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GEL107
Final (this material only includes lectures after MT2)
| Question | Answer |
|---|---|
| What 2 processes do the fossil record represent? | 1. Deposition of sediment 2. Evolution of organisms (both processes operate at different and variable rates) |
| 3 ways of ordering rock strata: | 1. Lithotratigraphy 2. Biostratigraphy 3. Chronostratigraphy |
| Lithostratigraphy | Based on characters of the sedimentary rocks themselves |
| Biostratigraphy | Based on the fossils within the rocks |
| Chronostratigraphy | telling time using BOTH absolute and relative methods. |
| Lithostratigriphical divisions: | - deposition is not continuous/everywhere HIATUS. The area between 2 hiatus is called a bed. Beds can form from either temporal(errosion) or sedimentary changes |
| High rates of deposition cause ____ beds. | Thick |
| Low rates of deposition cause ___ beds. | Thin |
| Formation: | A group of beds united by a set of common characteristics [sediment type, environment of deposition] |
| Axioms for interpreting stratified rocks: (3) | 1. superposition 2. Original horizontality 3. Lateral continuity |
| Event stratigraphy | Distinctive chemical signature or sedimentary feature that can be used to correlate (ex: iridium layer at the Cretaceous-tertiary boundary) |
| Biostratigraphy main ideas (2) | - Organisms evolve over time - Organisms only rarely evolve at a constant rate over time |
| Biostratigraphic divisions: | seen in the changes in fossils over time. |
| Stratigraphic range: | where/known occurrence of a fossil in the stratigraphic record |
| What does FAD stand for? | First Appearance Datum (of a fossil in the record) |
| What does LAD stand for? | Last Appearance Datum (of a fossil in the record) |
| What is important to remember when using FAD and LAD? | They do not necessarily represent the true origination and extinction of a species |
| High rates of evolution= ____ stratigraphic ranges. | short |
| Low rates of evolution= ___ stratigraphic ranges. | long |
| Assemblage | A group of co-occuring species, assemblages can characterize ZONES. |
| Zones | can be characterized by assemblages |
| What 2 types of "stratigraphy" make up the fossil record? | 1. lithostratigraphy 2. biostratigrapy |
| What/Why are index fossils important? | Index fossils are abundant fossils that only appear in a short segment of time- so you can roughly estimate the age of things around them because you are fairly certain of the index fossil age. |
| In order to be an index fossil ....(4) | 1. wide geographical range (intercontinental) 2. Short vertical range (stratigraphic) 3. Distinct morphological characteristics 4. Hard, mineralized skeletons |
| Movie analogy: what are sedimentary rocks? | The film itself: 1. how long is it? 2. sedimentation rate (at what rate does the movie play?) 3. erosion (what parts have been edited out?) |
| Movie analogy: what are the fossils? | The actors 1. Diversity (who are they) 2. Abundance (how many of them are there?) 3. Stratigraphic range: (when do they appear in the movie?) 4. Biogeographical range: (do they appear at one or more locations?) |
| Relative dates: | achieved from comparing with rocks and fossils are locally. |
| Chronostratigraphy | the process of taking relative dates to find absolute dates |
| What time had no fossils? | Pre-Cambrian |
| At what time did fossils start to be present? | Phanerozoic |
| Precambrian (3) | Divided into Hadean, Archaean, Proterozoic |
| What are most rock systems/times separated by? | Mass extinctions |
| Where does the name Cambrian originate? | Cambria= Roman name for Wales, which is where cambrian rock exists |
| Where does the name Silurian originate? | Named after an ancient Welsch tribe, Silures |
| Where does the name Cretaceous originate? | Creta=chalk. This section has a large amount of chalk. |
| Ecology+ biogeogrpahy BIASES- (5) | 1. generalist (wider range of environment) vs. specialist taxa 2. cosmopolitan (broad geographically) vs. Endemic 3. Abundant vs. rare taxa 4. Taxa that persist for longer vs shorts (in sediment) 5. Small body vs. large body |
| generalist taxa | applying to taxa that live in a lot of different enviroments |
| specialist taxa | applying to taxa that live in a few, specific environments |
| Cosmopoltian | applying to taxa that reside in a broad geographical range |
| Endemic | applying to taxa that reside in a narrow geographical range |
| Phylogeny BIASES (2) | 1. evolution itself changes organisms over time 2. A lineage can persist even though the first one can go extinct |
| Geology BIASES (3) | 1. more fossils from times wiht more active sedimentation 2. more fossils collected from rocks closer to the earth 3. younger rocks are more likely to be preserved than older rocks |
| Human (paleontologist) BIASES- (5) | 1. more work done in a certain time period 2. more work done in a certain region 3. Spilter vs. Lumper 4. Older, well known taxa are more likely to be recognized 5. more/less sampling between FAD and LAD increases/decreases confidence about actualtime |
| Lumper palentologist | likes to clump organisms together into one species (sees traits as variation rather than a full new species) |
| Spilter Palentologist | like to spilt up taxa into different species based on minor variations |
| Signor-Lipps Effect (bias) | - poorly sampled strata can make it impossible to distinguish a sudden extinction from a gradual extinction. |
| Lazarus Taxa (bias): | - taxa we'd thought to be extinct reappear at a later time. |
| Elvis Taxa (bias): | evolution of convergent morphologies after extinction event mistaken for persistence of extinct predecessor (impersonator) |
| Zombie effect (bias): | fossils physically reworked from older strata and re-deposited into younger strata (making it look like they lived longer than they did) |
| ***Main evolutionary patterns (3) | 1. species longevity 2. taxonomic turnover 3. mass extinction |
| Origination - Extinction= | Diversity |
| Valentine EMPIRICAL Model (1969) | - shallow marine invertebrates only - estimated species from # of families -Low diversity at first, but then accelerated. |
| Raup EQUILIBRIUM Model (1972) | - made pattern based on theory+ found biases from valentines work. |
| Biases that Raup found in Valentine's work: (1-4) | 1. sampling errors: species named more often than familes 2. Range Charts: taxa at a given time is not instantaneous 3. Duration of geological time intervals: not all same length 4. Monographic effects: quantity vs quality |
| Biases that Raup found in Valentine's work: (5-7) | 5. Lagerstatten: has better preservation than other places/times 6. Area-diversity relationships: larger regions=more diverse 7. Sediment volume: more sediment=more rocks at certain age, higher diversity seen |
| Sepkoski CONSENSUS model (1981) | Developed "3 great evolutionary faunas" -analyzed ORDER, then families, then genera -Logistic curve= density dependent model. |
| Three Great Evolutionary Fauna: | 1. Cambrian fauna 2. Paleozoic fauna 3. Modern fauna |
| Organisms in CAMBRIAN Fauna (Three Great Evolutionary Fauna: ) | trilobites, inarticulated brachiopods, worms |
| Organisms in PALEOZOIC Fauna (Three Great Evolutionary Fauna: ) | articulated brachiopods, corals, cephalopods, crinoids |
| Organisms in MODERN Fauna (Three Great Evolutionary Fauna: ) | Molluscs, bryozoans, fishes |
| Questions to ask about Three Evolutionary Fauna Theory:(6) | 1. ID at family level comparable to species level? 2. are the families true clades? 3. evidence from taxonomic databases? 4. "particle paleontology"- breaking up characteristics too much? 5. faunal transitions= large replacement? 6. What Processes? |
| Levels of interaction (genes--> biota) | genes--> cells--> tissues--> organs--> organism--> population--> species--> genera--> domains--> local populations--> communities--> biota (ecological and biogeographic) |
| Scales of interaction are both _____ and ______ | Temporal, Spacial |
| Processes acting at one level can ___ _ _____ at a higher level | Determine a pattern. |
| Is there direct fossil evidence for the origin of life? If so, what is it? | Nope. |
| Origin of life occured _____ | 3.7-3.8 BYA |
| What is life? | 1. capabale of natural selection 2. self-bounded 3. self-generating 4. Self-replicating 5. Cellular (smallest unit) |
| The fossil record is a result of what 2 processes? | 1. deposition and erosion sediment 2. evolution of organisms (both operate at different and variable rates) |
| Anagentic change implies _____ and relatively ____ rate of evolution. | Slow, constant |
| Punctuated equilibrium: | long periods of stasis punctuated by rapid, abrupt change CLADOGENESIS |
| Traditional view about Punctuated equilibrium | - the quick changes we see are really gradual changes made to look abrupt due to incompleteness in the fossil record. |
| Radical view about Punctuated equilbrium | - the quick changes we see is the true model. (more consistent with models of allopatric speciation) |
| Origin of the earth occurred ____ | 4.6 BYA |
| Nature of evidence regarding origin of life: (4) | 1. phylogeny: relationships among domains 2. Structure, ecology, biochem of living prokaryotes (cyanobacteria-modern, and stromatolites-mound) 3. fossils: of stromatolites and filamentous bacteria 4. geological data: biogeochemical cycles, carbon-isotp |
| World during Archean Eon: | -oceans dominated by hydrothermal systems, rates of oceanic crust production=high -low O2, high CO2 and N, very high Fe, No free oxygen. |
| Reasons for the Archean temperature to be HIGH (4) | (most popular with geochemists) 1. hydrothermal submarine vents 2. hyperthermophiles= phylogenetically primative 3. thermodynamic drive= strong 4. life successful because heatfacilitates chemical reations--> metabolism is key |
| Reasons for the Archean temperature to be LOW (4) | (more popular with biologists) 1. reducing environment is required for life 2. phylogenetic relationships are not clear- mesophiles could also be primative 3. biochemicals decompose at high temps (DNA) 4. RNA important--> genetics is key. |
| 1st fossil evidence? | 3.5 BYA (different than origination of life) |
| The low deep-sea oxygens levels in the Archean eon caused: | Banded Iron Formations (BIF). oxygen released by marine organisms would react with high amounts of iron. |
| Suspended SILREA is deposited as ______ | chert |
| Suspended IRON is deposited as _________ | iron oxides |
| chert+ iron oxides= | BIF banded iron formations (when captured with O2) |
| Oxygen could only be used in Archean times once ______ was used up. | iron. |
| Endosymbiont theory: | Prokaryotes because eukaryotes by an anaeorbic bacteria eating an aerobic bacteria. mitochondria)--> so reliant on each other that they became "1 organism" |
| Origin of Metazoans (animals) occured _______ | 700 MYA |
| Edicara fauna: | some of first metazoans- animals similar to sea pens (found in australia and russia) |
| Origin of Skeletons occured_____ | 540 MYA (at the cambrian explosion) |
| Idea for why skeletons originated: (3) | (not triggered by a simple chemical change) 1. protection from predation 2. adaptive evolution of Hox genes 3. Increased O2 levels. |
| What was the sudden diversification in the cambrian explosion due to? | Hox genes |
| Hox genes | genes that are responsible for coding the "body plan" (DNA). Occurs in groups, and the number in each group varies among taxa --- determine the type of segment structure by gradation ---they are transcription factors that bind to the enhancers for genes |
| Factors that promoted diversification in cambrian (3) | 1. Hox genes 2. competion: predation and adaptive radiation 3. abiotic factors (independent of biology)- like oxygen levels and continental configurations |
| Adaptive radiation | MORE FIT DIVERSIFICATION a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available and opens environmental niches |
| Evo-Devo (Evolutionary Developmental Biology | Study of developmental events and sequences to elucidate evolutionary events and sequences. (ontology) |
| Ontology | is the origin and the development of an organism: for example, from the fertilized egg to mature form. |
| Peramorphosis (heterochrony) | --juvenile of derived organism resembles the adult of an ancestor. 1. increased rate of development 2. ONSET of development occurs earlier in life 3. delayed developmental OFFSET |
| Paedomorphosis (heretrochrony) | retention by an organism of juvenile or even larval traits into later life. 1. Reduced rate of development 2. ONSET of development DELAYED 3. Developmental offset occurs earlier. |
| SOMETIMES, Ontology recapitulates _______ | phylogeny (but not all the time) |
| Heterochrony | developmental change in the timing of developmental events- leading to changes in size and shape. 1. Paramorphosis (derived adult resembles juvenille ancestor) 2. Peramorphosis (derived juvenille resembles adult ancestor) |
| Developmental Parameters for Heterchromy (3) | -Rate of Development -Time of onset of development - Time of offset of development |
| Structure of feathers | feather are tubular structures formed from epidermal cells that produce keratin (protein) NOT elongated scales. |
| Why are feathers important? | feathers are a significant evolutionary novelty or key evolutionary innovation. |
| The 5 stages of feather development | 1. unbranched hollow cylinder 2. plumulaceous (downy) tuft of barbs 3. formation of rachis(middle thing); open pennaceuous feather 4. barbule formed; closed pennaceous feather 5. asymmetrical vane of flight feather. |
| Stage 1 of feather development: | 1. unbranched hollow cylinder |
| Stage 2 of feather development | 2. plumulaceous (downy) tuft of barbs |
| Stage 3 of feather development | 3. formation of rachis(middle thing); open pennaceuous feather |
| Stage 4 of feather development | 4. barbule formed; closed pennaceous feather |
| Stage 5 of feather development | 5. asymmetrical vane of flight feather. |
| What stages of feather development can we see in living birds and adult forms of fossils? | ALl 5! |
| What dinosaur exhibits STAGE 1 of feather development? | Sinosauropteryx |
| What dinosaur exhibits STAGE 2 of feather development? | therizinosaurs |
| What dinosaur exhibits STAGE 3 of feather development? | trannosaurids |
| What dinosaur exhibits STAGE 4 of feather development? | microraptor, caudipteryx |
| What dinosaur exhibits STAGE 5 of feather development? | archaepteryx, confuciusornis |
| Extinction is the ____ not the ______ | Extinction is the NORM, not the EXCEPTION |
| How much of the world's biotia is extinct? | 99.99% |
| Species-level turnover is ___________. | High |
| local extinction | when a species ceases to exist in one are, but still exists elsewhere. |
| Geographic ranges may act as a buffer to extinction. What does this result in? | This results in low speciation ranges and long species duration |
| true (global) extinction | ALL species of a type have gone extinct on earth. |
| refugia | an area in which a population of organisms can survive through a period of unfavorable conditions, esp. glaciation. |
| origination vs. immigration | did the species originate in that area, or did they just move from another area (where they did originate) |
| extinction vs. emigration | did the species go extinct in that area, or did they just move to a new area |
| Stratigraphic sampling and extinction (4) | 1. Signor-Lipps effect 2. Lazarus taxa 3. Elvis taxa 4. Zombie taxa |
| Mass extinction vs. BACKGROUND extinction | mass extinction: more tha 50% of a species went extinct in a short period of time background extinction:you count up the amount of families that went extinct which can help you figure out the severity of the event. (because of genes/luck) |
| Mass extinction | geologically rapid (time), major reductions in global diversity (taxa) |
| What are the 5 mass extinctions? | 1. end-Ordovician 2. end-Devonian 3. end-Perian 4. End-Triassic 5. end-Cretaceous |
| Quality of Extinction | we can see which particular families become extinct and evaluate their features to find commonalities/see why they may have gone extinct. |
| Selectivity of Extinctions (5) | 1. Taxonomic selectivity 2. Phylogenetic selectivity 3. Morphological selectivity 4. Ecological selectivity 5. Biogeographic selectivity |
| Taxonomic Selectivity (selectivity of extinction) | different taxonomic levels affected differently |
| Phylogenetic selectivity (selectivity of extinction) | whole clades affected- or not. |
| Morphological Selectivity (selectivity of extinction) | individuals possessing certain morphological features are more vulnerable |
| Ecological Selectivity (selectivity of extinction) | specialists affected more than generalists |
| Biogeographic Selectivity (selectivity of extinction) | widespread taxa tend to survive more than geographically restricted taxa |
| Periodicities of extinctions (how often?) | 26 million years |
| Types of extinction (3) | 1. Catastrophic extinction 2. stepped mass extinction 3. graded mass extinction. |
| Catastrophic Extinction | abrupt and and global changes cause synchronous extinctions at a geological boundary, with few if any survivors |
| Stepped mass extinction | groups of species sensitive to change become extinct first, with more robust groups becoming extinct in subsequent episodes (background) |
| Graded mass extinction | Rate of extinction increases beyond background level, straddling a geological boundary. |
| Possible causes of mass extinction:(5) | 1. sea level change 2. Oceanic circulation change 3. Tectonic activity 4. Volcanic activity 5. Extraterrestrial impact |
| Sea level change (mass extinction) | - sea level falls, lowers temperature, increases ice caps - sea level rises-- Opposite, plus high carbon shales form |
| Oceanic Circulation (mass extinction) | effects on both marine and terrestrial (global conveyer belt) - fresh water from melting glacers can slow or slow down the conveyer belt. |
| How do you get global cooling from tectonic activity? | - if you have an uplifted mountain formation, more weathering is occurring. The weathering absorbs CO2, there is a decrease in greenhouse effect and you see a global cooling. |
| Volcanic activity (mass extinction) | - adds ash and other particulates in air (blocks sun) - in short term, atmospheric cooling, but - long term- global warming from the added CO2 and greenhouse gases SUPER PLUMES |
| Super Plumes (3) | volcanic-causes flood basalt (which covers a large geographical area) 1. Columbia Plateau 2. Deccan Traps 3. Siberian Traps |
| Columbia Plateau (super plume) | extended erupting MIDDLE MIOCENE |
| Siberian Traps (super plume) | . largest flood basalt on earth END OF PERMIAN EXTINCTION |
| Deccan Traps (super plume) | -flood basalt in indian END CRETACEOUS EXTINCTION |
| end-Permian Episode (mass extinction) | Severe and protracted, not very selective LARGEST EXTINCTION IN HISTORY (~95%) - Cambria and paleozoic fauna died - severe in tropics |
| Causes of end-Permian episode? (4) | 1. Extensive marine regression (sea level drop) 2. Major drop in C-13 and C-12 ratio in ocean resiviors 3. Overturn of oceans (high CO2- toxic) 4. increase in volcanic activity |
| end-Cretaceous episode (mass extinction) | MOST FAMOUS EXTINCTION Loss of large bodies organisms (terrestrial dinos/ nonavian ) and many marine (reptiles) taxa - lots of amphibians survied, reptiles, birds, mammals ~60-75% extinct |
| Causes of end-Cretaceous episode? (4) | 1. global cooling 2. lowered sea level 3. increased volcanic activity 4. extraterrestrial impact |
| Evidence for extraterrestrial impact in end-Cretaceous episode? (4) | 1. iridium layer (KT boundary)- not common on earth 2. shocked quartz: from impact/pressure 3. Sphrule+ tekite: gravel sized rock/debris (glass like) 4. Chicxulub crater |
| Late Pleistocene Extinction (not a big 5 extinction) | - Highly selective for Megafauna (large animals)--> smaller animals weren't as heavily affected - Asynchronous: the smaller of the megafauna died first, than the larger - patchy extinction both geographically and temporarly |
| Causes of Late Pleistocene Extinction | 1. Climate change? 2. Competitive exclusion? 3. Human hunting? |
| What is referred to as the 6th mass extinction? | What we may be causing right now.. |
| In the ice cores we sample now, what are we seeing increase? | CO2 ( this has been seen since the industrial revolution- increase in CO2, methane in the atmosphere) |
| The 2-5 degree rise in temperature over the 21st century will effect: (4) | 1. sea level rise 2. glacial retreat 3. extreme weather events 4. Increase in disease vectors (mosquitoes) |
| How do we study paleoclimate? (2) | 1. Isotope record (ice cores), 2. stratigraphic record (rock types tell us about environment) |
| biases with FADs and LADs (4) | 1. Signor-Lipps effect 2. Lazarus taxa 3. Elvis taxa 4. Zombie effect |
| Macroevolution | evolution on a scale of separated gene pools-focus on change that occurs at or above the level of species, in contrast with microE, which refers to smaller evolutionary changes (typically described as changes in allele frequencies) within a species/pop |
| Phyletic gradualism | slow, constant rate of evolution (Classic/traditional view) - anagenesis - eventually populations became so different from each other- they could interbreed |
| Fossil record is the record of what two processes? (2) | 1. Deposition of sediment 2. evolution of organisms |
| RATES OF EVOLUTION: | vary, sometimes fast, sometimes slow. Not all gradual and not all punctual. |
| What are adaptive radiations driven by? (2) | 1. Key evolutionary innovations (intrinsic) 2. Ecological Opportunities (extrinsic) |
| Intrinsic factors + examples | Pre-adaptations; concerning the morphology of the organism 1. Amnion (membrane of amphibian eggs) needs to be in water to live 2. Placenta- provides embryo with physiological needs+ protection 3. Protofeathers: thermoreg., sexual display. |
| Extrinsic factors + examples | concerning the environmental habitat of organisms 1. Dinosaurs' extinction allowed mammal diversification 2. Large bodied marine mammals--> whales could evolve and diversify 3. techtonic events- create rift lakes where "chichlid fishes" can live. |
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