Time, tectonics, & Darwin Flashcards
Plate tectonics: spreading ridges and subduction zones
Spreading ridges: where new material is made (usually on ocean floor)
Subduction zones: where rock is being pushed into Earth’s interior
Effect of plate tectonics on geobiology
Fossil record, paleogeography, tectonic degassing
Fossil record (plate tectonics)
Both producing and destroying- enough pressure/heat to create rock but not too much to destroy the fossil
Paleogeography (plate tectonics)
Migration- species later separated onto different continents
- Land bridges, mountains can drive speciation
Climate- land moving to different latitudes, necessitates adaptation to new climate (altitude, moisture)
- Mountains, continental interiors
Tectonic degassing (plate tectonics)
Faster tectonic speed means more degassing- gases in magma released to ocean/atmosphere (CO2/SO2), more degassing (CO2) directly affects climate (warmer planet)
Gradualism
- James Hutton (1726-1797)- “father of geology”
- Idea of slow, steady changes to earth system
- Means earth must be old- contrasts much religious thought
- Charles Lyell (1797-1875)- popularized Hutton’s ideas
Modern view
Gradualism layered with catastrophism- changing of steady states (slow change, rapid change, then slow change again)
Biological evolution
- Darwin- Tree of Life
- More organisms than will survive to sexual maturity, range of traits
Phyletic gradualism
Parallel idea to evolution- slow, steady changes to organisms
Punctuated equilibrium
Combination of not much happening followed by shorter periods with big change in morphology
- Contrasts phyletic gradualism
- Ex. Cambrian explosion
Cladospecies
System where a species is defined by the most parsimonious set of shared morphological traits
- Explicit hypothesis for evolution
Morphospecies
System where a species is defined by unique morphological traits
- Contrast to cladistics
Prokaryotes
- Single-celled
- Bacteria (archaea)
- Simple morphology
- Simple prokaryotes have limited functional diversity
Eukaryotes
- Plants, animals, fungi, protists
- Mostly multicellular
- Complex morphology
Prokaryotes: respiration
- Oxic respiration
- Fermentation
- Anoxic respiration- other forms beyond fermentation, not as much energy (if you’re single-celled and simple, it’s fine)
Eukaryotes: respiration
- Oxic respiration- CH2O + O2 → CO2 + H2O
- Fermentation- doesn’t require O2
Prokaryotes: autotrophic (synthesizers)
- Oxygenic photosynthesis
- Anoxygenic photosynthesis
- Chemosynthesis- without sunlight
Eukaryotes: autotrophic (synthesizers)
(Plants)
Oxygenic photosynthesis
Cladistics
Based on parsimonious (most simple) distribution of shared traits
- Creates hierarchical groups with implied ancestry
Cladogram
Form of a phylogeny
- Living species at tips, fossil species down towards base
- Best cladograms are reasonably stable when new traits are added
Monophyletic group
Group of organisms containing a common single ancestor and all of its descendants
Paraphyletic group
Group of organisms containing a common single ancestor but not all of its descendants
Polyphyletic group
Group of organisms containing multiple common ancestors
Homology vs. analogy
Homologous features/traits have a common origin (evolved once)
Analogy focuses on function of the trait- analogous features have the same function
