chapter 8: plate tectonics Flashcards
vicariance
isolation of a population
ectotherm
relies primarily on its external environment to regulate the temperature of its body
- reptile/amphibian
Endotherms
able to regulate their body temperatures by producing heat within the body
- birds
geologic/deep time
all of earth’s history
index fossils (guide fossils)
wide-ranging species; lifestyles more independent of small-scale patches
- ex: freely dispersed marine habitats
eons (3)
~1 billion years
- Archaen
- Proterozoic
- Phanerozioc (all of life)
era (current era?)
2nd largest time scale
- current era = Cenozoic!!
period
2+ eras
cambrien period
increase oxygen = explosion life
carboniferous period
increase in plant life = increased in buried dead plants = created fossil fuels today
life is about ___ years old
3.7 billion
half-life
amount of time for 1/2 radioactive material to decay to stable element
- calculate ratio of radio/stable to date samples
earth is about how old?
4.55 billion
are rocks today as old as earth?
NO, younger!
radio carbon dating
age of organic materials by tracking decay (1/2 life) of carbon-14 (isotope)
ways of estimating times
radio active decay/radio carbon dating, tree-rings, glacial ice cores/growth lines, luminescence (time since burial = amnt of light)
continental drift theory
continents/portions of continents rafted across earth’s surface on viscous upper mantle (above crust; crust = fixed to oven basins)
earths crust is..
dynamic
plate tectonics theory
Earth’s lithosphere, is separated into plates that move over the asthenosphere
- plates come together, separate, and collide
- origin/destruction of plates and their drifts
lithosphere
earth’s solid outer crust/top layer of earth
- crust + upper mantle
plate subduction
one plate goes under the other, causes mountains or volcanoes
- main driver of plate tectonics today
before tectonics
core = too hot = holds continents together (1.8+ billion years ago); only had life in oceans until it cooled
tillites
glacial deposits in africa and South America where the poles once were
- wegener’s theory
sea floor spreading
plate’s move apart
- mid-oceanic ridges form and underwater mountain ranges can form
stratigraphic evidence for continental drift
formation of mountains, oceanic ridges, island chains, glaciers, coal beds, sand dunes