Evolution of the Living Earth (EASC08023)
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This course is intended as a foundation course for all Earth Science students with emphasis on processes that operate at the global scale. The interactions between geology, chemistry, physics and biology affecting the origin and evolution of life, Earth surface processes, and the climate history of the planet are studied. These together form the characteristics of the environment in which we live.This course should also be of general interest to Biology students by providing a thorough basis for understanding the geological aspects of global environmental change, and in particular, the evolution of life in this context. Chemists will benefit from an application of basic chemical principles to complex natural systems, while the course also provides an important background for those interested in temporal phenomena e.g. archaeologists.The course will consist of four main components:The first part (4 weeks by Dr Stephen Brusatte) will present the evolution of the Earth in general and of life in particular. The roles of the atmosphere and geosphere on changes in the biosphere are discussed, emphasising the driving mechanisms (internal and external forcing) for change. Significant events in earth history are considered, including the origin of life, geochemical evolution of the atmosphere, and mass extinctions. After covering this module, students will be able to recall the main features of the evolution of the planet and life on earth.The second section (2 weeks by Dr. Alex Thomas) introduces the concept of global climate change across a spectrum of time-scales from many millions of years to inter-annual variations. The emphasis is on identifying the main processes that control climate variability and change on these different time-scales, and on using examples from Earth history to illustrate how these processes may interact. This leads to the concept of the climate system; a complex coupled system where components may interact to either enhance or reduce any initial change in climate. Natural processes including those related to tectonic activity, weathering of rocks, changes in solar output, changes in the Earths orbit around the sun, and natural auto-oscillations in the climate system (such as El Niño Southern Oscillation) are considered, as well as Anthropogenic processes of climate change related to changing greenhouse gas and aerosol concentrations in the atmosphere. From this module students will be able to recall the main timescales on which climate change occurs, and will be able to account for these scales of change with reference to current understanding on the topic. They will be able to assess the degree to which recent climate change is exceptional compared to previous times, and will understand the significance and reliability of future predictions based on climate model results.The third part (2 weeks by Dr. Bryne Ngwenya) is a basic introduction to the foundations of chemistry that underpins our fundamental understanding of natural chemical reactions. The course assumes very little chemistry and starts from first principles (fundamental building blocks of matter) to chemical reactions and what drives them. The lectures will run in parallel with assessed laboratory practical sessions designed to consolidate the application of the chemical concepts to natural substances/processes. On completion of this module, students will acquire a solid grasp of chemical principles upon which to build their chemistry skills relevant to Earth Materials and Practical Geochemistry and Data Analysis in later years.The final part (2weeks by Dr. Alex Thomas) looks at earth processes from an integrated point of view through a systematic study of biogeochemical cycles. The major biogeochemical cycles of carbon, nitrogen, and phosphorus are discussed and compared and detailed interactive practical sessions are used to illustrate measurement, analysis and synthesis of biogeochemical data. Links between the physical climate system and biogeochemical cycles are introduced to show how human activity is impacting on the environment. On completion of this module, students will be able to use the terminology and appreciate the merits of the cyclical approach to biogeochemistry. They will be able to recall the principal components of each biogeochemical element and the processes operating within each reservoir. They will appreciate the differences between the biogeochemical elements and also the human impact on each cycle.Appropriate clothing for practicalsSome of the practicals in weeks 6-11 involve working with chemicals. For your own safety, and that of others, you must wear suitable clothing. Footwear must be closed toe (no sandals or flipflops). Clothing should cover exposed skin: shorts, skirts and kilts are not suitable. Long hair should be tied back. Scarfs and long neck ties must not be worn in the laboratory. If you insist on dressing up for class then a bow tie is acceptable. You are also expected to bring a lab notebook to the environmental chemistry practicals.
Part I Origin and Evolution of Life (Dr Stephen Brusatte, SB)Week 1 Building a Habitable Earth, Origin of Life & its ComplexityThis week we will cover the basics of Earth formation and structure, the age of the Earth, the origin of liquid water and the atmosphere, why Earth is an ideal setting for the evolution of life. We will ask: What is life?, what materials are necessary for life?, how did life form?. Topics will include prokaryotic vs. eukaryotic cells, direct and indirect evidence for the earliest life, the oldest fossils. We will examine the Proterozoic world, cyanobacteria and the oxygen revolution in Earths atmosphere, origin of eukaryotes, the first multicellular life, Snowball Earth and its effects on evolution, the Ediacaran faunaWeek 2 The Cambrian Explosion, origin of body plans, and evolutionary innovationThis week we will look at life in the Phanerozoic, the origin of skeletons, the Cambrian Explosion: what it was and what caused it, the phylogeny of animals, the Burgess Shale, how Cambrian environments affected early animals. You will learn the origin of the major animal body plans, Darwin and the theory of evolution, and how to read a cladogram. The outcomes of the Cambrian explosion are explored: first large predators, modern food webs, substrate revolution, trilobites and other important Cambrian groups, Sepkoskis diversity curve and evolutionary faunas, introduction to mass extinctions.Week 3 Palaeozoic Ocean Evolution, and the invasion of the landHere we will investigate the Great Ordovician Biodiversification Event and the Palaeozoic fauna, the end-Ordovician mass extinction, amazing Silurian fossil sites in England and Scotland, conodonts and the origin of bony vertebrates, the origin of fishes and the evolution of jaws. Topics will include the earliest forays onto land and the Rhynie Chert of Scotland, the first terrestrial ecosystems, the origin of tetrapods and the rise of vertebrate faunas on land, exciting new tetrapod research in Scotland, the origin of reptiles and amphibians, synapsid-dominated faunas during the Permian, the formation of Pangea and its effects on terrestrial evolution, the end-Permian and Triassic mass extinctions, the Triassic recovery and rise of archosaurs, the earliest dinosaurs and their competitors.Week 4 Dinosaurs, mammals, and Oceanic faunaThe last week of the Origin and Evolution of Life part of the course we will study the evolution of dinosaurs across their ~160-million-year evolutionary history, the major groups of dinosaurs and their salient features and behaviours, dinosaur evolution and palaeogeography, the origin of birds and invasion of the sky. The end-Cretaceous extinction and the death of the dinosaurs, the earliest mammals and their explosive radiation after the end-Cretaceous extinction, archaic mammals of the early Paleogene, and the origins of the modern mammal groups, later Cenozoic cooling and the spread of grasslands, the origin of humans will aslos be studied. The end-Permian extinction and rise of the Modern fauna, the Mesozoic Marine Revolution, Mesozoic microfossils and their importance in biostratigraphy, Mesozoic marine reptiles, the diversification of sharks and teleost fishes, whales take to the water. The Gaia hypothesis, an overview of how life has impacted Earth over the course of the last few billion years will also be introduced.Part II Global Climatic and Environmental Change (Dr Alex Thomas, ALT)Week 5 Energy model of Planet Earth, Plate Tectonics, Weathering and ClimateWe will start by building a simple climate model to understand the controls on the Earths surface temperature. We will then introduce the climate System; structure, composition and circulation of the atmosphere and of the ocean. We will look at evidence for past climatic change and use these changes to investigate different controls on Climate change over geological time. The climate driving processes include weathering of rocks as a possible thermostat for Global climate; the role of tectonic processes in driving past greenhouse and icehouse times in Earth history.Week 6 Mechanisms of medium and short term climate change, past and futureCooling from the Cretaceous into the modern icehouse; glacial-interglacial cycles of the past 2 million years and the role of orbital forcing will be introduced. Looking at shorter more recent climate change we will look at natural short-term variations in climate due to stochastic processes, variations in solar irradiance, effects of volcanic eruptions, effects of large meteorite impacts and auto-oscillations such as the El Niño Southern Oscillation. Anthropogenic climate change and the role of greenhouse gases and aerosols will then be covered Including how we can identify the causes of current changes in the climate and how our climate is and will change into the futurePart III Environmental Geochemistry (Dr Geoff Bromiley GDB & Dr B T Ngwena, BTN)Week 7 Atoms, Electrons, and ReactionsThe first week of the chemistry part of the course will cover: The atom and its constituent parts; the nucleus, protons (p) and neutrons (n). Atomic number). Atomic weights expressed as atomic mass units. What is the mass of an atomic particle? Gram formula weight; Avogadros number. Definition of element (same p), and isotope (same p, various n). Summary of elements listed by numbers of protons. Representation of elements by their symbol, with their atomic number and mass number. Electrons: their relative mass, how far away from the nucleus they are. Electron orbitals: K, L, M shells, orbital pairs, electronic configurations. Elements listed by electronic configuration, which dictates the key chemical properties we are often interested in: bonding, volatility, metal vs non-metal. Define and explain the key parts of the periodic table, via groups, and via split into metal/amphoteric/non-metal. Bonding of atoms: ionic, covalent, metallic, Van der Waals. Ionic compounds and molecules. What is a chemical reaction? How do they occur. Reaction stoichiometries: How to write and balance a chemical reaction,Week 8 Solutions, Energy and the Chemistry of the EarthIonic solutions. Dissolving things. Solute and solvent. Concept of dissociation into ionic species in solution, solubility product and what this means. Activity and Concentrations. Redox chemistry, Eh and pH concepts.Energy considerations: idea of vibrational, translational and rotational contributions to how much energy it takes to heat up a substance by 1C (heat capacity), entropy (with entropy explained in simple terms). Energy considerations in making and breaking bonds - enthalpies. Distribution of the elements, importance of water and oxygen, chemical reactions in the oxygen cycle. The state-steady geochemical cycle.Part IV Global Biogeochemical Cycles (Dr Alex Thomas, ALT)Week 9 Introduction to Biogeochemistry, and the carbon cycleHere we will define what biogeochemical elements are and how we ca simplify their study into cycles. The terminology and simple box models will be introduced starting with the carbon cycle. Forms of carbon, their major reservoirs, atmosphere, hydrosphere, biosphere, and lithosphere, including fossil carbon burning will be investigated including ow carbon moves between these stocks. We will use some simple chemistry to understand the behaviour of carbon in these reservoirs and how this affects climate.Week 10 Nutrient cycle: Nitrogen and PhosphorousWe will look at the two biogeochemical cycles of two elements essential for life: nitrogen and phosphorous. We will identify the main chemical forms of these elements in the environment, the stocks in different environmental reservoirs and how these elements are moved between these reservoirs and their chemical form altered to affect their availability to be used by organisms. Biological transformations of nitrogen compounds; nitrogen fixation, ammonia, assimilation, nitrification, assimilatory nitrate fixation, ammonification and denitrification will be studied. Weathering of phosphorus minerals and flux of phosphorus to the rivers and oceans and the pH dependence on P bioavailability will be looked at.https://path.is.ed.ac.uk/courses/EASC08023_SV1_SEM1http://www.drps.ed.ac.uk/current/dpt/cxeasc08023.htm
Written Exam 0%, Coursework 100%, Practical Exam 0%
Additional Assessment Information
The course will be assessed via continuous assessment of the theory components by online quizzes, and two course work assignments, each based on the practical activities. There is no final exam.Assessment will be based on the following elements and the overall grade for the course will be based on the following weightings:(i) 50% from 5 online quizzes, each of the assessed quizzes counts for 10% of the overall course mark(ii) 25% from the practical assessment(iii) 25% from the Environmental Chemistry practical reports.To pass the course the overall mark must be at least 40%Assessment deadlinesThe online quizzes will be made available on Friday of each week at 9am and the deadline for the assessed quizzes will be 12:00 (noon) on the following Monday. The formative quizzes (for feedback only) will be released on Fridays and will be available to be completed, (and retaken) for the rest of the duration of the course).Quiz for Week Assessed/Feedback only Available Deadline1 Feedback only 9:00 am Friday Week 1 None2 Assessed 9:00 am Friday Week 2 12:00 (noon) Monday Week 33 Feedback only 9:00 am Friday Week 3 None4 Assessed 9:00 am Friday Week 4 12:00 (noon) Monday Week 55 Feedback only 9:00 am Friday Week 5 None6 Assessed 9:00 am Friday Week 6 12:00 (noon) Monday Week 77 Feedback only 9:00 am Friday Week 7 None8 Assessed 9:00 am Friday Week 8 12:00 (noon) Monday Week 99 Feedback only 9:00 am Friday Week 9 None10 Assessed 9:00 am Friday Week 10 12:00 (noon) Monday Week 11The Origin and Evolution of Life practical work must be submitted before 12:00 (noon) on Tuesday of week 6 to the Turnitin box on the course Learn page.The Environmental Chemistry lab report, must be submitted before 12:00 (noon) on Tuesday of week 11 to the Turnitin box on the course Learn page.All details related to extensions procedures and late penalties can be found in the School of Geosciences Handbook, which can be found on the Learn UG Student Information Hub.
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