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77 Cards in this Set
- Front
- Back
Stano's 3 Principles |
1. Superposition 2. Law of Original Horizontality 3. Law of Original Continuity |
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Superposition |
Oldest rocks are at the bottom (deposited first) youngest rocks are on top |
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Law of Original Horizontality |
Strata are deposited in horizontal layers that are parallel with each other |
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Law of Original Continuity |
Deposited continuously over lateral distances |
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3 Types of Age Boundaries |
1. Conformity: when the boundary is distinct 2. Disconformity: when you are missing time 3. Angular Unconformity: mountain building |
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Absolute Age |
Best way to determine is through radioactive decay |
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Reasons for Continental Drift |
1. Continents fit together 2. Distribution of fossils 3. Distribution of glacial deposits 4. Mountain belts |
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Fossils found on Gondwana |
1. Mesosaurus 2. Glossopetris |
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Geophysical Evidence of Plate Tectonics |
1. Mid-Ocean Ridge 2. No ocean crust older than 200 Ma 3. Paleomagnetics |
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3 Supercontinents |
Pangea 300-200 Ma (Carboniferous - Triassic) - most recent w Gondwana Rodinia 1200-800 Ma Nuna (ca. 2000 Ma) |
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Continental Breakup |
1. Rift Valley 2. Spreading produces linear sea 3. Continues spreading to produce a full ocean |
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Wilson Cycle |
Oceans = transitory features that are created as mega/super continents break up and disperse and then are destroyed when continents come back together |
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Fossil |
Remains of ancient organisms (anything left behind) - shells, bones or features made by them (footprints, burrows) |
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5 Main Categories of Fossils |
1. Bones 2. Shells 3. Cellulose 4. Trace Fossils 5. Soft Tissues |
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Bones |
- made of phosphate which is more resistant to weathering than soft tissues - most bones not found in the same place - conditions of fossilization (taphonomy) important in determining whether they will be preserved |
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Shells |
-made of carbonate which is not as resistant -typically found as molds of the inside |
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Cellulose |
- can be preserved as is if the plants are dried out or oxygen is excluded - wood can be petrified (filled w silica) -origin of all the coal in the world |
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Trace Fossils |
- includes tracks, burrows, and borings of animals - record behaviour of the animal that made them |
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Soft Tissues |
- normally decomposes so not preserved as fossil - known as fossil Lagerstatten - important in recreating the history of life |
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Faint Young Sun |
- sun only 80-85% as bright |
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Early Archean Characteristics (Warrawoona) 3.5 Billion Years Ago |
1. volcanic islands no true continents 2. sun only 80-85% as bright 3. volcanic atmosphere with NO oxygen |
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3 Steps in Synthesis of Life |
1. formation of simple organic molecules 2. combination simple organic molecules into complex organic molecules 3. replication 1+3 have been explained and occur naturally unable to solve 2 |
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Miller-Urey Experiment |
-volcanic gases+ spark = all amino acids essential to life -energy source is unimportant the reaction NEVER works if oxygen is present - |
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RNA - World |
- accepted DNA could not have been first complex organic molecule since its formation requires proteins - RNA can replicate itself and act as catalyst in reactions (like proteins) so favoured model |
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Speigelman Monster |
- shows that self-replicating living systems can consist of little more than short strand RNA
- QB Virus, could not live out of test tube shows simplest life form possible - got rid of excess functions |
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Where did life occur |
- probably evolved in hot spots
- mid ocean ridges |
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Evidence that Life Existed |
1. Stromatolites 2. Organic Microfossils |
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Stromatolites |
- layers of sediments reflect presence of mats of unicellular organisms build up - occur in extreme environments (Shark Bay) - oldest occur in rocks 3.5 Ga from Warrawoona - Baberton SA -continents started to grow which created shallow seas where stromatolites formed |
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Organic Microfossil |
-filaments and spheres of carbon that reflect the walls of unicellular organisms - formed in submarine hot springs rather than shallow seas |
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Age of Stromatolites |
Proterozoic |
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Banded Iron Formation |
- indicate iron reduced state in ocean - ocean and atmosphere prior to 2.4 Ga contained no free oxygen |
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Faint Young Sun |
- sun on Early Earth = only 75% as bright - required higher CO2 levels - as suns energy increased the CO2 decreased |
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Photosynthesis |
- all cyanobacteria use photosynthesis for metabolism - fixes CO2 and liberates oxygen and atmosphere -evidence of increasing oxygen after 2.7 Ga |
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3 Main Stages of Oxygenation of Earth |
1. Iron Ocean (prior to 1.8 Ga) 2. Canfield Ocean (1.8 - 0.6 Ga) 3. Modern Ocean (after 0.6 Ga) |
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Iron Ocean (prior to 1.8 Ga) |
- dissappearance of BIF at 1.8 Ga - oxygen oases formed in immediate vicinity of cyanobacteria |
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Canfield Ocean (1.8-0.6 Ga) |
- atmosphere and shallow oceans contain some free oxygen - brief appearance of iron ocean in conjunction with "snowball" glaciation |
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Modern Ocean (after 0.6 Ga) |
- atmosphere, shallow ocean and deep ocean all oxygenated |
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The Great Oxidation Event (1.8-2.4 Ga) |
- the transition from an oxygen-free world to one with limited oxygen in the atmosphere and shallow seas - most profound organism-induced global change in Earth history |
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3 Aspects of Evolution |
1. Speciation 2. Convergence 3. Co-Evolution |
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Speciation |
- different responses within a species to different environments (divergence) |
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Convergence |
- similar life habits in similar environments lead to evolution of similar morphology among organisms that are unrelated |
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Gene Pool |
all genetic information in a population |
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Anagenesis |
- continual evolution of a species until it becomes a new species - single lineage slowly progressing |
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Cladogenesis (Divergence) |
- splitting of one species into 2 as different populations of the species respond to changing circumstances - ancestral population splits -> splits -> splits |
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Convergence |
- how two organisms that are not related find the same solution to the same problem |
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Sabre Tooth |
- designed for cutting chunks of flesh out of prey and then leaving them to bleed out - evolved independently at least 5 times |
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Co-Evolution |
- how organisms adapt to each other and as a response to their environment (1) Arms Race - between predator and prey (2) Mutualism - relationship that is beneficial to both species |
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Van Valen (1973) |
The Red Queen Effect - always competing and improving - evolution in a species forces the evolution of all species it interacts with |
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Court Jester Effect (Baranosky 2001) |
- states that abiotic factors, which are not under organisms control also shape their evolution |
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Phylogeny |
- biological classification of organisms must reflect evolutionary history |
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2 Fundamental Divisions |
(1) Prokaryotes - unicellular, lack a cell nucleus or organelles - binary fission (2) Eurkaryotes - unicellular or multicellular, DNA in nucleus - sexual reproduction |
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Linnean Classification |
- based on hierarchy proposed by Carl von Linne (1735-38) - higher you are the better you are - no concept of evolution |
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Three Domains (Super Kingdoms) |
1. Bacteria 2. Archaea 3. Eukarya |
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Eukarya 4 Kingdoms |
1. Protoctista 2. Fungi 3. Plantae 4. Animalia |
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Classifying Organisms |
1. Cladistics 2. Molecular Phylogeny |
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Cladistics |
- proposed by Willi Hennig (1966) - offers hypothesis re: evolutionary history or relationships between organisms - uniting organisms that share unique features into clades - good for inferring patterns of relationships but cannot identify evolutionary mode |
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Strengths of Cladistics |
- testable and rigorous - can be used at almost any level of taxonomy - includes fossils and living species in the same cladogram |
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Monophyletic Group |
- all decendents form a common ancestors |
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Paraphyletic |
- common ancestor but does not include all descendants |
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Polyphyletic |
- more than one ancestor |
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Three Sets Morphological Characteristics |
1. Primitive - shared derived characteristic relates to ancestor 2. Derived - only one lineage has it 3. Convergent/Analogous - similar feature in unrelated organisms |
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Cladogram |
- shows the order of evolutionary appearances of derived characteristics |
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Molecular Phylogeny |
-Francis Crick -measures degree of substitution in DNA, RNA or proteins - directly measures genetic differences - as you go farther from modern organisms it gets less accurate |
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Strengths of Molecular Phylogeny |
- rigorous and testable - can be used at any level of taxonomy - directly measures genetic differences |
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Suspension feeding |
- take microorganisms out of water - no mouths during Ediacaran - no predators |
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Rangeomorphs |
- extinct clade - had no mouths so were suspension feeders |
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Snowball Earth Period (730-580 Ma) |
- Sturtian 715 Ma - Marinoan 635 Ma - Gaskiers 580 Ma |
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Mistaken Point |
- oldest Ediacaran fossils (580 Ma) found |
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Stem Group |
- on the line of arthropod but doesn't have all characteristics |
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Ediacaran Biota |
- went extinct rapidly w appearance of first shells of Cambrian biota = when life exploded |
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Garden of Ediacara |
- almost entirely autotrophic - no one had mouths and all just layed there so there were no predators |
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Early Cambrian |
- most profound and rapid diversification event in history of life - rise in diversity - reflects emergence of skeletons and brains |
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Archaeocyathan |
- first skeletal reef builders -extinct end of Early Cambrian |
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Burgess Shale |
- exceptional preservation of hard and soft-bodied marine animals - one of most important Lagerstatten fossils of all time - key info on stem-group arthropods |
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Causes of Cambrian Explosion |
1. Rise in Oxygen 2. Ecological Feedback |
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1. Rise in Ocean |
- formation of collagen required >10% present Atmospheric level by Ediacaran - exoskeleton requires even oxygen levels |
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2. Ecological Feedback |
- Cambrian Arms Race - evolutionary development of increasingly sophisticated armour and weapons = brains - Agronomic Revolution
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