ERTH 209 Final Study Materials (PDF)

(Lectures Part 3) Quizlet/study guide links: LECTURE #1: Stratigraphy and geological time: 1. Principle of layer superposition - In any sequence of undistributed layers, older layer is at the bottom of the succession and the younger layers take up a progressively higher posit...

(Lectures Part 3) Quizlet/study guide links: LECTURE #1: Stratigraphy and geological time: 1. Principle of layer superposition - In any sequence of undistributed layers, older layer is at the bottom of the succession and the younger layers take up a progressively higher position according to their age of formation 2. Principle of layer successive formation - At the time of formation of a layer only fluid above it. According to stratigraphy none of the above existing layers existed at that time in the stratigraphic succession - Found fossils and that's how he knew 3. Principle of original layer horizontality - Realized that sediments accumulated by the settling of the particles in suspension in fluid - He stated that originally, the layers should have been horizontal. Therefore, steeply inclined layers are evidence of an episode of crustal disturbance (plate moved) - He also said that older strata(horizontal layer of sedimentary rock) will reflect irregularities of the sea bottom 4. Principle of lateral layer continuity (no longer accepted) - Originally deposited strata extend in all directions until they terminate by thinning at the margins of the basin - Steno also considered that barriers possibly existed of deposition or lateral grade into a different sort of sediment - Sediment spreads over the entire area of the basin it is occupying, does not happen, and is not equally distributed The Four Principles Principle of Superposition: In an undisturbed sequence of sedimentary rocks, the oldest rocks are at the bottom and the youngest are at the top. Principle of Original Horizontality: Sedimentary rocks are originally deposited in horizontal layers. Tilted or folded layers indicate subsequent disturbance. Principle of Lateral Continuity: Sedimentary rock layers extend laterally in all directions until they thin out or terminate at the edge of the depositional basin.] Principle of Cross-Cutting Relationships: A geologic feature that cuts across another feature is younger than the feature it cuts. Interpreting Stratigraphic Successions Sedimentological Data: Analyzing the characteristics of sedimentary rocks, such as grain size, composition, and sedimentary structures, can help determine the depositional environment and relative ages of layers. Structural Features: Features like folds, faults, and unconformities provide clues about the geologic history of an area and the relative ages of rock units. Fossils: The study of fossils, or the remains of ancient life, can help correlate rock layers across different locations and determine their relative and absolute ages. Important Concepts: Normal Stratigraphic Succession: The standard sequence of rock layers, with the oldest at the bottom and the youngest at the top. Inverted Stratigraphic Succession: A sequence of rock layers that has been overturned, often due to tectonic activity. LECTURE #2: Stratigraphy and geological time 2: 1. Relative Ages By Superposition - Superpositions tells us what’s older and younger - Helps determine the relative ages of the rocks in either left or right successions 2. Sir William Smith (pioneered bio stratigraphy) - Interested in the way fossils worked in rocks - The final release was 1815 when it came to his final project that included the whole Wales and southern part of Scotland - Was the battle of Waterloo & Britain, and became the first known superpower (from 1805) & then won against the French which then made Britain the first global superpower - - (may need some revision I did my best to understand what was being said here) - - - It was later named “The map that changed the world” (the colours on the map represented different sediments) 3. Fossil Ranges - Sir William made a huge break when it came to fossils as well - Ranges of various fossils - Demonstrated that fossils could go extinct during Earth’s age (?) - A fossil from Brazil vs China formed at the same time  - A | on the graph represents index fossils/marker fossils - The top of the | is the uppermost occurrence (evolution), and the lowermost occurrence is the bottom (extinction) - Paradoxides were often found in sandstone - They would move in far distances - They were also found in limestone - Depending on which sediments they were found in, there would have been different processes for them 4. Correlation Based on Fossil Ranges - Sir William created a vast advancement for geology - Layers containing the same index fossil can be correlated from one section to another Nicolaus Steno: Developed the fundamental principles of stratigraphy, including the principles of superposition, original horizontality, and lateral continuity. John Strachey: Contributed to the understanding of layer terminations. Georges Louis Leclerc, Comte de Buffon: Made significant contributions to the study of Earth's age, though his estimates were later proven to be inaccurate. Tomaso d'Arduino: Utilized sedimentary structures to interpret stratigraphic successions. William Smith: Pioneered the use of fossils for correlating rock layers, leading to the development of biostratigraphy. Charles Lyell: Made significant contributions to understanding the relative age dating of igneous and metamorphic rocks, including the principles of inclusions and cross-cutting relationships. Additional Principles and Techniques: Fossil Correlation: Using distinctive fossils (index fossils) to correlate rock layers across different locations. Principle of Inclusions: Rock fragments included within another rock must be older than the rock containing them. Principle of Cross-Cutting Relationships: A geologic feature that cuts across another feature is younger than the feature it cuts. Principle of Baked Contacts: Rocks that have been baked or altered by an igneous intrusion are older than the intrusion. LECTURE #3: Stratigraphy and geological time 3: Eons Longest units in the geographical time scale Given in stratigraphic order from oldest to youngest below Separation was accurate at time when defined, but new scientific discoveries resulted in significant changes in the four eon's definitions Hadean Oldest eon in the Earth's history Began with the formation of our planet and has no rock record Earth consisted only of molten matter during this time If earliest crust was formed, it is not preserved in the rock record Hadean/Archean Boundary Given by the age of the oldest record in stratigraphic record Archean Includes the oldest rocks on Earth Initially, scientists thought that Archean rocks (Earth's oldest rocks) did not contain fossils, but later discoveries revealed the oldest fossils in the fossil record within Archean rock layers Archean/Proterozoic Boundary Banded iron formation (shown later) Proterozoic Originally defined as the geological time period containing the oldest fossils on Earth, which were thought to be exclusively small and microscopic Later, larger fossils (macroscopic fossils), visible without a microscope, were discovered in rocks from the uppermost part of the Proterozoic era Two eons that contain the oldest rocks and fossils in Earth's history, Archean and Proterozoic, are grouped as supereon Precambrian Proterozoic/Phanerozoic Boundary Cambrian explosion: Significant event of rapid increase in diversity and complexity of life forms Phanerozoic Youngest eon in Earth's geological history Large, visible fossils can often be found in many sedimentary rocks formed during this period Eras Archean, Proterozoic, and Phanerozoic eons can be further divided into smaller units based on the characteristics of the rocks and fossils found within them The Phanerozoic is divided into Paleozoic Mesozoic and Cenozoic Paleozoic Era Oldest in the Phanerozoic Eon There are small resemblances between the fossils discovered in these layers and the modern floras and faunas Contains Cambrian, Ordovician, Silurian, and Devonian Paleozoic/Cenozoic Boundary Permian/Triassic crisis affected mostly the species in the seas and oceans, 90% became extinct during the crisis The most severe crisis in the history of life Mesozoic Era Contain fossils that present some resemblances to modern life forms, it is subdivided into three periods: Triassic, Jurassic, and Cretaceous Mesozoic/Cenozoic Boundary Cretaceous/Tertiary event/crisis Meteorite impact that lead to the extinction of several major fossil groups in both continental and marine realms, including dinosaurs Cenozoic Era Divided into Paleogene, Neogene, and Quaternary Fossil debris discovered in these sediments present clear resemblances with the modern life forms After Cenozoic Era Boundary Major diversification of the multicellular life forms Radioactive Decay Radioactive decay is a natural process by which unstable isotopes of elements spontaneously transform into more stable isotopes. This transformation involves the emission of radiation in the form of particles or energy. Types of Radioactive Decay: Alpha Decay: Emission of an alpha particle (2 protons and 2 neutrons). Beta Decay: Emission of a beta particle (an electron or a positron). Gamma Decay: Emission 1 of gamma rays (high-energy electromagnetic radiation). Radioactive Decay Series A radioactive decay series is a sequence of radioactive decays that begins with a parent radionuclide and proceeds through a series of daughter radionuclides until a stable isotope is reached. A well-known example is the uranium-238 decay series, which ultimately leads to the stable isotope lead-206. Half-Life The half-life of a radioactive isotope is the time it takes for half of the atoms in a sample to decay. It is a constant property of a particular isotope and is independent of external factors such as temperature, pressure, or chemical environment. Half-Life Principle: The half-life principle is used to determine the age of rocks and minerals. By measuring the ratio of parent to daughter isotopes, geologists can calculate the time that has elapsed since the rock formed. Half-Life Resolution: The accuracy of half-life measurements is crucial for precise age dating. Advanced techniques, such as mass spectrometry, allow for highly accurate determinations of isotopic ratios. LECTURE #4: Fossil Record 1: Trace Fossils: Evidence of Ancient Life Trace fossils, also known as ichnofossils, are indirect evidence of ancient life. They are formed by the activities of organisms, such as burrowing, crawling, or feeding. Examples of Trace Fossils: Tracks and Trails: Footprints, worm trails, and other movement traces. Borings: Holes drilled into rocks or shells by organisms. Burrows: Tunnels created by organisms in sediment or rock. Root Traces: Evidence of ancient plant root systems. Mixed Body and Trace Fossils: Some fossils preserve both the body of an organism and its trace fossils. A classic example is the horseshoe crab, which can leave behind distinctive trace fossils. The Early History of Fossil Study Pre-Scientific Fossils: Humans have been aware of fossils for millennia. Ancient cultures often interpreted them as signs of divine power or mythical creatures. The First Scientific Observations:  Xenophanes of Colophon: A Greek philosopher who lived around 570-475 BC, observed marine fossils in inland locations and suggested that the Earth had been covered by water in the past. The Birth of Paleontology: The scientific study of fossils, paleontology, emerged in the 18th and 19th centuries. Scientists like Nicolas Steno, William Smith, and Charles Lyell developed the principles of stratigraphy and used fossils to understand the Earth's history. By studying trace fossils and body fossils, scientists can reconstruct ancient ecosystems, understand the behaviour of extinct organisms, and gain insights into the evolutionary history of life on Earth. LECTURE #5: Fossil Record 2: Fossils: Preserving the Past This set of notes explores various ways in which ancient life forms have been preserved as fossils. Chemical Composition of Organisms Organic Matter: Living organisms primarily consist of elements like Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), with smaller amounts of Sulfur (S) and Phosphorus (P). Other elements are typically present in trace quantities. Maturation Processes: During burial and decomposition, elements like Oxygen, Nitrogen, Hydrogen, and Sulfur are expelled, leaving behind a carbon-rich residue. Carbonization: Preserving the Imprint Carbonization is a fossilization process where organic material gets compressed and flattened, leaving behind a thin film of carbon that preserves the shape and details of the original organism. Pecopteris fern fronds: Fossilized from the Upper Carboniferous period, these fossils provide a glimpse of ancient plant life (Poland, EU). Lepidodendron lycopsid: This fossilized plant from the Upper Carboniferous (EU) showcases the diversity of flora in the past. Impressions are formed when a dead organism leaves its imprint in soft sediment. As the sediment hardens and the organism decays, a negative impression remains. Fossilization in Exceptional Environments High-Quality Fossilization (HQF): Some environments offer exceptional preservation conditions, leading to fossils with intricate details of even soft body parts. These "fossil ores" are invaluable for reconstructing past life. Examples: Fossilization in Amber: Amber, a fossilized resin, can trap insects and preserve them in remarkable detail. This specimen of Plesio Rex (insect) from the Eocene (Germany, EU) showcases this process. Fossilization in Tar Pits: Tar seeps can trap animals, leaving behind highly detailed fossils. This Cybister (insect) specimen from the Pleistocene (California, USA) demonstrates this type of preservation. Fossil Lagerstätten: Treasures of the Past Fossil Lagerstätten are rare geological formations where exceptional fossilization processes have preserved a diverse range of organisms, including soft-bodied creatures. These sites are crucial for understanding the history and evolution of life on Earth. There are only about 100 known fossil lagerstätten worldwide. Examples: Burgess Shale: This Cambrian formation in Canada (British Columbia) is a treasure trove of fossilized creatures, including Ottoia (flatworm). Chengjiang Fauna: Located in China, this Lower Cambrian site boasts one of the earliest known vertebrates, Haikouichthys. LECTURE #6: Early Life Evolution 1: CHON: The fundamental elements that form the basis of life on Earth are Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N), collectively known as CHON. These elements are essential for the formation of organic molecules, which are the building blocks of all living organisms. Early Earth's Atmosphere and the Origin of Life Oparin's Hypothesis:  Reducing Atmosphere: Oparin proposed that Earth's early atmosphere was a reducing environment, lacking free oxygen. Organic Molecule Formation: In this reducing atmosphere, simple inorganic molecules could react to form complex organic molecules, including amino acids and sugars. Primordial Soup: These organic molecules accumulated in bodies of water, forming a "primordial soup" from which life could emerge. Miller-Urey Experiment: Simulated Early Earth Conditions: This experiment simulated the conditions of early Earth, including a reducing atmosphere, water vapor, and electrical discharges. Organic Molecule Formation: The experiment successfully produced amino acids, demonstrating that organic molecules could form under these conditions. The Transition to Cellular Life Polymerization: Combining Simple Molecules: Simple organic molecules, such as amino acids and nucleotides, can combine to form larger polymers, like proteins and nucleic acids. The Role of Catalysts: Chemical reactions, such as polymerization, require catalysts to speed up the process. Early Cellular Life: Prokaryotes: The earliest forms of life were likely simple, single-celled organisms called prokaryotes. Fossil Evidence: The Apex Chert and Strelley Pool Chert formations in Western Australia provide evidence of early microbial life, including bacteria and cyanobacteria. LECTURE #7: Early Life Evolution 2: Stromatolites: Earth's Earliest Ecosystem Engineers Stromatolites are layered rock formations created by the activities of microbial mats, primarily cyanobacteria. They are among the oldest known fossils, providing evidence of early life on Earth. Structure of a Stromatolite A stromatolite typically consists of four main layers: 1. Growth Surface: The top layer, inhabited by oxygen-producing cyanobacteria and aerobic bacteria. 2. Undermat: A layer of non-oxygen-producing photosynthetic bacteria and other microorganisms. 3. Oxygen-Depleted Zone: A thicker layer populated by anaerobic bacteria. 4. Stromatolite Mass: The bulk of the stromatolite, composed of mineralized layers formed by microbial activity. The Rise of Oxygen and the Banded Iron Formations (BIFs) The proliferation of oxygen-producing cyanobacteria led to significant changes in Earth's atmosphere. One such consequence was the formation of Banded Iron Formations (BIFs). These distinctive rock formations consist of alternating layers of iron-rich minerals (like hematite and magnetite) and silica-rich chert. The iron in BIFs was oxidized by the oxygen produced by cyanobacteria, leading to its precipitation and deposition. The Emergence of Eukaryotes Eukaryotic cells, with their complex internal structures, evolved from simpler prokaryotic cells. Key events in eukaryotic evolution include: Endosymbiosis: The incorporation of bacteria into eukaryotic cells, leading to the development of mitochondria and chloroplasts. Nuclear Envelope: The formation of a nuclear membrane, separating the genetic material from the rest of the cell. Early Eukaryotes: Bitter Springs Formation: This formation in Australia contains some of the earliest known eukaryotic fossils, including red algae and green algae. Bangiomorpha: A filamentous red alga that lived about 1.2 billion years ago. Torridon Phycus: An early green alga with a unique survival strategy. Melano Trillium: A possible early animal, related to modern testate amoebas. LECTURE #8: Dinosaurs 1: Agnathans Group of vertebrates that lack jaws, skeletons made of cartilage, no fins or teeth, simple digestive and respiratory tract, and notochords Haikouichthys: Lower Cambrian, Chengjiang biota, Yunnan Province, China, agnatha Sacabambaspis: Ordovician Period, Bolivian Andes, South America, agnatha Fishes Primarily marine, colonized all the aquatic environments such as brackish and fresh waters with evolved jaws Most of them have a bony skeleton, fewer a cartilaginous one (sharks) More complex tract and organs Dunkleosteus: Upper Devonian, Ohio and Europe, fish Macropomides: Late Cretaceous, Hjoula, Lebanon, fish Amphibians: The First Steps on Land Amphibians represent a significant evolutionary step, marking the transition from aquatic to terrestrial life. Key characteristics of amphibians include: Double Respiration: They breathe both through lungs and skin, requiring moist skin for gas exchange. Aquatic Reproduction: Amphibians lay a large number of unprotected eggs in water, similar to fish. Reptiles: Mastering Terrestrial Life Reptiles evolved from amphibian ancestors and adapted to a fully terrestrial lifestyle. Key adaptations include: Efficient Respiration: Reptiles have well-developed lungs for efficient breathing. Amniotic Egg: This unique egg provides a protective environment for the developing embryo, allowing reptiles to lay eggs on land. Scaly Skin: Reptile skin is covered in scales, reducing water loss and protecting them from injury. Early Reptile Diversity: Diapsids: Characterized by two pairs of temporal fenestrae (openings in the skull), diapsids gave rise to modern reptiles, birds, and dinosaurs. Hylonomus: One of the earliest known diapsids, lived in the Late Carboniferous period. Synapsids: Characterized by a single pair of temporal fenestrae, synapsids eventually evolved into mammals. Pelycosaurs: Early synapsids, including Dimetrodon and Edaphosaurus, were large, lizard-like reptiles. Therapsids: More advanced synapsids, such as Keratocephalus, were better adapted to terrestrial life and exhibited features that foreshadowed the evolution of mammals. Vertebrate Evolution - Vertebrates evolved in the lower Cambrian, likely from chordates (Axial skeleton formed by a rod-like structure termed notochord) - Their early evolution involved the agnathans (fish-like organisms without jaws) and fishes (with jaws) Agnathan - Haikouichthys- The earliest vertebrate - Sacabambaspis- The earliest agnathan with a cephalic shield Fishes - Aquatic organisms, which evolved jaws, long evolutionary history that begins in the Middle Silurian - Primarily marine colonized all the aquatic environments such as brackish and fresh waters - Most of them have a bony skeleton, fewer cartilaginous one (sharks) - Dunkleosteus: Largest fish predator Amphibians - Evolution happened in the process of getting out of the water - Double Respiration: Through lungs and skin, must have a wet skin all the time - Reproduction resembles that of the fishes, a huge number of unprotected eggs laid in an aquatic environment - Eopelobates, Andrias, Epipolysemia Diapsid Reptiles - The evolution to the reptiles happened as the amphibians moved inland (evolved active breathing) - Rather than laying a huge number of unprotecting eggs laid in an aquatic environment they began to lay a small number of eggs protected by a shell - Early reptiles were diapsids and adopted a fully terrestrial life mode probably because of the plenty of food (e.g., insects, worms, etc) - Petrolacosaurus: late Early Carboniferous (Earliest reptile) - Hylonomus: Early diapsid from the late Carboniferous Synapsid Reptiles - Dominated in the Late Paleozoic (Carboniferous-Permian) and Early Triassic - Some vertebrates were capable to control their body temperature - Pelycosaurs (Black Sails) Dimetrodon (Predator) Edaphosaurus (Vegetarian) Evolved thermoregulation Therapsids (mammal- like) - Their bodies, by contrast to that of the pelycosaur ancestors appear adapted to retain the heat  - Ex: Keratocephalus has the size of a rhinoceros LECTURE #9: Dinosaurs 2: Diapsid Takeover - Evolved from the diapsid reptiles in the Upper Triassic during a longer process known as the “Diapsid Takeover” Dinosaur Origins - Dinosauromorpha Earliest, most primitive, non-dinosaur dinosauromorphs were small, lightly built, insectivorous or carnivorous, and many walked on all fours but ran bipedally Most primitive condition of dinosaurs was bipedalism (Debated) Primitive dinosaurs were bipedal and quadrupedal dinosaurs secondarily evolved (reverted to) their quadrupedal stance Early Evolution - Fossils only known South America as this is where dinosaurs first appeared Saurischians & Ornithischians - All dinosaurs have three bone that make up the pelvic girdle 1. Ilium 2. Ischium 3. Pubis - Pubis can be oriented in one of the two ways - Down and slightly forward as in the Lizard-Hipped (Saurischians) dinosaurs - At least part of the pubis points backwards as in the Bird-Hipped (Ornithischians) Theropods - Bipedal, active runners Characteristics: - Knife-like teeth (thin, curved, backwards, and serrated) - Extra openings in front of the antorbital fenestrae called the maxillary fenestrae - Large hands with grasping ability - Hollow vertebrae and limb bones Allosaurus - Major predator groups across most of the world for most of the Jurassic and Cretaceous - Some got big  - Fossil scavengers - Larger animals possibly hunted sauropods Tyrannosaurus - Apex predator forms didn't last long - Very Diverse: All had small two fingered forelimbs - Got immense sizes, very heavily built - Several species found in North America prior to T.rex (native to Asia) Sauropodomorpha - Necks became longer, heads became smaller, hind legs and front legs became more equal in length (quadrupedalism) - First large dinosaurs, and eventually reached gigantic proportions - The basic body plan of sauropods did not change - Ex: Plateosaurus (Prosauropods) (Upper Triassic), Ultrasaurus (Sauropoda) (Upper Jurassic) Stegosaurus Chewers - Cropped and stripped foliage with the rhampothecae (Beak) - Inset tooth row = muscular cheeks and chewing - Teeth are small, simple, triangular, lack regular grinding surface and do no fit together well Ankylosaurus - “Fused Lizards” - Encased in an armor of osteoderms, continuous shield around neck, throat, back, tail, and sometimes head, cheek and eyelids - With girth = large gut - Longer hindlimbs than forelimbs, but quadrupedal - Mid sized LECTURE #10: Evolution of Flight: Back to Diapsids - The ancient diapsids of the Late Paleozoic became diverse and adapted to various ecological niches - Some of the most spectacular are the tree gliders (Coelurosauravus) of the Upper Permian of Madagascar Pterosauria  - Pterosauria includes circa 300 species of flying reptiles that lived during the upper Triassic-Cretaceous stratigraphic interval; the pterosaurian age corresponds to that of the dinosaurs - The group's name means "winged reptiles" Pterosaurian Diet and Mode of Life - Dimorphodon ○ A varied diet of small prey ○ Small vertebrates, insects, and maybe fish ○ Sharp teeth suggest carnivorous - Rhamphorhynchuhs ○ Ate fish, similar to seagulls - Ctenochasma ○ Ate sea plants ○ The long teeth would filter out the seawater - Pteranodon ○ Adapted to swallow prey as a whole, similar to pelicans Pterosaurs Flight Capabilities - The representatives of this group were considered in the past gliders from higher places - Small-sized species used most likely the trees to start the flighting, whereas the larger ones started their glided flight from a cliff or a false - Pterosaurian flight capabilities were re-evaluated and it was demonstrated that some species could have moved their wings actively during the flight, making them highly maneuverable in the air Ancestors of Birds - Birds evolved in the Late Mesozoic from dinosaur ancestors, and more precisely from theropods - The earliest reptiles with avian features are known in the Late Jurassic, but bird-like organisms did not evolve until the early Cretaceous Origins of Birds - Two hypotheses try to explain the flapped flight origin - Arboreal hypothesis ○ Tries to explain the flight origin from the small-sized non-flying reptiles that glided from the trees - Cursorial hypothesis ○ Tries to explain the evolution of flight from the fast-running animals, which developed flapped flight on short distances in the attempt to avoid the obstacles at the ground level LECTURE #11: Plate Tectonics: Tectonic Plates:  ○ 7 major plates (Eurasian, Pacific, Australian-Indian, North American, South American, African, Antarctic) Australian/Indian Plane has 2 continents, Pacific has 0 NA Plate has the most active volcanoes African Plane will eventually combine with Eurasian Plane to become one continent ○ Plates slide along or push against one another, causing the formation of smaller plates within their boundaries. Textbook notes (welcome to fix any typos) Chapter 8: 8.2, 8.3, and 8.5 to 8.7 (only those fossilization types presented in the lectures). 8.2 - Interesting discover of fossilized wood in an etruscan tomb showed that fossils were used as ritualistic objects in some cultures - Greek rationalism brough the earliest accurate interpretations of the fossils nature - First mention of fossils was by Xenophanes of Colophon (576-480) BC. the existence of fossil shells in the modern continental areas demonstrate that regions were previously covered by sea - His work was lost - Herodotus (487-426 B.C) considered shells of marine organisms found in the mountains of greece and egypt as direct evidence for the existence of an ancient ocean - During the renaissance leo da vinci (1452-1519) had a similar interpretation of fossils from the alps - Two major events in the sixteenth and seventeenth century - 1. The publication of the work de omni rerum fossilium (1565-1566) by conrad gessner (1516-1565) showed resemblances between certain fossil debris and living organisms in seas and oceans. He demonstrated this in the case of sea urchins, shark teeth ect. - He also observed that some fossil shells do not have an equivalent in the modern faunas - 2. Neils stensenson (nicholas steno 1638-1686) who observed that fossils occur only with their “hard parts” (shells). The time something takes to fossilize is long enough for the body to decay 8.3 - Body fossils: most frequently, a fossil must have a part or whole of the organism preserved in order to be included in this category Shell and carcass more easily fossilized due to their mineral nature, soft body organisms occasionally preserved if buried rapidly after death and protected from predators. Paleontology  - Trace fossils: represent organism activities like feeding and movements. The original body of the organism that left a particular kind of trace fossils is only exceptionally preserved. Soft bodied organisms (worms and insects) have some chances to fossilize their body but frequently leave trace fossils. Paleontology and ichnology - Chemical fossils: represent chemical combinations of substances produced by an organism or existing in its body and the minerals in the surrounding environments. Chemical reactions could have happened during the organism's life or after its death. This is important when we study vestiges of soft-bodied, small sized organisms (bacteria and algae). Chemical fossils are of paramount importance in deciphering the life of history in very old sediments; chances of fossilization of the organism are extremely small. Geochemistry 8.5 - Common fossilization processes: lead to the preservation of an organism's hard parts - Soft tissues are lost through organic matter decay or at best leave an impression in the rock, there are 6 processes in this group - Perminalization: occurs in fossils with pores or cavities in the hard parts. Vertebrae bones are classic examples. Soft tissue decay after organisms death and burial leaving the cavities empty and fluids with high concentrations in various substances (calcium carbonate) can flow through them. New minerals can be formed in fossil cavities when the fluid concentration reaches critical values and mineral precipitation begins. This process leads to the original fossil material preservation (phosphatic tissues in the bones, woody tissue in the fossil trees). The newly added material is only that precipitated in the cavities. - Recrystallization: frequent, results in partial or complete change of the shell mineralogical composition after an organism's death. Mollusc shells or valves of aragonitic nature. Aragonite CaCO3 is transformed into calcite (rhombohedral CaCO3) after organisms death and burial. Driven by the unstable nature of aragonite, which then reaches more stable calcite. Only the mineralogical composition changes - not the chemical composition. - Dissolution: occurs mostly after the sediment a fossil was embedded in transforms to rock, when fossil shell or carcass comes into contact with the fluids flowing through the rock pores it can become dissolved due to the high chemical reactivity of both calcite and fluids. This creates an empty space in the rock, and preserves the internal and external features of the dissolved fossil. Mold=internal features, Cast = external features. - Replacement: occurs after a fossil dissolution, if fluids with high concentrations of a mineral continue to flow through the layer that embeds the fossil and through the empty space (result from fossil dissolution) a new mineral can be precipitated in this space. This leaves a replacement, pyritization is what happens when pyrite is precipitated  - Carbonization: most frequently occurring fossilization mode in plants and invertebrate fossils. Occurs when dead organisms are rapidly buried. Deep into the earth's crust at higher pressures and temperatures, under the influence of chemically reactive fluids in the rock pores, many elements are expelled from the dead body (nitrogen, sulphur,hydrogen,phosphorus) until only carbon remains. The fossils appearance is very thing carbon dark coloured and often shiny, further burial results in the fossil transformation into graphite - Metasomatism: represents the complete replacement of the chemical and mineralogical composition of a fossil under the action of highly reactive and concentrated fluids at the earth's surface or in the subsurface. Finer structures are represented in this kind of preservation. 8.6 - Soft tissues can be fossilized 5 ways. - Congealment: is a relatively rare kind of preservation which occurs at high latitudes, low temp so the layer of permafrost is very thick. Bodies are almost intact and stomach content can even be measured. Woolly mammoths from siberia (russia) - Dehydration (mummification) occurs in the desert regions, a dead body loses water and dries rapidly, a fully dried carcass is not a meal for predators, and the mummy will be buried under sediment through wind. - Fossilization in amber: best preserved fossils in the earth's fossil record. Amber is a viscous organic resin secreted by some conifer species, small animals (insects to salamanders) and plants (grass to flowering plants) can be trapped and isolated form the surrounding environment. All structure and cellular features are preserved, vesicles are common occurrences in amber and preserve a small amount of the earth's atmosphere. - Fossilization in tar pits: occurs in zones with oil seeps, larger organisms mostly vertebrates are stuck in viscous fluids at the earth's surface. Accumulated over 40,000 years from la brea (cali) - Impregnation: most frequent case that occurs in soft tissue. Mostly in the case of algae that lived in shallower waters with high concentrations of dissolved calcium carbonate of the continental shelves. Precipitated calcium carbonate in seawater can impregnate the dead algal bodies - algae fossilizes but without most microscopic structures. Impregnated algal bodies can be easily fragmented when transported by the sea currents. Ex-much of the sand of the Caribbean beaches is formed through algal body impregnation. 8.7  - Well preserved fossils are relatively rare occurrences in the earths crust, this is because of delicate tissue preservation (internal organs, color pattern). Lagerstätten: Layers with exceptionally well preserved fossils. The rapid burial in the Lagerstätten speciens are fossilized with their undigested last meal. (this has helped us identify the existence cannabilism in certain species). There are certain conditions that must be fulfilled: rapid burial, absence of sea currents at the sedimentary basin, absences of scavengers, existence of an anoxic layer (or with a higher content with carbon dioxide, methane and hydrogen sulphide - this prevents the organic matter decay process magnitude because scavengers cannot live in such conditions), existence of finer sediments favors the preservation of small structures, geologically stable basin (no crustal movement), relative isolation form the chemically active fluids that can cayse a significant loss of info through fossil destruction. - Burgess shale = most famous fossil lagerstätten. Very fine sediments 530 mill years old and detached from an unstable adjacent shelf accumulated at the slope base through periodic submarine landslides (slightly anoxic environment). Oragbnisms were rapidly burried. Very well preserved fossils. - Crato formation (brazil), approx 110 mill years old, known for the preserved insects, (butterflies show pattern on wings) solnhoffen limestones (approx 150 mil old) yielded a variety of shallow water inveratbrae and vertebrae. Archaeopteryx lithographica most famous fossil - caused debate. Chapter 10: 10-1 to 10.3 and 10.5 to 10.7 (take out 10.4, 10.8 and 10.9). 10.1 - Stratigraphy: the study of the successions of strata and bodies of rocks in the earths interiror. Involves the study of all rocks, used in the economy and for discovery of new mineral resources. It is unknown exactly when stratigraphy started Chapter 11: everything can be tested. Chapter 12: 12.4 (without 12.4.3) and 12.5. Latin Names 1) Early Organisms Cryptozoon:ancient stromatolites, fossilized structures, some of the oldest evidence of life on Earth. Bangiomorpha: One of the earliest multicellular eukaryotic organisms. Torridonophycus: Fossilized remains of early algae-like organisms from the Proterozoic era. Melanocyrillium: Fossilized remains of organisms thought to be early amoeboid protists. 2) Early Vertebrates and Fishes Haikouichthys: An early jawless fish-like vertebrate, one of the first animals with a backbone. Sacabambaspis: A primitive jawless fish with a bony shield covering its head. Dunkleosteus: A large, armored prehistoric fish (placoderm) known for its powerful jaw and sharp biting plates. 3) Early Reptiles and Amphibians Hylonomus: The earliest known reptile, resembling a small lizard, that lived in the Carboniferous period. Mesosaurus: A freshwater reptile from the early Permian period, important for evidence of continental drift. Edaphosaurus: A sail-backed herbivorous reptile from the Permian period. Dimetrodon: A well-known sail-backed predator, often mistaken for a dinosaur, but actually a synapsid from the Permian. 4) Therapsids and Archosaurs Keratocephalus: A large herbivorous therapsid (mammal-like reptile) from the Permian period. 5) Dinosaurs Herrerasaurus: One of the earliest dinosaurs, a small carnivorous theropod from the Triassic period. Allosaurus: A large carnivorous dinosaur from the Jurassic period, similar to a smaller Tyrannosaurus. Tyrannosaurus: A famous giant theropod predator from the late Cretaceous. Plateosaurus: A large, herbivorous prosauropod dinosaur from the Triassic period. Ultrasaurus: A potentially misclassified giant sauropod dinosaur, originally thought to be one of the largest ever discovered. Stegosaurus: A well-known herbivorous dinosaur with bony plates along its back and a spiked tail. Ankylosaurus: A heavily armored herbivorous dinosaur with a club-like tail for defense. Triceratops: A herbivorous dinosaur with three facial horns and a large frill for protection. 6) Flying Reptiles (Pterosaurs) Sordes: A small pterosaur with evidence of fur-like body covering, suggesting warm-bloodedness. Pteranodon: A large, toothless pterosaur with a distinctive cranial crest. Rhamphorhynchus: A long-tailed pterosaur with sharp teeth and a diamond-shaped tail vane.  7) Transitional Fossils Archaeopteryx: An iconic transitional fossil between dinosaurs and birds, with features of both, such as teeth, feathers, and a bony tail.