Evolutionary Patterns Flashcards
What evolutionary patterns can you look at from the fossil record?
Biodiversity
Morphological disparity - how common were certain features
Origination patterns - e.g. is speciation constant through time
Extinction patterns - e.g. does extinction vary through time
Taxonomic duration - e.g. does duration of certain taxa vary over different environments
Rates of evolution
Biogeographical patterns - e.g. does evolution happen faster in separate continents
What were the five big mass extinction events?
End Orodovician - due to a short glaciation event
End Devonian - pulses of extinction due to aquatic anoxia (led to the spread of forests)
End Permian - due to atmosphere pollution and heating due to Siberian Traps LIP
End Triassic - due to pollution and heating because of emplacement of the Central Atlantic LIP
KT - bollide impact
Why is it hard to study mass extinction events?
Need long continuous stratigraphic sections over the mass extinction event in a variety of habitats - marine and terrestrial
Signor-Lipps Effect can make this harder
What is Lazarus taxa?
Species appears to go extinct but then re-appears in the fossil record
What is Elvis taxa?
Species appears in the fossil record, goes extinct but then re-appears as a different taxa
This is due to convergent evolution
What is the Lilliput effect?
Everything shrinks after a mass extinction event as it is easier to survive when small
What are the two patterns of evolution?
Phylogenetic gradualism - small variations that help an organism survive better. Those with the trait survive and those without die. Gradually the population changes
Punctuated equilibirum - changes in a population happens in spurts. Periods of loads of change and then periods of no change (stasis).
What is species sorting?
Fledgling species are more likely to survive if they are ecologically different from their parents
What is species selection?
Differential rates of appearance and extinction of species within lineages
e.g. speciation happens more than extinction
What is habitat tracking?
Ecological communities follow habitats as they move through environmental change
What is the Red Queen and the Court Jester?
Red Queen - most speciation is driven by biotic factors
Court Jester - evolution is driven by environmental/external change
What is an example of macroevolution?
The origin of the birds
What defines a bird?
Feathers
Carpometacarpus
Unique foot structure - often due to perching
Pygostyle (tail)
Hollow bones with pneuamtic foramen (holes in the bone to allow in air bubbles)
Sternum and keel
Furcula (wish bone)
High EQ with advanced vision
