!) 4. Origin of inheritance through the transmission of genetic info (self-replicating) Origin of life mechanisms ≠ maintenance of life mechanisms. The formation of macromolecules occurs from precursor molecules. + thermal energy + catalyst Clay in creases the rak of production of vesicles into protocells. → leads to evidence of vesicle reproduction, growth, internal metabolism maintenance, regulation of membrane permeability, response to environment RINA molecules that act as catalysts ? function as enzymes→ ribozymes which self replicate Advantages of RNA molecules: can self replicate unlike DNA - natural selection favors molecules that replicate faster - fast replication increases fitness. - passing of RNA to daughter calls inheritance -inheritance + envers in RNA replication + variation in replication on through natural selection rate = evolution Fossils provide evidence of extinction ? of organisms that have undergone rapid morphological changes etc. Two methods to dak rocks are bio stetigraphy? radiometric dating. diabetes inaccurate, relies on fossil records without carrot date se dementary rocks. sedimentation dis continuity expensive gives relative age. Biostratigraphy uses faural succession, a vertical sequence of fossilized fauna & flora ; it allows you to draw conclusions about regions. This principle is used to define biozones. species that have specific ecological requirements that lived for a short time work as biomarkers for the chronological dating of sedimentary rocks. Tropical environments don't have many fossils because the environment is weathered + lots of erosion + acidic soil. Radiometric dating uses charges. or paganism in the Isotope composition of an during its transition into a fossil or fossil or igneous rock; it uses decay of carbon-14 in the organism. It uses the isotope composition in the atmosphere because it's constant. The older the fossil, the less carbon- 14. Discontinuity in the fossil recard reflects important geological, ecological, and evolutionary events. • The Cambian explosion increased diversity of animals. Adaptive radiation rapid increases in number of species with a common ancestor; mass extinction are used to define different geological periods. Bilakral symmetry was an evolutionary success because it caused an explosion of diversity of fossils. Mass extinction leads to I diversity. Ribosomal proteirs are Bacteria. used to understand the relationships between Archaea, Eukarya ← common ancestor of all life, not necessarily the first organism. The resolution of the base of the tree of life is low because ribosomal protons sequences are few compared to the number of diverging groups because of horizontal gene transfers when bacteria transfers its DNA to another bacterium at one paint in time + caused the acquisition of new metabolic pathways. •LUCA (last universal common ancestor) • all living organisms synthesize use only the I isomer of aming acids • the genetic code is almost universal. • L.U.C. A was most likely anaerobic, rich in CO₂, and H₂. • L.U.C.A was most likely anaerobic, rich in CO₂. and H₂. Domain of bacteria: diverse metabolism (organic or in organic. source of carbon on 3 Banergy); photosynthetic; aerobe/anaerobe; resistant to harsh conditions. The domain of archaea extremophiles ; prokaryotes; many are methanogens. •Domain of eukarya: evolved from prokaryotes; presence of exoskeleton; endomembrane; nucleus; serial en dosymbiosis hypothesis: organelles came from serial endosymbiosis; origin of nucleated eukaryotic cells by a merging of archaebacterial Beubacterial cells; some are unicellular/multicellular Evolution of multi-cellularity cooperation of unicellular organisms (colonial hypothesis).