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44 Cards in this Set
- Front
- Back
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Phyletic Gradualism |
Species evolve by slow and steady change |
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Anagenesis |
A taxon evolves slowly to form a new taxon. |
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Punctuated Equilibrium |
Descendants branch off from ancestors. Happens in concentrated instances, not gradually. |
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Cladogenesis |
A taxon splits to form 2 sister taxa |
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G.G. Simpson |
Studied rates of evolution. |
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Tachytely |
Very fast taxon lifetime (~1 mil) |
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Horotely |
Moderate lifespan, most taxa fall into this category (~10 mil) |
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Bradytely |
Long lifespan, no longer common (~100 mil) |
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Hypobradytely |
Very rare, cyanobacteria have this (~1,000 mil) |
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Exaptation |
Some features of an organism evolved to perform a different purpose. |
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Convergent Evolution |
Different organisms have features w/ similar functions but did not evolve the same way, no recent common ancestor. |
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Mosaic Evolution |
Different parts of an organism evolve simultaneously. |
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Co-Evolution |
Two different organisms evolving together in symbiosis. |
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Escalation |
Predators and prey develop methods to beat each other, speeding up the rate of evolution. |
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The Red Queen Hypothesis |
Escalation is the norm for evolution (Mesozoic Marine Revolution) |
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Cope's Rule |
As time progresses, animal size should also increase (not necessarily correct) |
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3 Characteristics of Mass Extinction |
1. The percentage of things that go extinct must be significant 2. Many forms of life must be affected/go extinct 3. Extinction must be global |
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Naked Coral Hypothesis |
Coral existed without skeletons for 7 mil. yrs. after End Permian. Due to high CO2 levels and elevated Ph in the oceans. |
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Metazoan Reef Gap |
Microbes built ocean reefs in place of coral. Stromatolite-sponge reefs |
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Trigger v. Mechanism
1. Bolide Impact 2. Volcanism 3. Climate Change 4. Anoxia/Euxinia |
1. Trigger 2. Trigger 3. Trigger/Mechanism 4. Mechanism |
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Anoxia |
Death by lack of Oxygen |
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Euxinia |
Death by toxic Hydrogen Sulfide |
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Characteristics of Life |
Made of organic molecules, energy dependent, self-regulating (metabolism), self-contained (membrane) |
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Life is Capable of... |
Growth, adaptation, reproduction with variation |
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Panspermia |
Life was transported to Earth from another world |
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Abiogenesis |
Alexander Oparin, 1924, life may have originated from non-living material only once on earth from a primevil soup. |
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Requirements for Life to arise |
-appropriate organic and inorganic substances with water - lots of time - no oxygen in the atmosphere (highly reactive, slows down or inhibits processes) - abundant source of energy |
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Lipid World Hypothesis |
Cells can grow and reproduce, store info, catalysis |
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Iron-Sulfer World Hypothesis |
Wachtershauser, life originated at deep sea vents. iron-sulfide minerals were surfaces for early metabolic reactions. Driven by gradient between hot fluid and cold ocean water. Produced organic molecules that acted as catalysts, led to increasingly complex reactions and catalysts. |
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RNA World Hypothesis |
In early cells, RNA was sole info carrier and catalyzed all metabolic reactions without DNA or proteins. |
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Biogenicity |
Whether or not something came from living systems (fossils) |
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Trace Fossils |
Preserved evidence for living activity (trails, burrows, etc.) |
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Microbially-Mediated Sedimentary Structures |
Physical structures which formed in association with microbial mats |
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Endosymbiotic Theory |
The first eukaryotic cells formed through symbiotic associations between prokaryotes |
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Choanoflagellates |
Protists that clustered to eventually form the choanocytes on a sponge |
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Biomarkers |
Organic compounds that are taxon specific |
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Ediacaran Biota |
582 Ma. Mostly cnidarians, preserved deep in the ocean where there was no sunlight. Some are soft bodied animals, others are obscure. First non-microscopic animals. |
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Biomineralization |
The ability of an animal to create a protective shell. Cloudina and Small Shellies were first to do so. |
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The Cambrian Radiation |
Variation of life exploded over 20 million years, larger sea animals filled empty niches. |
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What caused the Cambrian Radiation? |
1. Oxygen 2. Escalation 3. Sexual Reproduction 4. Unfilled niches 5. Phenotypic Plasticity |
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Ribozyme |
RNA Enzyme, suggests RNA was very versatile and used to operate w/o DNA or proteins |
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Mechanism |
That which does the killing. |
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Trigger |
Sets extinction into motion by triggering a mechanism. |
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microRNA |
restricts gene expression and phenotypic plasticity. More has been added to the genome with time. |
