BIOL 109: Evolutionary Biology - The History of Life PDF

BIOL 109: Evolutionary Biology 1st Semester, A.Y. 2024–2025 The History of Life Instructor: Rafael Joseph I. Terrazola, M.Sc.  Topic Outline 1. Geological Fundamentals 2. Before Life Began 3. The Emergence of Life 4....

BIOL 109: Evolutionary Biology 1st Semester, A.Y. 2024–2025 The History of Life Instructor: Rafael Joseph I. Terrazola, M.Sc.  Topic Outline 1. Geological Fundamentals 2. Before Life Began 3. The Emergence of Life 4. Precambrian Life 5. The Paleozoic Era 6. The Mesozoic Era 7. The Cenozoic Era BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Life has existed on Earth for an incredibly long time, approx. 3.5 billion years. During this vast stretch of time, life has evolved from single- celled organisms to the amazing diversity we see today. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Geological Fundamentals The History of Life  To understand the history of life, we need to understand the geological context in which it unfolded. Three major types of rocks: 1. Igneous rocks, formed from cooled magma. 2. Sedimentary rocks, formed through the accumulation, compaction, and cementation of various sediments over time. Most fossils are found in sedimentary rocks. 3. Metamorphic rocks, altered igneous or sedimentary rock under high temperature and pressure. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Radiometric dating – used to determine the absolute age of igneous rocks, providing a time scale for evolutionary events. Stratigraphy – the study of rock layers (strata) helps establish relative ages of sedimentary rocks and their embedded fossils. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 The Geological Time Scale The History of Life  BYA Billion Years Ago MYA Million Years Ago KYA Thousand Years Ago BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 Before Life Began The History of Life  Formation of the Universe and Solar System: Big Bang – origin of the universe (14 BYA) Formation of the Sun and solar system (4.6 BYA) Early Earth: Molten surface gradually cooling, forming a solid crust. Early atmosphere: mostly water vapor, very little oxygen. Formation of Oceans: Condensation of water vapor as Earth cooled. Oceans reaching modern salinity by about 4.5 BYA BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 The Emergence of Life The History of Life  Defining “Life” BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 Abiotic Synthesis Building blocks of life (amino acids, sugars etc.) forming spontaneously under early Earth conditions. Miller-Urey experiment Stanley Miller (supervised by Harold Urey) conducted an experiment where electrical discharges in an atmosphere of methane (CH4), ammonia (NH3), hydrogen gas (H2), and water (H2O) yielded amino acids and compounds, like hydrogen cyanide (HCN) and formaldehyde (H2CO). These compounds can react to form sugars, amino acids, purines, and pyrimidines. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The RNA World Hypothesis RNA as the primary genetic material in early life (catalytic and self- replicating properties) Protocells: Membrane-bound structures enclosing self-replicating RNA Possible precursors to true cells BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The Last Universal Common Ancestor (LUCA) Shared features (L-amino acids, genetic code, metabolic pathways) pointing to a single common ancestor. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 Precambrian Life The History of Life  Early Prokaryotes: Dominance of bacteria and archaea for over half of life’s history. Metabolic diversity: photosynthesis, chemoautotrophy. The Oxygen Revolution: Cyanobacteria and the evolution of photosynthesis. Gradual increase in atmospheric oxygen, leading to aerobic respiration and changes in Earth’s chemistry. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Origin of Eukaryotes: Endosymbiotic theory – mitochondria and chloroplasts originating from engulfed bacteria Eukaryotic cell structure: nucleus, membrane-bound organelles, cytoskeleton BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Multicellularity: Independent evolution in several lineages Advantages: cell specialization, larger size, increased complexity BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 The Paleozoic Era The History of Life  The Cambrian Explosion: Sudden appearance of most major animal phyla in the fossil record. Adaptive Radiation – Rapid diversification of body plans, including those of brachiopods, trilobites, molluscs, and echinoderms. Evolution of hard parts (skeletons), new feeding strategies (predation), and burrowing, driving ecological diversification. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Hypothesis for the Explosion: Environmental changes (e.g. increased oxygen levels) Genetic innovations (e.g. evolution of developmental genes) Ecological interactions (e.g. predator-prey relationships) BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Ordovician: Diversification of marine life, including early chordates and the first reefs. Silurian and Devonian: Evolution of jawed vertebrates, colonization of land by plants, arthropods, and the first tetrapods. Late Devonian: Evolution of early tetrapods from lobe-finned fishes, marking a major transition to life on land. Carboniferous: Extensive swamp forests dominated by giant lycophyte trees and ferns. Permian: Continents aggregated into Pangaea, and diversification of insects and early reptiles. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The End-Permian Mass Extinction: The most massive extinction event in the history of Earth At least 56% of the genera and more than 80% of all species of skeleton- bearing marine invertebrates became extinct Possible causes: Massive volcanic eruptions, leading to climate change, ocean acidification, and widespread environmental devastation. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 The Mesozoic Era: Age of Reptiles The History of Life  Triassic: Recovery from the Permian extinction, diversification of marine life, early dinosaurs. Jurassic: Breakup of Pangaea, rise of large dinosaurs, evolution of birds from theropod dinosaurs. Cretaceous: Dominance of dinosaurs, diversification of flowering plants and insects, evolution of snakes. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Mesozoic Marine Revolution: Escalation of predation in the oceans, leading to evolutionary arms races between predators and prey. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Rise of Flowering Plants Angiosperms becoming diverse by early Cretaceous Co-evolution of insects (pollination) BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Early Mammals: First mammals appearing in the Triassic Mostly small, nocturnal creatures coexisting with dinosaurs BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The End-Cretaceous Mass Extinction: Marked the end of the Mesozoic Era, causing the extinction of non-avian dinosaurs and many other groups. Cause: Impact of a large asteroid off the coast of Mexico (Chicxulub crater), triggering catastrophic environmental changes. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 The Cenozoic Era: Age of Mammals The History of Life  Paleogene Period: Rapid diversification of mammals, birds, and snakes. Neogene Period: Evolution of grasslands and savannas, radiation of grazing mammals, continued diversification of birds and flowering plants. Quaternary Period: Marked by Pleistocene glacial cycles, shaping the distribution and evolution of modern species. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Adaptive Radiation of Mammals: Filling ecological niches left vacant by dinosaurs Evolution of modern mammal groups: primates, whales, rodents, bats, etc. Continental Drift and Climate Change: Continents reaching their current positions Cooling trend, expansion of grasslands BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  Glacial-Interglacial Cycles: Dramatic climate fluctuations with major impacts on species distributions and evolution. Megafaunal Extinctions: Disappearance of many large-bodied mammals and birds, likely due to a combination of climate change and human hunting. BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The Rise of Humans: Evolution of hominins and the emergence of Homo sapiens BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025  The Future of Life? BIOL 109: Evolutionary Biology The History of Life 1st Semester, A.Y. 2024–2025 References Futuyma, D.J. and Kirkpatrick, M. (2017). Evolution, 4th ed. Sunderland, USA: Sinauer Associates, Inc.  Fin [email protected]