ESCI 2020-30 Discovering Dinosaurs Fall 2024 1st Midterm Study Guide PDF

School of the Environment, University of Windsor ESCI 2020-30 – Discovering Dinosaurs - Fall 2024 1st Midterm Study Guide st This is the study guide for the 1 Midterm exam (Lectures 1 –...

School of the Environment, University of Windsor ESCI 2020-30 – Discovering Dinosaurs - Fall 2024 1st Midterm Study Guide st This is the study guide for the 1 Midterm exam (Lectures 1 – 4). This guide is to HELP you study, and is NOT intended to be a complete itemization of course knowledge! Your primary resource for studying should be the lecture slides first and foremost, and your own notes. Particularly because you’ll need to look at the diagrams on the slides. If you need further explanation for something in particular, or need to take a closer look at a diagram, go to the textbook, however there is lots in the textbook that I won’t be asking. Rule is if it doesn’t appear on the slides, and I didn’t actually talk about it in the lectures, then it will not appear on the exam. You will especially need the textbook because labelling on diagrams is often too small to be readable in the lecture PDFs. Every diagram in the lectures is identified with a textbook ID specifically for that reason. Pay attention when looking at the multiple choice questions. Do not rush to circle the first correct answer. There may be more than one correct answer, with something like “B and C is true” as a more correct choice. Save this study guide for use in studying for the Final Exam as well. Important person names are in green, important genera are in red, and corresponding sections in the text book are blue (generally, everything that follows a chapter reference is in that same chapter until a different chapter reference appears). You should be familiar with the diagnostic characters for the important clade names listed on the last page (all of which are described within this Study Guide). I’ll talk about the midterm in the beginning of Lecture 4, and do a review after the lecture, so it would be very helpful to be there. 1 Introduction, Geologic Time, Stratigraphy The scientific method - Hypothesis, Model, Law, Theory Part 1 Hypothesis - an educated guess, based on observation, that can be supported or refuted through experimentation or more observation Model - a hypothesis that has at least limited validity Law - a description of a natural phenomenon or principle that invariably holds true under specific conditions and will occur under certain circumstances Theory - a scientifically accepted general principle supported by a substantial body of evidence offered to provide an explanation of observed facts and as a basis for future discussion or investigation The Theory of Evolution: Process by which organisms change over time as a result of changes in heritable physical or behavioral traits; The change is caused by genetic mutation; This change is driven by natural selection; This incremental change becomes significant over geologic time The age of the earth – originally thought to be 20 to 100 million years, based on incorrect assumptions regarding the rate at which Earth lost heat, and the rate which salt has accumulated in the oceans; current estimate is 4.55 billon years based on radiometric age dating Principle of Uniformitarianism – James Hutton, Charles Lyell - The present is the key to the past Stratigraphy - description, correlation and classification of strata in sedimentary and layered rocks Principles of stratigraphy Chapt. 2 Original horizontality - Most sediments are deposited in horizontal layers Superposition – older rocks are below, younger rocks above cross-cutting - if geological feature A cuts across geological feature B, then B is older than A unconformities - can represent lack of sedimentary deposition, or more commonly a period of erosion, can represent significant gaps in time, an example is angular unconformity Understand how to use the principles of stratigraphy to determine a sequence of geologic events from a sample stratigraphic section Faunal succession - Organisms evolve through time, and appear in a definite, invariable sequence in the geologic record. Thus, their preserved remains can by used to identify the relative age of rock units. Fossils are the remains or traces of a plant or animal that has been preserved in the Earth’s crust Index fossils: geographically widespread, geologically short existence, morphologically distinct Fossil assemblages - Even if fossils have long stratigraphic ranges, fossil assemblages with very narrow ranges can be used by examining overlapping range Geological time scale was build using fossils, which show how life has changed through time We can correlate strata in different locations using fossils (and fossil assemblages) found within rock units  Age dating Chapt. 2 Relative age dating - Order of events occurring relative to one another Absolute age dating - Providing an actual numerical age of rock or event by Radiometric dating Any element (and its properties) is determined by the number of protons; atoms with varying numbers of neutrons are isotopes of that element, isotopes with extra neutrons tend to be unstable Unstable isotope: spontaneous decay (change) to another type of atom + emitted radiation Alpha decay – loss of 2 protons and 2 neutrons, atomic mass goes down by 4 Beta decay – extra neutron emits 1 electron, becomes a proton, mass stays same, # of protons goes up by 1 Original atom = parent; New atom = daughter Half life is the length of time it takes for half of the parent isotope to decay to the daughter isotope Different isotopes have different half-lives: short half-lives are useful for dating relatively young rocks, and long-half life isotopes are useful for dating older rocks Lithostratigraphy: The relationship of one body of rock to another, each layer is a different rock type Chronostratigraphy: The temporal relationship between rock units, each layer is a different age Biostratigraphy: The method of relative age dating that utilizes the presence of fossil organisms found within strata, each layer contains a different fossil assemblage 2 Fossils and Fossil Preservation Fossils - remains or traces of a plant or animal that has been preserved in the Earth’s crust Conditions of preservation: presence of hard parts (shells, bones, teeth); rapid burial by sediment (remove most of the oxygen, protection from scavengers), which eventually lithifies into sedimentary rock Preservation is biased by: Geographic environment, Organisms, Time Normally preservation of hard-parts only, very rare and very difficult to preserve soft tissue Most common types of preservation: permineralization (minerals like quartz or calcite crystallize in pore spaces), recrystallization, replacement of original hard part by a new mineral, carbon films or impressions, casts or molds, trace fossils Only a relative few groups of organisms (8 Classes in 6 Phyla out of 111 Classes in 36 animal Phyla) have a chance at preservation because they contain hardparts - corals, brachiopods, mollusca (snails, clams), trilobites, echinoderms (crinoids), vertebrates Hard parts are most commonly composed of either calcium carbonate (calcite) or calcium phosphate Taphonomy is the study of everything that happens to an organism between death and fossilization. It includes decay, disarticulation, transport, fragmentation, accumulation, sorting, burial, and disturbance. If an organism gets buried very rapidly after death, or buried alive, in environments that discourage scavenging and disturbance by burrowers, complete and articulated organisms can be spectacularly preserved Exceptional preservation – lagerstätte Under burial conditions where physical, chemical and biological agents of destruction are absent, it may be possible through a variety of processes to preserve exceptional remains of organisms in terms of quantity (Konzentrat-Lagerstätten) or quality (Konservat-Lagerstätten). Fossil preservation is ultimately a race between decay and fossilization Under certain special circumstances, the chemistry surrounding (and within) the decaying organism can favor the early precipitation of minerals (such as pyrite, calcium carbonate, calcium phosphate, and others) that will allow the organism’s soft tissues (or their outline) to be preserved Extraordinary fossil preservation can: Provide information on animals normally known only from their fossilized hard parts Reveal otherwise unknown organisms Provide a more complete picture of ancient ecology (generally 70 to 90% of marine animals and all of the plants have very little chance to be preservable in most marine ecosystems) Show the evolutionary history of soft-bodied groups, and of soft-part characters of known groups Trace Fossils - Ichnofossils (ichnos – track or trace) are not the preserved remains of an organism, but the preserved activity of an organism, often in the form of molds and casts. The preserved burrows, footprints and trackways produced as an organism moves, rests, and feeds Dinosaur trace fossils can provide information on anatomy, social behavior, feeding strategies, how they moved and at what speed Chapt. 1 Other types of dinosaur fossils: coprolites (fossil dung), gastroliths (stomach stones), skin impressions, eggs Steps involved in collecting: 1. Planning, 2. Prospecting, 3. Collecting, 4. Preparing and Curating Chapt. 1 3 Evolution, Phylogeny and Cladistics Evolution of the Earth Structure of the Earth Inner core - solid, mostly metallic iron Outer core - liquid, mostly iron Mantle - solid, mostly silicate rocks, flows over geologic time Asthenosphere - solid, mostly silicate rocks Lithosphere - cool, strong top layer, mostly silicate rocks (crust is the brittle uppermost part of the lithosphere; oceanic crust and continental crust have different compositions and origins) Rock types: Igneous - formed from cooling of molten material, (magma) Sedimentary - formed on the Earth’s surface from the products of weathering and erosion Metamorphic - already-formed rocks that have undergone change by heat and/or pressure Principles of plate tectonics Chapt. 2 First proposed by Alfred Wegener Lithosphere is broken into plates that move relative to one another Earthquakes and volcanoes primarily associated with plate tectonic boundaries Types of plate boundaries: convergent, divergent, transform Plate tectonics is driven by circulation within the mantle. The level of tectonic activity has changed over time, and can in turn effect sea level (by lifting oceanic crust and displacing the oceans onto the continents) and global climate (more volcanism increases the amount of the greenhouse gas CO2 in the atmosphere) Late Triassic - Earth is dominated by the unified landmass Pangaea. Similar biotas around the world (within climatic constraints), and more extreme climates. Late Jurassic - Pangaea has begun to breakup while the southern continent of Gondwana remains. Late Cretaceous - Almost modern distribution of continents, supercontinents have broken up. Relatively high sea levels, and fragmented continents result in a more moderated climate Effects of tectonics on climate: The lay out of the continents, position of mountain ranges, and height of sea level as controlled by tectonics will affect global atmosphere and ocean circulation patterns Interpreting ancient environments: determined by the types of sedimentary rocks and the types of fossils contained therein Evolution of Life Chapt. 3 Descent with modification: The concept that organisms have changed and modified their morphology (morph – shape; ology – the study of) through each succeeding generation Organisms classified according to a system devised by the Swedish naturalist Carolus Linnaeus Hierarchical system ranking organisms in groups of decreasing size: Kingdom, Phylum, Class, Order, Family, Genus, species Individuals referred to by italicized generic (genus) and specific (species) names E.g. Tyrannosaurus rex and Homo sapiens Any name in the hierarchy – representing a group of organisms – is considered a taxon (plural taxa) Originally based solely on overall similarities between organisms, and not on relationship Homologous anatomical structures: can be traced back to a single original structure in a common ancestor  Analogous structures: structures with different origins that may perform similar functions Phylogenetic systematics is the technique by which relationships between organisms can be inferred using unique features of organisms and depends upon the hierarchical distribution of “characters” in organisms Cladogram: Branching diagrams that show hierarchies of diagnostic characters Use character hierarchies to establish clades or monophyletic groups Derived characters are “diagnostic” and specifies an evolved condition of that character in a descendent, and are evidence of monophyletic groups Primitive or ancestral characters specifies the condition of a particular feature in the ancestor Parsimony - the explanation with the least necessary steps is probably the best one Phylogenetic definition: define a group by considering two of its members, and then defining it as all organisms stemming from the most recent common ancestor of those two organisms Charles Darwin didn’t come up with evolution, but the idea that evolution was driven by Natural Selection Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring. DNA information (genes) is read to produce RNA, which in turn is read to produce proteins; proteins are then responsible for both organic structure and process; changes in DNA then is reflected as changes to structure and process; the farther the relationship between organisms, the more changes As natural selection acts on a population with genetic variability (“morphospace”), it will “push” the makeup of the population in a certain direction, which over many generations can result in major evolutionary change Parallel evolution: Unrelated organisms experiencing similar selective pressures may evolve similar characteristics and might occupy similar ecological niches Gradual evolutionary change over time can be seen in fossils as a result of natural selection Speciation occurs when different populations change in different directions enough that they can no longer interbreed Phylogenetic trees show the past history of speciation, and eventually separation of entire taxa Rapid evolution into new or empty ecological niches (for example, after extinction events) result in evolutionary radiations (such as Darwin’s finches) Ontogeny: the changes an organism goes through over its life span. Different evolutionary processes – Developmental change (e.g. neoteny - advancing reproductive maturity enabling reproduction before adult features develop), isometric (equal growth) and allometric (differential growth) scaling in ontogeny (growth history of an individual organism) and evolution (having certain bones or other structures grow faster/longer or slower/shorter), or have structures fuse together; nearly-completely fused or reduced structures may remain as “vestigial” morphological features 4 Tetrapods and the early Dinosauria Evidence of monophyly of life on Earth, united by many characters Chapt 4 Possession of RNA and DNA Cell membranes composed of lipids A genetic code all keyed to the exact same amino acids Cells that function using the same metabolic pathways Beginning a look at the major innovations towards Tetrapoda Phylum Chordata (“nerve cord-bearing”) Cambrian-aged Pikaia, pharyngeal gills, notochord, nerve cord Cephalochordata – modern Amphioxus, segmentation of body wall, upper and lower nerve and blood vessel branches, and many newly evolved biochemical metabolic pathways Vertebrata – name refers to joints in the spine, mineralized internal skeleton divided into discrete elements Gnathostomata – vertebrates with true jaws Osteichthyes (boney fishes) – divided into Actinopterygii (ray-finned fishes), Sarcopterygii (lobe-finned fishes) Homologous characters between lobe-finned fishes and Tetrapoda – shoulder girdle and 3 primary limb bones Tetrapod – defined as the clade containing salamanders, mammals, and all descendants of their most recent common ancestor; diagnosed by the appearance of 4 limbs with a distinctive arrangement of bones; skeletal plan with: Vertebral column sandwiched by paired forelimbs and hindlimbs Limbs attached to column by groups of bones called girdles Head composed of skull and mandible (lower jaw); Tail Amniota defined as the monophyletic group that includes birds, mammals, and all the descendants of their most recent common ancestor; Characterized by the invention of a special membrane for the egg- bound, developing embryo called an amnion that allows gas exchange but retains water, and enabled vertebrates to become fully terrestrial Major groups of the Amniotes Anapsids – no post-orbital temporal fenestra (openings in the skull roof behind the eyes) Synapsids – a single temporal fenestra Diapsids – two temporal fenestrae Anapsida originally believed to include Chelonia (turtles) but now looks to only be extinct groups Synapsida – “mammal-like reptiles” (e.g. Dimetrodon), and the mammals Diapsida is defined as the monophyletic group that includes birds, lizards, and all the descendants of their most recent common ancestor Lepidosauromorpha (lepido – scaly; sauros – lizard; morpho – shape) is composed of snakes, lizards, the tuatara, and a number of extinct lizard-like diapsids, including the large marine mosasaurs Archosauria – Teeth in sockets, antorbital fenestra (hole in front of eye socket) Chapt 4&5 Crurotarsi (crocodiles, alligators, Protosuchus) and Ornithodira Ornithodira contains 2 sister clades Pterosauria (flying reptiles, very diverse, many ate fish; Pterodactyl, Rhamphorhynchus, Quetzalcoatlus) and Dinosauria Diagnostic characters of the Dinosauria Chapt 4 Defined as Triceratops and Passer (sparrow), and all members of the clade descended from their most recent common ancestor Diagnosed by 1. Elongate deltopectoral crest (ridge) on humerus (upper arm) 2. Perforate acetabulum (hip socket with hole) 3. Fibula contacts ≤ 30 % of astragulus (ankle mostly supported by tibia) 4. Epipophyses (bony projections) on cervical (neck) vertebrae 5. Asymmetrical 4th trochanter (projection for muscle attachment) on femur (thighbone) Unlike earlier tetrapods, dinosaurs had a fully erect posture, leg joints that limited movement to a single plane Dinosauria consists of 2 sister clades: Chapt 5 Saurischia – lizard-like hip or pelvis, with pubis directed anteriorly (forward), and slightly downward Ornithischia - bird-like pelvis, at least a part of the pubis runs posteriorly Early Dinosauromorpha appear in the Middle and early Late Triassic, with the true Dinosauria appearing in the late Upper Triassic of South America, and spreading globally and completely taking over from the Dinosauromorpha by the very end of the Triassic At first only considered a weird curiosity, the finding of Archaeopteryx eventually revolutionized our understanding of dinosaur-bird relationships thanks to John Ostrom Feathers, thought once as a diagnostic character for birds, now seems to be a diagnostic character for Dinosauria, and maybe even originating further back. Therefore, feathers did not evolve specifically for flight. Their original purposes were likely for insulation (as hair is for mammals), and for display (species recognition and sexual selection) and may have originated from sensory hairs in the skin Sequential stages in the evolution of feathers: Type 1) simple, hollow, cylindrical filaments (hair-like) Type 2) tufts of elongate multiple filaments Type 3) filament tufts align in a single plane while also developing barbs and barbules Type 4) “closed” vane with interlocking barbs and barbules, providing a rigid structure (“contour” feather) Type 5) vane becomes asymmetrical (e.g. a flight feather) Key (=simplified) Level Classifications and Genera Phylum Chordata ├Cephalochordata – e.g. Amphioxus, Pikaia └Vertebrata └Gnathostomata (jawed vertebrates) └Osteichthyes (bony fishes) ├Actinopterygii (ray-finned fishes) └Sarcopterygii (lobe-finned fishes) – modern coelocanth └Tetrapoda └Amniota ├Synapsida – mammal-like reptiles (e.g. Dimetrodon), mammals ├Anapsida └Diapsida ├Lepidosauromorpha – lizards, mosasaurs └Archosauria ├Crurotarsi – crocodiles, alligators, e.g. Protosuchus └Ornithodira ├Pterosauria – e.g. Pterodactyl, Rhamphorhynchus, Quetzalcoatlus └Dinosauria ├Saurischia – lizard-hipped dinosaurs └Ornithischia – bird-hipped dinosaurs Important: See the Course Syllabus for Chapter References (and page numbers) for Each Lecture for both the 3rd and 4th Editions of Fastovsky and Weishampel Note: there are sections of Lectures 1, 2 and 3 that are not represented in the text book at all, and all information will be derived from the Lecture slides and your own most excellent notes. As you are studying, write out all of the important names several times as you come to them, and it will help you to remember them better.