18
Iridium
Common metal in asteroids
Why are creatures with specialist life styles at risk during times of environmental stress?
Environment rapidly changing = cannot adapt
K/P Survivors
Generalists and mammals
The Chicxulub Impact Crater
Landed in the Yucatan Peninsula of Mexico
What was poisoning the Cretaceous atmosphere?
Massive eruptions
Why does Didelphodon (an early marsupial mammal) have an advantage over specialists?
Opportunist
What effect did volcanic gas have on the reproduction of Tyrannosaurus rex?
Prevents eggshells from forming properly
What was the early warning of the approaching Chicxulub asteroid that the dinosaurs might have witnessed?
Showers of shooting stars
What effect does the changing atmosphere have on Torosaurus herds?
Too few young being born
Why did Anatotitan have to travel so far to find food?
Travel across ash wilderness when they're animals that thrived in lush lowland swamp environments
The Cretaceous-Paleogene (K/P) Extinction Event
-50% of all species extinct -80-90% of marine species extinct -Generalists like alligators survived
Evidence to Support Impact (5)
-Fern Spore to Pollen Ratio -Soot Layers -Tektites -Shocked Quartz -Tsunami Depsoits
K/P Extinction Causes
-Fragmentation of Pangea (Hurt ocean circ and climate) -Volcanic Activity (Deccan Traps hurt climate) -Chicxulub Impact
Louise and Walter Alvarez
-K/P associated with major extra-terrestrial impact event -Iridium in clay layer that occurs in a geological section that crosses the K/P
Initial Effect of Chicxulub Impact
-Largest tsunami in Earth's Biosphere -Pulse of intense heat and light vaporizing many creatures -Earth rung with seismic energy
Longer-Term Effects of Chicxulub Impact - Atmospheric Composition: Acid Rain
-Lot of rock vaporized was limestone creating CO2 -Acid rain hurt soil and surface oil (the base of the food chain)
Longer-Term Effects of Chicxulub Impact - Global Temperature
-Tons of dust and debris thrown into atmosphere -Stopped plants from photosynthesizing (ruined food chain)