Fossils and Extinction Flashcards
What are the important features of the Paleozoic era? What ended it?
Radiation of animal phyla - colonization of land
First land plants
First insects
First amphibians
A mass extinction ended it 251 MYA
What are the features of the Mesozoic era?
Diversity of dinosaurs at the end of the Jurassic period
Another mass extinction 65MYA
What are the features of the Cenozoic era?
Radiation of mammalian orders
Cyclical ice ages
What kind of scale are survivorship curves measured on?
A logarithmic scale
What are the “big five” mass extinction events?
Ordovician Devonian Permian Triassic Cretaceous
What causes gaps in the fossil record?
Hard parts like bones and shells are over-represented in marine and lowland species - these are more recent
Most taxa do not have hard parts, so they are not seen. Older species are seen much less frequently, as well as species from elevation
What was the cause of the permian extinction?
Massive volcanic erruption
A very rapid change in carbon atmosphere, including a drop in oxygen in the ocean
Lost 60-90% of taxa in 60,000 years
What happened at the end of the Cretaceous era? What were the impacts of the event?
A massive meteor impact
Immediate effects - fires, earthquakes, etc
Medium to long term - Release of radioactive material, release of CO2, Dust and vapour
What is the common pattern associated with species number after mass extinctions?
“Short term” periods (thousands of years) of mass extinction are usually followed by millions of years of recovery and increase in species
What effect did dispersion have on extinction at K-Pg events? How did diet type effect extinction?
Groups that were more dispersed had lower rates of extinction
The more specific, or specialist, of a diet the group had, the higher the rates of extinction
How did angiosperm plants competitively replace gymnosperms?
They interacted with diverse pollinators, which increased the diversity above gymnosperms
