Biology - Chapter 20: Earth Sciences

Core

Core

hot metal center

Mantle

hot, solid sphere

Crust

thin, outer shell

Lithosphere

crust + mantle, where the tectonic plates are

Asthenosphere

upper mantle

What was Earth's early atmosphere composed of?

carbon dioxide, water vapor, nitrogen (with small amounts of carbon monoxide, hydrogen sulfide, and hydrogen cyanide). LITTLE oxygen

Divergent boundary

plates move away --> ridge

Transform boundary

plates slide against each other --> fault

convergent boundary

collide --> mtns

subduction zone

plates slide under

oceanic-oceanic subduction

underwater volcano --> island

continental-continental subduction

mountains

continental-oceanic subduction

continental volcanos

hot spots

places where molten material from the mantle reaches the lithosphere

index fossils

easily identified fossils used to compare relative ages

direct dating

dating the actual fossil, artifact, or feature

indirect dating

dating remains by their association with other remains that can be dated

radiometric dating

use of half-life to determine age based on remaining isotopes it contains

half-life

when radioactive/chem compounds break down to half the previous sample

Geologic time scale

scale used by paleontologists to represent evolutionary time

Miller & Urey experiment

organic compounds could have arisen from simpler compounds on a primitive Earth

DNA or RNA first?

RNA is a more simple-based system, it could evolved into DNA-directed protein synthesis

Endosymbiotic Theory

theory by Lynn Margulis that many complex features of eukaryotic cells evolved through endosymbiosis (many cells combined together)

What factors have altered Earth's habitats?

continental drift, mountain building, island formation, changes in continent and ocean leveling, global climate change, meteor impacts

Milankovitch Cycles

causes "wobbles" that affect the tilt, changes amount of heat energy --> ice age

punctuated equilibrium

equilibrium that is interrupted by brief periods of more rapid change

extinction

species fails to adapt

mass extinction

collapse of food chain and ecosystem, drastic change for surviving animals that causes speciation

rapid evolution

Evolution in less than 100 years, can be caused by genetic drift or mass extinction

adaptive radiation

species evolved through natural selection and other processes, into diverse forms that live in different ways

convergent evolution

evolution of similar characteristsics in unrelated species

coevolution

two species evolve in response to changes in each other over time